Forming, Fitting, and Aligning.-Boiler Design and Material-Article

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This article for Boiler Design and Material course. It was submitted to Dr. Khalil Zaman as an assignment at Ambedkar University, Delhi. Its main points are: Certification, Tests, Tensile, Impact, Surface, Examination, E...
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ARTICLE NB-4000

NB-4100 General Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 179 NB-4110 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 179 NB-4120 Certification of Materials and Fabrication by Certificate Holder . . . . . . . . . . . . . . . . . . 179

NB-4121 Means of Certification . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 179 NB-4121.1 Certification of Treatments, Tests, and Examinations . . . . . . . . . . . . . . . . . . . . . . . . . . . . 179 NB-4121.2 Repetition of Tensile or Impact Tests . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 179 NB-4121.3 Repetition of Surface Examination After Machining . . . . . . . . . . . . . . . . . . . . . . . . . . . . 179 NB-4122 Material Identification . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 179 NB-4122.1 Marking Material . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 180 NB-4123 Examinations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 180 NB-4125 Testing of Welding and Brazing Material. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 180

NB-4130 Repair of Material . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 180 NB-4131 Elimination and Repair of Defects . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 180 NB-4132 Documentation of Repair Welds of Base Material . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 180

NB-4200 Forming, Fitting, and Aligning. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 180 NB-4210 Cutting, Forming, and Bending . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 180

NB-4211 Cutting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 180 NB-4211.1 Preheating Before Thermal Cutting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 180 NB-4212 Forming and Bending Processes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 180 NB-4213 Qualification of Forming Processes for Impact Property Requirements . . . . . . . . . . . . 180 NB-4213.1 Exemptions. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 181 NB-4213.2 Procedure Qualification Test. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 181 NB-4213.3 Acceptance Criteria for Formed Material . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 181 NB-4213.4 Requalification . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 181 NB-4214 Minimum Thickness of Fabricated Material . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 182

NB-4220 Forming Tolerances . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 182 NB-4221 Tolerance for Vessel Shells . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 182 NB-4221.1 Maximum Difference in Cross-Sectional Diameters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 182 NB-4221.2 Maximum Deviation From True Theoretical Form for External Pressure . . . . . . . . . . 182 NB-4221.3 Deviations From Tolerances . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 182 NB-4221.4 Tolerance Deviations for Vessel Parts Fabricated From Pipe. . . . . . . . . . . . . . . . . . . . . 182 NB-4222 Tolerances for Formed Vessel Heads. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 182 NB-4222.1 Maximum Difference in Cross-Sectional Diameters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 182 NB-4222.2 Deviation From Specified Shape . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 185 NB-4223 Tolerances for Formed or Bent Piping . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 185 NB-4223.1 Minimum Wall Thickness. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 185 NB-4223.2 Ovality Tolerance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 185

NB-4230 Fitting and Aligning. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 185 NB-4231 Fitting and Aligning Methods . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 185 NB-4231.1 Tack Welds . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 185

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NB-4232 Alignment Requirements When Components Are Welded From Two Sides . . . . . . . 185 NB-4232.1 Fairing of Offsets . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 185 NB-4233 Alignment Requirements When Inside Surfaces Are Inaccessible . . . . . . . . . . . . . . . . . 185

NB-4240 Requirements for Weld Joints in Components . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 186 NB-4241 Category A Weld Joints in Vessels and Longitudinal Weld Joints in Other

Components . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 186 NB-4242 Category B Weld Joints in Vessels and Circumferential Weld Joints in

Other Components . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 186 NB-4243 Category C Weld Joints in Vessels and Similar Weld Joints in Other

Components . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 186 NB-4244 Category D Weld Joints in Vessels and Branch Piping Weld Joints in Other

Components . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 186 NB-4245 Complete Joint Penetration Welds . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 191

NB-4250 Welding End Transitions — Maximum Envelope. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 191

NB-4300 Welding Qualifications. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 191 NB-4310 General Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 191

NB-4311 Types of Processes Permitted . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 191 NB-4311.1 Stud Welding Restrictions. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 191 NB-4311.2 Capacitor Discharge Welding. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 191 NB-4311.4 Inertia and Continuous Drive Friction Welding. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 191

NB-4320 Welding Qualifications, Records, and Identifying Stamps . . . . . . . . . . . . . . . . . . . . . . . . 191.1 NB-4321 Required Qualifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 191.1 NB-4322 Maintenance and Certification of Records. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 195 NB-4322.1 Identification of Joints by Welder or Welding Operator . . . . . . . . . . . . . . . . . . . . . . . . . 198 NB-4323 Welding Prior to Qualifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 198 NB-4324 Transferring Qualifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 198

NB-4330 General Requirements for Welding Procedure Qualification Tests. . . . . . . . . . . . . . . . . 198 NB-4331 Conformance to Section IX Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 198 NB-4333 Heat Treatment of Qualification Welds for Ferritic Materials . . . . . . . . . . . . . . . . . . . . 198 NB-4334 Preparation of Test Coupons and Specimens . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 198 NB-4334.1 Coupons Representing the Weld Deposit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 198 NB-4334.2 Coupons Representing the Heat Affected Zone . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 199 NB-4335 Impact Test Requirements. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 199 NB-4335.1 Impact Tests of Weld Metal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 199 NB-4335.2 Impact Tests of Heat Affected Zone . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 199 NB-4336 Qualification Requirements for Built-Up Weld Deposits . . . . . . . . . . . . . . . . . . . . . . . . . 201

NB-4350 Special Qualification Requirements for Tube-to-Tubesheet Welds . . . . . . . . . . . . . . . . . 201 NB-4351 General Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 201 NB-4352 Essential Variables for All Welding Processes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 201 NB-4353 Essential Variables for Shielded Metal-Arc Welding . . . . . . . . . . . . . . . . . . . . . . . . . . . . 202 NB-4354 Essential Variables for Gas Tungsten-Arc and Gas Metal-Arc Welding . . . . . . . . . . . 202 NB-4355 Essential Variables for Explosive Welding . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 202 NB-4356 Test Assembly. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 202 NB-4357 Examination of Test Assembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 202 NB-4358 Performance Qualification . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 202 NB-4358.1 Welders . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 202 NB-4358.2 Welding Operators . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 202

NB-4360 Qualification Requirements for Welding Specially Designed Welded Seals . . . . . . . . 202 NB-4361 General Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 202 NB-4362 Essential Variables for Automatic, Machine, and Semiautomatic Welding . . . . . . . . . 203 NB-4363 Essential Variables for Manual Welding . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 203

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NB-4366 Test Assembly. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 203 NB-4366.1 Automatic Welding. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 203 NB-4366.2 Manual, Machine, and Semiautomatic Welding . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 203 NB-4367 Examination of Test Assembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 203 NB-4368 Performance Qualification Test . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 204

NB-4400 Rules Governing Making, Examining, and Repairing Welds . . . . . . . . . . . . . . . . . . 204 NB-4410 Precautions to Be Taken Before Welding. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 204

NB-4411 Identification, Storage, and Handling of Welding Material . . . . . . . . . . . . . . . . . . . . . . . 204 NB-4412 Cleanliness and Protection of Welding Surfaces . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 204

NB-4420 Rules for Making Welded Joints . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 204 NB-4421 Backing Rings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 204 NB-4422 Peening . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 204 NB-4423 Miscellaneous Welding Requirements. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 204 NB-4424 Surfaces of Welds . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 204 NB-4424.1 General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 204 NB-4424.2 Preservice Examination . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 205 NB-4425 Welding Items of Different Diameters. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 205 NB-4426 Reinforcement of Welds . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 205 NB-4426.1 Thickness of Weld Reinforcement for Vessels, Pumps, and Valves. . . . . . . . . . . . . . . 205 NB-4426.2 Thickness of Weld Reinforcement for Piping . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 205 NB-4427 Shape and Size of Fillet Welds . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 205 NB-4428 Seal Welds of Threaded Joints . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 206 NB-4429 Welding of Clad Parts. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 206

NB-4430 Welding of Attachments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 206 NB-4431 Materials for Attachments. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 206 NB-4432 Welding of Structural Attachments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 206 NB-4433 Structural Attachments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 206 NB-4434 Welding of Internal Structural Supports to Clad Components . . . . . . . . . . . . . . . . . . . . 206 NB-4435 Welding of Nonstructural and Temporary Attachments and Their Removal. . . . . . . . 206 NB-4436 Installation of Attachments to Piping Systems After Testing . . . . . . . . . . . . . . . . . . . . . 209

NB-4450 Repair of Weld Metal Defects . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 209 NB-4451 General Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 209 NB-4452 Elimination of Surface Defects . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 209 NB-4453 Requirements for Making Repairs of Welds . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 209 NB-4453.1 Defect Removal. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 209 NB-4453.2 Requirements for Welding Material, Procedures, and Welders. . . . . . . . . . . . . . . . . . . . 209 NB-4453.3 Blending of Repaired Areas . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 209 NB-4453.4 Examination of Repair Welds . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 209 NB-4453.5 Heat Treatment of Repaired Areas . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 209

NB-4500 Brazing. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 209 NB-4510 Rules for Brazing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 209

NB-4511 Where Brazing May Be Used . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 209 NB-4512 Brazing Material . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 210

NB-4520 Brazing Qualification Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 210 NB-4521 Brazing Procedure and Performance Qualification. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 210 NB-4522 Brazing Requalification Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 210

NB-4530 Fitting and Aligning of Parts to Be Brazed. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 210 NB-4540 Examination of Brazed Joints . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 210

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NB-4600 Heat Treatment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 210 NB-4610 Welding Preheat Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 210

NB-4611 When Preheat Is Necessary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 210 NB-4612 Preheating Methods . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 210 NB-4613 Interpass Temperature . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 212

NB-4620 Postweld Heat Treatment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 212 NB-4621 Heating and Cooling Methods . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 212 NB-4622 PWHT Time and Temperature Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 212 NB-4622.1 General Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 212 NB-4622.2 Time–Temperature Recordings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 212 NB-4622.3 Definition of Nominal Thickness Governing PWHT . . . . . . . . . . . . . . . . . . . . . . . . . . . . 212 NB-4622.4 Holding Times at Temperature . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 212 NB-4622.5 PWHT Requirements When Different P-Number Materials Are Joined . . . . . . . . . . . . 214 NB-4622.6 PWHT Requirements for Nonpressure-Retaining Parts . . . . . . . . . . . . . . . . . . . . . . . . . . . 214 NB-4622.7 Exemptions to Mandatory Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 214 NB-4622.8 Requirements for Exempting PWHT of Nozzles to Component Welds and

Branch to Run Piping Welds . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 214 NB-4622.9 Temper Bead Weld Repair. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 217 NB-4622.10 Repair Welds to Cladding After Final Postweld Heat Treatment . . . . . . . . . . . . . . . . . 218 NB-4622.11 Temper Bead Weld Repair to Dissimilar Metal Welds or Buttering . . . . . . . . . . . . . . 220 NB-4623 PWHT Heating and Cooling Rate Requirements. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 222 NB-4624 Methods of Postweld Heat Treatment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 224 NB-4624.1 Furnace Heating — One Heat. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 224 NB-4624.2 Furnace Heating — More Than One Heat . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 224 NB-4624.3 Local Heating . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 224 NB-4624.4 Heating Items Internally . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 224

NB-4630 Heat Treatment of Welds Other Than the Final Postweld Heat Treatment . . . . . . . . 224 NB-4650 Heat Treatment After Bending or Forming for Pipes, Pumps, and Valves. . . . . . . . . 224

NB-4651 Conditions Requiring Heat Treatment After Bending or Forming. . . . . . . . . . . . . . . . . 224 NB-4652 Exemptions From Heat Treatment After Bending or Forming . . . . . . . . . . . . . . . . . . . . 224

NB-4660 Heat Treatment of Electroslag Welds . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 225

NB-4700 Mechanical Joints . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 225 NB-4710 Bolting and Threading. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 225

NB-4711 Thread Engagement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 225 NB-4712 Thread Lubricants . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 225 NB-4713 Removal of Thread Lubricants . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 225

NB-4720 Bolting Flanged Joints. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 225 NB-4730 Electrical and Mechanical Penetration Assemblies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 225

Figures NB-4221.1-1 Maximum Difference in Cross-Sectional Diameters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 182 NB-4221.2(a)-1 Maximum Permissible Deviation e From a True Circular Form . . . . . . . . . . . . . . . . . . 183 NB-4221.2(a)-2 Maximum Arc Length for Determining Plus or Minus Deviation. . . . . . . . . . . . . . . . . 184 NB-4233(a)-1 Butt Weld Alignment and Mismatch Tolerances for Unequal I.D. and O.D.

When Components Are Welded From One Side and Fairing Is Not Performed. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 187

NB-4243-1 Acceptable Full Penetration Weld Details for Category C Joints . . . . . . . . . . . . . . . . . 188 NB-4244(a)-1 Nozzle, Branch, and Piping Connections Joined by Full Penetration Butt

Welds . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 189

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NB-4244(b)-1 Nozzle, Branch, and Piping Connections Joined by Full Penetration Corner Welds . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 190

NB-4244(c)-1 Deposited Weld Metal Used as Reinforcement of Openings for Nozzle, Branch, and Piping Connections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 192

NB-4244(d)-1 Partial Penetration Nozzle and Branch Piping Connections . . . . . . . . . . . . . . . . . . . . . . 193 NB-4244(d)-2 Partial Penetration Nozzle for Coaxial Cylinders . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 194 NB-4244(e)-1 Oblique Connections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 195 NB-4250-1 Welding End Transitions — Maximum Envelope. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 196 NB-4250-2 Component to Pipe Weld . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 197 NB-4250-3 Pipe to Pipe Weld . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 197 NB-4427-1 Fillet and Socket Weld Details and Dimensions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 207 NB-4433-1 Types of Attachment Welds. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 208 NB-4511-1 Brazed Connections for Appurtenances and Piping, 1 in. Nominal Size and

Less (≤ DN 25) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 211 NB-4622.9(c)(5)-1 Temper Bead Weld Repair and Weld Temper Bead Reinforcement. . . . . . . . . . . . . . . 219 NB-4622.9(c)(5)-2 Temper Bead Reinforcement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 220 NB-4622.9(f)-1 Qualification Test Plate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 221 NB-4622.11(c)(6)-1 Temper Bead Weld Repair and Weld Temper Bead Reinforcement of

Dissimilar Metal Welds or Buttering . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 223

Tables NB-4232-1 Maximum Allowable Offset in Final Welded Joints . . . . . . . . . . . . . . . . . . . . . . . . . . . . 186 NB-4622.1-1 Mandatory Requirements for Postweld Heat Treatment of Welds. . . . . . . . . . . . . . . . . 213 NB-4622.4(c)-1 Alternative Holding Temperatures and Times . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 214 NB-4622.7(b)-1 Exemptions to Mandatory PWHT. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 215

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ARTICLE NB-4000 FABRICATION AND INSTALLATION

NB-4100 GENERAL REQUIREMENTS

NB-4110 INTRODUCTION

Components, parts, and appurtenances shall be fabri- cated and installed in accordance with the requirements of this Article and shall be manufactured from materials which meet the requirements of NB-2000.

NB-4120 CERTIFICATION OF MATERIALS AND FABRICATION BY CERTIFICATE HOLDER

NB-4121 Means of Certification

The Certificate Holder for an item shall certify, by application of the appropriate Code Symbol and completion of the appropriate Data Report in accordance with NCA-8000, that the materials used comply with the requirements of NB-2000 and that the fabrication or installation complies with the requirements of this Article.

NB-4121.1 Certification of Treatments, Tests, and Examinations. If the Certificate Holder or Subcontractor performs treatments, tests, repairs, or examinations re- quired by other Articles of this Subsection, the Certifi- cate Holder shall certify that this requirement has been fulfilled (NCA-3862). Reports of all required treatments and of the results of all required tests, repairs, and examinations performed shall be available to the In- spector.

NB-4121.2 Repetition of Tensile or Impact Tests. If during the fabrication or installation of the item the material is subjected to heat treatment that has not been covered by treatment of the test coupons (NB- 2200) and that may reduce either tensile or impact properties below the required values, the tensile and impact tests shall be repeated by the Certificate Holder on test specimens taken from test coupons which have

179

been taken and treated in accordance with the require- ments of NB-2000.

NB-4121.3 Repetition of Surface Examination After Machining. If, during the fabrication or installa- tion of an item, materials for pressure-containing parts are machined, then the Certificate Holder shall reexam- ine the surface of the material in accordance with NB- 2500 when:

(a) the surface was required to be examined by the magnetic particle or liquid penetrant method in accordance with NB-2500; and

(b) the amount of material removed from the surface exceeds the lesser of 1⁄8 in. (3.2 mm) or 10% of the minimum required thickness of the part.

NB-4122 Material Identification

(a) Material for pressure-retaining parts shall carry identification markings which will remain distinguish- able until the component is assembled or installed. If the original identification markings are cut off or the material is divided, the marks shall either be transferred to the parts cut or a coded marking shall be used to ensure identification of each piece of material during subsequent fabrication or installation. In either case, an as-built sketch or a tabulation of materials shall be made identifying each piece of material with the Certi- fied Material Test Report, where applicable, and the coded marking. For studs, bolts, nuts, and heat ex- changer tubes it is permissible to identify the Certified Material Test Reports for material in each component in lieu of identifying each piece of material with the Certified Material Test Report and the coded marking. Material supplied with a Certificate of Compliance, and welding and brazing material, shall be identified and controlled so that they can be traced to each component or installation of a piping system, or else a control procedure shall be employed which ensures that the specified materials are used.

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NB-4122 1998 SECTION III, DIVISION 1 — NB NB-4213

(b) Material from which the identification marking is lost shall be treated as non-conforming material until appropriate tests or other verifications are made and documented to assure material identification. Testing is required unless positive identification can be made by other documented evidence. The material may then be re-marked upon establishing positive identification.

NB-4122.1 Marking Material. Material shall be marked in accordance with NB-2150.

NB-4123 Examinations

Visual examination activities that are not referenced for examination by other specific Code paragraphs, and are performed solely to verify compliance with requirements of NB-4000, may be performed by the persons who perform or supervise the work. These visual examinations are not required to be performed by personnel and procedures qualified to NB-5500 and NB-5100, respectively, unless so specified.

NB-4125 Testing of Welding and Brazing Material

All welding and brazing material shall meet the requirements of NB-2400.

NB-4130 REPAIR OF MATERIAL

NB-4131 Elimination and Repair of Defects

Material originally accepted on delivery in which defects exceeding the limits of NB-2500 are known or discovered during the process of fabrication or installa- tion is unacceptable. The material may be used provided the condition is corrected in accordance with the require- ments of NB-2500 for the applicable product form, except:

(a) the limitation on the depth of the weld repair does not apply;

(b) the time of examination of the weld repairs to weld edge preparations shall be in accordance with NB-5130;

(c) radiographic examination is not required for weld repairs to seal membrane material when the material thickness is 1⁄4 in. (6 mm) or less.

NB-4132 Documentation of Repair Welds of Base Material

The Certificate Holder who makes a repair weld exceeding in depth the lesser of 3⁄8 in. (10 mm) or

180

10% of the section thickness, shall prepare a report which shall include a chart which shows the location and size of the prepared cavity, the welding material identification, the welding procedure, the heat treatment, and the examination results of repair welds.

NB-4200 FORMING, FITTING, AND ALIGNING

NB-4210 CUTTING, FORMING, AND BENDING

NB-4211 Cutting

Materials may be cut to shape and size by mechanical means, such as machining, shearing, chipping, or grind- ing, or by thermal cutting.

NB-4211.1 Preheating Before Thermal Cutting. When thermal cutting is performed to prepare weld joints or edges, to remove attachments or defective material, or for any other purpose, consideration shall be given to preheating the material, using preheat schedules such as suggested in Appendix D.

NB-4212 Forming and Bending Processes

Any process may be used to hot or cold form or bend pressure-retaining material (NB-4223), including weld metal, provided the required dimensions are at- tained (see NB-4214 and NB-4220), and provided the impact properties of the material, when required, are not reduced below the minimum specified values, or they are effectively restored by heat treatment following the forming operation. Hot forming is defined as forming with the material temperature higher than 100°F (121°C) below the lower transformation temperature of the material. When required, the process shall be qualified for impact properties as outlined in NB-4213. When required, the process shall be qualified to meet thickness requirements as outlined in NB-4223.1.

NB-4213 Qualification of Forming Processes for Impact Property Requirements

A procedure qualification test shall be conducted using specimens taken from material of the same speci- fication, grade or class, heat treatment, and with similar impact properties, as required for the material in the component. These specimens shall be subjected to the equivalent forming or bending process and heat treat- ment as the material in the component. Applicable tests

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NB-4213 NB-4000 — FABRICATION AND INSTALLATION NB-4213.4

shall be conducted to determine that the required impact properties of NB-2300 are met after straining.

NB-4213.1 Exemptions. Procedure qualification tests are not required for materials listed in (a) through (f) below:

(a) hot formed material, such as forgings, in which the hot forming is completed by the Material Organiza- tion prior to removal of the impact test specimens;

(b) hot formed material represented by test coupons which have been subjected to heat treatment representing the hot forming procedure and the heat treatments to be applied to the parts;

(c) material which does not require impact tests in accordance with NB-2300;

(d) material which has a final strain less than 0.5%; (e) material where the final strain is less than that

of a previously qualified procedure for that material; (f) material from which the impact testing is required

by NB-2300 is performed on each heat and lot, as applicable, after forming.

NB-4213.2 Procedure Qualification Test. The proce- dure qualification test shall be performed in the manner stipulated in (a) through (f) below.

(a) The tests shall be performed on three different heats of material both before straining and after straining and heat treatment to establish the effects of the forming and subsequent heat treatment operations.

(b) Specimens shall be taken in accordance with the requirements of NB-2000 and shall be taken from the tension side of the strained material.

(c) The percent strain shall be established by the following formulas.

For cylinders:

% strain p 50t

Rf 11 − RfRo2

For spherical or dished surfaces:

% strain p 75t

Rf 11 − RfRo2

For pipe:

% strain p 100r

R

where Rp nominal bending radius to the center line of the

pipe, in. Rfp final radius to center line of shell, in.

181

Rop original radius (equal to infinity for a flat part), in.

rp nominal radius of the pipe, in. tp nominal thickness, in.

(d) The procedure qualification shall simulate the maximum percent surface strain, employing a bending process similar to that used in the fabrication of the material or by direct tension on the specimen.

(e) Sufficient Cv test specimens shall be taken from each of the three heats of material to establish a transition curve showing both the upper and lower shelves. On each of the three heats, tests consisting of three impact specimens shall be conducted at a minimum of five different temperatures distributed throughout the transition region. The upper and lower shelves may be established by the use of one test specimen for each shelf. Depending on the product form, it may be necessary to plot the transition curves using both lateral expansion and energy level data (NB-2300). In addition, drop weight tests shall be made when required by NB-2300.

(f) Using the results of the impact test data from each of three heats, taken both before and after straining, determine either:

(1) the maximum change in NDT temperature along with:

(a) the maximum change of lateral expansion and energy at the temperature under consideration; or

(b) the maximum change of temperature at the lateral expansion and energy levels under consider- ation; or

(2) when lateral expansion is the acceptance crite- rion (NB-2300), either the maximum change in tempera- ture or the maximum change in lateral expansion.

NB-4213.3 Acceptance Criteria for Formed Mate- rial. To be acceptable, the formed material used in the component shall have impact properties before forming sufficient to compensate for the maximum loss of impact properties due to the qualified forming processes used.

NB-4213.4 Requalification. A new procedure qual- ification test is required when any of the changes in (a), (b), or (c) below are made.

(a) The actual postweld heat treatment time at tem- perature is greater than previously qualified considering NB-2211. If the material is not postweld heat treated, the procedure must be qualified without postweld heat treatment.

(b) The maximum calculated strain of the material exceeds the previously qualified strain by more than 0.5%.

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NB-4213.4 1998 SECTION III, DIVISION 1 — NB NB-4222.1

FIG. NB-4221.1-1 MAXIMUM DIFFERENCE IN CROSS-SECTIONAL DIAMETERS

(c) Preheat over 250°F (121°C) is used in the forming or bending operation but not followed by a subsequent postweld heat treatment.

NB-4214 Minimum Thickness of Fabricated Material

If any fabrication operation reduces the thickness below the minimum required to satisfy the rules of NB-3000, the material may be repaired in accordance with NB-4130.

NB-4220 FORMING TOLERANCES

NB-4221 Tolerance for Vessel Shells

Cylindrical, conical, or spherical shells of a completed vessel, except formed heads covered by NB-4222, shall meet the requirements of the following subparagraphs at all cross sections.

NB-4221.1 Maximum Difference in Cross-Sectional Diameters. The difference in inches between the maxi- mum and minimum diameters at any cross section shall not exceed the smaller of (D + 50) /200 and D /100, where D is the nominal inside diameter, in., at the cross section under consideration. The diameters may be measured on the inside or outside of the vessel. If measured on the outside, the diameters shall be corrected for the plate thickness at the cross section under consid- eration (Fig. NB-4221.1-1). When the cross section passes through an opening, the permissible difference in inside diameters given herein may be increased by 2% of the inside diameter of the opening.

NB-4221.2 Maximum Deviation From True Theo- retical Form for External Pressure. Vessels designed for external pressure shall meet the tolerances given in (a) through (c) below.

(a) The maximum plus or minus deviation from the true circular form of cylinders or the theoretical form

182

of other shapes, measured radially on the outside or inside of the component, shall not exceed the maximum permissible deviation obtained from Fig. NB-4221.2(a)- 1. Measurements shall be made from a segmental circular template having the design inside or outside radius depending on where the measurements are taken and a chord length equal to twice the arc length obtained from Fig. NB-4221.2(a)-2. For Fig. NB-4221.2(a)-1, the maximum permissible deviation e need not be less than 0.3t. For Fig. NB-4221.2(a)-2, the arc length need not be greater than 0.30Do.. Measurements shall not be taken on welds or other raised parts.

(b) The value of t, in., at any cross section is the nominal plate thickness less corrosion allowance for sections of constant thickness and the nominal thickness of the thinnest plate less corrosion allowance for sections having plates of more than one thickness.

(c) The value of L in Figs. NB-4221.2(a)-1 and NB- 4221.2(a)-2 is determined by (1) through (3) below.

(1) For cylinders, L is as given in NB-3133.2. (2) For cones, L is the axial length of the conical

section if no stiffener rings are used or, if stiffener rings are used, the axial length from the head bend line at the large end of the cone to the first stiffener ring, with Do taken as the outside diameter in inches of the cylinder at the large end of the cone.

(3) For spheres, L is one-half of the outside diame- ter Do, in.

NB-4221.3 Deviations From Tolerances. Deviations from the tolerance requirements stipulated in NB-4221.1 and NB-4221.2 are permitted, provided the drawings are modified and reconciled with the Design Report (NCA-3551) and provided the modifications are certified by a registered Professional Engineer in an addendum to the Design Report.

NB-4221.4 Tolerance Deviations for Vessel Parts Fabricated From Pipe. Vessel parts subjected to either internal or external pressure and fabricated from pipe, meeting all other requirements of this Subsection, may have variations of diameter and deviations from circular- ity permitted by the specification for such pipe.

NB-4222 Tolerances for Formed Vessel Heads

The tolerance for formed vessel heads shall be as set forth in the following subparagraphs.

NB-4222.1 Maximum Difference in Cross-Sectional Diameters. The skirt or cylindrical end of a formed head shall be circular to the extent that the difference in inches between the maximum and minimum diameters does not exceed the lesser of (D + 50) /200 and (D +

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NB-4000 — FABRICATION AND INSTALLATION Fig. NB-4221.2(a)-1

F IG

. N

B -4

22 1.

2( a)

-1 M

A X

IM U

M P

E R

M IS

S IB

L E

D E

V IA

T IO

N e

F R

O M

A T

R U

E C

IR C

U L

A R

F O

R M

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Fig. NB-4221.2(a)-2 1998 SECTION III, DIVISION 1 — NB

F IG

. N

B -4

22 1.

2( a)

-2 M

A X

IM U

M A

R C

L E

N G

T H

F O

R D

E T

E R

M IN

IN G

P L

U S

O R

M IN

U S

D E

V IA

T IO

N

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NB-4222.1 NB-4000 — FABRICATION AND INSTALLATION NB-4233

12) /100, where D is the nominal inside diameter, in., and shall match the cylindrical edge of the adjoining part within the alignment tolerance specified in NB-4232.

NB-4222.2 Deviation From Specified Shape (a) The inner surface of a torispherical or ellipsoidal

head shall not deviate outside the specified shape by more than 11⁄4% of D, inside the specified shape by more than 5⁄8% of D, where D is the nominal inside diameter of the vessel. Such deviations shall be mea- sured perpendicular to the specified shape and shall not be abrupt. The knuckle radius shall not be less than specified. For 2:1 ellipsoidal heads, the knuckle radius may be considered to be 17% of the diameter of the vessel.

(b) Hemispherical heads and any spherical portion of a formed head shall meet the local tolerances for spheres as given in NB-4221.2, using L as the outside spherical radius, in., and Do as two times L.

(c) Deviation measurements shall be taken on the surface of the base material and not on welds.

NB-4223 Tolerances for Formed or Bent Piping

The tolerances for formed or bent piping shall be as set forth in the following subparagraphs.

NB-4223.1 Minimum Wall Thickness (a) In order to assure that the wall thickness require-

ments of the design calculations are met, the actual thickness shall be measured, or the process shall be qualified by demonstrating that it will maintain the required wall thickness.

(b) As an alternative to (a) above, the requirements of Table NB-3642.1(b)-1 shall be followed.

NB-4223.2 Ovality Tolerance. Unless otherwise jus- tified by the Design Report, the ovality of piping after bending shall not exceed 8% as determined by:

100 × (Dmax − Dmin) / Do

where Dop nominal pipe outside diameter, in.

Dminp minimum outside diameter after bending or forming, in.

Dmaxp maximum outside diameter after bending or forming, in.

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NB-4230 FITTING AND ALIGNING

NB-4231 Fitting and Aligning Methods

Parts that are to be joined by welding may be fitted, aligned, and retained in position during the welding operation by the use of bars, jacks, clamps, tack welds, or temporary attachments.

NB-4231.1 Tack Welds. Tack welds used to secure alignment shall either be removed completely, when they have served their purpose, or their stopping and starting ends shall be properly prepared by grinding or other suitable means so that they may be satisfactorily incorporated into the final weld. Tack welds shall be made by qualified welders using qualified welding procedures. When tack welds are to become part of the finished weld, they shall be visually examined and defective tack welds shall be removed.

NB-4232 Alignment Requirements When Components Are Welded From Two Sides

(a) Alignment of sections which are welded from two sides shall be such that the maximum offset of the finished weld will not be greater than the applicable amount listed in Table NB-4232-1, where t is the nominal thickness of the thinner section at the joint.

(b) Joints in spherical vessels, joints within heads, and joints between cylindrical shells and hemispherical heads shall meet the requirements in Table NB-4232- 1 for longitudinal joints.

NB-4232.1 Fairing of Offsets. Any offset within the allowable tolerance provided above shall be faired to at least a 3:1 taper over the width of the finished weld or, if necessary, by adding additional weld metal beyond what would otherwise be the edge of the weld. In addition, offsets greater than those stated in Table NB-4232-1 are acceptable provided the requirements of NB-3200 are met.

NB-4233 Alignment Requirements When Inside Surfaces Are Inaccessible

(a) When the inside surfaces of items are inaccessible for welding or fairing in accordance with NB-4232, alignment of sections shall meet the requirements of (1) and (2) below:

(1)(a) For circumferential joints the inside diame- ters shall match each other within 1⁄16 in. (1.6 mm). When the items are aligned concentrically, a uniform mismatch of 1⁄32 in. (0.8 mm) all around the joint can result as shown in Fig. NB-4233(a)-1 sketch (a).

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NB-4233 1998 SECTION III, DIVISION 1 — NB NB-4244

TABLE NB-4232-1 MAXIMUM ALLOWABLE OFFSET IN

FINAL WELDED JOINTS

Direction of Joints

Section Thickness, in. Longitudinal Circumferential

Up to 1⁄2, incl. 1⁄4t 1⁄4t Over 1⁄2 to 3⁄4, incl. 1⁄8 in. 1⁄4t Over 3⁄4 to 11⁄2, incl. 1⁄8 in. 3⁄16 in. Over 11⁄2 to 2, incl. 1⁄8 in. 1⁄8t Over 2 Lesser of 1⁄16t or Lesser of 1⁄8t or

3⁄8 in. 3⁄4 in.

However, other variables not associated with the diame- ter of the item often result in alignments that are offset rather than concentric. In these cases, the maximum misalignment at any one point around the joint shall not exceed 3⁄32 in. (2.4 mm) as shown in Fig. NB- 4233(a)-1 sketch (b). Should tolerances on diameter, wall thickness, out-of-roundness, etc., result in inside diameter variations which do not meet these limits, the inside diameters shall be counterbored, sized, or ground to produce a bore within these limits, provided the requirements of NB-4250 are met.

(b) Offset of outside surfaces shall be faired to at least a 3:1 taper over the width of the finished weld or, if necessary, by adding additional weld metal.

(2) For longitudinal joints the misalignment of inside surfaces shall not exceed 3⁄32 in. (2.4 mm) and the offset of outside surfaces shall be faired to at least a 3:1 taper over the width of the finished weld or, if necessary, by adding additional weld metal.

(b) Single welded joints may meet the alignment requirements of (a)(1) and (a)(2) above in lieu of the requirements of NB-4232.

NB-4240 REQUIREMENTS FOR WELD JOINTS IN COMPONENTS

NB-4241 Category A Weld Joints in Vessels and Longitudinal Weld Joints in Other Components

Category A weld joints in vessels and longitudinal weld joints in other components shall be full penetration butt joints. Joints that have been welded from one side with backing that has been removed and those welded from one side without backing are acceptable as full penetration welds provided the weld root side of the joints meets the requirements of NB-4424.

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NB-4242 Category B Weld Joints in Vessels and Circumferential Weld Joints in Other Components

Category B weld joints in vessels and circumferential weld joints in other components shall be full penetration butt joints, except that piping 2 in. nominal pipe size (DN 50) and smaller may be socket welded. When used, backing strips shall be continuous in cross section. Joints prepared with opposing lips to form an integral backing strip and joints with backing strips which are not later removed are acceptable provided the requirements of NB-3352.2 are met.

NB-4243 Category C Weld Joints in Vessels and Similar Weld Joints in Other Components

Category C weld joints in vessels and similar weld joints in other components shall be full penetration joints, except that 2 in. nominal pipe size (DN 50) and smaller socket welded joints may be used on component nozzles and in piping. Joints that have been welded from one side with backing that has been removed and those welded from one side without backing are acceptable as full penetration welds pro- vided the weld root side of the joints meets the require- ments of NB-4424. Either a butt welded joint or a full penetration corner joint as shown in Fig. NB-4243-1 shall be used.

NB-4244 Category D Weld Joints in Vessels and Branch Piping Weld Joints in Other Components

Category D weld joints in vessels and similar weld joints in other components shall be full or partial penetration weld joints using one of the details of (a) through (e) below.

(a) Butt Welded Nozzles and Branch Piping Connec- tions. Nozzles and branch piping connections shall be attached by full penetration butt welds through the wall of the component, nozzle, or branch as shown in Fig. NB-4244(a)-1. Backing strips, if used, shall be removed.

(b) Corner Welded Nozzles and Branch Piping Con- nections. Nozzles and branch piping connections shall be joined to the component by full penetration welds through the wall of the component, nozzle, or branch similar to those shown in Fig. NB-4244(b)-1. Backing strips, if used, shall be removed.

(c) Deposited Weld Metal of Openings for Nozzles and Branch Piping Connections. Nozzles and branch piping connections shall be joined to the component

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NB-4000 — FABRICATION AND INSTALLATION Fig. NB-4233(a)-1

FIG. NB-4233(a)-1 BUTT WELD ALIGNMENT AND MISMATCH TOLERANCES FOR UNEQUAL I.D. AND O.D. WHEN COMPONENTS ARE WELDED FROM ONE SIDE

AND FAIRING IS NOT PERFORMED

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Fig. NB-4243-1 1998 SECTION III, DIVISION 1 — NB

FIG. NB-4243-1 ACCEPTABLE FULL PENETRATION WELD DETAILS FOR CATEGORY C JOINTS (NB-3352.3)

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NB-4000 — FABRICATION AND INSTALLATION Fig. NB-4244(a)-1

FIG. NB-4244(a)-1 NOZZLE, BRANCH, AND PIPING CONNECTIONS JOINED BY FULL PENETRATION BUTT WELDS

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Fig. NB-4244(b)-1 1998 SECTION III, DIVISION 1 — NB

FIG. NB-4244(b)-1 NOZZLE, BRANCH, AND PIPING CONNECTIONS JOINED BY FULL PENETRATION CORNER WELDS

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NB-4244 NB-4000 — FABRICATION AND INSTALLATION NB-4311.4

by full penetration weld to built-up weld deposits NB-4300 WELDING QUALIFICATIONS applied to the component, nozzle, or branch as shown

NB-4310 GENERAL REQUIREMENTSin Fig. NB-4244(c)-1. Backing strips, if used, shall be removed. Fillet welds shall be used only to provide a NB-4311 Types of Processes Permitted transition between the parts joined or to provide a seal.

Only those welding processes which are capable ofThe fillet welds, when used, shall be finished by grinding producing welds in accordance with the welding proce-to provide a smooth surface having a transition radius dure qualification requirements of Section IX and thisat its intersection with either part being joined. Subsection may be used for welding pressure-retaining(d) Partial Penetration Welded Nozzles and Branch material or attachments thereto. Any process used shallPiping Connections. Partial penetration welds in compo- be such that the records required by NB-4320 can benents and branch piping connections shall meet the prepared, except that records for stud welds shall beweld design requirements of NB-3352.4(d) for vessels traceable to the welders and welding operators and notor NB-3643 for piping branch connections. Nozzles necessarily to each specific weld.shall be attached as shown in Figs. NB-4244(d)-1 and

NB-4244(d)-2. (e) Oblique Nozzles and Branch Piping Connections. NB-4311.1 Stud Welding Restrictions. Stud welding

Oblique nozzles and branch piping connections shall is acceptable only for nonstructural and temporary be joined to the component by full penetration welds attachments (NB-4435). Studs shall be limited to 1 in. through the nozzle or branch as shown in Fig. NB- (25 mm) maximum diameter for round studs and an 4244(e)-1. Backing rings, if used, shall be removed. equivalent cross-sectional area for studs of other shapes

when welding in the flat position and 3⁄4 in. (19 mm) diameter for all other welding positions. Postweld heat treatment shall comply with NB-4600, except that timeA99 NB-4245 Complete Joint Penetration Welds at temperature need not exceed 1⁄2 hr regardless of base

Complete joint penetration is considered to be material thickness. Welding procedure and performance achieved when the acceptance criteria for the examina- qualification shall comply with the requirements of tions specified by this Subsection have been met. No Section IX. other examination is required to assess that complete penetration has been achieved.

NB-4311.2 Capacitor Discharge Welding. Capacitor discharge welding may be used for welding temporary attachments and permanent nonstructural attachments provided:NB-4250 WELDING END TRANSITIONS —

(a) temporary attachments are removed in accordanceMAXIMUM ENVELOPE with the provisions of NB-4435(b); and

The welding ends of items shall provide a gradual (b) the energy output for permanent nonstructural change in thickness from the item to the adjoining attachments such as strain gages and thermocouples is item. Any welding end transition which lies entirely limited to 125 W-sec, and the minimum thickness of within the envelope shown in Fig. NB-4250-1 is accept- the material to which the attachment is made is greater able provided: than 0.09 in. (2.9 mm); and

(a) the wall thickness in the transition region is not (c) a Welding Procedure Specification is prepared less than the minimum wall thickness of the adjoining describing the capacitor discharge equipment, the combi- pipe; nation of materials to be joined, and the technique of

(b) sharp reentrant angles and abrupt changes in application; qualification of the welding procedure is slope in the transition region are avoided. When the not required. included angle between any two adjoining surfaces of a taper transition is less than 150 deg., the intersection or corner (except for the weld reinforcement) shall be NB-4311.4 Inertia and Continuous Drive Friction

Weldingprovided with a radius of at least 0.05tmin; and (c) if the weld is subject to preservice inspection, (a) Inertia and continuous drive friction welding shall

not be used for the fabrication of vessels and piping.the length of the counterbore shall be 2tmin for pipe and tmin for components and fittings, as shown in Fig. (b) The weld between the two members shall be a

full penetration weld.NB-4250-2 or Fig. NB-4250-3.

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NB-4320 1998 SECTION III, DIVISION 1 — NB NB-4321

NB-4320 WELDING QUALIFICATIONS, RECORDS, AND IDENTIFYING STAMPS

NB-4321 Required Qualifications

(a) Each Certificate Holder is responsible for the welding done by his organization, and each Certificate Holder shall establish the procedure and conduct the tests required by this Article and by Section IX in

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Fig. NB-4244(c)-1 1998 SECTION III, DIVISION 1 — NB

FIG. NB-4244(c)-1 DEPOSITED WELD METAL USED AS REINFORCEMENT OF OPENINGS FOR NOZZLE, BRANCH, AND PIPING CONNECTIONS

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NB-4000 — FABRICATION AND INSTALLATION Fig. NB-4244(d)-1

FIG. NB-4244(d)-1 PARTIAL PENETRATION NOZZLE AND BRANCH PIPING CONNECTIONS

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Fig. NB-4244(d)-2 1998 SECTION III, DIVISION 1 — NB

FIG. NB-4244(d)-2 PARTIAL PENETRATION NOZZLE FOR COAXIAL CYLINDERS

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NB-4321 NB-4000 — FABRICATION AND INSTALLATION NB-4322

FIG. NB-4244(e)-1 OBLIQUE CONNECTIONS

order to qualify both the welding procedures and the performance of welders and welding operators who apply these procedures.

(b) Procedures, welders, and welding operators used to join permanent or temporary attachments to pressure parts and to make permanent or temporary tack welds used in such welding shall also meet the qualification requirements of this Article.

(c) When making procedure test plates for butt welds, consideration shall be given to the effect of angular, lateral, and end restraint on the weldment. This applies particularly to material and weld metal of 80.0 ksi (552 MPa) tensile strength or higher and heavy sections of both low and high tensile strength material. The addition of restraint during welding may result in cracking difficulties that otherwise might not occur.

(d) NCA-3131 provides specific additional require- ments when welding services are subcontracted to or

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through organizations not holding an appropriate Cer- tificate of Accreditation.

NB-4322 Maintenance and Certification of Records

The Certificate Holder shall maintain a record of the qualified welding procedures and of the welders and welding operators qualified by him, showing the date and results of tests and the identification mark assigned to each welder. These records shall be reviewed, verified, and signed by any authorized individual assigned by the Certificate Holder, and they shall be accessible to the Owner and to the Inspector.

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Fig. NB-4250-1 1998 SECTION III, DIVISION 1 — NB

FIG. NB-4250-1 WELDING END TRANSITIONS — MAXIMUM ENVELOPE

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