1.1 This standard specifies basic requirements for design, material, manufacture, inspection and acceptance of steel butt welding fittings with nominal diameter DN 350 and smaller for oil and gas pipeline project.
Fittings in this standard cover standard tees, elbows, reducing pipes and caps (heads).
Any agreement with any manufacturer will be included into the additional agreement of the purchaser and this manufacturer.
1.2 Fittings manufactured according to this standard are applicable to pipeline project trunk line and station yard for transmitting natural gas, crude oil, refined oil and liquid liquefied petroleum gas, thereinto, the quality of the transmitted natural gas shall meet the requirements for Class II gas in GB 17820; the transmitted crude oil shall meet the oil quality requirements of SY/T 7513; the transmitted refined oil shall meet the national current product standard requirements; and the transmitted liquid liquefied petroleum gas shall meet the requirements of GB 9052.1 or GB 11174.
Foreword I
1 Scope
2 Normative References
3 Terms and Definitions
4 Design of Fittings
5 Specification of Fittings
6 Requirements for Raw Materials
7 Requirements for Manufacturing Process
7.1 General Provisions
7.2 Confirmation of Manufacturing Process
7.3 Procedure Qualification and First Lot Inspection
7.4 Welding
7.5 Heat Treatment
8 Property Requirements
8.1 Tensile Property
8.2 Charpy Impact Toughness
8.3 Guided Bend Test of Weld
8.4 Hardness
8.5 Metallographic Structure and Grain Size Inspection
9 Dimension, Geometry and Permissible Deviation
9.1 Shape and Dimension of Fittings
9.2 Welding End
9.3 Pipe End Planeness and Verticality
10 Process Quality and Defect Treatment
10.1 Surface Quality
10.2 Defect Treatment
11 Inspection and Test
11.1 Mechanical Property Test and Metallographic Inspection
11.2 Geometric Dimension Inspection
11.3 Product Hardness Inspection
11.4 Non-destructive Testing
11.5 Purchaser Inspection
12 Hydraulic Test
13 Design Verification Test
13.1 Required Test
13.2 Specimen
13.3 Test Assembly
13.4 Fluid Medium
13.5 Verification Test Strength Calculation
13.6 Test Procedure
13.7 Availability of Test Results
14 Marking
15 Protection
16 Product Quality Certificate
17 Packing and Transport
Appendix A (Informative) Recommended Materials and Standards
Appendix B (Normative) Manufacturing Process Qualification
Appendix C (Informative) Steel Grade Explanation
Appendix D (Normative) First Lot Inspection
Bibliography
