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
