1.5 Welding of regulating valve Pick up

1.5.1 For parts rolled by steel plates, manual or semi-automatic gas shielded arc welding is generally adopted, and automatic submerged arc welding should be adopted for important parts.

1.5.2 For the mechanical work pieces that need to eliminate the welding stress, the finishing shall be carried out after eliminating the internal stress. Local elimination of internal stress is not allowed for major parts welded at the factory.

1.5.3 The external and internal quality of the formed welds in the factory shall conform to the design drawings and relevant regulations or specifications. For parts to be welded on site, joint groove of welding parts shall be reasonably designed, groove and blunt edge surface shall be regular and free from defects, grease and other sundry.

1.5.4 Welding method, process and welder of welding pressure vessel parts shall comply with relevant provisions in GB150 "Pressure vessel". Welder must pass the examination and obtain the certificate for on-the-spot inspection by the on-site representative at any time. Welder of heterosexual metal or stainless steel welding in the factory must pass the examination and take up the post, and be witnessed by the on-the-spot representative.

1.5.5 In the case of welding equipment on the site, the seller shall provide the materials, test blocks and welding rods required for the welder examination free of charge. If necessary, the seller shall propose the welder examination procedures on the site, and the theoretical examination and practical examination shall be approved by the site representative and installation supervisor of the Seller.

1.5.6 When the equipment is welded on site, the seller shall supply welding rods or wires with 200% of rated metal filler, the supplied materials shall be consistent with the factory's processing drawings and be able to adapt to the welding conditions on site.

1.5.7 The weld shall have a good appearance and be in the shape of fish scales. If there are weld nodules or weld scars, it shall be smooth and smooth and suitable for surface painting. Without any internal or external welding defects, all welding seams on the water surface of the weld requiring X-ray inspection or other non-destructive inspection shall be polished to streamline form. The weld on the pressure vessel shall be polished without weakening its structural strength.

1.5.8 Before the welding of the valve shell, the welding process evaluation test plate of the shell material should be made. After the completion of the test plate welding should be entrusted with CMA certified institutions for physical and chemical and mechanical properties testing and issued a test report.

The seller shall, according to the evaluation result of the test report, prepare the formal welding procedure specification or welding procedure instruction and submit it to the buyer for record.

1.5.9 All welding materials, flux and wire used for the contract equipment shall be inspected by a CMA certified institution.