Stainless steel welding wire must be baked at the temperature strictly in accordance with the instructions for use and kept warm before use. Receive welding rod, welders must use the electrode insulation cylinder, and do a good job of anti-aluminium welding wire clean, dry and sealed packaging, otherwise chemical cleaning and drying treatment is required before use.
Welding rod grades must be used uniformly and not mixed.
Prefabricated welds at the installation site must not be entered into the cold box assembly welding before the radiographic inspection is completed.
All butt welds shall be radiographic inspection, welds conforming to JB/T4730 "Nondestructive inspection of pressure-bearing equipment radiographic inspection" requirements, stainless steel welds conforming to JB/T473'12 a 2005 "Nondestructive inspection of pressure-bearing equipment radiographic inspection" requirements, all fillet welds shall be colouring inspection, conforming to JB/T4730 "Nondestructive inspection of pressure-bearing equipment radiographic inspection" level requirements. The weld shall have a smooth transition to the base material and the surface of the weld shall not have defects such as cracks, unfused, unfilled arcs, arc spots, tumours and unfilled arc pits.
It is recommended that aluminium pipeline fixed welds be welded with an embedded ring type stainless steel pad. The stainless steel strip used as a pad must be clean, oil-free and free from mechanical damage on the surface. The stainless steel strip and the groove aluminium interface should be welded and then ground flat. The welded joint with the gasket plate should be made flush with the inner wall of the pipe. Stainless steel lining rings without grooved aluminium are permitted for welded joints in aluminium pipes with an internal diameter smaller than
Aluminium pipes in the welding position should be given priority to double-sided simultaneous vertical welding. The installation of steel and aluminium transition joints needs to be welded under sufficient cooling (heat dissipation) to avoid cracking due to the different wire rise coefficients of steel and aluminium.
