For the heads that are spliced first and then formed, the amount of misaligned edges of the spliced plate should not be greater than 10% of the material thickness δs and not greater than 1.5mm. The amount of misalignment of the spliced composite steel plate shall not be greater than 30% of the thickness of the cladding and not greater than 1mm.

　　Welding materials, welding methods, welding environment, cleanliness requirements of workpieces and beveling to be welded, welding process qualification report, welding specified process, welding records and preservation period requirements of welder identification marks. According to the different design methods and materials, it should meet the corresponding standards.

　　The welded seam of the inner surface of the dish head that is spliced first and then formed, and the welded seam of the outer surface that affects the forming quality, should be polished to the same level as the base metal before forming.

　　Before the conical head is formed, the residual height of the welding on the inner and outer surfaces of the transition part should be polished to be flush with the base material.

　　There shall be no cracks, gap, pores, arc pits and spatter on the surface of the welded joint of the head.

　　After welding, the surface color of all welded joints of iron heads shall be inspected in the original state.

　　The requirements for repairing of the welded joint of the head shall meet the corresponding standards.

　　After the blank plate is cut, the surrounding defects that affect the forming quality of the head should be polished.