Basic welding

　　The first layer on the inner side adopts automatic submerged arc welding. Use the selected welding materials, strictly control the specifications, prohibit melting the coating, clean the roots by gouging the outer carbon arc and thoroughly grind them, and automatically weld the outer submerged arc.

　　Transition layer welding

　　Electrode arc welding is used, ultra-low carbon stainless steel electrode is selected, and the method of small specification, high welding speed, and straight pass welding is adopted to reduce the melting amount of the base metal and ensure a small fusion ratio. Dilution rate of weld metal to prevent welding cracks.

　　Welding of cladding

　　Electrode arc welding is used, and austenitic stainless steel electrode is selected, which has good thermal crack resistance, corrosion resistance and mechanical properties. Use small specifications when welding to prevent embrittlement of the coating and decrease in corrosion resistance.

　　Blank quality control

　　In order to prevent spallation under the action of shearing force during spinning, all the sheets are subjected to 100% ultrasonic inspection and re-inspection before spinning.

　　The binding rate is required to be 100%, and no unbound area is allowed. In order to prevent cracks on the periphery during forming, after cutting the outer periphery, use a grinder to polish it smoothly. The minimum grinding depth of the cutting surface is 2mm or more. The periphery is not polished. The stress concentration at the uneven cutting edge during spinning may cause radial cracks. .

　　Rebound control

　　The springback produced by the pressing drum and flanging is mainly achieved by selecting the appropriate pressing tire, the radius of curvature of the forming wheel and the angle of the forming wheel.