After acid washing, cleaning with ammonium chloride or zinc chloride aqueous solution or a mixture of ammonium chloride and zinc chloride aqueous solution in a tank is mostly not carried out using electroplating (cold plating) to ensure quality. Only small enterprises with small scale and outdated equipment adopt electroplating, and of course, their prices are relatively cheaper. At present, the Ministry of Construction has officially announced the elimination of outdated cold galvanized pipes, and in the future, it will not be electroplating. It is the reaction between molten metal and iron substrate to produce an alloy layer, thereby bonding the substrate and coating together. Hot dip galvanizing involves first pickling steel pipes to remove iron oxide from their surface, and then sending them into a hot-dip galvanizing tank. Hot dip galvanizing has the advantages of uniform coating, strong adhesion, and long service life. At present, the production processes of stainless steel stamping elbow fittings in China mainly include: conventional semi continuous hot rolling, CSP continuous casting and rolling, medium thick plate unit, and furnace coil unit.

1. Medium thick plate unit: mainly produces wide and thick plates for the production of straight seam submerged arc welded pipes. The quality of straight seam submerged arc welded pipes is reliable and widely used in the main line of high-pressure oil and gas transportation.

2. Furnace coil rolling mill: The furnace coil rolling mill includes a reciprocating roughing mill and a 4-roll reciprocating finishing mill. Two hot rolling mills were installed on the conveyor lines on both sides of the finishing mill. The output roller conveyor usually includes a laminar cooling system and a coiling station. On the furnace coil rolling mill, the thermal mechanical history of stainless steel stamped elbow fittings along the entire length changes significantly, especially in the production of micro stainless steel stamped elbow fittings, which will strongly affect the degree of recrystallization, grain growth, and precipitation generated on the finishing mill, and lead to drastic changes in the final microstructure and properties of the entire length of stainless steel stamped elbow fittings

3. Semi continuous rolling mill: including 1 furnace coil rolling mill and 5 precision rolling mills. On a semi continuous rolling mill, the hot rolling of the pipe during the finishing pass is essentially constant from one end of the pipe to the other. The time between passes on the finishing mill is usually less than 3 seconds.

4. CSP continuous casting and rolling: On the CSP production line, suitable controlled rolling, controlled cooling, and coiling processes are adopted for low-carbon manganese steel containing niobium, vanadium, and titanium composite microalloying, which can ensure that the mechanical properties and microstructure of the pipe fittings meet the technical requirements of modern X60 stainless steel stamping elbows and conform to the development trend of modern stainless steel stamping elbow pipe fittings. At present, China's CSP continuous casting and rolling production line has developed X60 stainless steel stamping elbow fittings, while other CSP production plants in the United States and abroad have developed and produced high-grade stainless steel stamping elbow fittings X60, X65, and even X70. The process feature is that there is center segregation in the continuous casting thin slab, and the elimination of center segregation in the continuous casting thin slab by galvanized seamless steel pipes is a key technical issue to further improve the quality of stainless steel stamping elbow fittings. In the 1960s and 1970s, A3 and 16Mn plates produced by Ansteel and other manufacturers were mainly used for stainless steel stamping elbows. As the pipe diameter increased and the conveying pressure increased, the strength of the fitting plate could not meet the requirements. After the 1980s, various oil welded pipe fittings factories began to use pipeline steel plates produced according to American API standards. Due to the immature technology of domestic stainless steel stamping elbow plate production plants at that time, imported plates were mainly used.