Industrial material: galvanized seamless steel pipe

Hot-dip galvanized seamless steel pipe: the amount of hot dip plating is higher, the average thickness of the galvanized layer is more than 65 microns, and its corrosion resistance is much higher than that of the hot-dip galvanized pipe. Regular galvanized pipe manufacturers, permitted to use cold galvanized pipe as water, gas pipe. The galvanized layer of cold galvanized steel pipe is an electric coating, and the zinc layer is independently layered with the steel pipe matrix. The zinc layer is thin, and the zinc layer is simply attached to the steel tube matrix and easy to fall off. Therefore, its corrosion resistance is poor. In new residential buildings, it is prohibited to use cold galvanized steel pipes as water supply pipes.

Galvanized seamless steel pipe process classification

1. medium and thick plate machine group: the main production of wide and thick plates, for the production of straight seam submerged arc welding pipe, straight seam submerged arc welding pipe quality is reliable, widely used in oil and gas high-pressure transmission main line.

2. the furnace coil mill: the furnace coil mill includes a reciprocating roughing mill and a 4-roll reciprocating finishing mill. Two hot coil mills are installed on the conveyor lines on both sides of the finishing mill. The output roller table usually includes a laminar cooling system and a take-up station. In the furnace coil mill, significant changes in the thermo-mechanical history of the entire length of the stainless steel pressed elbow pipe, especially in the production of micro-stainless steel pressed elbow pipe, 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 the stainless steel pressed elbow pipe

3. semi-continuous rolling mill: including 1 rack furnace coil mill and 5 rack finishing mill. In a semi-continuous mill, the hot rolling experienced by the pipe in the finishing pass is substantially constant from one end of the pipe to the other. The time between passes on the finishing mill is usually less than 3s.

4. CSP continuous casting and rolling: in the CSP production line containing niobium, vanadium, titanium composite micro-alloying low-carbon manganese steel, the use of appropriate controlled rolling control cooling and cooling process, can ensure that the mechanical properties and microstructure of the pipe in line with the technical requirements of modern X60 stainless steel stamping elbow, in line with the development trend of modern stainless steel stamping elbow pipe. China's CSP continuous casting and rolling production line has developed X60 stainless steel stamped elbow pipe fittings, while other CSP production plants in the United States and abroad have developed and produced high-grade stainless steel stamped elbow pipe fittings X60, X65 and even X70. The process is characterized by the existence of center segregation of continuous casting thin slab, and the elimination of center segregation of continuous casting thin slab by galvanized seamless steel pipe is a key technical issue to further improve the quality of stainless steel stamping elbows. The sheets used in stainless steel stamping elbows in the 1960s and 1970s are mainly A3, 16Mn produced by Angang and other manufacturers. With the increase of pipe diameter and the improvement of conveying pressure, The strength of pipe fitting plate can not meet the demand. After the 1980s, the oil welding pipe fittings factory began to use pipeline steel plates produced according to the American API standard, because the domestic stainless steel stamping elbow plate production plant technology is not mature, mainly using imported plates.