Hot rolled seamless steel pipe

　　Hot rolled seamless steel pipe is divided into general steel pipe, low and medium pressure boiler steel pipe, high pressure boiler steel pipe, alloy steel pipe, stainless steel pipe, petroleum cracking pipe, geological steel pipe and other steel pipes. Hot rolled steel pipes shall be delivered in hot rolling state or heat treatment state;

　　The production process of hot-rolled seamless steel pipe: pipe blank → heating → piercing → three roll cross rolling, continuous rolling → pipe stripping → sizing → cooling → straightening → hydrostatic test → marking → warehousing. The raw material for rolling seamless steel pipe is round pipe blank, which is cut by the cutter to process the blank with a length of about 1m, and then sent to the furnace for heating via the conveyor belt. The tube blank is sent into the furnace and heated to about 1200 ℃. The fuel for heating tube blanks is hydrogen or acetylene. The temperature control in the furnace is a key problem. After the billet is discharged from the furnace, it needs to be pierced by a piercer.

　　Generally, the common piercer is the cone roll piercer for steel pipe. This kind of piercer has high production efficiency, good product quality, large piercing and diameter expansion, and can pierce a variety of steel grades. After piercing, the tube blank is successively cross rolled and continuously rolled by three rollers. After extrusion, the pipe shall be removed for sizing. The sizing machine rotates into the steel embryo at a high speed through the tapered drill bit to drill holes, forming a steel pipe (the inner diameter of the steel pipe is determined by the outer diameter length of the sizing machine drill bit). After sizing, the steel pipe enters the cooling tower and is cooled by spraying water. After cooling, the steel pipe will be straightened. After being straightened, the steel pipe is sent to the metal flaw detector by the conveyor belt for internal flaw detection. If there are cracks, bubbles and other problems in the steel pipe, they will be detected. After quality inspection, steel pipes shall be selected strictly by hand. After the steel pipe is inspected, the number, specification, production batch number, etc. shall be sprayed with paint. The crane shall be used to hoist it into the warehouse.