API 5L seamless steel pipe is a kind of hollow section, there is no seam around the circular, square, rectangular steel. Seamless steel tube is made of steel or solid tube through the perforation of the capillary, and then made by hot rolling, cold rolling or cold. Seamless steel pipe with a hollow section, as pipe conveying fluid, compared withsteel and roundsteelinsolid, flexural torsional strength in the same time, the weight is light, is a kind of economic section steel, widely used in the manufacture of structural parts and mechanical parts, such as the oil pipe, automobile transmission shaft, bike frame and construction using steel scaffolding.
Standard specification for seamless steel pipe with external diameter * wall thickness mm. Seamless steel tubes for hot rolling and cold rolling (DIAL) seamless steel tubes two. Hot rolled seamless steel tubes are 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, etc.. Cold rolled seamless steel pipe (DIAL) in general, steel pipe for low and medium pressure boiler tube, high-pressure boiler steel pipe, alloy steel pipe, stainless steel pipe, oil cracking tube and other steel tube, including carbon thin-walled steel, alloy thin-walled steel, stainless steel, thin steel tube. Hot-rolled seamless pipe diameter is generally greater than 32mm, the wall thickness of 2.5-75mm, cold rolled seamless steel pipe diameter can be 6mm, wall thickness can be 0.25mm, thin wall pipe diameter can be less than 5mm thickness of 0.25mm, cold rolling than the high dimensional accuracy of hot rolled. General use of seamless steel pipe is 10, 20, 30, 35, 45 and other high quality carbon steel 16Mn, 5MnV and other low alloy structural steel or 40Cr, 30CrMnSi, 45Mn2, 40MnB, such as hot-rolled or cold-rolled steel. 10, 20 and other low carbon steel seamless pipe is mainly used for fluid delivery pipeline. 45, 40Cr, etc. made of carbon steel seamless pipe used in the manufacture of mechanical parts, such as automobiles, tractors, mechanical parts. General use of seamless steel pipe to ensure the strength and flattening test. Hot rolled steel pipe delivered in hot rolling or heat treated condition; cold rolled in heat treatment. Hot rolling, as the name implies, the temperature of the workpiece is high, so the deformation resistance is small, can achieve large deformation. For example, the slab thickness is about 230mm, and the final thickness is 1~20mm after roughing and finishing. At the same time, due to the small width to thickness ratio of steel plate, the requirement of dimension precision is relatively low, so it is not easy to appear the shape problem. For the requirements of the organization, it is generally realized by controlled rolling and cooling, that is, to control the rolling temperature, finishing temperature and crimp temperature to control the microstructure and mechanical properties of the strip.
