Difference between hot and cold seamless tube

Generally seamless steel tubes are made by hot rolling or cold rolling with 10,20,30,35,45 high quality carbon steel and 16Mn, 5MnV low alloy structural steel or 30CrMnSi, 40Cr, 45Mn2, 40MnB alloy steel. Seamless pipe, made by 10,20 and other low carbon steel production, is mainly used for conveying pipe, while made by 45,40Cr medium carbon steel to manufacture mechanical parts. What’s the difference between hot rolled seamless steel tube and cold rolled seamless steel tube?

Cold rolling seamless tube

Cold rolled seamless tube is a seamless steel tube for high dimensional accuracy and good surface finish. Cold rolled seamless pipe in addition to include the general steel, low and medium pressure boiler tube, high-pressure boiler tubes, alloy steel pipe, stainless steel pipe and oil cracking tube, also includes carbon thin wall steel pipe, alloy thin wall steel tube, thin-walled stainless steel pipe and special-shaped steel tube. The diameter of cold rolled seamless steel pipe is 6mm, wall thickness is 0.25mm, while the diameter of thin-walled tube can be 5mm, wall thickness can less than 0.25mm. The dimensional accuracy of cold rolling is higher than that of hot rolling.

Hot rolling seamless tube

Hot rolling is relative to the cold rolling. Cold rolling carries on rolling below the temperature of recrystallization, and hot rolling is above the recrystallization temperature. Hot rolled seamless steel pipe is generally divided into low, medium, high pressure boiler steel pipe, alloy steel pipe, stainless steel pipe, oil cracking pipe, geological steel pipe and other steel pipe. The outside diameter of hot rolled seamless tube is generally greater than 32mm and the wall thickness of that is 2.5-75mm.