The Difference between Cold Rolled and Hot Rolled Seamless Steel Pipes

The seamless steel pipes needed in cities today can be collectively referred to as hot-rolled seamless steel pipes and cold-rolled seamless steel pipes. These two sheets of steel have different manufacturing processes. Compared with hot-rolled seamless steel pipes, cold-rolled seamless steel pipes have relatively more complicated manufacturing steps. Not only is it necessary to carry out triple rolling, but also to carry out crack testing, cutting, and then entering the final return process. When cold-rolled seamless pipes are annealed, the pickling step is inevitable. During the pickling process, workers need to wear safety equipment. At the same time, it is necessary to check whether there are a lot of bubbles on the surface of the steel pipe. If there are more, the quality of the steel pipe will not meet the relevant requirements.

Compared with the cumbersome steps of cold-rolled seamless steel pipes, hot-rolled seamless steel pipes are much more common. It only needs to be in the hot rolled state after heat treatment. Cold deformation has high plasticity, generally used for bending, rolling, bending, and hammer arching. The welding performance of arc welding and contact welding is good. The thickness is small during gas welding, and cracks are easy to occur on parts with strict requirements or complex shapes. Machinability cold drawn or normalized state is better than the annealed state, generally used for manufacturing less stress and high toughness requirements. General-purpose seamless steel pipes are rolled from ordinary carbon structural steel, low-alloy structural steel, or alloy structural steel, and have the largest output. They are mainly used as pipelines or structural parts for conveying fluids. Seamless steel pipes made of this type of steel are widely used Hydraulic props, high-pressure gas cylinders, high-pressure boilers, fertilizer equipment, petroleum cracking, automobile axle sleeves, diesel engines, hydraulic pipe fittings, etc. are treated with surface quenching or high-frequency quenching. Therefore, depending on the chemical composition (mainly carbon content), heat treatment process, and use.

In appearance, these two steel pipes are also different. First of all, in terms of length, cold-rolled seamless steel pipes are slightly shorter. In terms of thick walls, the wall thickness of cold-rolled seamless steel pipes is slightly smaller. But in terms of the finish of the thick wall, it is brighter than the hot-rolled seamless steel pipe. At the same time, there are not too many obvious roughnesses on the surface of the steel pipe, and there are not too many burrs at the diameter.

The information is provided by the galvanized steel coil factory.