The difference between hot working and cold working

 hot rolling is hot working, and cold drawing is cold working. The main difference: hot rolling is rolling above the recrystallization temperature, cold rolling is rolling below the recrystallization temperature; cold rolling is sometimes heated, but the temperature is relatively low, because the processing occurs after cold rolling Hard, if the material forming requirements are relatively high, it must be annealed.

Cold-rolled and hot-rolled are generally plates or profiles, while cold-drawn are generally cylindrical cross-section wires. In addition, hot-rolled plates are generally steels with higher alloy content and higher strength, while cold-rolled steels are low-carbon and low-alloy steels. Cold rolling can increase the strength and ensure the surface quality of the material.

The difference between cold-drawn seamless steel pipes pipe and hot-rolled seamless steel pipe is different from that of plates.

Seamless steel pipes are divided into hot-rolled (extruded) seamless steel pipes and cold-drawn (rolled) seamless steel pipes due to their different manufacturing processes.

Cold drawn steel pipes generally need to be drawn multiple times, and there must be corresponding stress relief annealing between each drawing to ensure the smooth progress of the next cold drawing. From the appearance, cold-rolled seamless steel pipes pipes are often small in diameter, and hot-rolled seamless steel pipes are often of large diameter. The accuracy of cold-rolled seamless steel pipe is higher than that of hot-rolled seamless steel pipe, and the price is also higher than that of hot-rolled seamless steel pipe. Cold drawn seamless pipes generally have a small caliber, mostly below 127mm, especially the precision of the outside diameter of cold drawn seamless pipes are very high, and the length of cold drawn seamless pipes is generally shorter than that of hot-rolled seamless pipes. In terms of wall thickness, cold-drawn seamless pipes are more uniform than hot-rolled seamless pipes.