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 sometimes has heating, but the temperature is relatively low because processing will occur after cold rolling Hard, if the requirements for the forming of the material are relatively high, annealing is also required. Cold rolling and hot rolling are generally plates or profiles, while cold drawing is generally cylindrical cross-section wire. In addition, hot-rolled plates are generally steel with high alloy content and high strength, while cold-rolled steel is low-carbon and low-alloy steel. Cold rolling can increase the strength and ensure the surface quality of the material.
The difference between cold-drawn
seamless steel pipe and hot-rolled seamless steel pipe is different from that of the plate.
Seamless steel pipes are divided into two types: hot-rolled (extruded) seamless steel pipes and cold-drawn (rolled) seamless steel pipes due to their different manufacturing processes. Cold-drawn steel pipe generally requires multiple drawings, and there must be corresponding stress relief annealing between each drawing to ensure the smooth progress of the next cold drawing. From the outside, the cold-rolled seamless steel pipe tends to have a small diameter, and the hot-rolled seamless steel pipe tends to have a large diameter. The precision 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 diameter, mostly below 127mm, especially since the precision of the outer diameter of cold-drawn seamless pipes is 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.
