The difference between hot processing and cold processing is: that hot rolling is hot processing, and cold drawing is cold processing. The main difference is: that hot rolling is rolling above the recrystallization temperature, cold rolling is rolling below the recrystallization temperature; and cold rolling is sometimes heated, but the temperature is relatively low because processing will occur after cold rolling. Hard, if the molding requirements for the material are relatively high, annealing is required.
Cold rolling and hot rolling are generally plates or profiles, while cold drawing is generally wire rods with cylindrical cross sections. In addition, hot-rolled plates are generally steels with higher alloy content and higher strength, while cold-rolled plates are low-carbon and low-alloy steels. Cold rolling can increase the strength and ensure the surface quality of the material.
Seamless steel pipes are divided into two types: hot-rolled (extruded) seamless steel pipes and cold-drawn (rolled) seamless steel pipes due to different manufacturing processes.
Cold-drawn steel pipes generally require multiple drawings and corresponding stress relief annealing is required between each drawing to ensure that the next cold drawing proceeds smoothly. From the appearance, cold-rolled seamless steel pipes tend to have small diameters, while hot-rolled seamless steel pipes tend to have large diameters. 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 smaller diameters, mostly below 127mm. In particular, the accuracy 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.
Post time: Dec-25-2023