manufacturing process of a steel plate of high strength ecrouie, with excellent ability to welding and paint processing

摘要

A low-alloy steel is subjected to hot rolling, optionally hot coiling, then cold rolling and continuous annealing. The continuous annealing is performed by soaking the sheet at 730 to 850 DEG C for from 20 seconds to 2 minutes, whereafter the sheet is rapidly cooled with a cooling rate of from 30 to 300 DEG C/sec. If required, an overageing treatment at 300-500 DEG C may be imparted to the sheet, preferably by stopping the rapid cooling at an appropriate temperature to avoid reheating of the sheet. The composition of the steel is as follows: Element Wt% C 0.05-0.12 Si 1.2 max Mn 0.7-1.5 P 0.04-0.15 Sol Al 0.01-0.10 Fe [and impurities] Balance. e