Compared with similar foreign materials, the gap between China’s non quenched and tempered steel is as follows:
1) Poor quality of hot rolled products;
2) There is no certain control range for residual elements, resulting in great fluctuations in mechanical properties;
3) The chemical range specified in the standard is wide.
The performance requirements for non quenched and tempered steel include: hardness and strength, plasticity and toughness, fatigue performance, machinability, etc. There are many factors that affect the properties of non quenched and tempered steel, the most important one is toughness. Improving and improving the toughness of non quenched and tempered steel can further expand its application range. According to relevant statistics, 35-50% of automobile engine manufacturing in Japan with developed automobile industry and industrialized European countries use non quenched and tempered steel.
China started late and must catch up. The mechanical properties of non quenched and tempered steel are affected by many factors, such as steel chemical composition, smelting method, metallurgical quality, cold and hot processing technology and rolling forging controlled cooling technology. Continuously improving the metallurgical quality of non quenched and tempered steel, increasing varieties, optimizing cold and hot processing technology, and developing scientific cooling control technology are the reliable guarantee for stabilizing the mechanical properties and product quality of non quenched and tempered steel.