22Mn2SiVBS钢化学成分与组织的关系

Relationship Between Microstructure and Composition of 22Mn2SiVBS Steel

通过对合金元素与钢的组织转变动力学关系的研究,设计了22Mn2SiVBS空冷贝氏体型非调质钢。经电炉冶炼连铸连轧穿制成管坯后,检测了钢的化学成分和力学性能,讨论了钢中合金元素对其组织和力学性能的影响。结果表明,钢中微量合金元素分布不均匀,影响了组织转变的动力学条件,导致过冷奥氏体稳定性下降和过量铁素体的析出,降低了钢的力学性能。通过高温扩散处理,可以改善微量合金元素不均匀分布,获得均匀贝氏体组织,提高钢的力学性能。

Air-cooling microalloyed engineering bainitic steel 22Mn2SiVBS was designed through analyzing the relationship of alloy elements and microstructure transformation kinetics of the steel. The chemical compositions and mechanical properties of the test steel as pipe billet through continuous casting-rolling process were examined. The influence of the alloy elements on microstructure and mechanical properties of the steel was also discussed. The results show that the microstructure transformation kinetic conditions are affected by segregation of the alloy elements in the steel ,which leads to decrease of the stability of super-cooling austenite and the precipitation of excessive ferrite. Consequently, the mechanical properties of the steel are decreased. The segregation of the elements can be improved through high temperature diffusion treatment so as to acquire uniform bainitic microstructuresand increase the mechanical properties of the steel.