CSP流程钛微合金化高强钢的第二相粒子析出行为

采用光学显微镜、扫描电镜、透射电镜、物理化学相分析等方法并结合热力学计算,分析了CSP工艺生产的钛微合金化高强钢的析出物特征及析出规律.研究发现：屈服强度700 MPa级高强钢中存在大量球形的纳米级TiC和Ti( C,N)粒子及少量不规则形状、100 nm以上的Ti4 C2 S2粒子,TiN在连轧前完成析出,TiC主要在卷取和空冷时析出.不含钼钢和含钼钢(0.1% Mo)中MC相的质量分数为0.049%和0.043%,由于钼的加入,含钼钢中Ti的析出量较少,但析出粒子更为细小,并定量得到了不含钼钢和含钼钢的析出强化效果分别为126 MPa和128 MPa.

Precipitation behavior of Ti-microalloyed high-strength steel by CSP process

Optical microscopy, electron microscopy and physic-chemical phase analysis, in combination with thermodynamic calculations, were used to study precipitates and their precipitation regularity in Ti-microalloyed high-strength steel produced by CSP process. It is found that lots of spherical TiC and Ti( C,N) nanoparticles with a few of irregular shaped Ti4 C2 S2 above 100 nm in size exist in the steel with a yield strength of 700 MPa. TiN is completely precipitated from the steel before tandem rolling, but TiC mainly precipitates during coiling and cooling. The mass fractions of MC phases in the steel without Mo and the steel containing Mo are 0. 049% and 0. 043%, respectively. Owing to the addition of molybdenum, the amount of Ti precipitates in the steel containing Mo decreases while the precipitate size becomes smaller. The precipitation strengthening effects of the steel without Mo and the steel containing Mo are 126 MPa and 128 MPa, respectively.