Abstract：The high strength low alloy (HSLA) steels made with conventional processes have a high level of impurity and unstable mechanical properties. Some procedures were adjusted and improved forming a special technology for production of the relatively pure HSLA steel. The Zr alloyed HSLA steel made with the new technology exhibits low impurity. The content, size, shape and distribution of inclusions in such HSLA steel are remarkably modified by Zr addition. The inclusions are fine, spheric or near spheric in shape and disperse. Electron Probe and Energy Spectrum study reveal that the inclusions in such Zr alloyed HSLA steel are complex containing Ti2O3, Al2O3, ZrO2 located in the center and MnS lying on the surface. The specifics of inclusions are modified by Zr treatment and new technology. Thus the properties of Zr HSLA plate are improved greatly.
2006, Vol. 41 
