Effect Of Multi-modification On Structure And Properties Of Cr12 Steel

As a kind of high-carbon high-chromium ledeburite steel, Cr12 steel contains higher content of C(1.4-2.1%) and amount of Cr(11-13%). The network eutectic carbides existing in the casting steel is harmful for the strength and ductility of it which seriously shortens the using time of the steel. So breaking this network carbide is one of methods to improve the performance of this steel.In our work, the Al-Fe-Zn-Si modifier was used to modify the Cr12 steel. The microstructure and performance of it were studied by HSVM, SEM, XRD and so on. The results show that the Al-Fe-Zn-Si modifier can effectively refine the dendrite of the steel, reduce the amount of the coarse plate-like carbide, break the net-like carbide and improve it distribution. It is because that the addition of the modifier improves the activity of the carbon and provides the nuclei. In addition, it can also increase the under cooling and decrease the content of O,S and P. It is found that the microstructure of steel is the best when the addition level of the modifier is 0.8%.The high temperature heat-treatment results show that the common Cr12 steel is difficult to change the network eutectic carbide into dispersed particle-like carbide under the 1080℃treatment. But the net-like eutectic carbide can be easily broke and become the particle-like under the same heat-treatment after being modified by the Al-Fe-Zn-Si. It is considered that the improvement of the activity of C with the addition of the modifier is the reason for this transformation. The diffusion of C is boosted as the activity being improved which accelerates the burn out of the net-like carbide and the solution of the acuate part.The properties experiment results show that the rigidity is not improved very much but the ductility and wear-resistance are obviously improved.