变质及热处理对ASSAB 88组织及性能的影响

Effect of Modification and Heat Treatment on Microstructure and Mechanical Properties of ASSAB 88

对ASSAB 88冷作模具钢进行变质以及热处理,探讨了Sr变质剂和镍粉的加入对钢的碳化物及晶粒的影响,并且通过对硬度和冲击韧度的测定讨论了综合性能要求较高的冷作模具钢ASSAB 88的碳含量的选择。试验结果表明:通过硬度以及冲击韧度的测试得出,较合适的碳质量分数为0.9%;Sr变质剂在质量分数0.3%范围内加入以后,试样中磷的质量分数明显下降,由0.031%降为0.021%,综合力学性能显著提高,如冲击韧度由18.9J/cm2增加到28.8J/cm2;镍粉加入以后碳化物和晶粒的形貌发生了改善,碳化物网状结构逐渐断开,孤立程度增加;钢经过淬火和回火处理以后钢中碳化物的分布均匀,逐渐趋向于弥散分布,出现部分溶解,晶粒有细化趋势。

Through modification and heat treamaent for ASSAB 88, the effect of modifier Sr and Ni on carbides and crystallites in quantity was investigated, the proper carbon content was discussed by hardness and toughness test. The results of hardness and toughness test show that the mass fraction 0.9% is the proper carbon content. While Sr （0.3wt% in scope） is added, phosphorus content decreases from 0.031 wt% to 0.021 wt% and mechanical properties improves, for example, toughness increases from 18.9 J/cm^2 to 28.8 J/cm^2. The configuration and distribution of carbide and grains improves With the addition of Ni, the carbide network tends to break and isolate. After quenching and tempering, the distribution of the carbide in the steel is uniform, the carbide distributes dispersedly and dissolves partly, the grains in the steel tend to be refined.