模铸和电渣M2高速钢中碳化物的演变行为及对比

为了优化高速钢生产工艺、控制钢中碳化物,研究了不同冶炼工艺和加工工序下M2高速钢中碳化物的演变行为。采用金相显微镜、扫描电镜、能谱分析以及热力学计算等方法,对模铸和电渣重熔M2高速钢中碳化物的类型、形貌、面积分数和分布进行研究和对比。结果表明,模铸M2高速钢锻造、轧制、盘圆和拉丝成材过程中网状碳化物得到破碎,但仍存在不规则一次碳化物,各工序下碳化物面积分数为4.96%、4.54%、5.05%和5.08%。电渣M2高速钢锻造后网状碳化物交叉处堆积比较严重,且比相同工序下模铸M2高速钢的面积分数高。国内某厂家和日本不二越的电渣M2高速钢二次锻造材中碳化物面积分数分别为5.47%和5.33%。M2高速钢锻造坯中碳化物为M₆C、MC、M₇C₃。存在于基体中的尺寸大、形状不规则的M₆C和MC对后续加工和成品材会产生不利影响。

Evolution behavior and comparison of carbide in ingot casting and ESR M2 high speed steel

In order to optimize the production process of high speed steel and controlling carbides in steel,the evolution behavior of carbides in M2 high speed steel with different smelting and processing processes was studied. The type,morphology,area fraction and distribution of carbide in ingot casting and ESR M2 high speed steel were studied by means of metallographic microscope,SEM,EDS and thermodynamic calculation,etc. The results show that the network carbide is broken in the process of forging,rolling,coiling and drawing of ingot cast M2 high speed steel. but the irregular primary carbide still exists. The area fractions of carbides in each process are 4.96%,4.54%,5.05% and 5.08%. However,the accumulation of reticulated carbides at the intersection is still serious after the forging of ESR M2 high-speed steel. Its area fraction is higher than that of ingot cast M2 high-speed steel in the same process. The area fraction of carbide in the secondary forging of electroslag M2 high speed steel made by a domestic manufacturer and NACHI are 5.47% and 5.33% respectively. The carbides in M2 high speed steel forging billet are M₆C,MC and M₇C₃. The presence of M₆C and MC with large size and irregular shape in the matrix will have adverse effects on post-processing and finished products.