不同制备工艺对锻造高速钢轧辊组织和性能的影响

采用光学显微镜、扫描电镜、X射线衍射仪、洛氏硬度计和磨损试验机对比研究了电渣重熔、喷射成形以及粉末冶金工艺生产的锻造高速钢轧辊的组织性能。结果表明,采用电渣重熔工艺所得锻造高速钢轧辊组织中存在明显沿锻造方向分布的网状共晶碳化物,碳化物尺寸粗大,分布不均,导致其耐磨性最差;喷射成形工艺所得锻造高速钢轧辊网状碳化物组织得到明显改善,但局部区域碳化物偏聚较严重,碳化物尺寸较大且主要以M₆C型为主,其耐磨性比电渣重熔工艺有明显提升;粉末冶金工艺所得锻造高速钢轧辊组织晶粒细小,碳化物细小且弥散均匀分布,碳化物类型中MC型占比很高,表现出最优的耐磨性能。根据3种制备工艺下的组织和性能分析,并结合目前3种制备工艺的成熟度、经济性和制造能力,未来可对喷射成形工艺做进一步研究,并逐步在较大规格锻造高速钢轧辊中推广应用。

Effect of different preparation processes on microstructure and properties of forged high-speed steel roll

Microstructure and properties of the forged high-speed steel roll produced by electroslag remelting, spray forming and powder metallurgy were investigated by means of metallographic microscope, scanning electron microscope, X-ray diffractometer, Rockwell hardness tester and wear tester. The results show that there are obvious eutectic carbide network with large size and uneven distribution along the forging direction of the forged high-speed steel roll produced by electroslag remelting, which leads to the worst wear resistance. The carbide morphology of forged high-speed steel roll produced by spray forming is obviously improved, but the carbide segregation in local area is serious, the carbide size is large and mainly M₆C type, but its wear resistance is obviously improved compared with electroslag remelting process. Using the powder metallurgy technique, the microstructure and grain size of the forged high-speed steel roll are fine, the carbide is fine and evenly distributed and the MC type has the higher percentage, which leads to the highest wear resistance. Based on the analysis of the microstructure and properties, and also the maturity, economy and manufacturing capability of the three preparation processes at present, the spray forming process could be further studied in the future and enlarge the application in the forged high-speed steel roll with larger size.