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疲劳断裂和崩刃是Cr12MoV模具钢冲头在服役过程中的主要失效方式,为此,对失效冲头的硬度、显微组织和失效形貌进行了测试和观察。研究发现马氏体基体中析出的粗大的或者连续分布的碳化物导致了应力集中,进而导致冲头的疲劳性能和断裂韧性下降。对冲头进行调质处理,碳化物明显细化,且弥散分布,提升了冲头的使用寿命,此时冲头的失效方式主要为磨粒磨损。为了进一步提升冲头的寿命,在调质处理后的冲头表面采用真空阴极弧离子镀的方法沉积了AlCrTiSiN涂层。与调质处理的冲头相比,沉积AlCrTiSiN涂层冲头的寿命延长了50%左右,这主要是因为AlCrTiSiN涂层具有高的硬度和低的摩擦因数。
Fatigue fracture and chipping are the main failure modes of Cr12MoV die steel during service. Therefore, the hardness, microstructure and failure morphology of the failure punch were tested and observed. It is found that the coarse or continuous carbides precipitated in the matrix of martensite lead to stress concentration, which leads to the decrease of fatigue property and fracture toughness of punch. The punch quenched and tempered, carbide significantly refined, and the dispersion of the distribution, improve the service life of the punch, punch the main failure mode abrasive wear. In order to further improve the life of the punch, the surface of the quenched and tempered punch is deposited by vacuum cathodic arc ion plating on the AlCrTiSiN coating. Compared with the quenched and tempered punch, the life of the deposited AlCrTiSiN coated punch is increased by about 50%, mainly due to the high hardness and low friction coefficient of the AlCrTiSiN coating.