摘要
DC53钢用于制作粉未冶金压坏模具,用电火花加工模具型腔,由于电参数不佳和冷却不充分,在型腔表面产生很厚的白亮层,导致模具早期疲劳破裂。白亮层的本质是纳米晶淬火马氏体,晶格畸变大,内应力大;另一方面,模具几何尺寸如尖角效应,也产生局部应力集中。因此,在模具型腔所有尖角处,都有两种内应力叠加,致使模具在所有尖角处都产生裂纹,形成多源疲劳断裂。
DS53 steel is used to manufacture the shape-pressing die via the method of powder metallurgy where the mold cavity of the die is machined by electric spark machining.In this process,a thick white layer appears on the surface of the mold cavity due to improper parameters and cooling,thus leading to early fatigue fracture.The white layer is practically nanocrystalline quenched martensite with great lattice distortion and internal stress.On the other hand,the closed angle effect of the die dimensions also results in localized stress concentration.So there exists the superposition of two forms of internal stresses at the closed angle of the mold cavity,where there arise cracks and multi-origin fatigue fracture.
出处
《金属热处理》
CAS
CSCD
北大核心
2007年第z1期340-342,共3页
Heat Treatment of Metals
关键词
白亮层
尖角
疲劳断裂
型腔
纳米晶
淬火马氏体
电火花加工
white layer
closed angle
fatigue fracture
mold cavity
nanocrystalline
quenched martensite
electric spark machining