预应力淬硬磨削加工表面微观形貌仿真与实验

Simulation and Experiment of Micro-surface in Pre-stressed Hardening Grinding Process

为了揭示预应力对磨削淬硬过程及表面微观形貌的影响机理,根据热弹塑性有限元理论,在不同大小的预应力作用下,以45钢试件为研究对象,使用DEFORM-3D进行单磨粒切削仿真,并结合预应力淬硬磨削实验,对等效应变、沟槽深度、表层微观组织及表面微观形貌进行分析.研究表明:施加预应力对热-机械等效应变影响较小,对微观组织转变影响明显,进而影响位错密度和晶粒体积,间接影响表面粗糙度;在预应力取值较小时,随着预应力增大表面沟槽深度减小,有利于减小表面粗糙度值,但在预应力超过某一数值后,会引起表面褶皱,反而使表面粗糙度数值增大.

To reveal the effect of pre-stressing on grinding hardening process and micro-surface, single grain cutting simulations on test specimens made of 45 steel under action of different pre-stresses were carried out by using DEFORM-3D based on the thermal-elastic-plastic finite element theory. The equivalent strain, groove depth, surface layer microstructure as well as the micro-surface were analyzed by simulation and experiment of pre-stressed hardening grinding process. The results indicate that pre-stressing has little effect on thermal-mechanical equivalent strain, but has obvious effect on microstructure transformation which has indirect effect on surface roughness by affecting the dislocation density and grain size. As the pre-stress increases within a low range, the groove depth decreases and the surface roughness value reduces. However, once the pre-stress exceeds a certain value, surface fold appears and surface roughness value increases instead.