材料期刊网

目的：硬脆性材料在珩磨时的脆性去除会使得被加工件的表面质量达不到更高的应用要求，同时对磨具磨损严重，通过理论建模研究珩磨过程中单磨粒磨削参数与切屑第一变形区流动应力的关系，并得到实现延性去除的各参数阈值。方法针对304不锈钢，通过对单磨粒划擦的分析，数学推导得出在平面情况下切屑第一变形区流动应力与单磨粒刃圆半径、磨削深度以及半圆锥角的函数关系。结果在完全刃圆磨削和复合磨削阶段都会有实现材料延性去除的现象被发现，并得到完全刃圆磨削时，取刃圆半径r=1μm，在磨削深度h=0.07μm，流动应力取得极大值σ=227.7 MPa。复合磨削时，取半圆锥角θ=30°，r<1.5μm时，r的延性去除阈值为0.3~1μm。当取h=0.6μm，θ和r同样存在实现材料延性去除的阈值，分别为45°~75°和0.5μm左右。结论单磨粒刃圆半径、磨削深度和半圆锥角使材料实现延性去除的阈值范围在理论上被确定，为硬脆性材料的延性去除理论的进一步研究提供参考。同时适当减小磨粒刃圆半径，取45°~75°范围内的磨粒半圆锥角，使磨削深度增大，并实现材料的延性去除，可以提高材料的表面质量和磨削效率。

ABSTRACT:Objective Brittle removal of hard-brittle material in honing will lead to failure of the workpiece surface quality to meet higher application requirements, and cause serious abrasive wear at the same time. This paper aimed to study the relation-ship between the grinding parameters of single grain and flow stress in the first deformational area of chip in the honing process through theoretical modelling, and get the threshold of parameters in ductile removal.Methods For the 304 stainless steel, through analysis of the abrasive scratch caused by single grain, the function relationships between the flow stress in the first deformational area of chip and the single particle edge radius, the grinding depth and the semi cone angle in the plane case were derived by ma-thematics. Results The ductile removal for material was found in the complete edge grinding and the composite grinding stage. In complete edge grinding, under the condition of edge radiusr=1μm and grinding depthh=0.07μm, the flow stress reached its max-imum value ofσ=227.7 MPa. In composite grinding, under the condition of semi cone angleθ=30° andr<1.5μm, the ductile re-moval threshold wasr=0.3~1μm;whenh=0.6μm, the thresholds ofθ and r to achieve the ductile removal for material also ex-isted, which were 45°~75° and about 0.5μm, respectively.Conclusion The threshold ranges of single abrasive grain edge radius, the grinding depth and semi cone angle for the ductile removal of material were determined in theory, which provides reference for the further study of the ductile removal theory in hard-brittle material. At the same time, the edge radius of grain should be appro-priately reduced, and the semi cone angle should be set in the range of 45°~75°, so as to increase the grinding depth, realize the duc-ticle removal of material, and improve the surface quality and the grinding efficiency of material.