Investigate on distribution and scatter of surface residual stress in ultra-high speed grinding

Abstract

The purpose of this study is to investigate the residual stress induced by ultra-high-speed grinding of difficult-tomachine materials considering the thermomechanical coupling effect that is generated due to the friction between diamond tool and workpiece's surface. A three-dimensional finite element method taking the rotational motion of tool into account is proposed. The simulation consists of three operations including loading, unloading, and cooling. The influences of different grinding conditions (grinding speed and grinding depth) on the residual stress field are analyzed. Results show that the main grinding force comes from normal rather than tangential direction due to the tool's negative rake angle and their ratio is in the range of 1.2 to 1.7. The residual stress state on the finished surface is either tensile or compressive depending on various grinding condition; even both states may exist simultaneously. Further study shows that the ultra-high speed grinding can obtain lower surface residual tensile stress comparing with the high-speed grinding. Besides, a larger grinding depth is not advantage for obtaining a better machined quality in subsurface layer as the tensile maximum principal stress is also larger. Finally, the effects of different grinding conditions on residual stress scatters are analyzed utilizing mathematical statistic method. Results show that both smaller grinding depth and higher grinding speed are beneficial to achieve a better consistency of residual stress.

Review on grinding-induced residual stresses in metallic materials

“…Furthermore, based on the simulated grinding work of 40Cr steel with single abrasive grain, Fang and Zhang [125] reported that either tensile or compressive residual stress exists along the grinding direction on the finished surface depending on the different grinding conditions; especially, the compressive or tensile residual stresses may exist simultaneously. Compared with the high-speed grinding (i.e., wheel speed of 60∼120 m/s), the ultra-high-speed grinding (i.e., wheel speed of 180 m/s) could produce compressive residual stress or lower tensile residual stress on the machined surface; meanwhile, the residual stresses along the depth below the Fig.…”

The Metal Surface Layer Mechanical Condition Transformation in Machining Processes

“…Currently, the surface layer (SL) predominant role in ensuring the machine parts durability is generally recognized [1][2][3][4][5][6][7][8][9][10][11][12][13]. Especially the part surface layer, which forming throughout the manufacture technological process, receives the greatest loading during operation.…”

Residual Stresses Distributions in Grinding of 3J33 Maraging Steel with Miniature Electroplated CBN Wheel

“…Influences of grinding parameters on residual stresses have been studied in terms of wheel speed, workpiece speed, cutting depth, material removal rate, wheel characteristics, dressing conditions, and material conditions [4]. It is recommended that generation of residual stress is the result of various mechanical and thermal effects occurring at the machined surface region during grinding.…”

“…Ding et al [5] found that the values of the compressive stresses are decreased with the increase in depth of cut in creep feed grinding with brazed CBN Wheels. Chen et al [4] observed that ultra-high-speed grinding can obtain lower surface residual tensile stress than high-speed grinding. Brinksmeier et al [6] concluded that the increase in depth of cut and/or grinding speed increase the magnitude of tensile residual stresses.…”