Fatigue behavior improvement of hardened parts using sequential hard turning, grinding, and ball burnishing operations

Abstract

One of the major problems encountered in hardened components such as roller bearings, which work under fatigue loading conditions, is that the requirement of higher surface finishes (≈0.15 µm Ra) cannot be achieved by the sequential hard turning and ball burnishing processes. Such high surface qualities can be generated by additional finishing operations such as grinding. However, despite the improvement in the surface roughness, the grinding process increases both the tensile surface residual stresses and crack initiation sites on the ground surface; therefore, the fatigue behavior of the component may deteriorate. In this study, the effects of adding a grinding operation before the ball burnishing process on the fatigue behavior of AISI 4130 steel were experimentally studied. According to the achieved results, the burnished pre-ground samples show a considerable reduction in the final surface roughness and, at the same time, higher microhardness, higher endurance limit, and smaller area of the fatigue cracking zone. The burnished pre-turned and burnished pre-ground samples showed 4.24% and 10.95% improvements in the endurance limit compared to that of the turned samples, respectively.

Effect of non-zero mean stress bending-torsion fatigue on fracture surface parameters of 34CrNiMo6 steel notched bars

“…Fonte et al (Fonte et al, 2007) showed results for the fatigue crack surface roughness Ra and Rz according to ISO 4287 (ISO, 1997) with the fatigue crack propagation direction at the center of fracture surface. Although similar roughness results were achieved at the center and at the both sides of the fracture, areal surface Sx parameters according to ISO 25178 (ISO, 2012;Arsalani et al, 2020;Yang et. al., 2019) give complete information because a single line cannot identify pits or valleys and show the relationship between surface function, as confirmed by Stach et al (Stach et al, 2017).…”

The effects of hard turning and deep rolling on surface integrity and fatigue life of deep groove ball bearings

“…The compressive residual stresses provide an additional protection against surface-initiated spalling [5]. Therefore, the compressive stresses are desired to form instead of tensile stresses on raceways of bearing rings since they improve the fatigue life [6,7]. L50 theoretical life value (average life) determined using MESYS Rolling Bearing Calculation program under above-mentioned test conditions and lubrication parameters was found to be 431 hours.…”

“…It is well-known that hard turning processes in which cutting inserts with negative rake angle are employed produce the compressive stresses. Unlike compressive stresses, tensile stresses have a negative effect on fatigue life of machinery components as they lead to the crack initiation and rapid crack propagation [4][5][6][7][8]. They can occur in aggressive grinding conditions due to thermal shocks.…”

Experimental investigation and estimation of compressive residual stress of ball burnished rare earth based magnesium alloy

“…For instance, the TRS of 1223 MPa formed during turning of AISI 4130 steel has been transformed into CRS of −223.7 MPa by deploying ball burnishing process. 15 Also, it has been observed that the ball burnished surface delayed the fatigue crack propagation in stress concentration zones, thereby improving the fatigue strength drastically. 16 In recent times, machine learning techniques have become quite popular in modelling complex engineering problems precisely and are being regarded as a substitution for classical modelling methods.…”