Enhancement of Fatigue Strength on SAE 1541 Steel Link Plate with Slip Ball Burnishing Technique

Abstract

This research paper describes a technique for the enhancement of the fatigue strength of the chain link plate in the drive system of a military armoured vehicle. SAE 1541 steel link plates of chains were subjected to cyclical tensile stress due to repeated loading and un-loading conditions. The crack was getting originated from the pitch hole and growth perpendicular to the chain pulling load, due to fatigue mechanism. In general plate holes are manufactured using the conventional process. An additional novel technique called the slip ball burnishing (SBB) method is applied for improving the hole properties. The improvement is made by producing local plastic deformation, improving surface finish and compressive residual stress throughout in the pierced hole. Both the conventional process (CP) and the SBB technique have been evaluated by optical, profile, surface roughness and micro harness tests. Experimental fatigue test validations were done in both chain samples using the Johnson-Goodman method. SBB chains passed 3x106 cycles at the load of 17.61 kN and CP chains passed 3x106 cycles at the load of 13.92 kN. The conclusion was that SBB made a significant improvement of 26.51 per cent of fatigue strength compared to CP.