(V) Case study- Residual Stress Analysis of Axle Housing banjo Before & After Straightening

Abstract

This study is carried out to understand the Behavior of Housing Banjo at Brake Flange Weld Location since the Brake Flange is one of the major member in Axle Housing which takes Braking Load. This member will undergo Fatigue Load, bending Load & Torsional Load Condition in its service. Straightening is one operation which cannot be avoided as welded Housing banjo experience the thermal cycles, exhibit warp characteristics. Hence some amount of Bending happens in the Housing Banjo. In this case study, Residual Stress is analyzed before Straightening Operation & after straightening operation at brake Flange Weld Location including No weld Zone. 2 Number of Housing banjo are taken for the Study. The Residual stress is measured using X- Ray Diffraction Method. The Observed value before straightening is -214 MPa & After Straightening is -159 MPa. There is Drop of 25% in Residual Stress. These Residual Stresses are Compressive in Nature. The Housing Half of banjo is undergoing the Shot Blasting operation after forming stage. These shot lasting induces some amount of Low magnitude Residual Stress on the Housing Half surface during the cleaning process. During straightening operation load is applied on the Banjo Surface all around near the brake flange area. The amount of force applied will determine the amount of loss of Compressive residual stress because straightening operation involves some kind of cold working on the material. The induced strain alters the stress level & its nature locally in the material during the straightening operation. The Study shows there is drop in Residual stress when material undergo mechanical working similar to Straightening operation on it. Since the Nature of stress is being compressive ,it is not alarming about the Part performance of Housing Banjo.