Research On Estimation And Detection Of Remanufacturing Core And Process Quality For Drive Axle Housing

The paper takes automobile drive axle housing as object, through studied of drive axles’failure mode of a automobile axle company, analysed forging molding process, welding process, machining process, assembly process, material properties and technical requirements of drive axle housing, study remanufacturing engineering quality control and analysis techniques of theremanufacturing engineering discipline system, The work of this thesis is mainly reflected in the following aspects:According to the composition and function of drive axle, the statistical results of drive axle housing failure mode, research on domestic and foreign manufacturing quality control and engineering analysis methods, determine the research on the estimate and detection of remanufacturing core and process for drive axle housing content:the method of evaluating driving axle housing body micro-plastic damage, drive axle housing fatigue life assessment method and laser-pro welding quality evaluation method.Took drive axle housing’s body material—510L steel plate as tensile test specimens, Then stretched these test specimens to different plastic deformation to comprehensively evaluate the relationship between material’s plastic deformation rate and X-ray signals as well as magnetic signal with X-ray diffraction techniques and metal intelligent magnetic memory analysis techniques and scanning electron microscope, used scanning electron microscope to observe crystal structure variation characteristics of different plastic deformation rate, establish a510L plastic deformation rate and X ray diffraction peak width, intelligent magnetic memory signal curve, it can be used for evaluation of drive axle housing body plastic damage degree and local plastic damage, deformation alignment and other aspects, the method effectively solves micro-damage nondestructive evaluation problem.After the detection and analysis of plastic deformation, the specimen regained annealed treatment and the surface residual stress and X ray diffraction peak width by X-ray are analyzed. Samples surface have larger residual stress after heat treatment. Since reinforcement service stage, diffraction peak width gradually increased with the increase of plastic deformation, variations in the range of2.34-2.59. the diffraction peak width changes are mainly caused by grain refinement. Basing on the plastic deformation of sample heat treatment, microscopic stress on material strength effect are eliminated and the stability of mechanical properties are guaranteed.The neural network life prediction model of drive axle housing is built. Analysis of the method determine input layer, hidden layer and training functions; find characteristic parameter extraction method for drive axle housing residual lifetime prediction. In the instant analysis, took the deformation, residual stress and the gradient of magnetic intensity Kmax relating to axle housing’s fatigue damage as the input of neural network. The result demonstrates that:the deformation, residual stress and the gradient of magnetic intensity Kmax of axle housing as the characteristic parameter estimating the degree of fatigue damage, adopting trainbr training function can get good network performance and high precision of prediction.In order to intuitive analysis of laser-pro welding heat conduction, establish the method of the simulation of laser-pro welding heat conduction by finite element analysis software ABAQUS, the welded surfacing layer were prepared on the axle tube of drive axle housing with H13CrMoA. In order to study the stress distribution of layer along the depth direction, polishing the layer, detected residual stress, and observed welding layer, welding interface, heat affected zone microstructure by scanning electron microscope (SEM). The result demonstrates that:The heat affected zone of laser-pro welding are smaller; residual stress of the layer first increase and then decrease along the depth direction,320MPa near the fusion line; the welded surfacing layer has good fusion with base material, uniform structure, does not exist cracks, holes and other defects.