Study On Mechanical Property Prediction Model And Wear Mechanism Of Austempered Ductile Iron

Wear is the main failure form of agricultural tillage components,causing huge economic losses.Wear resistance is an important index for evaluating the quality of agricultural machinery.About 80%of the failure of agricultural machinery parts is caused by wear.In view of this problem,the research topic adopts Austempered ductile iron material,uses heat treatment modification technology to improve the wear resistance of Austempered ductile iron,designs two-step isothermal quenching test of Austempered ductile iron by orthogonal test,and studies the relationship between heat treatment parameters and mechanical properties of Austempered ductile iron.The main research contents are as follows:1.Nonlinear relationship and wear mechanism of Austempered ductile iron.(1)The heat treatment process of two-steped austempering was formulated for austempered ductile iron.The main process parameters included one-steped austempering temperature,one-steped austempering time,two-steped austempering temperature and two-steped austempering time.The tensile strength,Rockwell and wear weight loss of austempered ductile iron after heat treatment were obtained by orthogonal experimental design.(2)Based on the experimental data,a BP neural network model was constructed to describe the non-linear relationship between four heat treatment parameters and hardness and tensile strength of Austempered ductile iron.The results showed that the predicted results were within a reasonable range,which indicated that the established neural network model had high prediction accuracy and can provide guidance for the heat treatment process of austempered ductile iron.(3)Loose abrasive wear tests were carried out on the samples of austempered ductile iron after austempering.The results showed that the optimum heat treatment parameters for wear resistance of austempered ductile iron were as follows:one-steped austempering temperature 300 ?,one-steped austempering time 15min,two-steped austempering temperature 340 ? and two-steped austempering time 50min.The range analysis of orthogonal experimental design results showed that the order of influence of each parameter was one-steped austempering time?two-steped austempering temperatur?one-steped austempering temperature?two-steped austempering time.In the abrasive wear experiment,the wear mechanism of austempered ductile iron is mainly micro-cutting and multiple plastic deformation wear.