The Effect Of Grinding Parameters On Surface Integrity Of Austempered Ductile Iron

Austenitic bainite ductile iron(abbreviate ADI)has high tensile strength,yield strength,excellent elongation.Due to the properties of ADI,it has been widely used in the fields required the high strength materials,such as engine crankshaft,spiral bevel gear and rear axle.Although the ADI is of great strength and high hardness,it is easy to get hardening and poor machining performance during processing,which may greatly affect the popularization and application of ADI.In order to obtain better grinding surface,it provides theoretical guidance for the grinding of ADI,the influence of grinding depth,grinding wheel speed and reciprocating velocity of workpiece on the surface roughness and surface hardening layer of ADI are studied in this paper.The results of the test are listed as follows:(1)For ADI at 280? and 380?,the speed of grinding wheel has the greatest influence on the roughness of the grinding surface,the influence of grinding depth is the second impact factor,the influence of the workpiece's reciprocating speed is the smallest one.(2)In order to obtain the minimum surface roughness,the optimal scheme of ADI at 280? is: (1=48m/s,=20um,(1=14m/min,and for ADI at 380?,the optimal scheme is: (1=48m/s,=20um,(1=4m/min.Besides,two optimization schemes were tested and verified.(3)In this paper,the changing law of grinding surface roughness with the speed of grinding wheel is studied.With the increase of grinding wheel speed,the sawtooth profile of the grinding surface of the two kinds of ADI is gradually weakened,and the wrinkling phenomenon in the topography is gradually weakened.(4)For ADI at 280?,the speed of grinding wheel has the greatest influence on the hardened surface of the grinding surface,the influence of grinding depth is the second,the influence of the workpiece's reciprocating speed is the smallest one.For the ADI at 380 ?,the reciprocating velocity of the workpiece has the greatest influence on the hardened surface of the grinding surface,and the influence of the grinding depth is the second.The effect of the grinding speed is minimal.(5)In order to get the minimum hardened layer,the optimal scheme of ADI at 280? is: (1=48m/s,=20um,(1=4m/min,and for ADI at 380?,the optimal scheme is: (1=4m/min,=20um,(1=30m/s.Besides,two optimization schemes were tested and verified.(6)For ADI at 280 ?,the retained austenite of austenitic ductile iron is approximately 10% before grinding.After grinding,the retained austenite content of the grind surface is almost zero.For ADI at 380?,the retained austenite content is about 26.2% before grinding.After grinding,the content of the retained austenite decreases with the increase of workpiece reciprocating speed.