Research On Dry Tribology Property Of Nodular Cast Iron Micro-textured By Laser Peening

Based on the mechanical effect of laser peening(LP),micro-dents with different morphological parameters were fabricated on surface of a material,which can improve the friction and wear properties.Thereby,it is widely of great concerned in the field of friction and wear.In this paper,the ductile cast iron was used as the research material,micro-textured by LP,and the surface mechanical property was tested.The influence of micro-dent on the friction and wear properties of the material was studied by dry friction test and numerical simulation.The main work includes:(1)Based on the mechanism of LP,the influence mechanism of LP on the microstructure and mechanical properties of the nodular cast iron surface were discussed.On the ductile iron surface,the micro-dent array with different depth to diameter ratio and dent center distance was obtained by LP.The relationship between the LP energy and the micro hardness and residual stress of the textured surface was established.(2)The tribological characteristics of the textured surface under different process parameters(depth to diameter ratio,dent center distance)were analyzed by dry friction test.Based on the dry friction and wear theory,it was found that the dry friction performance of the textured samples with the center distance of 2mm and the depth to diameter ratio of 0.052 was the best.The dry friction and wear mechanism of the textured samples were studied by observing the wear surface morphology of the wear surface.(3)By comparing and analyzing the equivalent stress distribution and temperature distribution of the untextured and textured surface,in the reciprocating sliding wear process,we found that the stress concentration of the contact surface of the untextured was significantly larger than the textured surface.The average equivalent stress value of the textured surface was smaller than the untextured surface,and the stress concentration distribution was improved.The temperature rise of the untextured surface model was higher than the textured surface between the contact area,in the process of sliding wear,the temperature rise of the contact surface is serious,the temperature rise area was larger.The textured surface temperature is was generally lower than that of the smooth surface,and the surface temperature distribution condition can be improved without a large area temperature rise area.