Response Of Material Composition To Laser Remelting Biomimetic Treatment Of Iron Based Alloy And Property Characterization

The emergence of laser remelting bionic surface processing technology has effectively solved the problems of wear and fatigue of alloy steel parts.Previous studies have shown that the laser biomimetic machining technology can achieve the optimal wear resistance or fatigue resistance of a certain alloy steel material,which corresponds to an optimal laser parameter.The standard of the optimal laser processing parameters is that the hardness and depth of the unit can be larger,and the surface roughness of the processed bionic sample cannot be too large to affect its application in industry.Therefore,the key of laser melting biomimetic machining technology is to select appropriate laser processing parameters to obtain the required unit characteristics and mechanical properties.However,there are many kinds of alloy steel materials and different service environments.The research on laser biomimetic modification of a certain alloy steel material is time-consuming and laborious,which affects the actual production demand of laser biomimetic technology and restricts the development of laser biomimetic processing technology to a large extent.Therefore,the urgent problem to be solved is: given a certain alloy steel material,can we find out the corresponding laser processing parameters when the alloy steel material reaches the optimal target performance according to its material composition.Therefore,it is necessary to study the influence law among material composition,laser processing parameters and target performance,and the response of alloy steel composition to laser melting biomimetic treatment,so as to provide theoretical guidance for the application of Laser Biomimetic processing of different kinds of alloy steel materials.In this paper,five kinds of alloy steel materials,40 Cr,40Cr Ni Mo,5Cr Ni Mo,B2,H13,which are commonly used in industrial production,are selected as the research objects.With the help of the idea of coupling bionics,the striated unit structure is machined on the surface of the alloy steel by laser melting and solidification technology.The difference of the characteristic quantity,structure and hardness of the alloy steel with different composition after laser melting was analyzed.The response of the composition to the characteristic quantity and hardness of the unit after laser melting and biomimetic treatment was studied.Secondly,the response of the alloy steel with different composition to the wear and fatigue properties after the bionic treatment was analyzed.Finally,the change rule of the alloy steel material composition with the laser processing parameters under the most wear performance was studied in a certain range of laser processing parameters.Research shows:(1)The laser peak power density and material composition have influence on the characteristics of the cell.Under different laser peak power density,with the increase of laser peak power density,the cross-sectional depth of the cell of five alloy steel materials increases,and the surface roughness of the cell also increases.Under the same laser peak power density,the cell depth increases with the increase of carbon equivalent with the increase of carbon equivalent,the surface roughness decreases.(2)At the same peak power density of laser,the unit structure of laser melted steel is very different from that of matrix.The unit structure of alloy steel with five different components is composed of martensite,austenite and carbide.With the increase of carbon equivalent,the refining degree of unit grain increases.The hardness of the unit increases with the increase of carbon equivalent.(3)After laser melting and biomimetic treatment,the wear resistance and thermal fatigue resistance of five alloy steel materials have been improved.With the increase of carbon equivalent,the wear resistance and thermal fatigue of the samples are also increased.The increase of microhardness of the unit is beneficial to the improvement of the wear resistance and thermal fatigue resistance of the material.Among them,the wear resistance of five bionic samples increased to 40Cr(42.3%)> 40 Cr Ni Mo(34.6%)> 5CrNiMo (26.8%)> B2(25.4%)> H13(19.89%).