| One of the prospects of the development in the field of laser bionics technology is to realize the intellectualization of automatic matching between parameters and forming targets during the laser processing of imitation products so that to strengthen the wear resistance and other properties of material surface.Currently,lots of remarkable and positive results has achieved on the technology of laser bionic processing.However,owing to the kinds of die steel,the units are different along with the difference of the matrix material composition,state and laser processing parameters,plenty of experiments about orthogonal,optimization and evaluation were carried out frequently for the most appropriate laser processing parameters which could obtain appropriate unit and effectively improve the wear resistance and other properties of materials.So,based on above process is inefficient,which limits the target of on-demand machining of biomimetic surfaces and delays the laser development process on the material.At present,the key to the development of laser bionic intelligent processing technology is the selection of processing parameters.Specifically,the corresponding parameters can be automatically matched for selection on the basis of the shape and the properties of the units.Therefore,it is very important to find out the relationship model among the material,processing parameters and target characteristic parameters of molding,change the previous complex process model,and develop the database system that integrates unit forming,prediction of forming results,query of machining parameters and optimization selection.Meanwhile,,matching the parameters required by the characteristic quantity of unit intelligently according to the difference service conditions of various die steels is significant to accelerate the development of laser materials,improve the efficiency and reduce the testing process.In the study,40Cr,B2,H13,H12,5CrNiMo repair welding steels with different chemical compositions contents and H13 steels with different matrix structures were used as experimental objects to be processed biomimetic coupling surface with different unit respectively by laser remelting.Firstly,the differences in size,microstructure,grain size and hardness between units under various parent metal components were compared and analyzed,and the influences rule and mechanism of the chemical composition content of parent metal on the characteristic parameters of the unit were studied.The variation rules of unit area,depth-width ratio and hardness with the ratio of total alloy element content to carbon content of the alloy steel under five energy densities were fitted,respectively.And the corresponding mathematical models were established respectively,meanwhile,the quantitative relationship between the component content of die steel and the characteristic parameters of the unit was obtained under a certain range of parameters conditions.Secondly,the differences in size,microstructure,grain size and hardness among the units with various parent metal microstructure states were compared and discussed.Furthermore,the influencing mechanism of the microstructure state of the die steel on the units'characteristic parameters were explored,and the relationship model among the die steel,processing parameters and the characteristic parameters of the forming target was improved.At the same time,the influence of different chemical composition content and microstructure of die steel on the unit's characteristic parameters was discussed,and the corresponding effect on the wear resistance of bionic coupling surface was analyzed.Finally,a laser processing database system was preliminarily developed,which matches the units'characteristic parameters and corresponding parameters of different die steel,and the database application program interface was designed and manufactured.The results show that:(1)under the same energy density,with the increase of the ratio of gold to carbon,the depth,area and depth-width ratio of the unit increase,while the width decreases;The grain size of the unit decreases first and then increases,and the hardness of the unit increases first and then decreases,and both of them showed a turning point at the gold-carbon ratio 20.62.Meanwhile,the hardness and wear resistance of steels with different compositions were improved to varying degrees when the laser processed energy density was 841.438 J/cm~2.Specifically,the hardness was increased by 53.26%(40Cr)>46.82%(B2)>14.58%(H13)>7.16%(H12)<12.65%(5CrNiMo repair welding steel),respectively.The wear resistance was increased by 15.7%(40Cr)>13.43%(B2)>3.83%(H13)>2.30%(H12)<3.45%(5CrNiMo repair welding steel),respectively.In a word,the degree of improvement in wear resistance increases with the increase of unit's hardness.(2)The cross-sectional area and grain size of the units both were enlarged,while the degree of hardness improvement was reduced with the increase in the austenite nucleation ability of the substrate microstructure of H13 steel,under the same laser processing parameters conditions.The hardness of the unit rank as:annealing>quenching>tempering at 460oC>tempering at 600oC.Meanwhile,the micro-hardness and the corresponding wear resistance of H13 steel with different microstructures were also improved to varying degrees.The hardness of the unit was increased by 165.57%(annealed state)>7.22%(tempering at 460oC)>1.61%(tempering at 600oC)>0.35%(quenched state);The wear resistance of bionics coupling samples was increased by 39.10%(annealed state)>5.13%(tempering at 460oC)>3.97%(tempering at 600oC)<5.21%(quenched state),respectively.In other words,the hardness and size of the bionic unit positively affected the degree of wear resistance improvement. |
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