Study On Optimization Of Laser Cladding 0.3C-18Cr Alloy Coatings On 3Cr14 Stainless Steel Surface

3Cr14 stainless steel alloy content is low,the manufacturing cost is low,with a certain degree of corrosion resistance.However,the use performance is poor in a comprehensive environment requiring high hardness,high wear resistance,and corrosion resistance.To make its application more extensive,laser cladding technology is used to prepare alloy coatings with excellent wear resistance,corrosion resistance,and oxidation resistance on the surface.Laser cladding is an effective surface modification technology for preparing excellent performance coatings.It has been widely used in important fields such as mechanical processing,automobile manufacturing,aerospace,mold manufacturing,and national defense weapons.There are still defects such as poor quality of the cladding layer,porosity and cracks in the cladding layer.The selection of the process parameters and the composition of the alloy powder in the laser cladding process have a direct influence on the quality and performance of the laser cladding coating.In this paper,orthogonal experimental design is used to select the optimal cladding process parameters for laser cladding of 0.3C-18Cr alloy powder;by adjusting the content of Ni and Si elements in 0.3C-18Cr alloy powder,the content variation of Ni and Si elements is investigated for cladding.The effect of layer structure and performance;using an optimized laser cladding process to prepare a composite powder coating with different contents of Y₂O₃,and the following conclusions were obtained through inspection and analysis:?1?Orthogonal test method was used.The best process parameters of laser cladding 0.3C-18Cr alloy powder were determined by range analysis method:laser power P₁,scanning speed V_g2,feed rate V_f3,protective gas flow Y MPa.After adopting the best cladding process,the microstructure of 0.3C-18Cr alloy cladding layer is intragranular massive ferrite+small amount of martensite+upper bainite distributed along the grain boundary.The average microhardness of the clad layer prepared using the best clad process is 120 HV0.2 higher than that of the clad layer prepared using the worst clad process.?2?In the range of 0.5%to 3%Ni addition,with the increase of Ni content,the?-ferrite of the massive dendrite growing along the grain boundary in the cladding layer structure is significantly reduced and dispersed.And gradually disappeared.The microstructure of the cladding layer consists of dendritic?-ferrite distributed along the grain boundary,intragranular?-ferrite+partial lath martensite,low-carbon martensite,and small residual lumps of?-ferrite.When Ni content is 1%,the microhardness of the cladding layer is the highest,which is mainly due to the transformation of bulk or strip ferrite to low-carbon martensite,and the martensite lath bundle is small and dense.?3?In the range of 0.5%to 2%Si,with the increase of Si content,the microstructure of the cladding layer consists of a large number of lath martensite and residual austenite to intragranular?ferrite+plate martensite+grain boundary dendritic?-ferrite transformation.When the Si content reaches 3%,the microstructure of the cladding layer is composed of lath martensite and a small amount of carbide precipitated along the grain boundary.At this time,the microhardness of the cladding layer is the highest,and the average microhardness increases when the specific Si content is 0.5%.250 HV0.2.?4?After adding Y₂O₃,the dendritic length of the cladding layer decreases and the number of dendrites decreases.The porosity of the cladding layer decreases and the cladding layer becomes denser and more uniform.The cladding layer without Y₂O₃was composed of intragranular ferrite+upper bainite distributed along the grain boundary and a small amount of martensite.After adding Y₂O₃,the cladding layer was composed of lath martensite and grain boundary.Body composition;Y₂O₃ addition promotes the formation of martensite in the cladding layer,and with the increase of Y₂O₃ content,the lath martensite is slightly roughened,the amount of bainite is obviously reduced,and the carbon concentration of bainite carbide is increased.The large,lamellar carbide types are converted from low-carbon carbides to high-carbon carbides.?5?After adding Y₂O₃,the hardness of the clad layer increases significantly.When2%Y₂O₃ is added,the 0.3C-18Cr alloy clad layer has the best hardening effect,and the highest microhardness is 160 HV0.2 than that without Y₂O₃.When the addition amount of Y₂O₃ exceeds 3%,the strengthening effect is reduced due to the coarsening of martensite laths.