Research On In-situ Alloying Layer Construction Based On Stainless Steel Surface And Its Performance

Humans waste tens of thousands of tons of steel due to wear and corrosion every year,so how to protect materials from wear and corrosion has become a hot research topic today.At present,304 stainless steel has become a widely used steel because of its good corrosion resistance and heat resistance.At the same time,304 stainless steel also has its own shortcomings,making its adaptation to working conditions narrow.Therefore,this article considers surface treatment of 304 stainless steel,selects laser alloying technology,and uses metal Ta powder to form an alloyed layer on the surface of 304 stainless steel to achieve the purpose of improving its surface performance,which has important research significance.In this paper,laser alloying technology is used to construct in-situ Ta-based alloyed coatings under different laser parameters on the surface of 304 stainless steel to study the microstructure composition,hardness,wear resistance,and corrosion resistance of the prepared alloyed layers Wait.Use scanning electron microscopy,X-ray diffractometer and energy spectrum analyzer to study the structure and substance of the alloyed layer;use a microscopic hardness tester to test,record and analyze the hardness of the alloyed layer generated by laser alloying technology at different positions Hardness data,etc.;use the friction and wear tester to analyze the friction coefficient of the alloyed layer generated by the laser alloying technology and observe the friction and wear morphology,etc.;use the CS electrochemical workstation to analyze the corrosion curve of the alloyed layer generated by the laser alloying technology Analysis and observation of corrosion morphology,etc.Research shows:(1)In terms of composition and morphology: Ta-based alloyed coatings mainly contain Ta C,Fe Ni,γ-Fe,and Cr7C3.Its manifestation is a white block structure and white dendritic structure distributed longitudinally in the alloyed layer,and the size of the structure changes with the laser scanning speed and scanning power.In the alloyed layer,dendritic crystals are distributed longitudinally;clear white crystals are distributed on the upper part;only granular and linear crystals are distributed in the middle and lower part.(2)Hardness and friction and wear: According to the experimental results,it can be concluded that the average hardness of the alloyed layer is 3.43 times that of the 304 stainless steel substrate under the optimal process parameters(P=1000W;V=1.5mm/s).The influence of laser alloying gradually weakens with the increase of layer depth,the weight loss of wear is much lower than that of the matrix,which is about 50% of the matrix,and the friction coefficient is stable at ~0.45.And it can be seen that there are only relatively shallow friction marks on the surface of the alloyed layer,and a small amount of wear debris is found on the surface.(3)Electrochemical corrosion: Pitting corrosion occurs on the alloyed surface,and the corrosion current density measured by the electrochemical workstation is smaller than that of 304 stainless steel.It can be seen from the magnitude of the corrosion potential measured in the experiment that the corrosion potential of 304 stainless steel is higher than that of the alloyed layer.Therefore,during the corrosion process,the alloyed layer can protect the 304 stainless steel matrix from corrosion.Moreover,it can be seen from the corrosion morphology that the integrity of the laser alloyed stainless steel is obviously better than that of the stainless steel itself.The experimental results show that selecting appropriate process parameters,using laser alloying technology to prepare an alloyed layer on the surface of 304 stainless steel,increases the hardness,wear resistance and corrosion resistance of the stainless steel itself.Surface modification of 304 stainless steel can greatly reduce the cost of steel use and reduce the waste of steel to a certain extent.