| The short stress path rolling mill is one of the core mechanical and electrical equipment widely used in the steel manufacturing industry,and its application service failure is mainly due to the reduction in the accuracy of the rolling mill system caused by the excessive size of key components caused by fretting corrosion and wear.China is the country with the largest number of waste short stress path rolling mill in the world,among which there are more than tens of thousands of waste mills are caused by parts failures,resulting in huge waste of resources.Laser remanufacturing technology is a kind of green repair technology,which is characterized by saving resources and protecting the environment.It can make key parts of rolling mill equipment become new products after repairing and remanufacturing,and achieve the purpose of replacing the old with the new.However,at present,the alloy powder and preparation technology that can meet the laser repair of key parts of fretting corrosion and wear resistance are still lacking,which restricts the industrial application of laser remanufacturing the short stress path rolling mill.Therefore,the research on the composition design and microstructure and properties of laser remanufactured wear-resistant and corrosion-resistant nickel based alloy coating has great scientific research significance and extensive practical application value.This paper is based on the core problems of laser remanufacturing of the guide beams of the key parts of the short stress path rolling mill,which requires new alloy powders with high wear resistance and corrosion performance.The working environment and failure mechanism of the guide beam of the rolling mill are analyzed.Based on the material design idea of performance-organization-composition,the composition of laser remanufactured material for the guide beam of rolling mill is determined.The microstructure,phase type and content of the alloy are simulated and designed by JMatPro software,and the experimental verification is carried out to optimize the alloy composition design.The microstructure,phase composition,morphology and precipitate phase of the cladding layer were systematically studied by XRD,SEM,TEM,EBSD and other characterization methods.The mechanism of the influence of microstructure and energy density on the microhardness,high temperature wear and chloride ion corrosion resistance of the cladding layer was analyzed.The experimental results shows that the NiCrFeWBSiMo-CeO2 alloy optimized by JMatPro software has good formability based on the high temperature and high humidity of the rolling mill and the failure mechanism.The cladding layer has no defects such as cracks and metallurgical bonding with the matrix.The top of the NiCrFeWBSiMo-CeO2 laser cladding layer is dendritic or nearly equiaxed,while the middle and lower regions form columnar crystals.The ?-Ni phase is the main phase of the cladding layer,and simultaneously forms CrB,Cr3Ni2Si,Ni3Fe,W2C and(Fe,Cr)23C6 phases.When the energy density is 95.0 J/mm2,the average hardness of cladding layer is 590±23 HV0.2,the weight loss of reciprocating wear is 1.1 mg,and the self-corrosion current density is 2.31×10-6 A/cm2,the coating has good corrosion resistance.With the increase of wear temperature from 0? to 600?,the coefficient of friction and wear rate of the cladding layer decreases gradually.When the wear temperature is 600?,the coating layer of NiCrFeWBSiMo-CeO2 undergoes oxidation wear,adhesion wear and abrasive wear.The friction coefficient and wear rate are the lowest,which are 0.185 and 1.07×107 ?m3,respectively,with good high temperature wear resistance.The laser cladding remanufacturing test was carried out on the 1:5 scale parts of the guide beam of the short stress path rolling mill,it is proved that NiCrFeWBSiMo-CeO2 alloy can meet the requirements of laser cladding remanufacturing of the guide beam of the rolling mill,which lays a research foundation for laser remanufacturing of the key components such as the guide beam of the rolling mill. |
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