Sdudy On The Structure And Performance Near The Interface Of Samples Fabricated By Laser Remanufacturing Technology

All of laser processing technologies that used to repair wearing parts with highenergy laser beam are called laser remanufacturing technology, and the laser claddingremanufacturing technology is researched and used most widely at present. Theprocess engineering of laser cladding remanufacturing technology is that placing thecoating material on the surfaceof part in various ways, subsequently, utilizing highenergy laser beam to irradiate the coating until the material of the coating and thesubstrate is melted entirelym, the high-performance cladding layer that possessing thelow dilution rate and metallurgical bonding with substrate to come into being as aresult of the molten metal fast-solidifying.Refered to the application situation of the laser cladding remanufacturingtechnology in production combined with the metallurgical processes and evolvementrule of the molten metal, we developed five different composite powder used for laserremanufacture wearing parts through adding compound and alloy powder in the304stainless steel, and built the preparation system of the composite powder at the sametime. In this paper, samples of five different composite powder were prepared by lasercladding technology, and the structure and performance near the interface of sampleswere analysed with experimental method.Specifically, the section defect of cladding layer was calculated qualitatively andquantificationally used metalloscope; The microstructure morphology of claddinglayer and substrate close to interface was observed under scanning electronmicroscope, and the element diffusion of interface was analysed in the same way; Thehardness changing law of cladding layer and substrate near interface withmicrohardness tester; The bonding strength of interface and the tensile strength ofsubstrate near interface were measured by universal testing machine; The wear-resisting property of cladding layer was researched qualitatively andquantificationally by means of wear tester.The experimental results show that, The fusion layer whose wide changedbetween5μm to10μm produced at the interface of cladding layer and substrate durigthe laser cladding process，the existence of the fusion layer not noly allow thecladding layer metallurgical bonding with substrate, but also prevent the diffusion ofalloying element at the interface resulted in the dilution rate reduced. If CH compoundand borax added to304stainless steel powder，the microstructure, bonding strengthand abrasive resistance of cladding layer will remain about the same, but oxideinclusion generation on the surface of cladding layer reduced significantly and theformation ratio of internal defect fell by59.2%, in addition the hardness of claddinglayer best enhanced by7.71%. When Ni6OA alloy powder mixed with304stainlesssteel powder，the crystalline grain of cladding layer refined obviously, and thehardness, bonding strength and abrasive resistance of cladding layer were improved tosome extent, whose maximum respectively are10.76%,18.29%and35.7%. However,the formation ratio of internal defect increased by213.3%, and the defect mainlygathered in the surface of cladding layer. what’s more, the HAZ produced in substrateclose to interface for the range of0.6mm after laser cladding, and both the hardnessand tensile strength of substrate changed within the area of HAZ, respectively reducedby6.91%and15.14%in the annealing area.