Study On The Properties Of Laser Cladded Layer And Remanufacturing Of Precise Stamping Mould

Precise stamping technology is a deformation processing of high efficiency, highquality and high added-value which can attain high quality products at one time.However, with the development of precise stamping technology, mould service timehas become a key problem that restricts the development of precise stamping industry.As a matter of fact, it is of great theoretical and realistic value to study theremanufacturing of partly wasted stamping moulds to solve the high cost and shortlifetime problem. Fabricating a self-lubricating wear-resistant coating using lasercladding on the damaged stamping mould is of great value to the surfaceremanufacturing of precise stamping mould.Laser cladding is used to design the remanufacturing process of precise stampingmould. The wear-resisting anti-friction layer has been prepared on45#steel usingSemiconductor Laser with Fe360alloy powder as bonding phase, Cr3C2and MoS2assecond phase. Microstructures of the coatings were characterized by MetallurgicalMicroscopy, X-ray diffractometer (XRD), scanning electron microscope (SEM) andenergy dispersive spectrometer (EDS). Microhardness of the coatings was measuredby a microhardness tester. The friction and wear properties of the coatings wereinvestigated by HT1000, and the corresponding wear mechanisms were analyzed.Layer with best wear-resisting anti-friction property was obtained by orthogonalexperiment, the remanufacturing design of Cr12MoV has been discussedpreliminarily.The research results show that the deposited layer of Fe-Cr3C2-MoS2and thesurface of45steel achieved complete metallurgical bond at the interface. There exists5μm thick planar crystal at the interface, then transits to cellular crystal, thendendrites at the central of the layer and equiaxial grain at the top of the coating. Awear-resistant and anti-friction coating consisting of (Ni,Cr,Fe,C) as substrate andhard M3C2、M23C6carbide, lubricating phase MoS2/CrS were obtained usingFe-Cr3C2-MoS2as precursor. The average microhardness of the cladding is750HV0.2,about100HV0.2higher than that of Fe360layer. During laser cladding, Fe360alloypowder dissolved first, part of the Cr3C2and MoS2particles were preserved, the rest of the Cr3C2mainly dissolved into alloy liquid and formed Fe-Cr solid solution andCr23C6by crystallization when cooling; MoS2particles partly decomposed, S and Crcombined into CrS with lubrication, Mo partly dissolved into the matrix and partlycombined with C into particular carbides. The layer is strengthened by the newlygenerated solid solution and alloy carbides together. The abrasive results showed thatthe coefficient and rate of wear volume of composited layer Fe-12Cr3C2-6MoS2isonly0.22and0.5mm3/m separately, much lower than that of the Fe360layer(0.378,0.92mm3/m).Compared to45steel, the coefficient and rate of wear volume of thelayer has decreased47%and87%separately.With the layer formulation and scanning speed as factors, with the coefficientand rate of wear volume of layer as evaluation index, it has been analyzed that theoptimum layer formulation is Fe360-12Cr3C2-4.5MoS2, the optimum scanning speedis8mm/s. The reasonablely estimated coefficient and rate of wear volume were0.16and0.293mm3/m which are lower than all the other layers.The properties of the intuitively analyzed optimum layer Fe360-12Cr3C2-6MoS2and Cr12MoV laser quenching layer have been compared. The results showed thatcoefficient and rate of wear volume of the intuitively analyzed optimum layer hasdecreased52%and the anti-friction ability of mould has been improved greatly.Combining with the characteristics of Cr12MoV stamping die material and heattreatment performance, mould remanufacturing feasibility has been designed.