Research On The High Strength Copper/Steel Bimetal Forming Process Of Composite Guide Plate

At present, in the domestic and foreign automotive die industry, copper alloy and powdersintered copper/steel bimetal are used to make the guide plate by the large and medium-sizedstamping die-oriented parts. However, with the increasing demands of the high precision die forguide plate material properties, the current guide plate materials and forming methods can notmeet production needs. Therefore, this paper has developed a high strength copper alloys, thehigh strength copper/steel bimetal composite guide plates were produced by using liquid-solidphase forming process, which not only can improve the comprehensive properties of the guideplates to extend their useful life, but also can reduce the use of precious metals, and therebyreduce the production costs.Through the composition optimization design, the high strength copper alloy wasdeveloped, and the mechanical properties, friction and wear properties were tested. Theoptimum composition of copper alloys was Cu-Zn23-Al5.5-Fe4-Mn4.5with goodcomprehensive properties: tensile strength750~900MPa, hardness250~320HB, elongation of15to20percent under cast condition, the friction coefficient of using T10steel and highstrength copper alloys for dry friction was0.13to0.15. High strength copper alloy was suitablefor the guide plate application of the high-end automotive die.In order to the researched and developed high strength copper alloy composite on45steelplates by using liquid-solid phase forming process. Firstly, the base steel plates were pretreated,which using copper brush plating (10μm)+antioxidants and fluxing agent dipping infiltration+copper heat dipping infiltration (dipping infiltration temperature of1100~1150℃, the dippinginfiltration time of60~90s) comprehensive treatment process; and then high strength copperalloy was melted to1250~1300℃, after refining the copper alloy was poured on the pretreatedbase steel plate (100×100×20mm), high strength copper (5mm thick)/steel bimetal compositeguide plates were obtained.Interfacial bonding microstructure of the composite guide plate were analyzed byScanning Electron Microscopy (SEM), Energy Dispersive Spectroscopy (EDS), X-RayDiffraction(XRD) and so on, and the results show that the interfacial bonding of high strengthcopper/steel bimetal can be achieved by the mechanism of mechanical combination, fusioncombination and diffusion combination; at the transition layer interface, atoms preferentialdiffusion along the metal surface and intergranular infiltration, and grain boundary is the maindiffusion channel; the interfacial bonding occurs surface wet-spread and atoms diffusion whichlead to the formation of Fe-Cu alloy binary phase in the Fe-rich and Cu-rich areas.