激光协同微量润滑磨削20CrMnTi表面高性能制造机理OA

20CrMnTi alloy steel is extensively utilized as the preferred material for core transmission components in mechanical manufacturing,primarily attributed to its excellent matrix toughness and hardenability.The service reliability of these critical components highly depends on the high wear resistance and superior strength-toughness matching of the 20CrMnTi steel surface.However,existing surface machining and strengthening technologies struggle to balance production efficiency,manufacturing cost,and energy consumption,which has become a key bottleneck hindering the green and efficient manufacturing of high-performance mechanical parts.To address this critical challenge,the work aims to propose a laser-assisted minimum quantity lubrication(MQL)grinding technology,realizing the integration of surface machining and strengthening of 20CrMnTi steel through the synergistic coupling of laser heating and MQL.With the help of the directional and precise cooling of minimum quantity lubrication,it not only ensures sufficient martensitic transformation but also prevents stress concentration induced by excessive cooling.Meanwhile,the adsorptive boundary lubrication film formed by the lubricating medium effectively isolates the grinding wheel-workpiece interface and converts dry friction into low-resistance friction.Furthermore,the atomized lubricating medium blocks air contact and inhibits oxidation reactions at high temperatures.It requires only an extremely small amount of environmentally friendly lubricant,achieving a reduction of over 95%compared to traditional wet machining,thus striking a balance between green energy conservation and economic efficiency.This technology deeply couples the lubrication function with laser heating and grinding processes,forming an integrated surface strengthening mechanism.Through experimental verification of the dynamic thermal-mechanical coupling effect,the optimal laser power is determined to be 500 W.This integrated technology successfully fabricates a uniform modified layer with a thickness of 900 μm on the 20CrMnTi steel surface.Microstructural phase transformation mechanism analysis reveals that the surface layer is predominantly composed of tempered martensite,whose formation originates from the synergistic effect of precise cooling rate regulation by MQL and grinding-induced tempering after complete austenitization of the surface layer induced by laser heating.Specifically,the MQL provides a controlled cooling environment that not only ensures the transformation of austenite to martensite while inhibiting diffusion-type phase transformations but also creates favorable conditions for low-temperature tempering driven by grinding heat.This process promotes the uniform precipitation of supersaturated carbon in the form of coherent ε-carbides,simultaneously alleviating lattice distortion and internal stress,and avoiding the low toughness defect of as-quenched martensite.Experimental results demonstrate that the microhardness of the strengthened surface reaches approximately 640 HV.Friction and wear tests indicate that the failure mode of the MQL-ground surface layer is dominated by single abrasive wear,without obvious adhesive wear or brittle spallation characteristics.Compared with the untreated surface,the wear volume is reduced by 75%,and the wear rate curve is more stable,reflecting excellent wear resistance stability and strength-toughness matching.The laser-assisted MQL grinding technology adopted in this work possesses the technical advantages of high efficiency,energy saving,and controllability.This work systematically elaborates on the austenitization mechanism induced by laser heating and the martensite microstructure optimization mechanism regulated by MQL,providing a practical technical solution for the green manufacturing of high-performance surfaces of 20CrMnTi steel.Meanwhile,it lays a solid foundation for the theoretical development and engineering application of the integrated MQL-assisted grinding strengthening technology.