高速铣削淬硬钢的刀具破损试验及其力热耦合特性分析

Fracture experiment on milling cutters for high-speed machining of hardened steel and analysis of their thermo-mechanical coupling characteristics

针对高速铣削淬硬钢的刀具破损问题，进行了硬质合金立铣刀高速铣削TIO淬硬模具钢的破损试验，通过观察发现刀具的破损形态为崩刃，并对刀具的破损机理进行了初步讨论。建立了刀具切削过程的力热耦合方程，分析了切削力、切削热和力热耦合对刀具的影响，详细讨论了力、热单一物理场及其耦合场对刀具结构及刀具破损的作用机理。分析结果表明，刀具失效机理为力冲击引起的破损失效，切削力是造成刀具破损的主要因素；机械应力的数值远远大于热应力数值，热力耦合的综合应力稍大于机械应力；机械变形、热变形和综合变形的数值接近；力热耦合作用下，存在复杂的应力和变形机理，综合应力与变形是拉应力、压应力等各种因素耦合作用的结果。

Focusing on the tool fracture in high-speed milling of hardened steel, a fracture experiment on a cemented carbide milling cutter for high-speed milling of TIO hardened mould steel was conducted. It was observed that the fracture mode of the tool was tipping, and the fracture mechanism was initially discussed. The thermo-mechanical coupling equations of the cutting process were built. The effects of the cutting force, cutting temperature, and thermomechanical coupling on the tool were analyzed. The mechanism of the single physical field and thermo-mechanical coupling to the tool structure and fracture were discussed. The analysis results show that the failure mechanism is the fracture caused by force impact, and the cutting force is the main factor of tool fracture. The mechanical stress is much larger than the thermal stress. The thermo-mechanical coupling stress is a little larger than the mechanical stress. The mechanical deformation and thermal deformation approach the thermo-mechanical coupling deformation. The mechanism of stress and deformation is complex due to the effects of thermo-mechanical coupling. The comprehensive stress and deformation are the coupling effects of tensile stress and compressive stress.