拉刀是最长而且形状复杂的一种刃具,由於淬火时易变形,因而比较难处理。拉刀热处理后应具有高的硬度,良好的耐磨性,较佳的切削性,有锋锐的刃口光滑的表面和严格的弯曲公差。为了达到以上的目的,采用的钢材不但要达到那些要求,而且在热处理时变形应较小。一般采用的材料有P18、P Broach is the longest and complex shape of a tool, due to deformation easily hardened, and therefore more difficult to deal with. Broaches after heat treatment should have high hardness, good wear resistance, better machinability, a sharp edge smooth surface and strict bending tolerance. In order to achieve the above objective, the steel used should not only meet those requirements, but also should be less deformed during heat treatment. The commonly used materials are P18, P