Effect of the surface structure on the resistance to plastic deformation of a hot forging tool
Effect of the surface structure on the resistance to plastic deformation of a hot forging tool
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DOI：
10.1016/s0924-0136(01)00632-x
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发表时间：
2001-06
影响因子：
6.3
通讯作者：
H. Saiki;Yasuo Marumo-;Akihiro Minami;Takehiko Sonoi
中科院分区：
文献类型：
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作者：
H. Saiki;Yasuo Marumo-;Akihiro Minami;Takehiko Sonoi
由于高热负荷引起的刀具表面层软化，刀具寿命显著降低。为了优化刀具表面结构，系统研究了硬质涂层厚度对刀具塑性变形的影响。采用有限元法计算了反挤压过程中模具内的温度场和软化场的分布。在此基础上，结合软化层深度的假设，分析了刀具角部在不同摩擦条件下的塑性变形抗力，包括滑动速度和摩擦力。为了防止表面层塑性变形，在热载荷循环和工具表面结构的设计中应反映以下两点。第一个是在硬层下面的热软化层的厚度应该变得小于硬层的厚度。第二个是，如果形成约1mm厚的热软化层，则软化层的变形阻力的降低应在块体材料的变形阻力的20%以内。
Tool life decreases considerably due to the softening of the surface layer of a tool caused by a high thermal load. In order to optimize the surface structure of tools, the influence of the thickness of a hard coating film on the plastic deformation of the tool was investigated systematically. The distribution of temperature and softening in the tool for backward extrusion processes were calculated by finite-element analysis. On the basis of the results, the plastic deformation resistance of the tool corner was analyzed under various tribological conditions including sliding velocity and friction, incorporating the presumed depth of the softened layers. To prevent the surface layer from deforming plastically, the following two points should be reflected in the design of the thermal-loading cycles and the surface structure of the tool. The first is that the thickness of the thermally softened layer under the hard layer should become less than that of the hard layer. The second is that if a thermally softened layer of about 1mm thickness develops, the decrease in the deformation resistance of the softened layer should be within 20% of the deformation resistance of the bulk material.