文档介绍：翻译原文二:
Die Life and Die Failure
Proper selection of the de material and of the die manufacturing technique determines, to a large extent, the useful life of forming des. Dies may have to be replaced for a number of reasons, such as changes n dimensions due to wear or plastic deformation, deterioration of the surface finish, breakdown of lubrication, and cracking or breakage. In hot impression die forging, the principal modes of die failure are erosion, thermal fatigue, mechanical fatigue and permanent (plastic) deformation.
In erosion, monly called die wear, material is actually removed from the die surface by pressure and sliding of the deforming material, wear resistance of the die material, die surface temperature, relative sliding speed at the die/material interface and the nature of the interface layer are the most significant factors influencing abrasive die wear. Thermal fatigue occurs on the surface of the die impression in hot forming and results in “heat checking”. Thermal fatigue results from cyclic yelling of the de surface due to contact with the hot deforming material. This contact causes the surface layers to expend, and, because of the very steep temperature gradients, the surface layers are subject pressive stresses. At sufficiently high temperatures, pressive stresses may cause the surface layers to deform. When the de surface cools, a stress reversal may o