The Impact Analysis Of Hardened Steel Machined Surface On Service Process

Domestic enterprises of auto panel die mold pay more attention to thestructural integrity of product at present, but they doesn’t emphasis on thesurface integrity, which results in the big gap between domestic and internationallevels of mold life. Surface quality of milled hardened steel directly affectsthe service performance and life of molds, so it has important theoretical valueand practical significance to study the influence rules about the surface structureof hardened steel milled with high speed on the performance and damageevolution in the service process, which can clarify the technical requirements ofhigh-speed milling of hardened steel.This issue comes from National Natural Science Foundation of “Surfacemicrostructure characterization and damage evolution mechanism of high-speedmilling of hardened steel (51205096)”. Based on the analysis of thegeometric structure of machined surface in high-speed milling of hardened steel,this thesis explored the machined surface load distribution, wear degree anddamage evolution in service process, in order to provide the support forimproving the processing technology of high-speed milling of hardened steelauto mold, which can ensure the performance and life of molds.After classifying interpretation geometric characteristics of hardened steelmolds which considered the complexity of hardened mold surface, this thesisobtained the geometry structure model of machined surface under differentcutting parameters, and carried out corresponding verified experiments.According to machined surface geometry features, the loading feature of themachined surface structure was obtained. Based on the Hertz theory, surfacecontact deformation model for machined surface asperity was established.By using the basic theory of elastic finite element method and DEFORMsoftware, this thesis carried out the simulation experiments with thesmooth surface and machined surface under different conditions respectively, andafter analyzing the results of the numerical simulation stamping service processes comparatively, obtained the influence rules of the different machined surfaces onservice load and wear distribution.Based on the theory of microscopic damage evolution as well asthe hardened steel mold material micro-voids hexahedral cell model and the loadcondition of machined surface, it was obtained that evolution characteristicsof different shapes of void cell which can preliminarily predict the surfacedamage tendency, after analyzing the proceeding surface damage evolution.