淬硬钢塑料模具铣削加工表面特性及其耐腐蚀性能研究

Hard milling has become one of the pivotal technologies of molds production, but the machined surface damage and corrosion failure of plastic mold of hardened steel are difficult to control. To solve this problem, this project does some researches about active control of surface characteristic and corrosion resistance of machined surface in hard milling. On the basis of depth theoretical analysis and systematic cutting experiments, the changes of microstructure and grain status, acted in the milling process of the workpiece surface, are researched by the method of numerical simulation, statistical analysis, mathematical model and so on. The formation mechanism of white lateral plastic flow of materials machined surface is researched to revel the influence of lateral plastic flow of materials machined surface caused by cutting parameters, cutter parameters and other parameters. The formation law of machined surface shape in hard milling is shown to establish prediction models of variety of morphology parameters of surface and the profile bearing ratio of microscopic surface and to analyze the wear resistance. It revels the influence of residual stress on the surface machined by hard milling and establishes a prediction model. In the midst of analyzing the main corrosion form, reason and formation process, the relationship between process parameters and corrosion resistance of the milling surface of hardened steel is established. The raised active milling control of corrosion resistance of the machined surface of plastic mold of hardened steel will provide a new way to control the corrosion of the milling surface and increase the production efficiency of mold. Meanwhile, this project makes theory richer and has a considerable economics and social significance.

模具的硬态铣削加工已成为模具制造业关键技术之一，但淬硬钢塑料模具加工表面损伤和腐蚀失效难于控制。本项目拟开展硬态铣削加工表面特征及其耐腐蚀性能的主动控制方面研究，在深入的理论分析和系统的切削试验基础上，通过数值仿真、统计分析、数学模型等方法，对加工表面各类微缺陷的形成机理进行分析；研究已加工表面材料白色侧向塑流带的形成机制，揭示切削参数和刀具参数等因素对加工表面材料侧向塑流的影响规律；分析硬态铣削加工表面形貌的形成规律，建立多种表面形貌特征参数的预测模型和微观表面轮廓支承率预测模型；分析淬硬钢加工表面的主要腐蚀形式、腐蚀原因及形成过程，确定加工工艺参数与加工表面耐蚀性能的关系。提出淬硬钢塑料模具铣削加工表面耐腐蚀性的切削加工主动控制新方法，将开辟切削加工表面腐蚀防控的一条新路径，提高模具生产效率，丰富切削理论，具有重大的经济意义和深远的社会意义。

模具的硬态铣削加工已成为模具制造业关键技术之一，但塑料模具钢加工表面损伤和腐蚀失效难于控制。本项目在深入的理论分析和系统的切削试验基础上，通过数值仿真、统计分析和数学建模等方法，对加工表面微缺陷、白色侧向塑流、形貌特征、腐蚀失效行为进行了深入研究。对塑料模具钢加工表面各类微缺陷处进行元素分析，研究微缺陷形成机理。建立加工表面侧向塑流数学模型，指出已加工表面材料白色侧向塑流带的形成机制，随进给量和行距增大，侧向塑流程度呈现减轻的趋势，随切削深度和刀具半径值增大，侧向塑流程度呈现加重的趋势。研究工艺参数对表面三维形貌的影响规律，结合BP神经网络技术，建立加工表面三维形貌特征参数预测模型和微观表面轮廓支承指数预测模型，预测精度满足要求，在进给量较小时，加工表面偏斜度为负值，表面支撑指数较大。基于全浸腐蚀和电化学腐蚀试验，分析加工表面腐蚀形成机理和主要腐蚀形式；指出各类缺陷的腐蚀安全性，孔洞类、裂纹类缺陷能明显削弱加工表面耐腐蚀性能，在附着填充类微缺陷周围易形成点蚀，加工表面侧流处更易形成疏松的腐蚀结构；确定工艺参数对加工表面耐腐蚀性能的影响规律，加工表面偏斜度和陡峭度值与工件的耐腐蚀性能相关性较大，当偏斜度接近于零，陡峭度值越小加工表面耐腐蚀能越好。提出可从改变加工参数入手进行淬硬钢模具加工表面腐蚀防控的新思路，项目研究成果可为减少加工过程中的表面损伤、避免低于预定寿命的早期腐蚀失效等淬硬钢塑料模具高速铣削加工技术问题提供理论指导和数据支持。