高速铣削时硬质合金刀具与NAK80模具钢化学性能匹配研究
2020-10-16
作者：曾伟国1，夏琴香1，谭升洪2，梁根森2
单位：1华南理工大学机械与汽车工程学院；2广东科龙模具有限公司
摘要：高速铣削加工时温度较高，易引起刀具与工件之间产生化学反应，加剧刀具与工件磨损，缩短刀具寿命。实现刀具材料和工件材料的化学性能匹配，可有效保证模具型面加工质量和提高生产效率。化学性能匹配主要从刀具材料与工件材料的氧化以及扩散方面进行研究。通过理论计算得到刀具与工件材料的化学反应自由能；结合高温氧化试验，研究NAK80模具钢的高温氧化产物并探究其抗氧化性能；基于变系数浓度扩散模型，利用元素扩散试验获得了NAK80模具钢与刀具材料间的元素扩散强度。结果表明，NAK80模具钢的氧化程度随温度升高而加剧，温度高于1300K可发生完全氧化；NAK80模具钢中的Fe元素扩散深度随硬质合金刀具中Co元素含量的增加而增加。
关键词：高速铣削；化学性能匹配；NAK80；抗氧化性能；元素扩散强度
中图分类号：TG54；TG113.23；TH162文献标志码：ADOI：10.3969/j.issn.1000-7008.2020.05.005
Research on Chemical Properties Matching of Carbide Tool and NAK80
Die Steel During High Speed Milling
Zeng Weiguo，Xia Qinxiang，Tan Shenghong，Liang Gensen
Abstract:High temperature occurs easily during highspeed milling，which not only causes the chemical reaction between tool material and workpiece material，but also increases the wear of tool and workpiece material，greatly shortening the tool life.A reasonable chemical matching of tool material and workpiece material can effectively ensure the processing quality of mould surface and improve production efficiency.Chemical property matching is mainly studied from the oxidation and diffusion of tool materials and workpiece materials. In order to predict the chemical reaction of cemented carbide tool material and NAK80 mould steel in highspeed milling process，the free energy of chemical reaction between tool and workpiece materials is calculated.Combining with high temperature oxidation test，the high temperature oxidation product of NAK80 and its antioxidant properties are studied.In addition，a variable coefficient concentration diffusion model is used to calculate the element diffusion coefficient，and the element diffusion intensity between NAK80 and cemented carbide tools is obtained by elemental diffusion experiments.The results show that the oxidation degree of NAK80 increases with the increasing of temperature，and NAK80 can be completely oxidized above 1300K.The diffusion depth of Fe element in NAK80 die steel increases with the increase of Co content in cemented carbide tools.
Keywords:high speed milling；tool matching；NAK80；antioxidant properties；elemental diffusion strength