柴油发动机缸体用合金铸铁的刀具材料匹配性研究

发布时间：2018-11-04 09:30

【摘要】：作为汽车、船舶、内燃机车、工程机械、军工装备等领域的一个重要配套动力来源,柴油发动机的发展对我国的工业进步、经济发展与国防建设都起到关键性的作用。与汽油发动机相比而言,柴油发动机具有着耐用、节能、经济与环保的特点。WP10型柴油发动机缸体用合金铸铁通过Cu、Cr、Sn等合金元素的添加,合金铸铁的力学性能、铸造性能得到了明显改善,但合金元素的添加同时也降低了合金铸铁的切削加工性能,导致刀具磨损严重,影响了加工效率与加工成本。硬质合金涂层刀具具有耐磨、稳定性高等特点,成为加工合金铸铁的一种常用刀具材料。对于合金铸铁进行刀具材料(包括涂层材料)的合理匹配,选择合适的刀具材料(包括涂层材料)可以延长刀具寿命、降低加工成本、提高加工效率。本文围绕柴油发动机缸体用合金铸铁的刀具基体材料及涂层材料匹配性进行了研究,主要研究内容如下:(1)利用高温扩散实验研究了合金铸铁与硬质合金的化学、物理与力学性能匹配。从化学性能匹配出发,合金铸铁与YG类硬质合金间在高温下出现了明显的元素扩散现象,Fe与W均观察到了比较显著的扩散。其中合金铸铁中的Fe向YG类硬质合金中的扩散非常显著,且扩散深度随着刀具材料中的Co含量升高而升高;而刀具材料中的W向合金铸铁中的扩散与刀具材料的牌号关系不大。从物理、力学匹配性出发,YG6X、YG6A硬度高,其他各项性能指标均比较均衡,适合用与精加工、半精加工。YG8冲击韧性高、抗弯强度强,适用于粗加工。(2)利用高温氧化实验、高温扩散实验、切削实验研究了合金铸铁与涂层材料的匹配,发现具有Al2O3膜的CVD的(TiCN)复合涂层硬质合金刀具在高温下与合金铸铁间的元素扩散很小,且刀具内部的扩散在比较高的温度下才发生,抗扩散性能卓越。PCVD的TiN与PVD的TiAlN在较低的温度下就观察到了与合金铸铁间及刀具内部的元素扩散,抗扩散性能较差。切削实验结果表明材质为(Ti,Al)N-Ti(C,N)-TiN的F40M涂层硬质合金刀具相比材质为Ti(C,N)-A1203的MK1500涂层硬质合金刀具在切削合金铸铁刀具磨损量更小,加工表面粗糙度更低;但在切削初期阶段更易磨损,且存在崩刃现象。(3)对柴油发动机缸体上平面精加工、半精加工与粗加工过程中刀具的失效形式进行了研究。研究发现崩刃、刀具涂层剥落、刀具基体材料的片状剥落、微裂纹、硬质点磨损、粘结磨损与扩散磨损是合金铸铁加工中主要的磨损形式。本研究对于柴油发动机缸体用合金铸铁加工的刀具基体材料及涂层材料的选择有着一定的指导作用。
[Abstract]:As an important power source of automobile, ship, diesel locomotive, construction machinery, military equipment and so on, the development of diesel engine plays a key role in industrial progress, economic development and national defense construction of our country. Compared with gasoline engine, diesel engine has the characteristics of durability, energy saving, economy and environmental protection. The mechanical properties of alloy cast iron for cylinder block of WP10 diesel engine are obtained by adding alloying elements such as Cu,Cr,Sn. The casting properties were improved obviously, but the addition of alloy elements also reduced the cutting performance of alloy cast iron, resulting in serious tool wear, which affected the machining efficiency and cost. Cemented carbide coated cutting tools are widely used as tool materials for machining alloy cast iron due to their high wear resistance and high stability. For alloying cast iron, the tool material (including coating material) can be reasonably matched. Selecting suitable tool material (including coating material) can prolong the tool life, reduce the machining cost and improve the machining efficiency. In this paper, the matching properties of tool matrix and coating material of alloy cast iron for diesel engine cylinder block are studied. The main contents are as follows: (1) the chemistry of alloy cast iron and cemented carbide is studied by high temperature diffusion experiment. Physical and mechanical properties match. Based on the matching of chemical properties, the diffusion of elements between cast iron and YG type cemented carbides appears at high temperature, and the diffusion between Fe and W is more obvious than that between cast iron and YG cemented carbides at high temperature. The diffusion of Fe in alloy cast iron to YG cemented carbide is very significant, and the diffusion depth increases with the increase of Co content in the cutting tool material, but the diffusion of W to alloy cast iron in the cutting tool material has little relationship with the grade of the cutting tool material. Starting from physical and mechanical matching, YG6X,YG6A has high hardness and other performance indexes are more balanced. It is suitable for finishing and semi-finishing. YG8 has high impact toughness and strong bending strength. It is suitable for rough machining. (2) the matching of alloy cast iron with coating material is studied by high temperature oxidation experiment, high temperature diffusion experiment and cutting experiment. It is found that the diffusion of elements between CVD and cast iron is very small at high temperature, and the diffusion within the tool only occurs at a relatively high temperature. The diffusion properties of TiN of PCVD and TiAlN of PVD were excellent. The diffusion of elements between TiN of PCVD and TiAlN of PVD was observed with the alloy cast iron and the tool interior at low temperature, and the diffusion resistance was poor. The results of cutting experiments show that the wear of (Ti,Al) N-Ti (Con N)-TiN F40M coated cemented carbide tool is less than that of MK1500 coated cemented carbide tool with Ti (Con N) -A1203 material in cutting alloy cast iron tool. Lower surface roughness; However, in the early stage of cutting, it is easier to wear, and there is a phenomenon of breakage. (3) the failure modes of cutting tools in the process of plane finishing, semi-finishing and rough machining of diesel engine cylinder block are studied. It is found that the main wear forms in alloy cast iron machining are breakage, tool coating exfoliation, flake of cutting tool matrix, microcrack, hard spot wear, bond wear and diffusion wear. This study has a certain guiding effect on the selection of cutting tool substrate and coating material used for diesel engine cylinder block alloying cast iron.
【学位授予单位】：山东大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TK425;TG711

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