Key factors affecting the performance of diamond wire drawing die coatings
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摘要: 金刚石拉丝模以其超高的硬度被广泛应用于金属拉拔和绞线压紧等领域。金刚石涂层金属拉拔性能与微观组织密切相关。【目的】本研究通过前期大量尝试,筛选出900℃和950℃两个关键温度工艺,并开展了两种工艺对微观组织影响和失效机理差异的研究。【方法】基于模拟仿真方法分析拉丝模内温度分布,通过SEM、XRD、Raman光谱等对其进行组织结构分析。【结果】结果表明:沉积过程拉丝模内部温度梯度较小,对金刚石涂层沉积直接影响较小。高温可以促进碳活性基团进入压缩区和定径区形成纳米金刚石,较低的温度会减弱碳活性基团的扩散能力,在压缩区和定径区形成微米金刚石。纳米金刚石涂层性能好,但结合力较弱导致大块金刚石涂层脱落失效。微米金刚石膜硬度高,表面粗糙度控制较难,会导致花丝失效。【结论】基于此分析,本研究提出了一种在微米金刚石涂层原位沉积纳米金刚石涂层的方式,可以有效提高拉丝模使用寿命。
Abstract: Abstract: Diamond has high hardness, elastic modulus and other properties, irreplaceable role in the tool market, for the relevant enterprises to bring stable earnings.The diamond wire drawing die is extensively employed in the metal drawing and strand tightening fields, primarily due to its remarkable hardness. This attribute enables the die to withstand the immense pressures and friction encountered during the drawing process, ensuring that the wires are pulled through with precision and minimal resistance. The high hardness of the diamond not only facilitates the reduction of the wire diameter but also contributes to the integrity and strength of the finished product. The metal drawing properties of diamond coating are closely related to the microstructure.
【Objectives】In this research, the selection of two pivotal temperature 900℃ and 950℃, was based on extensive prior experimentation. These temperatures were chosen for their significant impact on the material's properties and the outcomes of the processes. The effect of the two processes on microstructure and the difference of failure mechanism were studied.
【Methods】Based on the simulation method, the temperature distribution in the drawing die is analyzed, Scanning Electron Microscopy (SEM) is employed to observe the surface topography of diamond drawing die at high magnification. X-ray Diffraction (XRD) analysis is then conducted to investigate the crystallographic structure of the diamond drawing die. Additionally, Raman spectroscopy is used to analyze quality of the diamond drawing die.
【Results】The results show that the temperature gradient inside the die is small so the direct effect of temperature on diamond coating deposition is small. High temperature can promote carbon active groups to enter the compression and sizing regions to form nanodiamonds, while lower temperature will weaken the diffusion ability of carbon active groups and form micrometer diamonds in the compression and sizing regions. Nanometer diamond coating has good performance, but weak binding force leads to the failure of large diamond coating. Micrometer diamond film hardness is higher, surface roughness control is difficult, will lead to a coarse metal surface.
【Conclusions】Based on this analysis, a method of in-situ deposition of nanometer diamond coating on micron diamond coating is proposed in this study, which can effectively improve the service life of wire drawing die, the wire drawing distance can be increased to more than 100km.
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Key words:
- diamond /
- drawing die /
- finite element simulation /
- failure mechanism
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