Effect of electromagnetic vibration field on the properties of metal powder injection molding
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摘要: 在金属粉末注射成形(MIM)过程中引入电磁振动场后,采用SEM和金相显微镜分析注射生坯和烧结样品的微观组织,系统评价注射生坯和烧结后样品的密度与力学性能。通过对比不同的振动参数对注射生坯性能的影响结果,从而获得最佳的振动参数。研究结果表明当振动场引入MIM注射成形过程后,相比于静态注射会显著提高生坯和烧结样品的密度和性能,且随着振动力场的加强,密度和性能皆出现先上升后下降的现象,这与喂料流动性有关。该工艺为突破目前MIM制备大型零部件困难的技术瓶颈提供了可能。Abstract: The electromagnetic vibration field was introduced into the injection process of metal powder injection molding (MIM). The density and mechanical properties of the green body and sintered samples were systematically evaluated. Meanwhile, the microstructure of the green body and sintered samples was investigated by SEM and microscope. The effects of different vibration parameters on the performance of injection green body were studied to obtain the most suitable vibration parameters. The results show that when the vibration field is introduced into the MIM injection process, the density and properties of green body and sintered samples are significantly improved compared with the static injection proces. With the strengthening of the vibration field, both the density and properties increase firstly and then decrease, which is related to the feeding fluidity. The technology can provide a possibility for breaking through the technical bottleneck of preparing large parts with MIM.
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图 1 (a)动态注射机原理[13];(b)喂料DSC-TG曲线和(c)注射生坯图片
Figure 1. Schematic diagram of dynamic injection machine (a), DSC-TG curve (b) and green body (c)
表 1 样品合金成分
Table 1. Alloy compositions of the sample
% C N Cr Ni Mo Mn 其它 Fe 0~0.02 0.75~0.90 16.5~17.5 0~0.1 3.3~3.5 10~12 0~0.1 Balance 表 2 在不同振动参数下螺旋线长度
Table 2. Helix length with different vibrating parameters
振动参数 螺旋线长度L/mm 频率/Hz 振幅/μm 0 0 101 1 30 148 2 30 119 3 30 139 4 30 127 5 30 119 3 5 125 3 15 130 3 45 129 表 3 不同参数下样品的力学性能
Table 3. Mechanical properties of samples generated under different parameters
合金 振动参数 密度/(g·cm−3) 氮含量/% R0.2/MPa Rm/MPa εP 洛氏硬度(HRC) 频率/Hz 振幅/μm X15CrMnMoN17 0 0 7.50 0.75~0.78 676 825 2.5 22 X15CrMnMoN17 1 30 7.52 0.75~0.78 716 1010 7.0 26 X15CrMnMoN17 2 30 7.53 0.75~0.78 727 1000 8.5 28 X15CrMnMoN17 3 30 7.55 0.75~0.78 725 1040 12.0 28 X15CrMnMoN17 4 30 7.54 0.75~0.78 734 1030 10.5 31 X15CrMnMoN17 5 30 7.52 0.75~0.78 720 966 5.0 28 X15CrMnMoN17 3 5 7.51 0.75~0.78 701 906 6.9 26 X15CrMnMoN17 3 15 7.53 0.75~0.78 716 987 9.8 26 X15CrMnMoN17 3 45 7.53 0.75~0.78 720 1000 10.0 27 -
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