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研究了不同脱脂气氛 (不同比例N2 与H2 的混合气体 )和脱脂方法 (热脱脂、溶剂脱脂 +热脱脂、冷凝蒸汽脱脂 +热脱脂 )对PIM硬质合金脱脂坯及合金碳含量的影响。结果表明 :N2 热脱脂粘结剂容易以炭黑的形式残留在脱脂坯中 ,造成合金增碳 ;H2 热脱脂导致合金脱碳 ;75 %N2 +2 5 %H2 (体积分数 )混合气体热脱脂既能有效地脱除粘结剂 ,又能保证合金碳含量相对稳定 ;溶剂脱脂和冷凝溶剂脱脂能显著缩短脱脂时间 ,而且由于高温保持时间短 ,在后续热脱脂过程中采用H2 作保护气也可获得满意的碳含量 ,说明该方法对工艺条件的适应性强。通过调整热脱脂高温保持时间 ,可在一定范围内对脱脂坯的碳含量进行调整 ,说明过程的可调控性好。与溶剂脱脂相比 ,冷凝蒸气脱脂粘结剂脱除率更高 ,脱脂坯有较高的强度 ,有效地防止了脱脂坯软化变形的现象。
The effects of different degreasing atmospheres (mixture of N2 and H2 at different ratios) and degreasing processes (thermal degreasing, solvent degreasing + thermal degreasing, steam condensing degreasing + thermal degreasing) on the carbon content of the PIM cemented carbide degreasing billets and alloys were studied. The results show that: N2 thermal degreasing binder easily remains in the form of carbon black in the skim billet, causing the alloy carbon; H2 thermal degreasing lead decarburization; 75% N2 +2 5% H2 (volume fraction) mixed gas thermal degreasing Which not only can effectively remove the binder, but also ensure the alloy carbon content is relatively stable; solvent degreasing and condensing solvent degreasing can significantly shorten the degreasing time, and because of high temperature to maintain a short time, in the subsequent thermal degreasing process using H2 as a protective gas Satisfactory carbon content can be obtained, indicating that the method adaptability to process conditions. By adjusting the hot degreasing high temperature holding time, carbon content of the degreasing billet can be adjusted within a certain range, indicating that the process can be controlled well. Compared with the solvent degreasing, the removal rate of condensing steam degreasing binder is higher, and the degreasing billet has higher strength, which effectively prevents softening and deforming of the degreasing billet.