YG8硬质合金注射成形脱脂工艺的研究

采用传统蜡基和(油+蜡)基改进型两种粘结剂,对粒度为1.97μm的WC-8Co混合粉末注射成形,研究了两种喂料的热脱脂、溶剂脱脂+热脱脂工艺,确定了热脱脂、溶剂脱脂+热脱脂的优化工艺路线。从脱脂速度和脱脂时间、脱脂缺陷和脱脂工艺控制的难易程度等方面比较了两种粘结剂的热脱脂和溶剂脱脂效果。研究了热脱脂温度、时间、不同脱脂方式以及粘结剂组成对脱脂坯碳含量的影响。结果表明,以氢气为脱脂气氛,在450℃以下进行热脱脂可以将有机聚合物完全脱除而且不产生脱碳,溶剂脱脂后再进行热脱脂更有利于控碳和减少脱脂缺陷,而且大大缩短脱脂时间。(油+蜡)基改进型粘结剂在热脱脂和溶剂脱脂时具有更好的脱脂特性。

Study on Debinding Process of Cemented Carbide Green Part by Powder Injection Molding

By using a traditional paraffin wax base multi-component binder and a kind of (wax+oil) improved binder, the WC-8Co powder mixture with particle size of 1.97μm has been injected by powder injection molding. The thermal debinding process and solvent +thermal debinding combined process have been studied to determine the optimal debinding processes. The efficiency of the two binders on thermal debinding and solvent debinding has been compared from debinding rate, defects of the brown parts and debinding process. The influences of thermal debinding temperature, time, different debinding methods and binder component on the carbon content of the brown parts have also been studied. The results have shown, when the green part is thermally debinded below 450℃ under H2 atmosphere,the polymer binder in the green part can be removed completely without carbon loss in WC powder. Solvent debinding before thermal debinding has advantage in controlling carbon content of the brown part and defects, and the debinding time is shortened greatly. The (wax+oil) improved binder has better debinding characteristics during thermal debinding and solvent debinding.