Modification of Paraffin Wax for Manufacturing Difficult-to-Form Green Compacts and Its Application in WC-Co Cemented Carbides

难成形生坯用石蜡的改性及其在WC-Co硬质合金中的应用

The production of deep well-shaped WC-Co cemented carbide blocks via industrial powder pressing remains a challenging technical problem,primarily due to the unsuitability of the forming agent.The forming agent paraffin wax was modified through four types of modifiers,including organic high-molecular-mass resins,plasticizers,surfactants and lubricants.The qualitative screening of resin types was explored and an orthogonal experiment involving the combination of these four paraffin wax modifiers was conducted to obtain an optimized quantitative ratio of modifiers.The results reveal that the insertion of the small molecule chain of resin into the interstitial spaces of paraffin wax crystals is likely a crucial factor for improving the compatibility between the resin and paraffin wax.Through orthogonal experiments,the optimized formulation for the forming agent is determined:100 parts of 58#paraffin wax,15 parts of EVA-2,4 parts of DPHP,4 parts of oleic acid amide and 2 parts of stearic acid.This optimized formulation is applied to industrial production at one Chinese company,and qualified deep well-shaped cemented carbide products are achieved,which contain 90wt%WC and 10wt%Co.

工业模压生产深井字形WC-Co硬质合金块是一个难以解决的技术难题,主要是所用石蜡基成形剂不合适造成的。采用有机高分子树脂、增塑剂、表面活性剂和润滑剂这4种改性剂对成形剂石蜡做了改性,研究了树脂种类的定性筛选和4种石蜡改性剂组合的正交实验,以得到改性剂的优化定量比例。结果表明,树脂中小分子插入石蜡支晶间隙可能是树脂和石蜡相容性提高的一个重要原因。通过正交实验,确定了成型剂的最佳配方为:100份58#石蜡、15份EVA-2、4份DPHP、4份油酸酰胺和2份硬脂酸。该优化配方在一家中国公司的工业生产中得到了应用,生产出了质量合格的深井形状硬质合金产品,其中WC质量分数为90%,Co质量分数为10%。