注射成形钛零件的研究

Research of injection molding titanium parts

金属粉末注射成形(MIM)是一种极具竞争潜力的钛零件低成本近终形规模制造技术,控制氧、碳污染和收缩畸变是工艺过程的关键.通过不同种类钛粉的组合,可调整体系的粉末形状和粒度组成,降低初始氧含量,改善注射、脱粘和烧结过程的工艺特性;优先选择可通过溶解、蒸发和低温裂解去除的有机粘结剂;溶剂萃取,高真空和高纯、低露点Ar气有利于高效低污染脱粘,脱粘终点为0.16%～0.20%C;增加相对密度有利于提高强度,降低氧、碳污染程度可显著加大伸长率,而烧结过程中的温度和真空度是主要因素;MIM-Ti的基本力学性能与I/M-Ti 3～4级相当,尺寸精度可控制在±(0.18～0.20)%.

Metal injection molding （MIM） is a low cost ＆ near-net shape manufacture technique on a large production scale for titanium parts. Key points in the process are contamination of oxygen ＆ carbon and shrinkage distortion. Different combination of titanium powders can adjust particle size and shape in feedstock system, decrease the initial oxygen content, improve the process of injecting, debinding and sintering. It is necessary to select organic binders which are wiped off by dissolution, evaporation and decomposition at lower temperature. The solvent extraction and debinding in high vacuum or in high pure low dew point Ar are favorable for high debinding efficiency and low contamination. C content should be controlled in the range of 0.16%--0.20% after debinding. The strength increases when density increases, the elongation is effected remarkably by contamination level of oxygen ＆ carbon, the remarkable factors in MIM process are sintering temperature and vacuum degree. The basic mechanical properties of MIM-Ti are commensurate to that of I/M-Ti 3 - 4 grade. The tolerance may be controlled within ± （0.18--0.20）%.