论文部分内容阅读
烧结过程控制对粉末冶金整个工艺过程起着至关重要的作用,控制不好,将导致烧结后的零件在尺寸和性能上不稳定或达不到产品设计要求,并可能还会出现氧化、脱碳、渗碳、崩裂和积碳等工业中常见的问题。随着对粉末冶金产品的性能和成本控制要求不断提高,金属Cr因其价格低并具有很好的强化效果,成为粉末冶金工业开拓的重点方向。但是金属Cr容易氧化,对烧结气氛要求较高,因此对烧结工艺提出了挑战。随着烧结炉技术的发展和氮基保护气体广泛使用,在网带炉中烧结含Cr成分的零件已经成为现实。利用热电偶、氧分压和CO分析仪等设备组成的分析系统,评估了以氮氢混合气体作为保护气氛的网带烧结炉的实际烧结情况,分析了几种烧结过程中常见的缺陷及其原因,并提出了相应的改善措施,同时也总结了含Cr材料所需的烧结条件及其控制。
Sintering process control plays a crucial role in the entire powder metallurgy process. Poor control will result in unsteady size or performance of sintered parts or may not meet product design requirements. Oxidation may also occur Carbon, carburizing, cracking and carbon deposition industries common problems. With the continuous improvement of the performance and cost control requirements of powder metallurgy products, metal Cr has become a key direction for the development of the powder metallurgy industry because of its low price and good reinforcing effect. However, metal Cr is easily oxidized and has a high requirement on the sintering atmosphere, thus posing a challenge to the sintering process. With the development of sintering furnace technology and the widespread use of nitrogen-based protective gas, it has become a reality to sinter parts containing Cr in a belt furnace. Using the analysis system composed of thermocouple, oxygen partial pressure and CO analyzer, the actual sintering conditions of the mesh belt sintering furnace with nitrogen and hydrogen mixed gas as the protective atmosphere were evaluated, and several common defects in the sintering process were analyzed The reasons and the corresponding improvement measures are put forward. At the same time, the sintering conditions and the control of Cr-containing materials are also summarized.