温压过程致密化机制探讨

Densification Mechanism of Warm Compaction

从温压的压制压力、压制温度、压坯中铁粉颗粒的显微硬度和润滑剂在压坯中的分布等方面对温压过程致密化机制作了分析．结果表明，温压过程中铁粉的固结规律基本上与传统压制过程的相同．温压压坯密度比传统压制提高的值相当于相同压制压力下有效压制压力的增大．温压温度的作用在于延缓铁粉压制过程的加工硬化程度和提高铁粉的塑性变形能力．润滑剂在最佳的温压温度下具有粘流性，部分被挤出压坯，有效地减小铁粉颗粒之间及颗粒与模壁之间的摩擦，降低了脱模压力．

Throughout studying the relationship between the compact density and the compacting pressure the compacting temperature, tasting the microhardness of particles in the compact, detecting the distribution oflubricant in the compact, the densification mechanism of warm compaction can be concluded as following: the compaction principle of iron powder is the same as that of conventional compaction. while the effective pressure during warm compaction is larger than that of conventional compaction. The temperature during compaction can slow down the progress of work hardness and improve the plasticity of iron powder. The lubricant is only effective at the optimum temperature. Under this condition, the lubrication takes place of viscous flow, which can be squeezed oat of the compact, effectively reducing the friction between particles and between particle and die wall, and also decreasing the ejection pressure.