粒度搭配对水雾化铁粉工艺性能的影响

为了研究粒度组成对水雾化铁粉松装密度、流动性、压缩性及压制过程的影响,将-80+100目和-325目两种粒径的水雾化纯铁粉以不同比例搭配进行研究.结果表明:通过控制不同的粒度组成,铁粉松装密度在2.84～3.42 g/cm3内变化、铁粉流动性在20～31 s/50 g内变化;与纯粗粉样品A相比,在粗粉中添加质量分数25%细粉的样品B在低压(300 MPa)下压坯密度增加,高压(≥300 MPa)时压坯密度减少;细粉质量分数为75%时的样品D与样品C相比,压坯密度均增加;全部采用-325目细粉的样品E与样品D相比,压坯密度均降低.当压制压力低于300 MPa时,压坯致密化主要由颗粒的滑移、重排决定;当压制压力高于300 MPa时,压坯致密化主要以粉末的塑性变形为主.

Effect of particle size mixed on the properties of water-atomized iron powder

Different proportions of two kinds(-80+100 mesh and-325 mesh) of water atomized pure iron powder were taken to study the different effect on the apparent density,flowability,compressibility and compression process.The results showed that the apparent density of iron varied in the range of 2.84~3.42 g/cm3 and the flowability in 20~31 s/50 g by controlling the composition of different particle size.Compared to coarse powder,when 25% fine powder was added in the coarse powder,the green density increased at the low pressure(<300 MPa) and decreased under high pressure(≥ 300 MPa).When the fine powder’s ratio increased to 75%,the green density increased.Further more,the fine powder’s ratio increased to 100%,the value of green density is decreased.At low pressure(<300 MPa),the mechanism of compact densification is the slippage and rearrangement of particle;Under high pressure(≥ 300 MPa),however,the mechanism of compact densification is the plastic deformation of powder.