汽车减震器用高压缩性还原铁粉研究
发布时间：2018-07-22 17:29
【摘要】：铁基粉末冶金汽车减震器零部件在使用过程中受到交变载荷的作用,对包括疲劳强度在内的综合性能要求非常高,而高压缩性铁基基粉则是保证该类零部件产品具有优良综合性能的关键。安徽马钢粉末冶金有限公司采用现有还原铁粉生产工艺制备的还原铁粉的压缩性一般低于6.80g/cm3,不利于粉末冶金制品的完全致密化烧结,难以得到综合性能优异的粉末冶金汽车减震器结构件。本文针对这一问题,从影响还原铁粉压缩性的一次还原温度、二次还原温度与气氛、合批配料等方面入手,系统研究了上述几个因素对还原铁粉压缩性的影响及控制关键,并将研究成果应用于粉末冶金汽车减震器活塞。主要结论如下:1)隧道窑一次还原温度最高为1160℃,相较于1120℃与1180℃,海绵铁颗粒致密化程度高,孔隙度较小,分布均匀,化学成分纯净,且不会过烧,有利于后序二次还原及压缩性能的提高;2)采用纯氢气替代氨裂解气作还原气氛,可充分脱碳、脱氧,并可防止铁粉渗氮,提高铁粉纯度,可得到含铁量高于99.0%的还原铁粉,从而改善铁粉压缩性;3)精还原炉中的二次还原温度最高为930℃,提高了铁粉退火软化效果,改善了铁粉塑性,提高产品压缩性能;4)配料比例为颗粒≥105μm约28~32%、≤75μm约50~54%,合批时间为28~30min时,可以获得压缩性≥6.86g/cm3(500MPa压力下)的高质量还原铁粉;5)以高压缩性还原铁粉为基粉,添加0.8%石墨和1.6%的300目铜粉制备的粉末冶金汽车减震器活塞的综合性能优良,主要表现为:成形时压制压力分布平稳,压坯密度高达6.57g/cm3,烧结坯外径硬度HRB67-73,外法线硬度HRB45-50,压溃力9.77-10.40 kN,从而验证了还原铁粉生产工艺控制的科学性和有效性。
[Abstract]:Iron base powder metallurgy automobile shock absorber parts are subjected to alternating load during the process of use, which requires very high comprehensive performance, including fatigue strength. High-compressibility iron-base powder is the key to ensure that this kind of parts have good comprehensive properties. The compressibility of the reduced iron powder prepared by Anhui Masteel Powder Metallurgy Co., Ltd. using the existing process of reducing iron powder production is generally less than 6.80g / cm ~ 3, which is not conducive to the complete densification and sintering of powder metallurgy products. It is difficult to obtain powder metallurgy automobile shock absorber structure with excellent comprehensive performance. In order to solve this problem, the effects of the above factors on the compressibility of reduced iron powder are systematically studied from the following aspects: the first reduction temperature, the second reduction temperature and the atmosphere, the batch proportioning and so on, and the key to control the compressibility of the reduced iron powder. The research results are applied to the piston of powder metallurgy automobile shock absorber. The main conclusions are as follows: (1) the highest reduction temperature in the tunnel kiln is 1160 鈩，
本文编号：2138216
[Abstract]:Iron base powder metallurgy automobile shock absorber parts are subjected to alternating load during the process of use, which requires very high comprehensive performance, including fatigue strength. High-compressibility iron-base powder is the key to ensure that this kind of parts have good comprehensive properties. The compressibility of the reduced iron powder prepared by Anhui Masteel Powder Metallurgy Co., Ltd. using the existing process of reducing iron powder production is generally less than 6.80g / cm ~ 3, which is not conducive to the complete densification and sintering of powder metallurgy products. It is difficult to obtain powder metallurgy automobile shock absorber structure with excellent comprehensive performance. In order to solve this problem, the effects of the above factors on the compressibility of reduced iron powder are systematically studied from the following aspects: the first reduction temperature, the second reduction temperature and the atmosphere, the batch proportioning and so on, and the key to control the compressibility of the reduced iron powder. The research results are applied to the piston of powder metallurgy automobile shock absorber. The main conclusions are as follows: (1) the highest reduction temperature in the tunnel kiln is 1160 鈩，
本文编号：2138216
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