材料期刊网

<正> 目前各国广泛应用的合油轴承有两种:即青铜-石墨、铁-石墨含油轴承.后者生产成本低,强度高,磨损小,能承担较大的荷重,但其抗卡性及耐腐蚀性能不如青铜-石墨含油轴承.铁-石墨合油轴承所用的铁粉,一般都用还原法制取,纯度只要求含铁量>92%.制造这种铁粉的原料极为泛,如高品位的铁矿和铁鳞、酸浸沉坭、黄铁矿渣等工叶废料,都可利用.轴承中所需加入的石墨量,往往随所要求的机械性能和铁粉纯度的不同而有所差别,但通常保持在6%以下.由于铁粉纯度和石墨含量的不同,文献中对铁-石墨含油轴承性能的数据,差别亦很大,合油25%容积的铁-石墨轴承的许可使用PV值,在无油补充的情况下,一般不超过25千克/厘米~2·米/秒,在有油补充的情况下,不应超过100千克/厘米~2·米/秒.

The antiseizure property of the iron-graphite porous bearings can be improved by using purer grades of iron powder.A grade of iron powder of>98% Fe,processed by the reduction of rimmedsteel mill scale with charcoal,is found to be suitable for this purpose.Bearings made of a coarsegrade iron powder(～80%>0.06mm)and containing～1.5% graphite give a good combinationof mechanical strength and antifriction properties.When the graphite content is lower than 0.5%,excessive free ferrite in the matrix results seizure between the rubbings surfaces.On the other hand,with the graphite content in excess of 3.0%,voluminous free carbide in the matrix induces heavymechanical wear.In comparison with the bronze-graphite porous bearings of the same hardness,an iron-graphite porous bearing possesses a higher strength,a larger oil content,a smaller coefficientof friction and less wear loss.