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铸造铅青铜ZQPb25(含25%铅),是一种很好的轴承材料。优点是摩擦系数小,抗磨性能好,韧性高,并且具有耐高温高压的特性能;缺点是因为铜和铅的熔点相差极大,又不互溶,所以铸造性能不好,容易产生逆偏析,使铸件表层铅含量增加;同时铅的颗粒粗大,分布也极不均匀,因而达不到预期的抗磨效果。目前很多动力机械所用的轴承饲套大都采用含6%锡的锡青铜ZQSn6-6-3材料。锡是较为稀缺的资源,且价格昂贵;而且采用锡青铜ZQSn6-6-3做轴承铜套材料时,其抗磨性能差,寿命短,使用不尽理想。据国内外资料介绍;在铸造的铅青铜zQPb25中加入微量稀土后,可以消除铸件的逆偏析,细化铅颗粒,并使其分布均匀,从而提高抗磨性能。作者在zQPb25中加入不同类型微量稀土后,也得到相同的试验结果,其中以加入混合轻稀土的效果最好。在试验的基础上,进一步应用于生产,经试制出的在铅青铜(ZQPb25)中加入0.3%混合轻稀土的几个轴承铜套在几艘拖轮柴油机上代替锡青铜ZQSn6-6-3轴承铜套(主轴铜套和夹兰铜套),经过一年多的实际运转使用,结果表明:加有稀土的ZQPb25比ZQSn6-6-3的轴承铜套具有更好的抗磨性能,磨损量减少5倍左右:而且也减少了对主轴的磨损,保护了主轴。由于ZQSn6-6-3轴承铜套磨损严重,原规定每年要更换一次,但采用加有稀土的ZQPb25轴承铜套后,因为磨损量很小,有些还在继续使用。
Casting lead bronze ZQPb25 (with 25% lead) is a good bearing material. The advantages are small friction coefficient, good abrasion resistance, high toughness, and high temperature and high pressure characteristics; the disadvantage is that the melting point of copper and lead vary greatly, but not miscible, so the casting performance is not good, prone to reverse segregation, So that the casting lead content increased; the same time, coarse lead particles, the distribution is also very uneven, so as to achieve the desired anti-wear effect. At present, most of the bearings used in power machinery are mostly made of tin bronze ZQSn6-6-3 with 6% tin. Tin is more scarce resources, and expensive; and the use of tin bronze ZQSn6-6-3 bearing copper sleeve material, its poor wear resistance, short life, the use of less than ideal. According to the introduction of domestic and foreign materials, after adding trace amount of rare earth into the cast bronze zQPb25, the reverse segregation of castings can be eliminated and the lead particles can be refined and distributed evenly to improve the anti-wear performance. The same experimental results were obtained when the authors added different types of trace rare earths to zQPb25, with the best addition of mixed light rare earths. On the basis of the experiment, it is further applied to the production of several bearing copper sleeves with 0.3% mixed light rare earth added to the lead bronze (ZQPb25) by trial production in several tug diesel engines instead of tin bronze ZQSn6-6-3 bearing copper Set (spindle copper and copper folder), after more than a year of practical use, the results show that: plus rare earth ZQPb25 ZQSn6-6-3 than the bearing copper sleeve with better wear resistance, reduced wear and tear 5 times or so: but also reduce the spindle wear and tear, protecting the spindle. As ZQSn6-6-3 bearing copper wear serious, the original provisions to be replaced once a year, but with rare earth ZQPb25 bearing copper sleeve, because the amount of wear is small, some are still continue to use.