制动鼓铸造工艺的改进

介绍了生产灰铸铁制动鼓铸件原来采用的铸造工艺:底注开放式浇注系统,铸件由两个边冒口补缩;生产结果:缩松废品率约为20%。为消除缩松缺陷,对原铸造工艺进行了改进:(1)只用一个冒口补缩铸件;(2)浇注系统仍为开放式,但取消横浇道,冒口直接设在直浇道下部;(3)采用宽度加大的冒口颈,改善补缩作用。试验结果:彻底解决了缩松问题,而且通过降低浇注速度、提高型砂性能和造型紧实度,有效控制了冲砂缺陷。

Improvement of Casting Method Used for Brake Drum

The former casting method of gray iron brake drum was introduced:the bottom non-pressurized gating system was adopted,the casing was fed with two side feeder.As the production result,shrinkage porosities-caused rejection rate was about 20%.In order to eliminate the shrinkage porosities,the former casting method was improved:1)Setting only one riser to feed the casting;2)The gating system was still non-pressurized but the runners were cancelled and the feeder was set immediately under the sprue;3)The riser neck with enlarged width was adopted to improve feeding effect.The test result showed that the shrinkage porosities defects were completely eliminated and,by reducing pouring rate,improving properties of the molding sand and increasing the compactness of sand mold,the new method-caused sand washing defects have been also solved.