【摘要】 介绍了6C船用柴油机油底壳的铸件结构及技术要求。用原工艺生产的铸件存在表面粗糙不良品率高的问题,分析了表面粗糙的原因及有关影响因素。为提高大型壳体类铸件的表面质量,采取了以下措施:(1)用再生砂代替擦洗砂,使用醇基石墨涂料,采取分层2次刷涂工艺;(2)通过将w(P)量从不大于0.035%提高到0.048%~0.070%,提高铁液流动性,将浇注温度由1 430℃降到1 375℃;(3)加强操作工艺管理,严格控制脱模时间、上涂料时间以及开箱时间。结果显示:铸件表面粗糙度得到改善,凸台和底面粘砂情况也得到明显改善,6C油底壳不良品率下降到32%,超过了车间预定的指标43%,减少了清理工序的工作量,降低了铸件人工成本。更多还原

【Abstract】 The configuration and technical requirement of 6C marine diesel engine bottom crankcase casting was introduced.Since the problem of high poor-quality products rate due to rough surface existing with the castings produced with former production process,the reason causing surface rough and relative influencing factors were analyzed. In order to improve the surface quality of big case-shaped castings the following measures were adopted:(1)Using reclaimed sand to substitute the scrubbed sand,using alcohol-base graphite coating and using layers-separating brushing process to conduct two times of brushing.(2)Improving fluidity of iron melt by increasing P content from 0.035% to 0.048% ~0.070%;depressing the pouring temperature from 1 430 ℃ to 1 375 ℃.(3)Reinforcing operation process management,strictly control stripping time,coating time and opening time. The result showed:the surface roughness of castings had been improved,the burning-on defect on the boss and bottom surface had been also obviously improved,the poor quality rate of the 6C bottom crankcase decreased to 32%which was better that the target rate of 43%,the working load of cleaning procedure was reduced and the labour cost of the castings was reduced.更多还原