缸体砂芯组芯工艺与散装工艺的质量对比

Cylinder Block Quality Comparison between Using Preassembled Cores Setting Process and Using Scattered Cores Setting Process

对采用散装砂芯下芯工艺和采用砂芯预组装2种下芯工艺的缸体质量进行了比较。6DL缸体生产实践表明,与散装工艺相比,采用整体组芯工艺的优点是:(1)砂眼缺陷由0.77%降低到0.24%,加工发现砂眼缺陷由1.79%降低到0.46%,砂眼缺陷明显减少了;(2)砂芯之间增加了凹凸定位,保证了各个砂芯之间相对位置准确,提高了铸件尺寸精度,减少了加工余量忽大忽小的情况;(3)通过采用专用的浸涂涂料,使砂芯之间无间隙,减少了铸件内腔粘砂、披缝情况,提高了铸件的内腔质量;(4)采用整体组芯后,砂芯之间无间隙,浇注时无渗铁液现象,避免了因渗铁液导致的铸件报废,同时减少了铁液浇注质量,提高了工艺出品率。

Cylinder block quality comparison was conducted between using preassembled cores setting process and using scattered cores setting process. The production practice of 6DL model engine block showed,compared with using scattered cores setting process, using preassembled cores setting process had following advantages： （1）Sand inclusion defect was reduced from 0.77% to 0.24% ,sand inclusion defect found during machining was reduced from 1.79% to 0.46%.（2）Concave and convex location design between each cylinder cores was added that ensured the relative position of each cores correct, and thereby the dimension precision of castings was improved and the machining allowance fluctuation was reduced. （3） Special immersion coating was used that eliminated gap between cores and thereby the burning-on and finings defects in inner cavity of casting were reduced and therefore the quality of inner cavity of casting was improved. （d）After using preassembled cores setting process no gap existing between cores,therefore the casting rejection caused due to iron melt leakage during pouring process was avoided,and at the same time,the poring weight per casting was reduced and thereby the process yield rate was increased.