4H11V16缸体铸件缺陷分析与工艺改进

Defect Analysis and Process Improvement of 4H11V16 Cylinder Block Casting

4H11V16缸体铸件在小批量试制的过程中,废品率较高,使产品的合格率在77%左右一直无法有效提升。通过对缸体的制芯工艺、排气设计、组芯过程等方面进行深入的研究,并结合现场调查与计算机模拟分析,找到了原铸造工艺出现断芯、气孔、冷隔这三种主要缺陷产生的原因。采取了相应的改进措施:(1)通过调整砂芯配合间隙并对组芯工艺进行验证,同时开展水套芯刷涂料试验,解决了水套芯断芯的的问题;(2)通过优化砂芯烘干工艺、增加砂芯及型腔的排气通道、砂芯局部掏空等措施解决了气孔缺陷;(3)通过改进浇注工艺、增加集冷冒口等措施,使冷隔缺陷得以解决。工艺优化后,缸体铸件综合成品率由77%提升至94%以上。

In the process of small batch trial production of 4H11V16 cylinder block castings9 the rejection rate is high,which makes the product qualification rate around 77%unable to be effectively improved.Through in-depth research on the core making process,exhaust design,core assembly process and other aspects of the cylinder block,combined with field investigation and computer simulation analysiss the causes of the three main defects of the original casting process,namely,broken core,air hole and cold shut,were found.The problem of water jacket core breaking has been solved by adjusting the matching gap of sand core,verifying the core assembly process and conducting the coating test of water jacket core.The blowhole defect was solved by optimizing the drying process of sand core,increasing the exhaust channel of sand core and mold cavity,and local hollowing of sand core;The cold shut defect was solved by improving the pouring process and increasing the collector riser.After the process optimization,the comprehensive yield of cylinder block castings increased from 77%to more than 94%.