灰铸铁缸盖整体水套芯冷芯工艺的失效与对策

Cold-Box Process Failure and Countermeasures in Production of Integral Jacket Core for Gray Iron Cylinder Head

分析了黄梅雨季水套芯失效原因,认为水分、温度、压力和时间是灰铁缸盖整体水套芯冷芯工艺的四大控制要点。对局部疏松失效、涂料烘干后变形失效、砂芯断裂失效,以及水腔脉纹失效原因也进行了详细分析,指出人为形成压力差是解决局部射不实的途径;对后期固化、不合理的升温速率和烘干温度的监控可以避免水套砂芯变形;吹胺量和吹胺吹气条件适当,冷芯盒砂芯不会断裂;而防止砂芯表面开裂和控制型内瞬时压力能杜绝脉纹缺陷的出现。

The reasons causing jacket core failure in the raining season were analyzed. It was considered that the moisture, temperature, pressure and time are four key points to control the cold-box process used to produce integral jacket core for gray iron cylinder heads. The reasons causing local looseness of the core, core deformation after coating having been dried, core breaking, as well as the veining defect in water cavity were also analyzed in detail. It was pointed out that artificially creating pressure difference is the way to avoid local looseness of the core; monitoring and controlling the post curing , improper temperature increasing rate and drying temperature can prevent the jacket core from deformation; when amine blowing volume and blowing conditions were proper, the cold-box cores would not break; as well as, keeping core surface from cracking and controlling the moment pressure in the mould can avoid veining defect.