薄壁铸钢件用自硬树脂砂应力与铸件裂纹的研究

Study on Stress of No bake Resin Sand Used for Thin Wall Steel Casting and Tears of Casting

热裂产生的主要原因之一就是型 (芯 )砂容让性差 ,尤其是用自硬树脂砂生产薄壁铸钢件时 ,这个问题显得特别突出。本文对型 (芯 )砂容让性的概念作了评述 ,在借鉴和改进了用于精确定量评价自硬树脂砂容让性好坏的应力试样的基础上 ,设计了裂纹试样。由浇注、加工、测量的结果得出型 (芯 )砂的容让性的准确值和造成铸件热裂的容让性临界值 ,为改善自硬树脂砂的容让性 ,防止铸件裂纹的形成 ,提供了有力的评定标准。

One of main reasons to result in casting hot tears is poor yieldability of the mold(core),particularly when thin wall steel castings are produced by a no bake resin sand,the problem is more serious.In this paper,the concept of yieldability of mold (core) is reviewed;and a tearing sample is designed based on referring to and improving the stress sample used in accurately quantificational judging the yieldability of no bake resin sand.On the base of the pouring,machining and measuring results,the accurate value and the critical value of mold (core) yieldability causing casting tears can be acquired.This presents a strong evaluation for improving yieldability of the no bake resin sand and eliminating casting tears.