再生砂微粉含量对树脂砂强度的影响

Influence of Fines Content of Reclaimed Sand on Strength of Resin Sand

研究了再生砂微粉含量对树脂砂强度的影响。结果表明：为保证型（芯）砂终强度稳定在0．8～1．6MPa，必须严格控制再生砂微粉含量在2．0％以下；要保持抗拉强度不变，微粉含量越高，所需要的树脂加入量越多；大量微粉的存在不但降低树脂砂透气性，而且大量消耗树脂，导致树脂砂的发气量增大，发气时间延长。

The influence of fines content of reclaimed sand on strength of resin sand was investigated. The result showed that, in order to keep the final strength of resin sand in the range of 0.8~1.6 MPa,it＇s necessary to control strictly the fines content of reclaimed sand less then 2.0% ;in order to keep the tensile strength unchanged,the higher the fines content,the more the resin addition was needed. The existing of large amount of fines not only reduced permeability of the resin sand, and also consumed large amount of resin that would lead to gas evolution increasing, and lengthening of the gas evolution duration.