| 摘要 |
<p>Foundry aggregate particles are precoated with carbonaceous material having a ring and ball softening pt. of 50-200 deg.C. The particles are mixed with foundry binder and water to form a mixt. contg. 2-15 wt. % binder and up to 5 wt. of carbonaceous material (based on total weight of aggregate). The compsn. is also claimed in wich the aggregate particles are also coated with the binder. The carbonaceous coating prevents sand burning onto the castings, so smoother and defect-free castings can be produced. By precoating the particles with the carbonaceous material, the problems caused by dust are avoided. Precoating with the material and with binder improves the green strength of the mould and leads to more efficient use of binder.</p> |
