Lost wax casting metal material is mainly derived from outsourcing materials, the waste of this enterprise casting, casting riser.And outsourcing is often in bulk metal materials, very few have pressed into tubular, material is easy to confuse together, made of different materials such as material mixed with 304 or 430 316.Precision casting enterprise, therefore, as far as possible choose purchase compressed into tubular materials.The chemical composition of each batch purchasing material with a spectrum analyzer for analysis.Possible, on-the-spot investigation should be made for the supplier to evaluate whether the material storage for identification, protection and isolation, etc.To the scrap of the (waste casting, casting riser) to remove rust, degreasing, deoxidization and clean and dry processing, control of S, P elements.And scrap for different material must carry on the identification, protection, storage space, can't confused.