型砂缺陷要点详解.pdf

Casting Defects Opportunities in the Foundry Industry! September 14-16, 2011 Casting Scene Investigator “CSI” Influences on Casting Defects Melting Gating and Operations Pattern Feeding Equipment Pouring Process Moulding Plant Defects Accidents – Oil Sand Preparation Leaks Core and Properties Production and Quality Casting Defect Reference • AFS Publication Greensand Control Four Basic Tasks: • Add the proper amount of water • Add the proper amount of bonding clay • Add the proper amount of carbonaceous material • Add the proper amount of new sand Since variations are introduced from the sand system design, there are three steps in system control • Identification of variables affecting consistency of the sand • Achieving control over the variables that can be controlled • Optimize conditions Questions To Ask Before You Decide Which Casting Defect • How many similar defects? • When does the defect occur? – Time of Day? – Day of the Month? – Etc • Is it in the same location each time? • Which impression on the pattern? • Did we change anything? Water As An Additive Primary Purpose • Activate the Clay in the molding sand. • Impart plasticity and bond strength to the clay binders system. • Make the molding sand system moldable!