The bimetallic jaw wear-resistant castings were successfully poured by using bimetallic liquid pouring / transformation molding technology. The composite casting method includes two process steps of “changing the upper mold” and “bimetallic liquid pouring”. The process takes the pouring mode of high chromium cast iron and then low carbon steel, and the two metals are injected into the mold before and after the transformation respectively (as shown in the figure).
According to the analysis of bimetal microstructure by Guan Ping, the cast iron layer is mainly composed of tempered martensite and retained austenite; The carbon steel layer is typical eutectoid steel structure (ferrite and pearlite). The thickness of the transition zone is about that its composition also shows transition characteristics, the interface structure is uniform, dense and less defects, the two layers of metal show metallurgical bonding, and the initial impact resistance of the sample material is greatly improved.
The bimetallic liquid pouring / transformation molding process does not need quantitative pouring ladle, and the on-site operation is fast. The cast iron wear-resistant layer of jaw plate can be poured out directly; Before transformation, the metal upper mold has good heat dissipation performance, which is conducive to the rapid cooling of the high chromium cast iron poured in first, and can refine the grain; The combination can be controlled to any curved surface through numerical control processing. The wavy interface of the jaw plate in the figure above increases the bonding area between bimetals. The combination is firm and reliable, and can adapt to the production of bimetallic wear-resistant parts with arc curved surface and uneven interface thickness.