A method for manufacturing crankshafts from ductile cast iron based on iron sand-coated castings

Abstract

The present invention discloses a method for manufacturing crankshafts from ductile cast iron based on iron sand-coated castings, which falls within the field of metal matrix composite casting technology. This method comprises the precise attachment of porous TiC preforms to the surface of the connecting rod journal recess during the iron mold sand coating phase. During casting, the high-temperature-resistant ductile iron melt impregnates the pores of the preform. By utilizing the heat generated during casting, a metallurgical bond is formed between the TiC particles and the matrix. This process simultaneously forms a gradient-functional composite layer on the journal surface as the crankshaft is formed. This composite layer has a thickness of 0.2 to 1.0 mm with a TiC volume fraction of 30 to 50% and achieves a metallurgical bond with the substrate.This significantly improves the hardness, wear resistance, and corrosion resistance of the pin. By integrating the preparation of the surface composite layer with precision casting, the invention offers an efficient method that solves problems encountered with conventional surface composite materials, such as weak adhesion and complex manufacturing.