Effect of chiller design and material on the chilled zone property of the chilled cast iron roller

摘要

Using different methods to produce a roller with a good abrasive resistance at the surface layer and a good toughness at the center portion, the chill casting process is the best choice. This process is simple and its production rate is fast. Roller produced by this method is so called chilled iron roller. The object of this study is to investigate the effect of chiller design and material on the chilled zone property of the chilled iron roller (φ70mm×L120mm). At first, the chilled roller was made by the same chiller material with four kinds of dimensions. Experiment results showed that chilled iron roller, which radius is the same with the radial thickness of chiller, developed a good abrasive resistance at surface layer and a good toughness at the center. Then use of different materials (S45C, SKD61, FC200) of chiller with same size to cast the chilled roller. This was used to study the effects of thermal conductivity of chillers during solidification on the chilled zone of chiller. Finally, a linear regression equation between the thickness of chilled zone of the roller and the radial thickness of chiller was optimized, if the roller was made by using S45C chiller. Regarding the metallurgical parameters, the relations between the carbon and silicon contents of chilled gray iron roller, and the depth of chilled zone associated with hardness change of chilled iron roller are also discussed. The chilled zone of roller using the low C & Si is deeper than that using high C & Si. But the hardness at the surface layer of chilled zone is lower, if low C and Si were used. The relationships between the microstructures and the hardness distribution along the section of roller were also analysised and discussed.