Rare earth silicon and magnesium nodulizer

Abstract

A rare-earth silicon-magnesium nodulizer is characterized in that the nodulizer comprises the following components by weight percentages: 25-35% of cerium in light rare-earth silicon magnesium, 37-52% of yttrium in heavy rare earth; 15-25% of silicon and 5-15% of magnesium. The rare-earth silicon-magnesium nodulizer further contains neodymium accounting for 5-8% of the total weight. In the rare-earth silicon and magnesium, the cerium in the light rare-earth silicon and magnesium and the yttrium in the heavy rare earth have obvious effect on graphite nodulizing. Firstly, the boiling point of the rare-earth silicon magnesium is higher than that of the magnesium, thus molten iron does not churn and splash when the rare-earth silicon magnesium is added to the molten iron; secondly, cerium-yttrium based rare-earth silicon magnesium has stronger desulfurization and deoxidation capacity than the magnesium, and the generated compounds such as sulfidized rare earth, oxide rare earth and the like have high melting point and good stability; and thirdly, the rare-earth silicon magnesium and nodulizing interference silicon magnesium in the molten iron can form a stable compound, thus the rare earth containing nodulizer has stronger anti-interference capacity than a magnesium nodulizer.

Description

technical field [0001] The invention relates to a rare-earth silicon-magnesium nodulizer, in particular to a rare-earth silicon-magnesium nodulizer for treating nodular cast iron. Background technique [0002] As we all know, the production of ductile iron nodularizer is essential. For castings with different wall thicknesses and different weights, the selection of nodulizers is different because of their inconsistent solidification and cooling conditions. For small thin-walled parts, solidification is fast and supercooling is large, which is suitable for the growth of spherical graphite, and carbides are also easy to appear, which increases the tendency of whitening. Especially when the residual magnesium exceeds 0.068%, carbides are more likely to be produced. Therefore, it is generally advisable to use low rare earth and low magnesium nodulizers. For castings with a wall thickness above 120mm, due to the low solidification rate in the center of the casting, there is a ...

AI Technical Summary

Problems solved by technology

For small thin-walled parts, solidification is fast and supercooling is large, which is suitable for the growth of spherical graphite, and carbides are easy to appear at the same time, increasing the tendency of whitening