Ductile iron rare earth Mg-Si nodularizer

Abstract

The invention relates to a ductile iron rare earth Mg-Si nodularizer used in the conventional pour-over process spheroidization treatment of the ductile iron production process. The raw materials contain magnesium ingot, silicon calcium alloy, silicon barium alloy, rare earth ferrosilicon alloy and 75 ferrosilicon and comprise the following components by weight percent: 10-14% of Mg, 1.0-4.0% of Re, 35-50% of Si, 2.0-6.0% of Ca or Ca and Ba and the balance Fe. The nodularizer is produced by the conventional mix-melting method, is irregularly massive and has the grain size between 3-25mm to 5-40mm. By using the nodularizer of the invention, the magnesium content can be increased, the spheroidization treatment cost can be significantly reduced; and the spheroidization quality is stable, the roundness of graphite nodules is good, Re, Ca and Ba are added to realize the functions of purifying molten iron, promoting graphitization, delaying degradated spheroidization, promote nucleation to form fine-grained structure and the like.

Description

technical field [0001] The invention relates to a rare-earth magnesium-silicon spheroidizer for ductile iron, which belongs to alloy materials used in spheroidization treatment in the production process of nodular cast iron. Background technique [0002] In the production process of ductile iron, spheroidizing treatment is an essential link. In the existing production in our country, the spheroidizing treatment generally adopts the spheroidizing agent flushing method. Chinese patent CN91108271.9 (as-cast high-toughness ductile iron nodularizer) and CN91108270.0 (cast-state high-strength ductile iron nodularizer) have improved the nodulizer formula, and its nodularization effect is good, but the addition Large, the cost of spheroidization is high. Chinese patents CN00112456.0 (as-cast high-strength nodular cast iron cored wire nodulizer) and CN00112455.2 (as-cast high-toughness nodular cast iron cored wire nodulizer) have greatly improved the magnesium content in the formul...

AI Technical Summary

Problems solved by technology

Chinese patent CN91108271.9 (as-cast high-toughness ductile iron nodularizer) and CN91108270.0 (as-cast high-strength ductile iron nodularizer) have improved the nodulizer formula, and its nodularization effect is good, but the addition Large, high cost of spheroidization

Chinese patents CN00112456.0 (as-cast high-strength nodular cast iron cored wire nodulizer) and CN00112455.2 (as-cast high-toughness nodular cast iron cored wire nodulizer) have greatly improved the magnesium content in the formula and reduced the The addition amount has played a significant role in saving the cost of spheroidizing treatment and improving the effect of spheroidizing. However, because the application of cored wire-type spheroidizing agent requires the change of spheroidizing treatment process and the investment in wire feeding equipment, it is widely used in my country. subject to great restrictions

But on the other hand, due to the low melting point and boiling point of magnesium, when the spheroidizing agent is added, a large amount of magnesium will rapidly gasify, which will intensify the boiling of molten iron and reduce the absorption rate of magnesium, resulting in difficulty in controlling the spheroidizing process and unstable spheroidizing quality

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