Heat-resistant ductile cast iron and preparation method thereof

Abstract

The invention relates to heat-resisting spheroidal graphite cast iron and a preparation method thereof. The preparation method comprises the following steps: smelting alloy, wherein the alloy comprises the following ingredients by mass: 2.7-3.5% of C, 4.0-5.0% of Si, 1.5-3.5% of W, 0.02-0.05% of Mg, 0.1-0.5% of V, Re being less than 0.03%, 0.15-0.6% of Mo, 0.05-1.0% of Mn, 0 to 0.03% of P, 0 to 0.02% of S, and the balance of iron and unavoidable impurities, discharging molten iron, inoculating the molten iron, spheroidizing, and casting. The heat-resisting spheroidal graphite cast iron prepared by the preparation method is of excellent high-temperature oxidation resistance, high-temperature anti-cracking property and thermal fatigue performance, and is good in mechanical property, low in production cost, and suitable for producing parts of an engine emission system.

Description

technical field [0001] The invention relates to a nodular cast iron material and a production process of the nodular cast iron, in particular to a heat-resistant material used in the production of exhaust system components such as exhaust manifolds, turbocharger housings, and catalyst boxes for automobile engines. Ductile iron. Background technique [0002] At present, the most widely used heat-resistant cast irons are medium-high-silicon ductile iron, medium-silicon-molybdenum vermicular iron and high-nickel austenitic cast iron. The existing ferritic ductile iron has good casting performance and excellent cutting performance, and the manufacturing cost is low, but there are relatively large limitations in heat resistance such as oxidation resistance and heat crack resistance, and the service temperature is less than 800 ℃. In recent years, with the high performance of automobile engines and the improvement of fuel utilization rate, the temperature of exhaust gas has been...

AI Technical Summary

Problems solved by technology

However, the graphite form of the heat-resistant cast iron can be spherical or worm-like. Due to the different graphite forms, the mechanical properties of the heat-resistant cast iron will also be quite different, and when the graphite form is worm-like, the oxidation rate of the material Faster, which reduces the heat resistance of the material

[0004] Chinese patent document CN101165200 discloses a high-silicon ferritic heat-resistant cast iron with high temperature strength and high oxidation resistance. The composition contains Si: 5% to 7%, Cr: 0.01% to 0.1%, and the content of Si is very high , leading to high brittleness of the material and difficult processing

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