Preparation method of high strength low temperature resistant nodular cast iron

Abstract

The invention relates to the field of spheroidal graphite cast iron, in particular to high-strength low-temperature-resisting spheroidal graphite cast iron and a preparing method thereof. The spheroidal graphite cast iron comprises, by mass percent, 3.2% to 3.5% of carbon, 2.1% to 2.3% of silicon, 0.4% to 0.5% of manganese, 0.4% to 0.6% of copper, 0.2% to 0.4% of nickel, 0.2% to 0.4% of molybdenum, 0.04% to 0.06% of magnesium, 0.05% to 0.08% of chromium, 0.005% to 0.008% of titanium, 0.002% to 0.003% of vanadium, not larger than 0.04% of phosphorus, not larger than 0.02% of sulphur and the balance iron. The preparing method of the high-strength low-temperature-resisting spheroidal graphite cast iron comprises following steps: firstly, raw materials are smelted; secondly, spheroidizing treatment and inoculation are carried out; and thirdly, heat treatment is carried out. Through reasonable arrangement of all element components, the tensile strength of the spheroidal graphite cast iron is improved, a proper nucleating agent is prepared, internal inoculation matched with inoculation in a ladle is adopted, the inoculation effect is reinforced, meanwhile, during heat treatment, the heating temperature, the heat preservation time, the cooling rate and the manner are reasonably arranged, the strength and low temperature resistance of the iron are effectively improved, the spheroidal graphite cast iron is high in strength and excellent in low temperature resistance, and the preparing method is simple and efficient.

Description

technical field [0001] The invention relates to the field of nodular cast iron, in particular to a preparation method of high-strength and low-temperature resistant nodular cast iron. Background technique [0002] Ductile cast iron is a high-strength cast iron material developed in the 1950s. It obtains nodular graphite through spheroidization and inoculation treatment, which effectively improves the mechanical properties of cast iron, especially the plasticity and toughness, thus obtaining a carbon Steel also has high strength. Its comprehensive performance is close to that of steel. It is based on its excellent performance that it has been successfully used to cast some parts with complex stress and high requirements for strength, toughness and wear resistance. Ductile iron has rapidly developed into a cast iron material that is second only to gray cast iron and is widely used. Due to its special performance, high-strength and low-temperature-resistant ductile iron has i...

AI Technical Summary

Problems solved by technology

The low temperature resistance of ordinary ductile iron is not enough, and the strength still needs to be further improved, which cannot meet the requirements of low temperature and high strength.

[0003] Chinese patent CN 105420592 A discloses a "low temperature resistant nodular cast iron and its preparation method". The nodular cast iron it provides has better low temperature resistance and toughness, but for low temperature environments, its strength needs to be further improved