Method for producing low-temperature impact resistance high-strength nodular cast iron

Abstract

The invention discloses a method for producing low-temperature impact resistance high-strength nodular cast iron, which comprises processes of material preparing, smelting, desulfurizing, molten iron adjusting and spheroidizing. The method is characterized in that: in the material preparing process, based on 100 percent, base iron accounts for 30 to 70 percent, steel scarp accounts for 10 to 20 percent, and recirculated iron accounts for 10 to 60 percent; other additives are added based on the total weight of the base iron, the steel scarp and the recirculated iron, wherein spheroidizing agent accounts for 1.6 to 2.0 percent, inoculant accounts for 0.4 to 0.6 percent, desulfurizer accounts for 1.2 to 1.8 percent, and carburant accounts for 1 to 3 percent; furthermore, 0.15 to 0.50 percent of Cu is added. On the premise of ensuring low temperature impact performance, the nodular cast iron improves strength,, meets the requirement that the nodular cast iron of the mark has higher low-temperature impact resistance and high normal-temperature strength, and can be widely used for manufacturing important high-strength cast of vehicles, locomotive, draught fans and engineering machinery used in low temperature environment and manufacture of cast having strict requirement on fatigue strength.

Description

technical field [0001] The invention relates to a production method of nodular cast iron, which belongs to iron-carbon alloy, in particular to a production method of low-temperature impact-resistant high-strength nodular cast iron. It is mainly suitable for the manufacture of important high-strength parts of automobiles and construction machinery used in low-temperature environments. Background technique [0002] Ductile iron mainly exists in the form of spherical graphite by using magnesium or magnesium alloy as a nodularizing agent. At present, nodular cast iron has been widely used. However, due to different application fields, the requirements for its performance are also different, and its production methods are also different. At present, my country's standards only specify the impact value and low-temperature impact value requirements for grades QT400-18 and QT400-18L ductile iron (as shown in Table 1), but for the material of grade QT450-10 ductile iron, due to rel...

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Problems solved by technology

Obviously, the grade QT450-10 ductile iron, in terms of low temperature impact toughness performance, its strength cannot meet the requirements of low temperature application at low temperature

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