Low-nickel austenite heatproof cast steel and smelting method thereof

Abstract

The invention relates to low-nickel austenite heatproof cast steel and a smelting method thereof. The cast steel is characterized in that: the cast steel comprises components of, by weight: 0.70-1.0% of C, 2.50-3.50% of Si, 12.0-14.0% of Mn, 19.0-22.0% of Cr, 0.4-1.0% of Ni, 0.35-0.50% of N, and balance of Fe and inevitable impurities. The smelting method comprises steps of: raw material preparing, feeding, material melting, calcium silicon and rare earth deoxidating, electromagnetic stirring, calcium silicon deoxidating, and ingot casting. According to the method, the cast steel is smelted by using a medium frequency induction furnace; components of the heatproof cast steel are optimized; smelting power is regulated; an electromagnetic stirring + argon shield refining method is adopted; and a calcium silicon + rare earth combined deoxidation method is adopted, such that low-nickel austenite heatproof cast steel is smelted. Through the regulation of the contents and ratio of C, N, andMn elements in the low-nickel austenite heatproof cast steel, the nickel content can be reduced, and stable monophase austenite tissues can be formed.

Description

technical field

[0001] The invention relates to a heat-resistant cast steel and a smelting method thereof, in particular to a low-nickel austenitic heat-resistant cast steel and a smelting method thereof, belonging to the technical field of iron and steel smelting. Background technique

[0002] Heat-resistant cast steel has good high-temperature strength and high-temperature oxidation resistance, and is widely used in heat-resistant fields such as high-temperature heating furnaces and boiler equipment. In order to improve the service temperature and high-temperature oxidation resistance of heat-resistant cast steel, heat-resistant cast steel used above 1000°C usually contains a relatively high proportion of Cr, and at the same time, more precious metal Ni is added to achieve the expansion of austenite. phase zone and the purpose of stabilizing austenite. For example, the commonly used 4Cr25Ni20Si2 steel (referred to as 25-20 steel) in the boiler burner nozzle of a power pla...