Novel austenitic stainless steel for ultra (super) critical coal-fired unit

Abstract

The invention relates to heat-resistant austenitic steel, and particularly relates to novel austenitic stainless steel for an ultra (super) critical coal-fired unit. The novel austenitic stainless steel is characterized by comprising the following raw materials by mass percent: no more than 0.1% of C, no more than 0.5% of Si, no more than 1% of Mn, 19-23% of Cr, 28-33% of Ni, 0.20-0.45% of Nb, 0.90-2.10% of Mo, 12.51-3.02% of Al, no more than 0.04% of P, no more than 0.01% of S, 0.010-0.15% of N, 0.001-0.010% of B and the balance of Fe. The high-temperature tensile strength (greater than or equal to 460MPa at 600 DEG C), the lasting creep properties (the lasting ultimate strength is greater than equal to 110MPa under the conditions at 600 DEG C and 100,000 hours), and the high-temperature oxidation resistance (the oxidation increase is smaller than or equal to 0.036mg/cm<2> under the conditions at 700 DEG C and100 hours) of the austenitic stainless steel disclosed by the invention are much better than these of the traditional Incoloy800 austenitic stainless steel; the novel austenitic stainless steel can be widely applied to the fields such as the ultra (super) critical coal-fired unit, agricultural engineering, chemical engineering, foods, livelihood appliances and the like.

Description

technical field [0001] The invention relates to heat-resistant austenitic steel, in particular to a new type of austenitic stainless steel for super (super) critical thermal power units. Background technique [0002] Large-capacity, high-parameter ultra-(ultra)critical thermal power generation units are currently the development direction of thermal power units in the world. The steel used for ultra-(ultra)critical thermal power units has high-temperature tensile strength, durable creep performance and high-temperature oxidation resistance of steel. Put forward extremely high requirements; traditional Incoloy800 series alloys, the composition mass fraction is C≤0.1%, Si≤1.00%, Mn≤1.5%, Cr19~23%, Ni30~35%, Al0.15~0.60%, Ti0 .15~0.60%, Cu≤0.75%, P≤0.045%, S≤0.015%, and the rest is Fe; although it has high high temperature tensile strength (600℃, about 443MPa), durable creep performance (600℃ , 100,000 hours of durable ultimate strength is about 107MPa) and high temperature ox...

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Problems solved by technology

[0002] Large-capacity, high-parameter ultra-(ultra)critical thermal power generation units are currently the development direction of thermal power units in the world. The steel used for ultra-(ultra)critical thermal power units has high-temperature tensile strength, durable creep performance and high-temperature oxidation resistance of steel. Put forward extremely high requirements; traditional Incoloy800 series alloys, the composition mass fraction is C≤0.1%, Si≤1.00%, Mn≤1.5%, Cr19~23%, Ni30~35%, Al0.15~0.60%, Ti0 .15~0.60%, Cu≤0.75%, P≤0.045%, S≤0.015%, and the rest is Fe; although it has high high temperature tensile strength (600℃, about 443MPa), durable creep performance (600℃ , 100,000 hours of durable ultimate strength is about 107MPa) and high temperature oxidation resistance (700 ℃, 100 hours of oxidation weight gain is about 0.04mg / cm 2 ), but it is still difficult to fully meet the requirements of high-temperature tensile strength, durable creep performance and high-temperature oxidation resistance of high-temperature steel for large-capacity, high-parameter super (super) critical thermal power generating units

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