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Heat-resistant tube for nitrogen-containing and niobium-containing boiler and preparation method thereof

A technology for heat-resistant tubes and boilers, applied in the field of heat-resistant tubes, can solve the problems of many molten steel oxidation inclusions, the performance of steel needs to be improved, and the deoxidation method is not sufficient, so as to improve surface cracks and peeling defects, excellent high temperature Anti-steam oxidation and flue gas corrosion performance, the effect of less inclusions

Inactive Publication Date: 2021-05-07
湖州盛特隆金属制品有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0003] However, the heat-resistant steel used in the existing heat-resistant pipes still needs to be optimized in composition and performance, and the deoxidation method in the smelting process is not sufficient, resulting in more oxidized inclusions in molten steel, which will affect subsequent rolling. Thermoplasticity, difficult rolling, can not achieve the effect of one fire
[0004] Therefore, the existing austenitic heat-resistant steel has the problems of too many inclusions, the performance of the steel needs to be improved, and the difficulty of rolling

Method used

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  • Heat-resistant tube for nitrogen-containing and niobium-containing boiler and preparation method thereof
  • Heat-resistant tube for nitrogen-containing and niobium-containing boiler and preparation method thereof
  • Heat-resistant tube for nitrogen-containing and niobium-containing boiler and preparation method thereof

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Effect test

Embodiment 1

[0035] A heat-resistant tube for boilers containing nitrogen and niobium, comprising the following components in weight percentage: C: 0.05-0.08%, Si: 0.2-0.6%, Mn: 0.8-1.5%, S≤0.005%, P≤0.030%, Cr: 25.0-27.0%, Ni: 20.0-21.0%, N: 0.22-0.28%, Nb: 0.40-0.50%, Mo: ≤0.5%, and the balance is iron and other unavoidable impurities.

[0036] A process for preparing a heat-resistant tube for a boiler containing nitrogen and niobium, comprising the following steps:

[0037] a, AOD reduction and desulfurization: control P<0.03%, O<0.004%, S<0.002% in the stainless steel liquid, get A product;

[0038] b. LF refining: further desulfurize and deoxidize product A, control O<0.0035% and S≤0.001% in molten steel, and use silicon-calcium wire to denature inclusions, so that the sum of eight inclusions in molten steel is ≤6.5 , get product B;

[0039] c. Casting: cast and process product B at low temperature, with a superheat of 60-70°C, to obtain product C;

[0040] d. Heating: raise the te...

Embodiment 2

[0044] TP310HCbN super austenitic stainless steel cast ingot is a nitrogen-containing and niobium-containing boiler heat-resistant tube, including the following components by weight percentage: C: 0.06%, Si: 0.39%, Mn: 1.29%, S: 0.001%, P: 0.027 %, Cr: 25.30%, Ni: 20.53%, N: 0.25%, Nb: 0.46%, V: 0.10%, and the balance is iron and other unavoidable impurities. The sum of the eight inclusions ≤ grade 3.5.

[0045] The preparation process of the above-mentioned heat-resistant pipe comprises the following steps:

[0046] a. AOD reduction and desulfurization: use stainless steel return material for smelting, p<0.025% in the return material, use appropriate amount of aluminum, low carbon, low sulfur super lime and fluorite, control P<0.03%, O<0.004 in molten steel %, S<0.002%, get A product;

[0047] b. LF refining: further desulfurization and deoxidation treatment of product A, using low-carbon, low-sulfur super lime and fluorite and deoxidizer for slag adjustment and slag surfac...

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Abstract

The invention discloses a heat-resistant tube for a nitrogen-containing and niobium-containing boiler and a preparation method thereof. The heat-resistant tube comprises the components in percent by weight: 0.05-0.08% of C, 0.2-0.6% of Si, 0.8-1.5% of Mn, less than or equal to 0.005% of S, less than or equal to 0.030% of P, 25.0-27.0% of Cr, 20.0-21.0% of Ni, 0.22-0.28% of N, 0.40-0.50% of Nb. A preparation process comprises the steps: controlling P to be less than 0.03%, O to be less than 0.0035% and S to be less than or equal to 0.001% in molten steel during steelmaking; conducting occluded foreign substance denaturating treatment by using a silicon calcium line; heating a steel ingot to 780-820 DEG C; preserving the temperature for 1.5-2.5 hours; then raising the temperature to 1250-1270 DEG C; preserving the temperature for 1.5-2.5 hours; and carrying out rolling to obtain a product. The heat-resistant tube has the characteristics of being few in occluded foreign substance, improving the thermoplasticity of subsequent rolling and improving the performance of steel.

Description

technical field [0001] The invention relates to a heat-resistant pipe, in particular to a heat-resistant pipe for nitrogen-containing and niobium-containing boilers and a preparation method thereof. Background technique [0002] Austenitic heat-resistant steel can be divided into solid solution strengthening type, carbide precipitation strengthening type and intermetallic compound strengthening type according to the strengthening type. The solid solution strengthened austenitic heat-resistant steel is mainly formed by adding W, Mo, N and other elements to form gaps and replace solid solutions, so that the steel is strengthened. This type of steel has good corrosion resistance and cold and hot workability, and the use state is Solid solution state, typical steel grades are TP304 and TP316, etc. [0003] However, the heat-resistant steel used in the existing heat-resistant pipes still needs to be optimized in composition and performance, and the deoxidation method in the smel...

Claims

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Application Information

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IPC IPC(8): C22C38/02C22C38/04C22C38/48C21D8/10C22C33/04
CPCC21D8/105C22C33/04C22C38/001C22C38/02C22C38/04C22C38/48
Inventor 袁飞蔡晓峰朱青青施勇顾从江王垒陶杰华
Owner 湖州盛特隆金属制品有限公司
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