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Ultra-supercritical high-nitrogen martensite cast steel and preparing method thereof

An ultra-supercritical and martensitic technology, applied in the field of heat-resistant steel, can solve the problems of low nitrogen solubility, nitrogen escape, nitrogen segregation, etc., achieve excellent high-temperature durable heat strength, ensure high-temperature durable heat strength, delay The effect of creep strain accumulation

Inactive Publication Date: 2020-01-03
TIANJIN UNIVERSITY OF TECHNOLOGY
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0005] The purpose of the present invention is to solve the problem that the solubility of nitrogen in the existing nitrogen-containing heat-resistant cast steel is low, and it is easy to cause nitrogen segregation and nitrogen escape during the solidification process, and to provide a super super cast steel with Hf and rare earth elements added. Critical martensitic cast steel, which is prepared by high-pressure vacuum technology and pressurized electroslag remelting technology, its structure is a complete martensitic structure, with good comprehensive mechanical properties and high temperature properties

Method used

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  • Ultra-supercritical high-nitrogen martensite cast steel and preparing method thereof
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  • Ultra-supercritical high-nitrogen martensite cast steel and preparing method thereof

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Experimental program
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Effect test

Embodiment 1

[0036] Embodiment 1: Preparation of ultra-supercritical high-nitrogen martensitic cast steel

[0037] The first step: according to the composition ratio (C: 0.03%; N: 0.1%; Cr: 9.0%; V: 0.5%; Nb: 0.03%; W: 6.5%; Co: 3.9%; Mo: 0.9%; Mn : 0.06%; Si: 0.05%; Ni: 0.015%; Hf: 0.02%; La+Ce: 0.01%; the balance is Fe) and alloy burning loss proportioning raw materials.

[0038] Step 2: Introduce a nitrogen protective atmosphere into the vacuum induction furnace, and add alloy raw materials in sequence according to the burning loss and volatilization characteristics of alloy elements. Nitrogen is added in the form of ferrochromium nitride. In the process, pressurization is adopted to ensure that the nitrogen element will not escape in the form of nitrogen, and the pressure is greater than or equal to 10 atmospheres;

[0039] Step 3: After the steel ingot is cooled, cut a small sample of the steel ingot for spectral analysis, and the measured chemical composition is qualified.

[0040...

Embodiment 2

[0042] On the basis of the alloy composition of Example 1, the content of nitrogen element is increased to 0.25%, and a rare earth alloy is added, and the specific method is as follows:

[0043] The first step: according to the composition ratio (C: 0.03%; N: 0.25%; Cr: 9.0%; V: 0.5%; Nb: 0.03%; W: 6.5%; Co: 3.9%; Mo: 0.9%; Mn : 0.06%; Si: 0.05%; Ni: 0.015%; Hf: 0.03%; La+Ce: 0.03%; the balance is Fe) and alloy burning loss proportioning raw materials.

[0044] Step 2: Introduce a nitrogen protective atmosphere into the vacuum induction furnace, and add alloy raw materials in sequence according to the burning loss and volatilization characteristics of alloy elements. Nitrogen is added in the form of ferrochromium nitride. In the process, pressurization is adopted to ensure that the nitrogen element will not escape in the form of nitrogen, and the pressure is greater than or equal to 10 atmospheres;

[0045] The third step: Alloying the smelted molten steel with rare earth. ...

Embodiment 3

[0049] On the basis of the alloy composition in Example 2, the nitrogen content was adjusted to 0.3%, and the vacuum pressure electroslag remelting process was carried out on the cast steel. The specific method is as follows:

[0050] The first step: according to the composition ratio (C: 0.03%; N: 0.3%; Cr: 9.0%; V: 0.5%; Nb: 0.03%; W: 6.5%; Co: 3.9%; Mo: 0.9%; Mn : 0.06%; Si: 0.05%; Ni: 0.015%; Hf: 0.05%; La+Ce: 0.04%; the balance is Fe) and alloy burning loss ratio raw materials.

[0051] Step 2: Introduce a nitrogen protective atmosphere into the vacuum induction furnace, and add alloy raw materials in sequence according to the burning loss and volatilization characteristics of alloy elements. Nitrogen is added in the form of ferrochromium nitride. In the process, pressurization is adopted to ensure that the nitrogen element will not escape in the form of nitrogen, and the pressure is greater than or equal to 10 atmospheres;

[0052] The third step: Alloying the smelted...

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Abstract

The invention discloses ultra-supercritical high-nitrogen martensite cast steel and a preparing method thereof. The ultra-supercritical high-nitrogen martensite cast steel mainly comprises, by weight,0.005-0.05% of C, 0.04-0.65% of N, 8.0-12.0% of Cr, 3.5-6.5% of W, 3.5-4.5% of Co, 0.5-1.5% of Mo, 0.4-0.8% of V, 0.01-0.15% of Nb, 0.03-0.80% of Mn, 0.02-0.10% of Si, 0.005-0.04% of Ni, 0.01-0.10% of Hf, 0.008-0.10% of La+Ce and the balance Fe. Mainly, by reducing the carbon content, increasing the nitrogen content and strengthening nitrides, the high-temperature performance and anti-oxidizationperformance of the heat-resistant cast steel are improved; by means of a proper amount of the trace element Hf and the rare earth elements La+Ce, the texture of steel is improved, and it is ensured that the complete martensite texture is finally obtained. By means of the preparing process with the combination of pressurized vacuum induction and pressurized electro-slag remelting, the solid solubility of nitrogen in the steel is effectively increased, and the texture of a steel ingot is more even and compact.

Description

technical field [0001] The invention belongs to the technical field of heat-resistant steel, and relates to a novel ultra-supercritical high-nitrogen martensitic cast steel and a preparation method thereof. Background technique [0002] At present, my country's energy utilization is dominated by primary energy applications, and my country's thermal power generation accounts for more than 75% of the total power generation. In order to alleviate the energy shortage problem, improving the efficiency of energy use is the primary task of the development of all countries in the world. The development of ultra-supercritical technology can improve energy efficiency, and steel for ultra-supercritical materials is the key to the development of this technology. At present, many countries maintain a positive attitude towards the research of this material. The United States, Japan, and Europe are the technology leaders of ultra-supercritical materials in the world. The research on ultr...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C22C38/02C22C38/04C22C38/44C22C38/46C22C38/48C22C38/52C22C33/06C21D6/00
CPCC21D6/004C21D6/005C21D6/007C21D6/008C22C33/06C22C38/001C22C38/002C22C38/005C22C38/02C22C38/04C22C38/44C22C38/46C22C38/48C22C38/52
Inventor 董治中孔维雄宁保群王志奇
Owner TIANJIN UNIVERSITY OF TECHNOLOGY