Method for manufacturing steel ingots through ultra-supercritical steam turbine blade steel electro-slag remelting

A technology for steam turbine blades and electroslag remelting steel, which is applied to the manufacture of ultra-supercritical steam turbine blade steel electroslag remelting ingots, the manufacture of low Al steel ingots, and the field of high purity and low Si, and can solve the problem of the bottom end of electroslag ingots The difference in oxygen content and purity at the filling end, the large amount of element burning loss, and the lack of uniform chemical composition, oxygen content, and purity of electroslag ingots have achieved the effect of uniform purity

Active Publication Date: 2015-04-22
FUSHUN SPECIAL STEEL SHARES
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Due to the low content of silicon and aluminum, during the electroslag remelting process, the burning loss of elements in the steel is large, and the oxygen content of the gas increases, which leads to the increase of oxidized inclusions, and the oxygen content at the bottom end and filling end of the electroslag ingot It is very different from the purity, and it is difficult to ensure the uniformity of the overall chemical composition, oxygen content, and purity of the electroslag ingot
In order to solve this problem, many domestic manufacturers use argon or nitrogen devices in the crystallizer of ordinary electroslag furnaces, or use protective atmosphere electroslag furnaces, vacuum electroslag furnaces and other equipment to smelt this kind of low-silicon and low-aluminum stainless steel. The overall chemical composition, oxygen content, and purity of electroslag ingots are uniform; foreign countries use constant melting rate protective atmosphere electroslag furnaces and vacuum electroslag furnaces to smelt this kind of low-silicon and low-aluminum stainless steel, which can realize the overall chemical composition of electroslag ingots. , oxygen content, and purity are uniform, but the investment in smelting equipment is very large

Method used

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  • Method for manufacturing steel ingots through ultra-supercritical steam turbine blade steel electro-slag remelting
  • Method for manufacturing steel ingots through ultra-supercritical steam turbine blade steel electro-slag remelting
  • Method for manufacturing steel ingots through ultra-supercritical steam turbine blade steel electro-slag remelting

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Experimental program
Comparison scheme
Effect test

Embodiment 1

[0082] 1. Steelmaking process

[0083] ①Electric furnace process

[0084] The total furnace capacity is 31.83t, and the ingredients are high-quality steel scrap and pig iron; the alloy materials are low-chromium, metal chromium, nickel plate, tungsten iron, cobalt plate, molybdenum iron, vanadium iron, niobium iron, boron iron and Benxi Iron and steel return materials. Tapping control: C: 0.06%, P: 0.004%, tapping temperature 1684°C;

[0085] ②LF process

[0086] Use aluminum particles and carbon powder for diffusion deoxidation and maintain the atmosphere, the amount of aluminum powder is 35kg, CaC 2 The amount of powder is 75kg, added in two batches, the white slag time is guaranteed to be 40min, the tapping temperature is 1660°C, and S: 0.007%.

[0087] ③VOD / VHD furnace

[0088] After the molten steel is scraped to clean the initial slag, it is put into the VOD tank. Along with the slag material (lime, fluorite), add 49kg of deoxidizer Al powder, 15 kg of Ca-Si ...

Embodiment 2

[0098] 1. Steelmaking process

[0099] ①Electric furnace process

[0100] The total furnace capacity is 31.90t, and the ingredients are high-quality steel scrap and pig iron; the alloy materials are low-chromium, metal chromium, nickel plate, tungsten iron, cobalt plate, molybdenum iron, vanadium iron, niobium iron, boron iron and Benxi Iron and steel return materials. Tapping control: C: 0.07%, P: 0.005%, tapping temperature 1655°C;

[0101] ②LF process

[0102] Use aluminum particles and carbon powder for diffusion deoxidation and maintain the atmosphere, the amount of aluminum powder is 41kg, CaC 2 The amount of powder is 80kg, added in two batches, the white slag time is guaranteed to be 40min, the tapping temperature is 1670°C, and S: 0.006%.

[0103] ③VOD / VHD furnace

[0104] After the molten steel is scraped to clean the initial slag, it is put into the VOD tank. Along with the slag (lime, fluorite), add 35kg of deoxidizer Al powder, 20kg of Ca-Si bl...

Embodiment 3

[0114] 1. Steelmaking process

[0115] ①Electric furnace process

[0116] The total furnace capacity is 31.88t, and the ingredients are high-quality scrap steel and pig iron; the alloy materials are low-chromium, metal chromium, nickel plate, tungsten iron, cobalt plate, molybdenum iron, vanadium iron, niobium iron, boron iron and Benxi Iron and steel return materials. Tapping control: C: 0.06%, P: 0.005%, tapping temperature 1680°C;

[0117] ②LF process

[0118] Use aluminum particles and carbon powder for diffusion deoxidation and maintain the atmosphere, the amount of aluminum powder is 40kg, CaC 2 The amount of powder is 70kg, added in two batches, the white slag time is guaranteed to be 35min, the tapping temperature is 1680°C, and S: 0.005%.

[0119] ③VOD / VHD furnace

[0120] After the molten steel is scraped to clean the initial slag, it is put into the VOD tank. Along with the slag material (lime, fluorite), add 35kg of deoxidizer Al powder, 30kg of C...

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Abstract

The invention discloses a method for manufacturing steel ingots through ultra-supercritical steam turbine blade steel electro-slag remelting. Specifically, a smelting method adopting an electric-arc furnace, LF,VOD / VHD, double-supporting-arm electro-slag furnace remelting is adopted, components Si, Al and B of a consumable electrode is strictly controlled, the adding amount of Al powder or Fe-Si powder mixture is strictly controlled in the electro-slag slagging process, the oxidation burning loss of elements in the electro-slag remelting process is reduced by evenly and strictly controlling the adding amounts of the Al powder and the Fe-Si powder in a slag bath in the remelting process of the consumable electrode, and even and uniform integral chemical components, gaseous oxygen content and purity degree of electro-slag ingots are ensured. The method is suitable for smelting of common electro-slag furnaces, device input is reduced, and smelting cost is reduced. The low-Si, low-Al ultra-supercritical steam turbine blade steel gaseous oxygen content obtained by means of the method is smaller than or equal to 30*106, and non-metallic inclusions conform to assessment stipulations of ASTM E45 standard A law and accordingly meets the blade steel purity degree requirement for an ultra-supercritical steam turbine.

Description

technical field [0001] The invention belongs to the technical field of metal material refining, and relates to a method for manufacturing a high-purity, low-Si, and low-Al steel ingot, in particular to a method for manufacturing an electroslag remelted steel ingot for blade steel of an ultra-supercritical steam turbine. Background technique [0002] Stainless steel with a silicon content of ≤0.10% and an aluminum content of ≤0.015% is called low-silicon and low-aluminum stainless steel. The current chemical composition control requirements for ultra-supercritical generator blade materials require the use of such low-silicon and low-aluminum stainless steel. With the development of steam turbine manufacturing technology, the capacity of a single unit is getting larger and larger, and steam turbines are developing towards supercritical and ultra-supercritical units. High-purity steam turbine blade steel can ensure that the steam turbine blade has the required mechanical proper...

Claims

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Application Information

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IPC IPC(8): B22D23/10B22D7/00
CPCB22D7/00B22D23/10
Inventor 卢伦陈德利韩涛孙利军张秀丽王继红崔鸿刘振天李忠伟徐朋董晓亮张丽娜韩志远赵艳苏东起郭仁辉李骥
Owner FUSHUN SPECIAL STEEL SHARES
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