Method for preparing high-nitrogen steel from chromium concentrate powder

A technology for chromium concentrate powder and high nitrogen steel is applied in the fields of smelting high-strength stainless steel and high-nitrogen stainless steel. problems such as mass production of steel, to achieve the effect of wide and reliable source of raw materials, reduction of solidification and remelting links, and low carbon content

Active Publication Date: 2015-08-26
上海相济新材料科技有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

When smelting high-nitrogen steel at atmospheric pressure, nitrogen is difficult to add and easily escapes from the melt to form nitrogen gas, so it is generally smelted under high pressure, which limits the output
Some documents have proposed the method that can smelt high-nitrogen steel under normal pressure or near normal pressure, such as CN103451508A has proposed that the high-nitrogen alloy melt is flow-limited and blended into Fe-Cr-Mn melt, and CN103436768A has proposed that Fe-Cr- Mn melt is slowly blended into high-nitrogen alloy melt, CN103451509A proposes to add basic steel materials etc. in high-nitrogen alloy melt, and the main raw materials for adding Cr and N are all ferrochrome nitride and a small amount of high-nitrogen ferrochrome, and This kind of ferrochromium nitride and high nitrogen ferrochromium raw materials has a small output and high price, especially it cannot guarantee stable useful chemical composition requirements and impurity element restriction requirements, cannot meet the needs of mass production of high nitrogen steel, and cannot guarantee high High quality mass production of nitrogen steel
The use of carbon-reduced chromium oxide raw materials to prepare nitrogen-containing ferrochrome to directly manufacture high-nitrogen steel can have a stable source of raw materials and lower manufacturing costs and ensure product quality, but carbon-reduced chromium oxide is generally roasted with high-carbon ferrochrome To prepare, it needs energy consumption and there is smoke pollution and raw material loss

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0038] A representative Indian chromium concentrate powder is selected as the raw material for the embodiment of the present invention, and its compound composition content (wt%) is about: Cr 2 o 3 56.29, FeO16.20, Al 2 o 3 10.87, CaO0.60, MgO11.60, SiO 2 3.72 and sulfur 0.0062, phosphorus 0.01, others ≤ 1.0. In addition to chromium and iron oxides in the chrome concentrate powder raw materials, other oxides rarely participate in the reaction under the conditions of the present invention, so when preparing decarburized ferrochrome with high-carbon ferrochrome powder, it is only regarded as Cr 2 o 3 and FeO to participate in the chemical reaction; calculated chromium and oxygen in Cr 2 o 3 The content (wt%) in FeO is 68.4 and 31.6 respectively, and the content (wt%) of iron and oxygen in FeO is 77.8 and 22.2 respectively, so that the chromium content (wt%) in the chrome concentrate is 38.5, and the iron content (wt%) is 12.6, and the oxygen content (wt%) participating ...

Embodiment 2

[0048] Prepare about 1000kg of high-nitrogen steel, the main component content (wt%) is Cr18~20, Mn17~19, N0.8~0.9, Mo1.5~2.0, C≤0.03, Si≤1.5, S≤0.05, P≤0.05 . The raw materials used are the same as in Example 1.

[0049] step:

[0050] 1) Preparation of decarburized ferrochrome M=400kg: mix chrome concentrate powder and high-carbon ferrochrome powder according to the molar ratio of carbon to oxygen of 1:1.5 to obtain 188.1kg of chrome concentrate powder and 211.9kg of high-carbon ferrochrome powder , then add sodium silicate binder for mixing, and press it into brick-shaped mixed ferrochrome blocks of 50×100×200. After drying at low temperature, put them into a vacuum heating furnace. The internal pressure is 800Pa, and then the temperature is raised to 1200 to reduce the pressure in the furnace to 500Pa; when the temperature reaches 1500°C after keeping the temperature rising slowly for 5 hours, the pressure in the furnace is controlled at 100Pa and the decarburization rea...

Embodiment 3

[0055] Prepare about 1000kg of high-nitrogen steel, the main components are the same as in Example 1, except that the nitrogen content (wt%) of the solid nitrogen-containing metal manganese of 5.5 is cast after the vacuum smelting and then blown into the nitriding gas for the manganese used, other raw materials With embodiment 1.

[0056] step:

[0057] 1) The preparation of decarburized ferrochrome, nitriding and smelting of high-nitrogen alloy melt is the same as in Example 1;

[0058]2) To smelt high-nitrogen steel, first add 220kg of solid nitrogen-containing metal manganese to the high-nitrogen alloy melt at one time after vacuum smelting and then blowing in nitriding gas, and then add 20kg of molybdenum and iron to maintain the melt temperature after the metal manganese is melted Between 1550 and 1600°C, add 560kg of industrial pure iron to the melt one after another at a rate that does not solidify on the surface of the melt. After the industrial pure iron is completel...

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Abstract

The invention provides a method for preparing high-nitrogen steel from chromium concentrate powder. In the method, chromium concentrate is employed to replace carbon reduced chrome oxide as a main raw material for preparing intermediates of high-nitrogen steel and preparing high-nitrogen steel directly. The raw material source is wide and reliable, the operation of calcination of carbon-reduced chrome oxide by utilization of high-carbon ferrochrome is omitted, the production cost is lowered, the production efficiency is raised, smoke pollution is reduced, a low carbon content and a high and controllable nitrogen content can be ensured, melting of high-nitrogen steel with different component requirement can be controlled to ensure a low carbon content and a high and controllable nitrogen content, and high-quality high-nitrogen steel bases and castings can be obtained.

Description

technical field [0001] The invention relates to a method for smelting high-strength stainless steel, which belongs to the field of iron and steel smelting. Background technique [0002] High-nitrogen austenitic stainless steel (hereinafter referred to as high-nitrogen steel) has attracted the attention of the manufacturing industry and application fields for its excellent properties such as nickel saving, corrosion resistance, high strength, and high plasticity. It has gradually expanded its application range and can be used in wider application fields and It can be applied in more complex environmental conditions. [0003] High-nitrogen steel is mainly composed of chemical elements such as iron (Fe), chromium (Cr), manganese (Mn), nitrogen (N), and the nitrogen content is generally 0.6wt% to 1.0wt%. When smelting high-nitrogen steel at atmospheric pressure, nitrogen is difficult to add and easily escapes from the melt to form nitrogen gas, so it is generally smelted under ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C22C33/06C22C38/58
Inventor 王淮孙岩铎
Owner 上海相济新材料科技有限公司
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