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A method for manufacturing high-nitrogen steel with carbon-containing ferrochrome

A technology for high nitrogen steel and decarburized ferrochromium, applied in the field of smelting high nitrogen stainless steel and smelting high strength stainless steel, can solve the problems of limited output, high price, difficult to add nitrogen, etc., to reduce solidification and remelting links, chemical quality The effect of accurate purpose and reduction of manufacturing cost

Active Publication Date: 2017-01-25
上海相济新材料科技有限公司
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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
[0004] In order to ensure the mass production capacity and quality of high nitrogen steel, it is very important to have a stable source of raw materials, especially the control of chemical composition and impurity elements in the production process of high nitrogen steel. Tests have shown that controlling the carbon content, CrN and Cr 2 N content is related to N dissolution stability and N escape control degree in high nitrogen steel smelting. For example, the higher the CrN content in ferrochromium nitride and high nitrogen ferrochromium, the more unstable N in molten steel is. On the contrary, Cr in ferrochrome nitride and high nitrogen ferrochrome 2 The higher the N content, the more stable the N in molten steel, and the Cr in the existing high-nitrogen ferrochromium and ferrochromium nitride raw materials 2 The content and relative amount of N and CrN fluctuate greatly, so it is difficult to guarantee the stability of high nitrogen steel product quality by directly using ferrochromium nitride and high nitrogen ferrochromium as nitrogen supply raw materials

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0038] Prepare about 1000kg of high-nitrogen steel, using the following raw materials: ①Carbon-containing ferrochrome is high-carbon ferrochrome powder (carbon 9wt%, chromium 60wt%, iron 30 wt%, other elements 1 wt%), and the particle size distribution ratio of the powder is detected For: 150-200 mesh accounts for 70%, 200-250 mesh accounts for 20%, ≥250 mesh accounts for 5%, ≤150 mesh accounts for 5%; 3wt%, oxygen 12wt%, other elements 1wt%), the particle size distribution ratio of the detected powder is: 150-200 mesh accounts for 80%, 200-250 mesh accounts for 15%, ≥250 mesh accounts for 3%, ≤150 mesh accounts for 3% 2%; ③ industrial pure iron (carbon ≤ 0.03wt%); ④ electrolytic manganese metal; ⑤ ferromolybdenum (molybdenum 60wt%); ⑥ other alloying elements.

[0039] step:

[0040] 1) Preparation of decarburized ferrochrome: set the weight of high-carbon ferrochrome powder as M c , the weight of carbonized ferrochromium oxide powder is M o , the weight after mixing the tw...

Embodiment 2

[0046] Prepare about 1000kg of high-nitrogen steel, using the following raw materials: ①Carbon-containing ferrochrome is medium-carbon ferrochrome powder (carbon 3.5wt%, chromium 64wt%, iron 32 wt%, other elements 1 wt%), and the particle size distribution of the powder is detected The ratio is: 150 mesh to 200 mesh accounts for 70%, 200 mesh to 250 mesh accounts for 20%, ≥250 mesh accounts for 5%, and ≤150 mesh accounts for 5%; Iron-based alloys with a content of ≤0.1wt%; ④Nitrogen-containing manganese metal melts with a nitrogen content of 2wt% obtained after vacuum smelting of electrolytic manganese metal and blown into nitriding gas; ⑤Fe-molybdenum (molybdenum 60wt%); ⑥Other alloys element.

[0047] step:

[0048] 1) Preparation of decarburized ferrochrome: set the weight of medium-carbon ferrochrome powder mixed with decarbonized ferrochrome oxide powder to be 400kg, calculated according to the molar ratio of 1:1.5, and the C / O is 12 / 24. The weight of carbon ferrochrome...

Embodiment 3

[0054] Prepare about 1000kg of high-nitrogen steel. The raw materials used are the same as in Example 1 except that the metal manganese is solid metal manganese that is poured after vacuum smelting using electrolytic metal manganese.

[0055] step:

[0056] 1) Preparation of decarburized ferrochromium: The proportion of ingredients and the briquette loading are the same as in Example 1. Put it into a vacuum heating furnace, heat up and vacuumize, and when the temperature reaches 1000 ° C, the pressure in the furnace drops to 200 Pa; the pressure in the furnace drops to 80a~100Pa; then rapidly raise the temperature to 1300°C and then slowly raise the temperature for 48 hours to make the temperature reach 1450~1490°C, control the pressure in the furnace to 70Pa~85Pa and then consider the end of decarburization;

[0057] 2) Prepare high-nitrogen ferrochrome intermediates by direct nitriding with decarburized ferrochrome blocks: Nitriding gas is passed into a vacuum heating furnac...

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Abstract

The invention provides a method for manufacturing high nitrogen ferrochrome intermediates by utilization of carbon-containing ferrochrome raw materials and for manufacturing high-nitrogen steel by utilization of high nitrogen ferrochrome intermediates directly. Chemical components of high-nitrogen steel can be controlled effectively, a low carbon content and a high and controllable nitrogen content are ensured, smelting of high-nitrogen steel with different nitrogen contents and with different component requirements are easy to control and refining effects can be achieved. The method is helpful for smooth melting of high-nitrogen alloy and other metal and alloys during the smelting process, nitrogen escape is reduced, a high-nitrogen steel melt with a high and stable nitrogen content can be obtained. Furthermore the obtained high-nitrogen billet has a high nitrogen content and has less bubbles inside, and the manufacturing cost can be lowered.

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 Patents(China)
IPC IPC(8): C22C33/06
Inventor 王淮孙岩铎
Owner 上海相济新材料科技有限公司
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