Method for duplex smelting for high-nitrogen steel through pressurized ladle refining and pressurized electroslag remelting

A technology of pressurized electroslag and ladle refining, applied in the field of pressurized ladle refining and pressurized electroslag remelting double smelting of high-nitrogen steel, which can solve the problems of disturbing the smelting process, high requirements for measurement and control systems, and easy silicon increase, etc. question

Active Publication Date: 2021-06-04
NORTHEASTERN UNIV LIAONING
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  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

But there are the following deficiencies: (1) The continuous addition of nitrided alloys under high pressure requires extremely high requirements for the measurement and control system; (2) The decomposition of the nitrided alloys added to the slag causes the slag pool to boil, disturbing the melting process, and the use of silicon nitride It is easy to increase silicon when nitrogen is added; (3) In order to improve the composition uniformity of the ingot, it is often necessary to remelt twice or even three times

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  • Method for duplex smelting for high-nitrogen steel through pressurized ladle refining and pressurized electroslag remelting
  • Method for duplex smelting for high-nitrogen steel through pressurized ladle refining and pressurized electroslag remelting
  • Method for duplex smelting for high-nitrogen steel through pressurized ladle refining and pressurized electroslag remelting

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preparation example Construction

[0107] The preparation method provided by the present invention adopts the combination of bottom blowing nitrogen and pressurized gas phase-liquid steel interface nitriding to carry out nitrogen alloying, which has high efficiency and uniform nitrogen distribution, and then carries out pressurized electroslag remelting to further remove molten steel The inclusions and impurity elements in the high-nitrogen steel make up for the insufficient removal of inclusions and impurity elements in the pressurized ladle refining process, and improve the hot workability of the steel, so that the internal structure of the high-nitrogen steel is uniform and dense. The preparation method is simple and suitable for use. in industrial mass production.

[0108] In the present invention, the molten steel produced by AOD+LF furnace, VOD+LF furnace or converter+LF furnace is used as raw material, and nitrogen is blown from the bottom in a pressurized ladle furnace and gas phase-liquid steel interfac...

Embodiment 1

[0118] The smelting equipment used is an 80t pressurized ladle refining furnace and a 20t pressurized electroslag remelting furnace. The maximum pressure is 5MPa, the inner diameter D of the crystallizer is 950mm, and the weight of the consumable electrode is about 15t.

[0119] Calculated by formula I, formula II, formula V and formula VI to get p 1 is 0.40MPa, bottom blowing pressure p 2 is 1.02MPa, casting pressure p 5 It is 1.10MPa, the pressurized electroslag remelting pressure p 6 is 1.50MPa. The smelting raw materials and their quality are as follows: AOD+LF furnace produces 80.11t of molten steel, 80.30kg of nickel-magnesium alloy (80Ni-20Mg) and 40.13kg of cerium.

[0120] The composition of molten steel is: C: 0.33%, Mn: 0.42%, Cr: 15.50%, Si: 0.52%, Mo: 1.03%, S: 0.015%, P: 0.008% and the balance of Fe.

[0121] The target composition of high nitrogen martensitic stainless steel 30Cr15Mo1N is: C: 0.32%, Mn: 0.40%, Cr: 15.30%, Si: 0.50%, Mo: 1.0%, N: 0.40%, S: ≤...

Embodiment 2

[0138] The smelting equipment used is an 80t pressurized ladle refining furnace and a 20t pressurized electroslag remelting furnace. The maximum pressure is 5MPa, the inner diameter D of the crystallizer is 950mm, and the weight of the consumable electrode is about 15t.

[0139] Calculated by formula I, formula II, formula V and formula VI to get p 1 0.10MPa, bottom blowing pressure p 2 is 0.70MPa, casting pressure p 5 is 0.80MPa, and the pressure of electroslag remelting is p 6 is 1.50MPa. The smelting raw materials and their quality are as follows: VOD+LF furnace produces 80.12t of molten steel, 80.20kg of nickel-magnesium alloy (80Ni-20Mg) and 40.10kg of cerium.

[0140] The composition of molten steel is: C: 0.55%, Mn: 0.42%, Cr: 17.41%, Si: 0.46%, Mo: 1.13%, S: 0.020%, P: 0.008% and the balance of Fe.

[0141] The target composition of high nitrogen martensitic stainless steel 55Cr18Mo1VN is C: 0.54%, Mn: 0.40%, Cr: 17.30%, Si: 0.45%, Mo: 1.10%, N: 0.20%, S: ≤0.01%, ...

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Abstract

The invention provides a method for duplex smelting for high-nitrogen steel through pressurized ladle refining and pressurized electroslag remelting, and belongs to the technical field of high-nitrogen steel smelting. According to the invention, nitrogen alloying, deep deoxidation and deep desulfurization are sequentially carried out on molten steel in a pressurized steel ladle, and meanwhile, efficient nitrogen alloying is realized in the nitrogen alloying process in the mode that nitrogen bottom-blowing and pressurized gas phase-molten steel interface nitriding are combined, so that nitrogen is uniformly distributed, and the content of impurities in the molten steel is reduced through nickel-magnesium alloy and rare earth; and then the pressurized electroslag remelting is carried out, so that the content of inclusions and impurity elements in the molten steel is further reduced, segregation of the steel is improved, and the high-nitrogen steel is uniform and compact in structure. The result of the embodiment shows that the high-nitrogen steel is low in impurity content, uniform and stable in component and capable of meeting the use requirements in the fields of aviation, aerospace, petroleum, chemical engineering, energy, ocean, bioengineering and the like.

Description

technical field [0001] The invention relates to the technical field of high-nitrogen steel smelting, in particular to a method for double-linked smelting of high-nitrogen steel by pressurized ladle refining and pressurized electroslag remelting. Background technique [0002] As an important alloying element in steel, nitrogen can greatly increase the strength of steel without significantly reducing toughness through solid solution strengthening, fine grain strengthening and precipitation strengthening. The synergistic effect can improve the stability of the passivation film and enhance the repassivation ability, thereby significantly improving the corrosion resistance of steel. High-nitrogen stainless steel is a kind of stainless steel whose nitrogen content exceeds the equilibrium solubility at atmospheric pressure. It has better mechanical properties and corrosion resistance than traditional stainless steel. It has been widely used in aviation, aerospace, petroleum, chemic...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C21C7/072C21C7/00C21C7/06C21C7/064C22B9/18C22C33/04
CPCC21C7/072C21C7/06C21C7/064C21C7/0006C22C33/04C22B9/18C22C38/001C21D6/005C21D6/002Y02P10/25C21C5/005C21C7/0075C21C2007/0093C21C7/10C21D2211/001
Inventor 李花兵姜周华冯浩夏凌风朱红春张树才焦卫超
Owner NORTHEASTERN UNIV LIAONING
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