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Preparation method of high nitrogen steel

A high-nitrogen steel and molten steel technology, applied in the field of high-nitrogen steel smelting, can solve problems such as limited thickness of nitriding layer, long nitriding time, unsuitable for large-scale production, etc., and achieves obvious effects

Active Publication Date: 2015-08-26
KUNMING UNIV OF SCI & TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, the nitriding time of solid solution nitriding is long, and the thickness of the nitriding layer is limited. It is mainly used for surface modification and is not suitable for large-scale production.

Method used

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  • Preparation method of high nitrogen steel

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Effect test

Embodiment 1

[0023] In this embodiment, Cr9Mn11Ni0.5 austenitic stainless steel (see Table 1 for composition) is used as the processing object, and specifically includes the following steps:

[0024] Table 1 Composition of stainless steel Cr9Mn11Ni0.5 alloy used in experiments (%)

[0025]

[0026] (1) Place the alloy Cr9Mn11Ni0.5 austenitic stainless steel in the melting crucible 2, close the melting furnace, start the vacuum device 5 to evacuate to 100Pa, turn on the melting device 3 to heat the sample until it melts, open the nitrogen cylinder valve 4 to fill 0.6MPa industrial nitrogen (nitrogen purity over 99%); the molten metal is kept in a high-pressure nitrogen atmosphere for 20 minutes and the temperature of the molten metal is kept at 1450°C to ensure that the N 2 fully dissolved;

[0027] (2) Adjust the power to keep the molten metal at 1400°C (the liquidus temperature is 1430°C, and the solidus line temperature is 1330°C). The holding time is 5min, 10min, 15min, and 20min re...

Embodiment 2

[0031] This embodiment takes Cr9Mn11Ni0.5 austenitic stainless steel as the processing object, and specifically includes the following steps:

[0032] (1) Place the alloy Cr9Mn11Ni0.5 austenitic stainless steel in the melting crucible 2, close the melting furnace, start the vacuum device 5 to evacuate to 100Pa, turn on the melting device 3 to heat the sample until it melts, open the nitrogen cylinder valve 4 to fill 0.1MPa industrial nitrogen (nitrogen purity over 99%); the molten metal is kept in a high-pressure nitrogen atmosphere for 15 minutes and the temperature of the molten metal is kept at 1550°C to ensure N 2 fully dissolved;

[0033] (2) Adjust the power to keep the molten metal at 1380°C (the liquidus temperature is 1430°C, the solidus temperature is 1330°C), the holding time is 5min, 10min, 15min, 20min respectively, and the temperature is controlled during the whole process With the help of thermocouple 8, turn off the power of the equipment after the heat preser...

Embodiment 3

[0037] This embodiment takes Cr9Mn11Ni0.5 austenitic stainless steel as the processing object, and specifically includes the following steps:

[0038](1) Place the alloy Cr9Mn11Ni0.5 austenitic stainless steel in the melting crucible 2, close the melting furnace, start the vacuum device 5 to evacuate to 100Pa, turn on the melting device 3 to heat the sample until it melts, and open the nitrogen cylinder valve 4 to fill 2MPa industrial nitrogen (nitrogen purity over 99%); the molten metal is kept warm for 30 minutes under a high-pressure nitrogen atmosphere and the temperature of the molten metal is kept at 1400°C to ensure that the N 2 fully dissolved;

[0039] (2) Adjust the power to keep the molten metal at 1350°C (the liquidus temperature is 1430°C, the solidus temperature is 1330°C), the holding time is 5min, 10min, 15min, 20min respectively, and the temperature is controlled during the whole process With the help of thermocouple 8, turn off the power of the equipment aft...

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Abstract

The invention discloses a preparation method of high nitrogen steel, and belongs to the technical field of high nitrogen steel smelting. The method comprises specific steps of clearing up a smelting pot, preparing experimental steel, closing an induction furnace, carrying out vacuumizing treatment, after vacuumizing, starting a heating smelting device, smelting the experimental steel, and controlling the overheating degree of the temperature; opening a nitrogen inlet valve, inflating nitrogen to serve as a nitrogen source, after nitrogen in molten metal is satured, adjusting the power of an induction coil outside a casting crucible to control the cooling rate, preserving the temperature when the molten metal is below the liquid phase line temperature and above the solid phase line temperature, and cooling to the room temperature along with the crucible. The method is suitable for improving the content of nitrogen in the steel, and on the basis of the prior art, the nitrogen content in the steel can be further improved; and a new thinking is provided for high nitrogen steel preparation.

Description

technical field [0001] The invention relates to a preparation method of high nitrogen steel, which belongs to the technical field of high nitrogen steel smelting. Background technique [0002] Nitrogen alloying has many benefits for stainless steel: first, nitrogen alloying can significantly increase the strength of stainless steel, but does not reduce plasticity; secondly, nitrogen is a strong austenite stabilizing element, which can reduce or even replace nickel in stainless steel, economic benefits Significantly; in addition, nitrogen alloying can also improve the corrosion resistance of stainless steel. The steel whose nitrogen content exceeds the upper limit that steel can achieve under conventional smelting conditions (0.08% for ferrite matrix and 0.4% for austenite matrix) is called high nitrogen steel, because the solubility of nitrogen in austenite is much greater than its The solubility in ferrite and martensite, and the research work on nitrogen alloying are more...

Claims

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Application Information

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IPC IPC(8): C21C7/00C22C33/04
Inventor 金青林阳康
Owner KUNMING UNIV OF SCI & TECH
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