A kind of adding method of high-nitrogen chromium ferroalloy in the process of preparing cast steel

Abstract

The invention discloses an adding method for high-nitrogen ferrochrome during preparation of cast steel. The adding method comprises the steps of (a) grain size screening is conducted, specifically, the high-nitrogen ferrochrome are sorted and screened according to different grain size ranges; (b) drying is conducted, specifically, the high-nitrogen ferrochrome obtained after grain size screening is dried; and (c) alloy is added, specifically, the high-nitrogen ferrochrome with different grain size ranges is added sequentially according to the ratio by three times. Through the provided adding method for the high-nitrogen ferrochrome, the problem of low yield of a traditional adding method is solved, and the utilization rate of the alloy is increased.

Description

technical field

[0001] The invention relates to a method for adding ferroalloy, in particular to a method for adding high-nitrogen ferrochrome. Background technique

[0002] At present, the distribution of vanadium in the steel can be improved by adding nitrogen to the cast steel material. In the case of nitrogen deficiency in the cast steel material, most of the vanadium does not fully exert its precipitation strengthening effect, which can be said to be wasted. After adding nitrogen, the vanadium in the steel that was originally in a solid solution state becomes the vanadium in the precipitated state; the wear resistance and comprehensive performance of the steel are greatly improved, and the precipitation of V (C, N) in steels with different carbon contents The increase of the nitrogen content of the fortification effect was linearly increasing. However, the traditional method is to directly add molten steel in the ladle, and the nitrogen recovery rate is not higher than...

Examples

Embodiment 1

[0028] The amount of molten steel for smelting is 4.2t, and 50kg of high-nitrogen ferrochromium is added, of which 10kg is added to the bottom of the ladle with a particle size of ≤3mm, 15kg is added 5 minutes before tapping for 4-8mm, and 25kg is added 10 minutes before tapping for 9-50mm. After treatment, the N content increased from 0.0337% before treatment to 0.1157%, of which the content of high-nitrogen chromium, iron and nitrogen was 9.26%, and the N recovery rate was 74.41% according to the detection situation.

Embodiment 2

[0030] The amount of molten steel for smelting is 5.6t, and 60kg of high-nitrogen ferrochromium is added, of which 12kg is added to the bottom of the ladle with a particle size of ≤3mm, 30kg is added 7 minutes before tapping for 4-8mm, and 18kg is added 13 minutes before tapping for 9-50mm. After treatment, the N content increased from 0.0432% before treatment to 0.1214%, of which the high-nitrogen chromium iron nitrogen content was 9.58%, and the N recovery rate was calculated according to the detection situation to be 76.19%.

Embodiment 3

[0032] The amount of molten steel for smelting is 7.8t, and 150kg of high-nitrogen ferrochromium is added, of which 30kg is added to the bottom of the ladle with a particle size of ≤3mm, 75kg is added 7 minutes before tapping for 4-8mm, and 45kg is added 13 minutes before tapping for 9-50mm. After treatment, the N content increased from 0.0250% before treatment to 0.1765%, of which the high-nitrogen chromium iron nitrogen content was 9.35%, and the N recovery rate was 84.26% according to the detection situation.

technical field

[0001] The invention relates to a method for adding ferroalloy, in particular to a method for adding high-nitrogen ferrochrome. Background technique

[0002] At present, the distribution of vanadium in the steel can be improved by adding nitrogen to the cast steel material. In the case of nitrogen deficiency in the cast steel material, most of the vanadium does not fully exert its precipitation strengthening effect, which can be said to be wasted. After adding nitrogen, the vanadium in the steel that was originally in a solid solution state becomes the vanadium in the precipitated state; the wear resistance and comprehensive performance of the steel are greatly improved, and the precipitation of V (C, N) in steels with different carbon contents The increase of the nitrogen content of the fortification effect was linearly increasing. However, the traditional method is to directly add molten steel in the ladle, and the nitrogen recovery rate is not higher than...

Examples

Embodiment 1

[0028] The amount of molten steel for smelting is 4.2t, and 50kg of high-nitrogen ferrochromium is added, of which 10kg is added to the bottom of the ladle with a particle size of ≤3mm, 15kg is added 5 minutes before tapping for 4-8mm, and 25kg is added 10 minutes before tapping for 9-50mm. After treatment, the N content increased from 0.0337% before treatment to 0.1157%, of which the content of high-nitrogen chromium, iron and nitrogen was 9.26%, and the N recovery rate was 74.41% according to the detection situation.

Embodiment 2

[0030] The amount of molten steel for smelting is 5.6t, and 60kg of high-nitrogen ferrochromium is added, of which 12kg is added to the bottom of the ladle with a particle size of ≤3mm, 30kg is added 7 minutes before tapping for 4-8mm, and 18kg is added 13 minutes before tapping for 9-50mm. After treatment, the N content increased from 0.0432% before treatment to 0.1214%, of which the high-nitrogen chromium iron nitrogen content was 9.58%, and the N recovery rate was calculated according to the detection situation to be 76.19%.

Embodiment 3

[0032] The amount of molten steel for smelting is 7.8t, and 150kg of high-nitrogen ferrochromium is added, of which 30kg is added to the bottom of the ladle with a particle size of ≤3mm, 75kg is added 7 minutes before tapping for 4-8mm, and 45kg is added 13 minutes before tapping for 9-50mm. After treatment, the N content increased from 0.0250% before treatment to 0.1765%, of which the high-nitrogen chromium iron nitrogen content was 9.35%, and the N recovery rate was 84.26% according to the detection situation.