Thick-wall large-diameter X80M pipeline clean steel and smelting method thereof

A smelting method and large-diameter technology, applied in the field of metallurgy to achieve the effect of facilitating slag premelting, reducing desulfurization pressure and improving internal quality

Active Publication Date: 2018-09-14
NANJING IRON & STEEL CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0002] At present, the high-grade pipeline steel X80M used in the China-Russia East Line of PetroChina and the new gas pipeline project of Sinopec has extremely strict requirements on the purity of molten steel. The requirements for inclusions in A, B, C, and D categories are all 1.5, and the product requires a wall thickness of 30.8mm or more. , the plate width is more than 3700mm, the billet is required to be more than 300mm, and the width is more than 2500mm, and the pass rate of inclusions is only about 88% using the existing production process

Method used

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  • Thick-wall large-diameter X80M pipeline clean steel and smelting method thereof
  • Thick-wall large-diameter X80M pipeline clean steel and smelting method thereof

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0024] A clean steel smelting method for a thick-walled large-diameter X80M pipeline provided in this embodiment includes the following steps:

[0025] S1. The desulfurization station uses lime and magnesium powder for composite desulfurization. After desulfurization, the slag is cleaned. S≤0.0020% in molten iron, and S≤0.0010% after converter;

[0026] S2. Steelmaking adopts the process route of BOF→LF furnace refining→RH refining→continuous casting; converter tapping temperature is 1660℃~1680℃; converter tapping adopts pre-melted refining slag + active lime for slagging;

[0027] S3. After the molten steel reaches the LF furnace, heat up the slag. The bottom blowing argon gas flow rate is 300Nl / min~500Nl / min during the temperature rise process. Add aluminum wire appropriately according to the slag condition, and then carry out desulfurization operation after reaching the white slag and submerging the arc. Lime is added Volume 1Kg / t, aluminum wire 0.1Kg / t, bottom blowing argo...

Embodiment 2～ Embodiment 6

[0031] A thick-walled and large-diameter X80M pipeline clean steel provided in Examples 2 to 6 is produced by the production method described in Example 1. The chemical composition and mass percentage are shown in Table 1, and the parameter control is shown in Table 2. The test results are shown in Table 3:

[0032] Table 1

[0033]

[0034]

[0035] Table 2

[0036] furnace number

Vacuum

vacuum time

calcium treatment

Stirring time

Large amount of surplus steel

superheat

Example 1

2mbar

20min

180m

20min

3t

39℃

Example 2

2mbar

20min

160m

20min

2t

37℃

Example 3

2mbar

20min

160m

20min

3t

36℃

Example 4

2mbar

20min

160m

20min

2t

35℃

Example 5

2mbar

18min

160m

20min

3t

38℃

[0037] table 3

[0038]

steel type

Inspection quantity / piece

Level 1.5 qualified quantity / piece

1.5 pa...

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PUM

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Abstract

The invention discloses thick-wall large-diameter X80M pipeline clean steel and a smelting method thereof, and relates to the technical field of metallurgy. The thick-wall large-diameter X80M pipelineclean steel comprises the followingchemical components of, by mass, 0.04-0.06% of C, 0.10-0.30% of Si, 1.70-1.80% of Mn, no more than 0.013% of P, 0.0010% of S, 0.060-0.070% of Nb, 0.006-0.020% of Ti, 0.20-0.30% of Ni, 0.10-0.20% of Cr, 0.10-0.30% of Cu, 0.10-0.20% of Mo, 0.015-0.050% of Al, 0.0005-0.0040% of Ca and the balance Fe and impurities. By changing the inclusion morphology and promotingachieving of the upward-floating mechanism of inclusions in the static mixing and standing processes, a production technique capable of effectively improving the smelting efficiency of the large-wall-thickness pipeline clean steel is provided, and the qualification rate of the 1.5-grade inclusions is stably increased to 99% or above.

Description

technical field [0001] The invention relates to the technical field of metallurgy, in particular to a thick-walled large-diameter X80M pipeline clean steel and a smelting method. Background technique [0002] At present, the high-grade pipeline steel X80M used in the China-Russia East Line of PetroChina and the new gas pipeline project of Sinopec has extremely strict requirements on the purity of molten steel. The requirements for inclusions in A, B, C, and D categories are all 1.5, and the product requires a wall thickness of 30.8mm or more. , The board width is more than 3700, and the blank needs to be more than 300mm and the width is more than 2500mm. The pass rate of inclusions in the existing production process is only about 88%. Contents of the invention [0003] The present invention aims at the above-mentioned technical problems, overcomes the shortcomings of the prior art, and provides a clean steel smelting method for thick-walled and large-diameter X80M pipeline...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C22C38/02C22C38/58C22C38/06C22C38/42C22C38/44C22C38/48C22C38/50C21C7/064C21C7/10C22C33/04
CPCC21C7/0056C21C7/064C21C7/10C22C33/04C22C38/002C22C38/02C22C38/06C22C38/42C22C38/44C22C38/48C22C38/50C22C38/58
Inventor 翟冬雨
Owner NANJING IRON & STEEL CO LTD
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