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A method for controlling inclusions in pipeline steel

A control method and pipeline steel technology, applied in the field of iron and steel, can solve the problems of easy crushing, long length of inclusions, exceeding the standard, etc., and achieve the effect of stable production and improved pass rate of first inspection

Active Publication Date: 2022-03-11
RIZHAO STEEL HLDG GROUP
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0003] However, it is easy to form composite inclusions after calcium treatment, such as calcium aluminate with low melting point, etc. The calcium aluminate with low melting point will soften at the rolling temperature and is easily crushed, thus forming intermittent long inclusions in the steel. Strip inclusions, which exceed the standard due to their longer length
[0004] Based on this, it is necessary to provide a method for controlling inclusions in pipeline steel to solve the problem of excessively long inclusions caused by calcium treatment in pipeline steel

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0041] A pipeline steel, which controls inclusions according to the following method, specifically including the following steps:

[0042] S1. Converter smelting: the end point temperature T is 1619°C, and T[O] is 594ppm;

[0043] S2. The tapping hole is good, the tapping time is 4.5min, the tapping time is 145 times (mainly the tapping time), the steel flow has no scattered flow phenomenon, and the tapping slag is blocked;

[0044] During the tapping process, 300kg of topping slag lime and 100kg of modifier are added for slag washing;

[0045] S3, refining in LF furnace:

[0046] (1) Refining time control: the refining time is 69 minutes;

[0047] (2) Micro-positive pressure control throughout the process;

[0048] (3) Aluminum supplementation in the process: no aluminum alloy is added within 8 minutes before soft blowing;

[0049] (4) Gas control: argon gas protection during wire feeding;

[0050] (5) The target of the final slag system is [CaO]: 58.35%, [Al 2 o 3 ]: ...

Embodiment 2

[0074] A pipeline steel, which controls inclusions according to the following method, specifically including the following steps:

[0075] S1. Converter smelting: the end point temperature T is 1618°C, and T[O] is 424ppm;

[0076] S2. The tapping hole is good, the tapping time is 5.1min, the number of tapping holes is 29 times (mainly the tapping time), the steel flow has no scattered flow phenomenon, and the tapping slag is blocked;

[0077] During the tapping process, 300kg of topping slag lime and 100kg of modifier are added for slag washing;

[0078] S3, refining in LF furnace:

[0079] (1) Refining time control: the refining time is 60 minutes;

[0080] (2) Micro-positive pressure control throughout the process;

[0081] (3) Aluminum supplementation in the process: no aluminum alloy is added within 8 minutes before soft blowing;

[0082] (4) Gas control: argon gas protection during wire feeding;

[0083] (5) The target of the final slag system is [CaO]: 57.83%, [Al ...

Embodiment 3

[0107] A pipeline steel, which controls inclusions according to the following method, specifically including the following steps:

[0108] S1. Converter smelting: the end point temperature T is 1646°C, and T[O] is 576ppm;

[0109] S2. The tapping hole is good, the tapping time is 4.1min, the tapping time is 129 times (mainly the tapping time), the steel flow has no scattered flow phenomenon, and the tapping slag is blocked;

[0110] During the tapping process, 300kg of topping slag lime and 100kg of modifier are added for slag washing;

[0111] S3, refining in LF furnace:

[0112] (1) Refining time control: the refining time is 77 minutes;

[0113] (2) Micro-positive pressure control throughout the process;

[0114] (3) Aluminum supplementation in the process: no aluminum alloy is added within 8 minutes before soft blowing;

[0115] (4) Gas control: argon gas protection during wire feeding;

[0116] (5) The target of the final slag system is [CaO]: 56.77%, [Al 2 o 3 ]: ...

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Abstract

The present invention relates to the technical field of iron and steel, in particular to a method for controlling inclusions in pipeline steel. The control method includes the following steps: S1, converter smelting; S2, tapping; S3, LF furnace refining: performing calcium pre-softening during the refining process. Blowing, calcium treatment and soft blowing after calcium, the target of the final slag system is [CaO]: 53%‑59%, [Al 2 o 3 ]: 26%‑34%, [SiO 2 ] ≤ 10%, [MgO] ≤ 10%, FeO+MnO ≤ 1.2%; S4, continuous casting machine protection casting billet. This control method meets the requirements of high production efficiency, stable product performance, and low cost, especially the production conditions of relatively high scrap steel. The process features are suitable soft blowing process, high cleanliness of molten steel, small secondary oxidation of continuous casting, and simple and easy operation. etc., this control method can improve the detection pass rate of pipeline steel inclusions, achieve the technical effects of reducing revisions, improving product quality and reducing costs.

Description

technical field [0001] The invention relates to the technical field of iron and steel, in particular to a method for controlling inclusions in pipeline steel. Background technique [0002] Pipeline steel has been widely used in the construction of oil and natural gas pipelines. In order to meet the ever-increasing toughness requirements of pipeline steel, especially the HIC (hydrogen-induced cracking) performance requirements of sour gas pipelines, in the past 60 years, technological People have made a lot of research on reducing the S content in steel. Ca treatment is a key technology in the production of pipeline steel. Its purpose and function is to spheroidize and modify the sulfide (mainly in the form of MnS in molten steel) in the steel, that is, to become spherical non-deformable inclusions with high melting point. CaS to improve the crack resistance of pipeline steel. w([Ca]) / w([S]) is in the range of 1.5 to 3.0. Since the solubility of calcium in molten steel is ...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C22C33/04C21C7/00C21C7/072B22D11/18B22D11/111
CPCC22C33/04C21C7/0056C21C7/0087C21C7/072B22D11/18B22D11/111
Inventor 秦哲张俊志鲍振振王中辉李晓冬王云东朱志强刘先同张万金蒲锐张海波王锃董光军薛俊峰汪晓川
Owner RIZHAO STEEL HLDG GROUP
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