Method for smelting high-grade pipe line steel with RH single-link process

A high-grade, pipeline steel technology, applied in the field of steelmaking, can solve the problems of high cost, lower temperature in the refining process, long cycle, etc., and achieve the effect of making up for heat loss, simplifying the smelting process, and reducing production costs.

Active Publication Date: 2014-12-24
SHOUGANG CORPORATION
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  • Claims
  • Application Information

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Problems solved by technology

Chinese patent 102732666A "Method for Controlling Non-metallic Inclusions in Medium and Heavy Plates of Anti-Hydrogen-Induced Cracking Pipeline Steel" discloses a method for deep desulfurization and control of inclusions on the basis of this dual-operation smelting pipeline steel process. There are disadvantages of long cycle and high cost
[0004] Chinese patent 200910084425.4 "A Method for Producing Pipeline Steel J55 by RH Refining Process" uses a single RH process to produce pipeline steel. This method is only for the production of J55 grade pipeline steel in a 210-ton converter, and the mass percentage of the final S element in the product is only Can be controlled to a level of ≤0.006%
In addition, this method only mentions the calcium treatment denaturation technology of MnS inclusions, and does not mention how to reduce the damage of hard calcium aluminate inclusions to the properties of steel, so it is far from meeting the performance requirements of higher-grade pipeline steels
For high-grade pipeline steel of X80 grade, if the RH single-link process is adopted, the sulfur content is difficult to control stably, and the temperature drop in the refining process greatly affects casting

Method used

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  • Method for smelting high-grade pipe line steel with RH single-link process
  • Method for smelting high-grade pipe line steel with RH single-link process
  • Method for smelting high-grade pipe line steel with RH single-link process

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Effect test

Embodiment 1

[0031] During the tapping process of the converter, before the tapping amount reaches 1 / 3 stage, aluminum and iron are added to the molten steel, and the mass percentage of aluminum in the molten steel after deoxidation is controlled to be 0.13% (see Table 1); the tapping amount reaches 1 / 3 to 2 / 3 stage, add lime 8kg / t steel to molten steel. After the steel tapping is completed, the top gun is used to blow argon gas to the molten steel for strong stirring, the intensity of argon blowing is controlled at 5NL / min / t steel, and the time of argon blowing is 8 minutes. After blowing argon on the molten steel, carry out RH vacuum treatment. After evacuating for 3.5 minutes and the vacuum degree is 984Pa, add desulfurizer to the molten steel through the vacuum silo. After adding the desulfurizer, keep the vacuum degree at 992Pa. RH vacuum cycle treatment of molten steel for 3 minutes (see Table 2), further deep desulfurization of molten steel. Among them, the addition amount of desu...

Embodiment 2

[0033] During the tapping process of the converter, before the tapping amount reaches 1 / 3 stage, aluminum and iron are added to the molten steel, and the mass percentage of aluminum in the molten steel after deoxidation is controlled to be 0.12% (see Table 1); the tapping amount reaches 1 From / 3 to 2 / 3 stage, add lime 9kg / t steel to molten steel. After tapping, use the top lance to blow argon gas to the molten steel for strong stirring, the intensity of argon blowing is controlled to 7NL / min / t steel, and the argon blowing time is 5 minutes. After blowing argon to the molten steel, carry out RH vacuum treatment. After evacuating for 4.5 minutes and the vacuum degree is 923Pa, add desulfurizer to the molten steel through the vacuum silo. After adding the desulfurizer, keep the vacuum degree at 984Pa, continue RH vacuum cycle treatment of molten steel for 3 minutes (see Table 2), further deep desulfurization of molten steel. Among them, the addition amount of desulfurizer is 4....

Embodiment 3

[0035] During the tapping process of the converter, before the tapping amount reaches 1 / 3 stage, aluminum and iron are added to the molten steel, and the mass percentage of aluminum in the molten steel after deoxidation is controlled to be 0.15% (see Table 1); the tapping amount reaches 1 / 3 to 2 / 3 stage, add lime 10kg / t steel to molten steel. After the steel tapping is completed, the top gun is used to blow argon gas to the molten steel for strong stirring, the intensity of argon blowing is controlled at 6NL / min / t steel, and the time of argon blowing is 7 minutes. After blowing the molten steel with argon, carry out RH vacuum treatment. After evacuating for 4.5 minutes and the vacuum degree is 977Pa, add desulfurizer to the molten steel through the vacuum silo. After adding the desulfurizer, keep the vacuum degree at 992Pa, continue RH vacuum cycle treatment of molten steel for 3 minutes (see Table 2), further deep desulfurization of molten steel. Among them, the addition am...

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Abstract

The invention provides a method for smelting high-grade pipe line steel with a RH single-link process. During a converter tapping process, high aluminum content in molten steel is controlled, such that desulfurization and impurity control in subsequent refining process can be benefited. During an RH vacuum refining stage, a desulfurization agent is added, and S content in the molten steel is controlled no higher than 0.0020%; oxygen blowing is carried out upon the molten steel, and a reaction is carried out between oxygen and aluminum in the molten steel, such that aluminum content in the molten steel is controlled at 0.03-0.05%. Also, heat loss during the desulfurization process is supplemented, and the impurity is converted into mainly clustered Al2O3 impurity which is easy to remove; and calcium treatment and soft blowing are carried out, such that the impurities in molten steel is mainly CaS impurities of small particles with deformation coefficient close to 1. According to the method provided by the invention, X80 pipeline steel quality requirement can be achieved, production process flow is short, and cost can be substantially reduced.

Description

technical field [0001] The invention relates to the technical field of steelmaking, in particular to a method for smelting high-grade pipeline steel by using an RH single-pass process. Background technique [0002] The strength and low-temperature impact toughness of pipeline steel are its important performance indicators. Therefore, in the smelting process of pipeline steel, deep desulfurization and inclusion control are the key technologies. The goal of control is that the mass fraction of sulfur in the finished product is ≤0.0020%. [0003] Pipeline steel smelting has many quality requirements and is difficult. At present, the conventional pipeline steel smelting steps are double operations: converter blowing→LF refining→RH refining→slab continuous casting. Chinese patent 102732666A "Method for Controlling Non-metallic Inclusions in Medium and Heavy Plates of Anti-Hydrogen-Induced Cracking Pipeline Steel" discloses a method for deep desulfurization and control of inclusio...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C21C7/10
Inventor 李海波朱国森高攀邵肖静吕迺冰杨健马耀峰亢小敏
Owner SHOUGANG CORPORATION
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