阅读说明：本技术 一种ls钢连铸浇注方法 (LS steel continuous casting pouring method ) 是由 汪祝红 于 2020-11-20 设计创作，主要内容包括：本发明方法公开了一种LS钢连铸浇注方法,按照如下步骤进行：1、联系保护渣生产厂家,包晶钢保护渣成份按说明书要求的各项指标进行控制生产；2、结晶器软水流量调整,由原来的115-120m3/h调整为100-105m3/h；3、在线结晶器保证每个流次符合3000吨以内的通钢量,否则安排更换不符合要求的结晶器。本发明方法能够解决钢水在结晶器内凝固过程,发生包晶反应和角部二维传热冷却不均匀产生角部裂纹,在结晶器下口发生角裂纹漏钢的问题。(The invention discloses an LS steel continuous casting pouring method, which comprises the following steps: 1. connecting protective slag manufacturers, and controlling the production of the peritectic steel protective slag according to various indexes required by the specification; 2. the soft water flow of the crystallizer is adjusted from the original 115-120m3/h to 100-105m 3/h; 3. the on-line crystallizer ensures that the steel passing amount of each flow is within 3000 tons, otherwise, the crystallizer which does not meet the requirement is arranged to be replaced. The method can solve the problems that peritectic reaction and uneven two-dimensional heat transfer and cooling of the corner part occur in the solidification process of the molten steel in the crystallizer to generate corner crack, and the corner crack leaks at the lower opening of the crystallizer.)

1. The LS steel continuous casting method is characterized by comprising the following steps: 1) the series protective slag manufacturer produces peritectic steel protective slag, and the components of the peritectic steel protective slag are controlled and produced according to the indexes of the following table;

2) the soft water flow of the crystallizer is adjusted from the original 115-120m3/h to 100-105m 3/h; 3) and the on-line crystallizer ensures that the steel passing amount of each flow is within 3000 tons, otherwise, the crystallizer which does not meet the requirement is arranged to be replaced.

Technical Field

The invention relates to an LS steel continuous casting method in a steel plant square billet continuous casting process, which realizes high-efficiency continuous casting by changing the existing casting process and twisting the difficulty of the LS steel casting in the square billet continuous casting process at present, and has very obvious economic benefit.

Background

The most common processes for continuously casting LS steel by small square billets are as follows: the blank shell cooling effect is unsatisfactory in the crystallizer, cause the blank shell to take place to tear in the crystallizer, the continuous casting billet very easily takes place angle crack bleed-out after going out the crystallizer end opening, it is very big to continuous casting secondary cooling destruction, further worsen continuous casting cooling process, the continuous casting process is forced to produce at low casting speed section always when pouring LS steel, can't realize the high-efficient continuous casting of billet, and the production rhythm of refining process and process smelting is disturbed, and bring the puzzlement for whole production rhythm, the performance of the first steelmaking branch factory productivity of steel mill has seriously been restricted. High-frequency steel leakage occurs in the continuous casting production process, workers generate fear during LS steel pouring, and even part of workers generate the psychological of frightening. How to further explore and research the prior art of the small square billet continuous casting LS steel is a problem which needs to be solved urgently by the small square billet continuous casting at present. The search literature discloses: (1) the method is characterized in that the Mungjun, Liuyi text is arranged between a small square billet steel leakage mechanism and a countermeasure in a paper published in the annual meeting of the five provinces of steelmaking academy in the east of China 2011, and states that molten steel is injected into a crystallizer, a meniscus is formed due to surface tension and density, a primary billet shell is formed at the root of the meniscus, the billet shell shrinks to generate an air gap, and the strength of the billet shell is reduced after heat regeneration, the billet shell is attached to a copper plate due to the hydrostatic pressure of the molten steel, and the process is repeated until the billet shell is discharged out of the crystallizer; when the carbon content is 0.10-0.18%, peritectic transformation occurs in the blank shell solidification process: (Be + L-gamma), the large air gap caused by the large shrinkage of the phase transition line affects the heat conduction of the crystallizer, which causes the uneven thickness of the blank shell, and because the corner part is two-dimensional heat transfer, the air gap is formed at first, the heat transfer is blocked, because the corner part has two-dimensional heat transfer all the time, the cooling strength is not low all the time, although the face part is one-dimensional heat transfer, the strength is higher all the time when the corner part is attached to the copper wall blank shell due to the action of hydrostatic pressure of steel, the phenomenon of weakening of the cooling strength occurs at the transition part of the corner part and the face part, a larger air gap is generated, the blank shell is thin, and when the blank shell is subjected to larger; (2) the book "research review of deformation and angular cracking bleed-out of continuous casting billet" in the text of "research review of deformation and angular cracking bleed-out of continuous casting billet" published in 2004 by xu Zhihong, xu, the book expresses "research result of angular cracking bleed-out of continuous casting billet, analyzes cause and mechanism of deformation and angular cracking bleed-out of continuous casting billet, and on the basis of the cause and mechanism, proposes the content of the basic idea of solving deformation and angular cracking bleed-out of continuous casting billet in the actual production process". (3) The afterglow is expressed in the text of ' small square billet continuous casting low-carbon steel longitudinal crack bleed analysis ' published in journal 2011 (4) of the first national committee for continuous casting youth working academic conference, ' the blank shell at the corner in the crystallizer has the fastest cooling speed and the largest temperature drop, the peritectic reaction occurs firstly, the volume shrinkage degree is the largest, and after an air gap is formed, the thermal resistance is larger at the position, so the blank shell at the corner is the thinnest. "is used herein. From the above information: at present, no factory and mining enterprises or scientific research institutions provide, and no actual measures and process changes are needed for peritectic reaction in the LS steel pouring process, so that the current situation of LS steel pouring at present is reversed.

Disclosure of Invention

The invention aims to provide an LS steel continuous casting pouring method which can solve the problems that during the solidification process of molten steel in a crystallizer, peritectic reaction occurs, corner cracks are generated due to nonuniform two-dimensional heat transfer and cooling of corners, and corner cracks and steel leakage occur at the lower opening of the crystallizer.

The technical scheme for realizing the invention is an LS steel continuous casting pouring method, which is carried out according to the following steps: 1. the peritectic steel covering slag of a linked protection slag manufacturer replaces the original low-carbon covering slag, the problem of lubrication and replacement between a copper wall of a crystallizer and a continuous casting billet is solved, and the peritectic steel covering slag components are controlled and produced according to various indexes in the following table;

2. the soft water flow of the crystallizer is adjusted from the original 115-120m3/h to 100-105m 3/h; 3. the on-line crystallizer ensures that the steel passing amount of each flow is within 3000 tons, otherwise, the crystallizer which does not meet the requirement is arranged to be replaced.

The inventors have found that during continuous casting, after the shell has shrunk away from the mould surface, the shell is re-pressed against the mould surface by the hydrostatic pressure of the molten steel. The shell is subjected to huge deformation stress, but the ductility of the shell is poor under high temperature, and when the deformation of the corner of the shell is larger than the critical deformation, corner cracks are generated. The Chuisy scientific teaching indicates that the non-uniformity of the shell thickness in the mold is the main cause of the crack generation. When the carbon content W (C) = 0.12% in the molten steel, the heat flow led out of the crystallizer is the lowest, and the billet shell is the thinnest. Song Wei Sn indicates that the casting blank has the worst plasticity when the Be ferrite and the Y austenite reach a certain proportion. Wolf, swiss metallurgist m.wolf considers: the steel containing 0.1% carbon has the smallest micro-segregation, because all ferrite is transformed into austenite just after solidification, and the largest local contraction is generated under the meniscus of the crystallizer, so that the crystal grains in the area are coarse (see, the enrichment of precipitates (sulfide, oxysulfide and the like) among the crystal grains is intensified, and the grain boundary of the billet shell is locally embrittled [6 ].

In the practical process of on-site production, the condition of the copper pipe of the LS just-off-line crystallizer is tracked: the method finds that when the steel passing amount of the crystallizer copper pipe is more than 3000 tons, the angular cracking and steel leakage are greatly increased when LS steel is produced. The taper of the copper pipe of the off-line crystallizer is measured, and the taper is reduced after abrasion, even a negative taper phenomenon occurs at a certain position. The inner cavity curve changes, the LS steel with larger shrinkage at the moment, the change of the inner cavity of the copper pipe cannot be adapted to the shrinkage of the blank shell, the nonuniformity of the blank shell is further aggravated, cracks are directly caused, and the steel leakage probability of corner cracks of the crystallizer is greatly increased. The inventor designs peritectic steel covering slag to replace the original low-carbon covering slag according to the discovery, and solves the problem of lubrication and replacement between the copper wall of the crystallizer and the continuous casting billet; the casting times in LS steel production ensure that the taper of the online crystallizer of each casting time meets the requirement; and optimizing the flow parameter of the soft water of the crystallizer. The process effectively reduces the probability of angle crack breakout in the LS steel pouring process, reduces the angle crack breakout of the LS steel from 14 times to 0-3 times in the original one pouring time, and well solves the impact of the angle crack breakout on production. The angle crack breakout is reduced by more than 10 times on the existing basis, each breakout can cause the picking of 1.72 tons of qualified casting blanks, 17.2 tons of qualified casting blanks are converted into scrap steel in total, the difference between the two is 1000 yuan/ton, one casting time generates economic benefit =17.2 × 1000=1.72 ten thousand yuan, at least not less than 60 casting times per year, and generates direct economic benefit =60 × 1.72=103.2 ten thousand yuan.

Detailed Description

An LS steel continuous casting pouring method comprises the following steps: 1. the peritectic steel covering slag produced by a linked protection slag manufacturer replaces the original low-carbon covering slag, the problem of the lubrication and replacement between the copper wall of a crystallizer and a continuous casting billet is solved, and the peritectic steel covering slag components are controlled and produced according to the indexes in the following table;

2. the soft water flow of the crystallizer is adjusted from the original 115-120m3/h to 100-105m 3/h; 3. the on-line crystallizer ensures that the steel passing amount of each flow is within 3000 tons, otherwise, the crystallizer which does not meet the requirement is arranged to be replaced.