Method for preventing slab continuous casting bonding bleed-out

Abstract

The invention discloses a method for preventing slab continuous casting bonding bleed-out, and relates to the technical field of continuous casting processes, the method comprises the following steps: selecting casting powder, and controlling the thickness of a liquid slag layer in a normal casting state to be 10-15mm; controlling the liquid level fluctuation of the crystallizer to be + / -3mm; the water gap insertion depth is controlled to be within a first threshold value range; and the change frequency of the withdrawal and straightening speed is controlled to be within a second threshold range. According to the method, the occurrence probability of bonding breakout accidents is reduced to the maximum extent, the slab continuous casting production efficiency and the product quality are comprehensively improved, huge economic losses caused by slab continuous casting bonding breakout are reduced, and considerable economic benefits are brought to iron and steel enterprises.

Description

Technical Field

[0001] The invention relates to the technical field of continuous casting technology, in particular to a method for preventing slab continuous casting from sticking and leaking. Background Art

[0002] Slab continuous casting is a solidification and shrinkage process in which molten steel changes from liquid to solid. It is one of the main links in steelmaking production and plays a key role in steelmaking production efficiency and production quality. In the slab continuous casting process, steel leakage, especially bonding leakage, is prone to occur due to various reasons such as production process, production materials and production equipment. Steel leakage accidents not only affect the continuous casting production efficiency and cause economic losses to the enterprise, but also the molten steel flowing out of the ingot shell in the crystallizer will damage the continuous casting equipment such as the crystallizer, fan-shaped segments and rollers, causing equipment accidents and even inducing production safety accidents. In order to effectively prevent bonding leakage from occurring in the slab continuous casting production process, it is necessary to invent an effective and feasible technical method. Summary of the invention

[0003] The technical problem to be solved by the present invention is to overcome the disadvantages of the prior art and provide a method for preventing steel leakage during slab continuous casting.

[0004] In order to solve the above technical problems, the technical solution of the present invention is as follows: A method for preventing slab continuous casting from sticking and breaking out, comprising: Select protective slag and control the thickness of the liquid slag layer to 10~15mm under normal casting conditions; Control the crystallizer liquid level fluctuation to ±3mm; Controlling the nozzle insertion depth to be within a first threshold range; The frequency of change of the straightening speed is controlled to be within a second threshold range.

[0005] As a preferred solution of the method for preventing slab continuous casting from sticking and breaking out of steel according to the present invention, after selecting the protective slag and controlling the thickness of the liquid slag layer to be 10-15 mm under normal casting conditions, the method further comprises: Control the amount of protective slag to be greater than 0.4kg / t.

[0006] As a preferred solution of the method for preventing slab continuous casting sticking and leaking of the present invention, wherein: the first threshold value range is 120mm~175mm.

[0007] As a preferred solution of the method for preventing slab continuous casting from sticking and breaking out of steel, the method of controlling the change frequency of the straightening speed to be within the second threshold range comprises: Control the straightening speed to be constant under normal casting conditions.

[0008] As a preferred embodiment of the method for preventing sticking breakout in slab continuous casting according to the present invention, after the frequency of controlling the strand withdrawal speed change is within the second threshold range, the method further includes: Determine the boundary between the thick and thin slag rings, and perform slag skimming operations on the slag rings with a thickness greater than the boundary between the thick and thin slag rings for several times.

[0009] As a preferred embodiment of the method for preventing sticking breakout in slab continuous casting according to the present invention, the boundary between the thick and thin slag rings is 3 mm.

[0010] The beneficial effects of the present invention are: The present invention minimizes the occurrence probability of sticking breakout accidents, comprehensively improves the production efficiency and product quality of slab continuous casting, and also reduces the huge economic losses caused by sticking breakout in slab continuous casting, bringing considerable economic benefits to iron and steel enterprises. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following will briefly introduce the drawings required for the description of the embodiments. Obviously, the following drawings are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0012] Figure 1 It is a flow chart of the method for preventing sticking breakout in slab continuous casting provided by the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0013] To make the content of the present invention more clearly understood, the following will further elaborate on the present invention based on the specific embodiments and in combination with the drawings.

[0014] Figure 1 It is a flow chart of the method for preventing sticking breakout in slab continuous casting provided by the embodiments of the present application. The method specifically includes the following steps: Step S101: Select a mold powder and control the thickness of the liquid slag layer in the normal casting state to be 10 - 15 mm.

[0015] Specifically, the principle for selecting the mold powder is: in the normal casting state, ensure that the thickness of the liquid slag layer is within the range of 10 - 15 mm. At the same time, the consumption of the mold powder is above 0.4 kg / t to effectively ensure the heat transfer effect and lubrication performance of the mold powder.

[0016] In this embodiment, the mold powder used is the mold powder of Qingdao Stoberg. In the normal casting state, the thickness of the liquid slag layer is 12 - 15 mm, and the consumption of the mold powder is 0.6 kg / t.

[0017] Step S102: Control the crystallizer liquid level fluctuation to ±3 mm.

[0018] Specifically, the crystallizer liquid level fluctuation is kept within the range of ±3mm. The stopper rod automatic control system should be used throughout the pouring process to ensure that the equipment works well.

[0019] If the flow performance of molten steel is poor and the liquid level fluctuation in the crystallizer is greater than the control range, the straightening speed should be immediately reduced and the stopper rod should be manually controlled to ensure that the liquid level fluctuation is in a stable state.

[0020] Step S103: controlling the water nozzle insertion depth to be within a first threshold range.

[0021] Specifically, determine the insertion depth to ensure service life. The nozzle insertion depth is related to the cross-section of the ingot and the straightening speed. Different cross-sectional shapes should have different insertion depths. Combined with practical experience, and considering the requirements of the nozzle slag line and the feasibility of operation, the nozzle insertion depth should be kept within the specified range. The nozzle insertion depth should be able to stably pass the slag line operation on the basis of fully ensuring the uniform flow of molten steel, and to a certain extent effectively extend the nozzle service life.

[0022] In this embodiment, the first threshold range of the nozzle insertion depth is 120 mm-175 mm.

[0023] Step S104: controlling the change frequency of the straightening speed to be within a second threshold range.

[0024] Specifically, under normal casting conditions, the straightening speed is controlled to be constant and unchanged.

[0025] Step S105: determining the slag ring thickness boundary line, and performing several slag scooping operations on the slag ring whose thickness is greater than the slag ring thickness boundary line.

[0026] Specifically, in order to reduce the thick slag ring phenomenon, it is necessary to determine the boundary line between the thin and thick slag rings to avoid adhesion and steel leakage accidents caused by thick slag strips.

[0027] In this embodiment, the dividing line between the thickness of the slag ring is 3 mm, that is, the slag ring with a thickness of more than 3 mm is used for slag scooping to ensure the stability of liquid slag flow and avoid adhesion and steel leakage accidents caused by thick slag strips.

[0028] It should be noted that when performing slag removal operations, it is necessary to follow the principle of small amounts and multiple times.

[0029] In addition, the imported steel leakage prevention alarm system of Voestalpine is used, which is always under full dynamic monitoring during the casting process. In order to ensure the working performance of the alarm system, the use of parts is checked regularly, and parts with quality problems and hidden dangers are replaced in time.

[0030] Therefore, the technical solution of the present application minimizes the probability of adhesion and steel leakage accidents, comprehensively improves the production efficiency and product quality of slab continuous casting, and also reduces the huge economic losses caused by adhesion and steel leakage in slab continuous casting, bringing considerable economic benefits to steel companies and promoting the high-quality development of steel companies.

[0031] In addition to the above embodiments, the present invention may also have other implementation modes; any technical solutions formed by equivalent replacement or equivalent transformation shall fall within the protection scope required by the present invention.

Claims

1. A method for preventing slab continuous casting from sticking and breaking out, characterized in that: include: Select protective slag and control the thickness of the liquid slag layer to 10~15mm under normal casting conditions; Control the crystallizer liquid level fluctuation to ±3mm; Controlling the nozzle insertion depth to be within a first threshold range; The frequency of change of the straightening speed is controlled to be within a second threshold range.

2. The method for preventing slab continuous casting from sticking and breaking out according to claim 1, characterized in that: After selecting the mold slag and controlling the thickness of the liquid slag layer to be 10-15 mm under normal casting conditions, the method further includes: Control the amount of protective slag to be greater than 0.4kg / t.

3. The method for preventing slab continuous casting from sticking and breaking out according to claim 1, characterized in that: The first threshold range is 120mm~175mm.

4. The method for preventing slab continuous casting from sticking and breaking out according to claim 1, characterized in that: The controlling the change frequency of the straightening speed to be within the second threshold range comprises: Control the straightening speed to be constant under normal casting conditions.

5. The method for preventing slab continuous casting from sticking and breaking out according to claim 1, characterized in that: After the control of the change frequency of the straightening speed is within the second threshold range, the method further includes: Determine the dividing line between the thin and thick slag rings, and perform several slag dredging operations on the slag rings whose thickness is greater than the dividing line between the thin and thick slag rings.

6. The method for preventing slab continuous casting from sticking and breaking out according to claim 5, characterized in that: The thickness dividing line of the slag ring is 3mm.

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