CN201026526Y - High steel flux submerged nozzle for thin slab continuous casting - Google Patents

Abstract

A high molten steel flux submerged nozzle for thin slab continuous casting related to continuous casting equipment, which is composed of a circular tube-shaped molten steel inflow end, a flat molten steel outflow end, and a connection between the molten steel inflow end and the molten steel outflow end The slender cylindrical body with a smooth and continuous cross-section is composed of three parts. The molten steel outflow end is in the form of a four-open hole structure with left and right symmetry. method, the horizontal diversion angle α of the lower edge is between 25° and 30°, the two lower discharge holes are divided by the center diversion body, the center diversion body has a large aspect ratio, and the horizontal diversion angle β is 75-80° °, the maximum dimension L in the width direction of the nozzle at the molten steel outflow end is between 270 and 300mm, which is used to meet the requirement that the molten steel flux is greater than 3.8t/min. The structural features of the utility model can move up the high-temperature zone of the melting pool of the crystallizer and control the fluctuation of the liquid level of the melting pool, and can satisfy high flux of molten steel.

Description

High steel flux submerged nozzle for thin slab continuous casting

technical field

The utility model relates to metallurgical continuous casting equipment, in particular to a submerged nozzle for thin slab continuous casting.

Background technique

Continuous steel casting (referred to as continuous casting) is a technology that continuously condenses molten steel into billets, in which the water-cooled copper mold is called a crystallizer, and the nozzle made of refractory material connects it with the tundish, and the molten steel passes through The nozzle is continuously injected into the crystallizer for cooling.

The thickness of the slab produced by thin slab continuous casting is generally between 50 and 90 mm, and the width is about 1000 to 1650 mm. Different from the flat plate mold of the conventional slab continuous casting machine, the wide-faced copper plate of the thin slab continuous casting mold usually has a curved surface composed of continuous arc transitions, such as the funnel-shaped crystallization of SMS CSP thin slab continuous casting machine H2 crystallizer (long funnel type) for Thin Slab Continuous Casting Machine of Danieli Company. The funnel-shaped crystallizer realizes the expansion of the upper space of the molten steel pool, makes it possible to inject molten steel with a submerged nozzle, and provides basic conditions for the melting and feeding of protective slag on the surface of the molten pool. On the other hand, limited by the increase in the upper space of the funnel-shaped mold, the liquid steel outflow end of the submerged nozzle for thin slab continuous casting machines is generally processed into a flat shape, that is, the dimension along the width of the mold is significantly larger than that along the width direction of the mold. Dimensions in the thickness direction. The molten steel inflow end where the nozzle is connected to the tundish is usually in the shape of a circular tube, and the connection between the inflow end and the outflow end is an elongated cylindrical body with a smooth and continuous transition in section shape.

As a protective agent to prevent the oxidation of molten steel and a lubricant to reduce the movement resistance between the solidified billet shell and the copper plate of the mold, the solid particle mold powder added to the liquid surface of the molten steel pool of the mold needs to be provided by high-temperature molten steel. And melt. The melting condition of the mold powder and the quality of the copper plate fed into the mold and the solidified slab shell have a significant impact on the smooth flow of the continuous casting process and the surface quality of the slab, which requires that the high-temperature molten steel from the submerged nozzle is relatively concentrated in the mold melting. In the upper part of the pool, it is especially necessary to ensure that the liquid level of the molten pool between the submerged nozzle and the mold copper plate is active. Thin slab continuous casting machine funnel-type mold liquid steel pool surface space is limited by the thickness of the cast slab and the submerged nozzle. Therefore, it is particularly important to use the high-temperature molten steel from the submerged nozzle to ensure and promote the activation of the molten pool liquid level. Important, the structure of the molten steel outflow end of the nozzle will play an important role here. However, the liquid level of the active mold molten steel pool should also be properly controlled. Excessive activity will aggravate the undulation and fluctuation of the molten pool liquid level, which will cause slag entrainment and cause billet quality and process operation accidents.

Focusing on the control trend of the molten steel movement behavior in the molten pool of the thin slab continuous casting mold mentioned above, the funnel-shaped mold of the CSP thin slab continuous casting machine of SMS company adopts a large opening and a flat nozzle with double-sided holes (see Figure 1), Danieli The H2 crystallizer of the company's thin slab continuous casting machine uses a four-hole flat nozzle (see Figure 2). The submerged nozzle shown in Figure 1 is an ordinary double-sided hole nozzle. The large-opening side hole structure design can reduce the jet intensity of the molten steel outflow nozzle, thereby reducing the impact on the molten steel pool of the mold to a certain extent. As shown in Figure 2, the four-hole submerged nozzle directly transports the high-temperature molten steel to the liquid surface of the molten pool around the nozzle through the upper discharge hole, and the high-temperature zone is moved upwards, but because the molten steel jet from the upper discharge hole is basically vertical Upward, the impact on the liquid level of the molten steel pool of the mold is more serious.

The flux of molten steel plays a decisive role in moving up the high temperature zone of the molten pool of the mold and controlling the fluctuation of the liquid level in the molten pool, which is related to the cross-sectional size of the billet and the casting speed. At present, the molten steel flux of various thin slab continuous casting machines is generally around 3.0t/min. Although the current submerged nozzles for various thin slab continuous casting can basically meet the requirements The problem of casting machine productivity has gradually been raised, and the high flux of molten steel brought about by increasing the casting speed has obviously aggravated the fluctuation of the liquid level of the molten pool of the mold. At present, the flux of molten steel required to be satisfied by the nozzle has reached 3.8t/min.

Contents of the invention

In order to solve the above-mentioned technical problems, the utility model provides a submerged nozzle that can move the high temperature zone of the molten pool of the crystallizer upward, control the fluctuation of the liquid level of the molten pool, and meet the high flux of molten steel.

The main technical solutions of the utility model are as follows:

A flat submerged nozzle for a thin slab continuous casting machine crystallizer, which is composed of a circular tube-shaped molten steel inflow end, a flat molten steel outflow end, and a cross-sectional shape connecting the molten steel inflow end and the molten steel outflow end The elongated cylindrical body with smooth and continuous transition consists of three parts. Its main technical feature lies in the structure of the molten steel outflow end.

The liquid steel outflow end of the utility model is in the form of left and right symmetrical four-hole structure. The upper edge of the two upper spout holes adopts the method of gradually shrinking the section from the inside to the outside, and the horizontal diversion angle α of the lower edge is 25-30°. In between, the two lower spout holes are divided by the central diversion body, the central diversion body has a large aspect ratio, the horizontal diversion angle β is between 75° and 80°, and the maximum dimension L in the width direction of the nozzle at the molten steel outflow end is Between 270 and 300mm, it is used to meet the requirement that the flux of molten steel is greater than 3.8t/min.

Compared with the prior art, the utility model has the following advantages:

1. The liquid steel flow rate of the upwardly inclined upper spout hole is about 5-7% of the total flow rate. This design can realize the obvious upward movement of the high temperature zone of the mold pool around the nozzle;

2. The cross-section design of the gradually retracting upper spout hole eliminates the low-pressure suction area and the reflux vortex;

3. The horizontal inclination angle of the molten steel jet in the lower spout hole is greater than 75°, which greatly reduces the influence of the swirling flow of molten steel in the molten pool of the mold on the fluctuation of the liquid level in the molten pool.

Description of drawings

Concrete structure of the present utility model is provided by following accompanying drawing.

Fig. 1 is the prior art structure schematic diagram of SMS company;

Fig. 2 is a schematic diagram of Danieli's prior art structure;

Fig. 3 is a structural representation of the utility model;

Fig. 4 is A-A sectional view of the utility model.

Detailed ways

Below in conjunction with accompanying drawing and embodiment the utility model is further described.

As shown in Figures 3 and 4, the utility model is composed of a circular tube-shaped molten steel inflow end 1, a flat molten steel outflow end 3, and a cross-sectional shape connecting the molten steel inflow end 1 and the molten steel outflow end 3 with a smooth and continuous transition The slender cylindrical body 2 is composed of three parts, the molten steel outflow end 3 is in the form of a left and right symmetrical four-hole structure, and the upper edges of the two upper spout holes 4 adopt a method of gradually shrinking the section from the inside to the outside. The horizontal diversion angle α of the lower edge is between 25° and 30°, the two lower outlet holes 5 are divided by the center diversion body 6, and the center diversion body 6 has a large aspect ratio, and the horizontal diversion angle β is between 75° and 30°. 80°, the maximum dimension L in the width direction of the nozzle 3 at the molten steel outflow end is between 270 and 300mm, which is used to meet the requirement that the flux of molten steel is greater than 3.8t/min.

Example 1

The horizontal diversion inclination angle α of the lower edge of the two upper spout holes 4 is 26°, the horizontal diversion angle β of the central diversion body 6 is 79°, and the dimension L in the width direction of the nozzle 3 of the liquid steel outflow end is 276mm.

Example 2

The horizontal diversion angle α of the lower edge of the two upper spout holes 4 is 28°, the horizontal diversion angle β of the central diversion body 6 is 75°, and the dimension L in the width direction of the nozzle 3 of the liquid steel outflow end is 295mm.

Example 3

The horizontal diversion angle α of the lower edge of the two upper spout holes 4 is 30°, the horizontal diversion angle β of the central diversion body 6 is 77°, and the dimension L in the width direction of the nozzle of the molten steel outlet 3 is 283mm.

Claims (1)

1. A high molten steel flux submerged nozzle for thin slab continuous casting, which is mainly composed of a molten steel inflow end (1), a molten steel outflow end (3), and a connection between the molten steel inflow end (1) and the molten steel outflow The end (3) is composed of three parts, a slender cylindrical body (2) with a smooth and continuous transition in section shape, and is characterized in that: the molten steel outflow end (3) described in the utility model adopts a left and right symmetrical four-hole structure , the horizontal diversion inclination angle α of the lower edge of the two upper spout holes (4) is 25-30°, the horizontal diversion angle β of the central diversion body (6) is between 75-80°, and the outlet of the molten steel outlet (3) The maximum dimension L in the width direction is 270 to 300 mm.

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