CN1171752A - Tundish Impact Liner - Google Patents

Abstract

A tundish impact pad (20) for reducing turbulence in a tundish comprises a body of refractory material adapted to withstand contact with molten steel in a tundish (10), the body includes a base (22) having an impact surface (24), an outer sidewall (26,40) extending upwardly from the impact surface (24), a top surface (32) connected to the sidewall (26,40) and defining an opening (30) therein, wherein the top surface (32) has an inner annular portion (42) substantially parallel to the impact surface (24), the side walls (26,40) have an inner surface (28) substantially perpendicular to the impact surface (24), wherein there is a substantially right angle corner (24A) between the side wall (28) and the impact surface (24) and a substantially right angle corner between the side wall (28) and the top surface inner ring portion (42).

Description

Tundish Impact Liner

The invention relates to a tundish impact liner, that is, a corrosion-resistant material backing plate arranged at the bottom of the tundish to receive the molten metal injection flow from the ladle into the tundish.

US Patent 5169591 discloses an impact pad for a tundish of continuously cast steel comprising a base, an annular top surface and a discontinuous side wall extending between the base and the annular top surface, the side wall Has a concave inner surface, which may be curved.

US Patent 5,358,551 discloses an impact pad comprising a base and a side wall extending around the base, the inner surface of the side wall having an inwardly and upwardly extending portion. The inner surface may be concave.

Although both of the foregoing impingement pads were designed to reduce turbulence in the tundish, we have surprisingly found that turbulence can be further reduced by providing an impingement pad with inner corners defined in the liner. Between the base of the pad, the annular wall and the upper surface. Accordingly, we have found that providing such internal angles is advantageous and leads to improvements in reducing surface turbulence, minimizing slag inclusions, preventing cracking of the flux coating in the tundish, reoxidation of the molten steel, and ensuring that the molten steel Proper flow channels in the tundish.

Accordingly, in one aspect the present invention provides a tundish impact pad comprising a body of refractory material capable of withstanding contact with molten steel in the tundish; Extended annular outer side wall, a top surface connected to the side wall and defining the opening therein, the top surface having an inner ring portion substantially parallel to the impact surface and the side wall having an inner surface substantially perpendicular to the impact surface , wherein a substantially right-angled corner is formed between the side wall and the impact surface and between the side wall and the inner ring portion of the top surface, respectively.

The molten steel flowing in through the opening and in contact with the impact surface flows outward, then it turns inward under the action of the inner surface of the side wall, and finally flows out of the opening.

The side wall is preferably annular, ie it extends continuously around the impact surface.

The opening shape is preferably non-uniform, ie it has a longer dimension and a shorter dimension perpendicular to the longer dimension. For example, it can be a rectangle or an ellipse.

For convenience, the top outer surface of the pad can also be parallel to the impact surface.

The impact liner of the invention not only changes the flow direction of the injected molten steel, but also can evenly disperse the injected molten steel flow.

Since the use of the pads of the present invention enables the steel flow to be dispersed over a larger area than with round or other uniformly shaped pads, the flow is more uniform across the surface while ensuring reduced splash and turbulence . Because the non-uniform shape of the impact pad is a larger "target" for the injected steel stream than a uniformly shaped pad (such as a circle or square) of the same width, even if the steel stream is not perfect Centering the ground on the centerline of the impact pad will also give the desired result.

The invention is particularly suitable for improving residence time distribution parameters when pouring molten steel. Because the present invention simplifies the cavity shape, it reduces cost and has a corresponding overall size reduction compared to prior impact pads.

The impact pad according to the invention consists of a refractory composition capable of withstanding continuous contact with molten metal, in particular with molten steel such as in continuous casting operations. A standard medium-high alumina monolithic refractory with an alumina content of about 55% to 85% by weight is generally required. Due to the chemical reaction of the molten steel, it is preferred to use a basic refractory material, preferably a magnesium-based monolithic refractory material, with MgO accounting for about 58% to 93% by weight.

In another aspect, the present invention provides a tundish for containing a quantity of molten steel, which has a bottom and side walls closed to form an impingement zone and outlet, the impingement liner configuration of the present invention In the impact zone on the bottom of the tundish.

Embodiments of the present invention are described below in the form of examples with reference to the accompanying drawings, wherein:

Figure 1 is a cross-sectional side view of a tundish comprising an impact liner of the present invention, the impact liner being disposed at the bottom of the tundish;

Figure 2 is a top view of the impact pad of Figure 1, showing the location of the cross-section of Figure 1 (along line I to I);

Fig. 3 is a cross-sectional view along line III-III in Fig. 2;

FIG. 4 is an enlarged view of a portion of the impact pad of FIG. 3. FIG.

A conventional tundish 10 is shown in FIG. 1 and includes a liner 12 and a pair of gates or outlets 14 which allow molten metal (usually referred to as molten steel) to flow continuously from a molten pool 16 of the tundish 10. The flow continues out of the tundish 10 and into a mold (not shown) where a metal casting can be formed. Typically, a ladle refractory sleeve 18 or similar tundish filling device is disposed above the tundish 10 and continuously introduces a stream of molten metal into the tundish 10 . A tundish impact pad 20 constructed in accordance with the present invention is generally placed in the center of the bottom 15 of the tundish 10 .

As shown in Figures 1 to 4, the tundish impact pad 20 is preferably rectangular in shape with its long sides parallel to the longitudinal axis of the tundish. The pad includes a base 22 with a horizontal impact plane 24 . The liner 20 also includes a continuous annular outer side wall 26 , 40 having an inner wall surface 28 . Impact pad 20 also includes a top surface 32 connected to sidewalls 26, 40 parallel to impact surface 24 and having a non-uniform opening 30 formed therein. By "non-uniform" is meant that the opening 30 is not circular or square, but has a longer dimension 30' (see FIG. 2) and a shorter dimension 30" substantially perpendicular to the longer dimension 30'.

As can be seen from FIGS. 1-4 , the inner surface 28 of the sidewall extends upwardly around the entire perimeter of the impact surface 24 at an angle substantially perpendicular to the impact surface 24 . The continuity feature of the inner surface 28 is best shown in FIG. 2 , where its continuity is shown in phantom.

3 and 4, sidewall 28 forms two sharp corners 28A and 28B with impact surface 24 and underside portion 42 of top surface 32, respectively, which also extend continuously around the interior of the impact pad.

As shown in FIG. 1 , the outer wall 26 may be tapered inward from the top surface 32 toward the base 22 , and two ear portions 27 are formed at two opposite side ends. When certain types of tundishes are used, the ears 27 help to attach the impact pad 20 to the base or bottom 15 of the tundish. Alternatively, the impact pad 20 is simply mounted on the bottom of the tundish in a conventional manner.

It should be noted that the bottom of the top surface 32 has an annular portion 39 , 42 (see FIG. 3 ), which is parallel to the impact surface 24 . This annular overhanging surface 42 helps to guide the molten steel properly during casting of the tundish 10 . It should be noted that the longer dimension 30' of the opening 30 is aligned with the longer dimension of the tundish (i.e. the dimension between the outlets 14, as shown in FIG. Short dimension is aligned.

Rather than being inverted inwardly tapered like sidewall 26, outer sidewall portion 40 is preferably slightly inverted outwardly tapered (eg, 2[deg.] to 5[deg.] of taper), as shown in FIG. Alternatively, side walls 26 and 40 are made straight and straight side wall 26 may or may not be provided with ears 27 .

The refractory material from which impact pad 20 is made must be able to withstand continuous contact with molten steel throughout the life of tundish 10 . The material must have sufficient refractory performance, and a standard medium-high alumina monolithic refractory material can usually be used. For example, refractory materials with an alumina content between approximately 55% and 85% may be used. Due to the chemical reaction of the molten steel, it is preferred to use a basic refractory material, in particular a monolithic refractory material based on MgO, wherein the content of MgO is preferably between 58% and 93%.

As shown in FIGS. 1-4, the configuration of the impact pad 20 is preferably rectangular, although other non-uniform configurations are also possible. For example, oval or other types of polygonal pads could be used as long as the pad has an opening whose long dimension aligns with the long dimension of the tundish 10 and whose short dimension aligns with the short dimension of the tundish 10 .

When using the tundish liner 20 shown in FIG. 1 , the molten steel flowing into the channel 34 from the position above the liner 20 impacts the impact surface 24 , and then the molten steel moves radially outward as indicated by the arrow 35 . When the molten steel impacts the inner surface 28 of the side wall, as shown by 36 in Figure 1, it first flows inwards and then upwards, and finally disperses outwards in the radial direction as shown by arrows 37 and 38 in Figure 1, so that as much as possible Turbulence on the surface of the molten pool 16 is reduced and helps guide slag and other impurities away from the steel stream 34 .

The corners indicated by dotted lines in the plane of FIG. 2 do not have to be rounded as shown, but may be right-angled if desired.

The vertical corners between the sidewalls and the impact surface and/or inner ring portion of the top surface may also be less rounded if desired.

Claims (9)

1. an impact pad (20), it comprises that can be born a refractory material of body that contacts with molten steel in the tundish (10), this main body comprises a pedestal (22) with shock surface (24), one from the upwardly extending lateral wall (26 of shock surface (24), 40), one and sidewall (26,40) the continuous top surface (32) of also determining an opening (30) therein, it is characterized in that, top surface (32) has the annular inner portion (42) that is arranged essentially parallel to shock surface (24), sidewall (26,40) has vertical with shock surface (24) basically inner surface (28), wherein between sidewall (28) and shock surface (24), a rectangular basically bight (28A) is set, and between sidewall (28) and top surface annular inner portion (42), has rectangular basically bight.

2. the tundish impact pad according to claim 1 is characterized in that, described opening (30) has a longer size (30 ') and shorter size (30 ") vertical with this length size (30 ').

3. the tundish impact pad according to claim 2 is characterized in that, described opening (30) is rectangle or ellipse.

4. one kind according to claim 1,2 or 3 tundish impact pad, it is characterized in that the outer surface of cupular part of liner (32) is parallel to shock surface (24).

5. the tundish impact pad according to aforementioned each claim is characterized in that, sidewall (26,40) is annular.

6. the tundish impact pad according to aforementioned each claim is characterized in that, liner (20) is to be made by the monolithic refractory that a kind of alumina content accounts for weight 55% to 85%.

7. one kind according to each tundish impact pad in the claim 1 to 5, it is characterized in that, liner (20) is to comprise that magnesia and magnesia account for 58% to 93% monolithic refractory of weight.

8. tundish (10) that is used for a certain amount of molten steel of splendid attire (16), it has bottom (15) and sidewall (12), bottom (15) and sidewall (12) form a shock zone and outlet (14), it is characterized in that tundish (10) comprises one as the described impact pad of each aforementioned claim (20) at the impact zone of its bottom (15).

9. tundish according to claim 8, it is characterized in that, impact pad (20) has an opening (30) that receives motlten metal stream, described opening (30) has a longer size (30 '), and (30 "), the longer size (30 ') of opening (30) is alignd with the longer size of tundish with a shorter size vertical with this longer size (30 ').

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