US3796252A - Support arrangement for a continuous casting with drawing bolt and head - Google Patents

Abstract

In commencing a continuous casting operation where the strand is conducted along an arcuate, deflecting or vertical path from the mold, a withdrawing bolt and head is positioned within the mold and is withdrawn with the strand through a support arrangement adapted to the cross-section of the strand being cast. As it passes through the support arrangement, the withdrawing bolt and head is pressed against spaced, fixed support rollers in the support arrangement by adjustable pressure rollers which are released from contact with the withdrawing bolt and head when the head begins to pass the pressure roller.

Description

United States Patent [191 Baumann et al.

[ Mar. 12, 1974 SUPPORT ARRANGEMENT FOR A CONTINUOUS CASTING WITH DRAWIN BOLT AND I-IEAD [75] Inventors: Hans G. Baumann; Wilhelm Koch,

both of Duisburg, Germany [73] Assignee: Demag Aktiengesellschaft, Duisburg,

Germany [22] Filed: June 22, 1971 [21] Appl. No.: 155,562

[52] US. Cl. 164/282, 164/82 [51] Int. Cl B22d 11/12 [58] Field of Search 164/82, 274, 282

[56] Y References Cited UNITED STATES PATENTS 3,550,675 12/1970 Hess et al. 164/282 3,638,713 2/1972 Knell 3,645,323 2/1972 Vogt et a1. 164/282 FOREIGN PATENTS OR APPLICATIONS France 164/282 10/1969 Germany 164/274 2/1969 U.S.S.R 164/274 Primary Examiner-R. Spencer Annear Attorney, Agent, or Firm-Toren and McGeady ABS'I RACT In commencing a continuous casting operation where the strand is conducted along an arcuate, deflecting or vertical path from the mold, a withdrawing bolt and head is positioned within the mold and is withdrawn with the strand through a support arrangement adapted to the cross-section of the strand being cast. As it passes through the support arrangement, the withdrawing bolt and head is pressed against spaced, fixed support rollers in the support arrangement by adjustable pressure rollers which are released from contact with the withdrawing bolt and head when the head begins to pass the pressure roller.

1 Claim, 1 Drawing Figure Pmmaoum m4 3796252 /0 Veil/m:

HANS 66% NN WILHELM K SUPPORT ARRANGEMENT FOR A CONTINUOUS CASTING WITH DRAWING BOLT AND HEAD SUMMARY OF THE INVENTION The present invention is directed to a support arrangement located at the outlet from a continuous casting mold and, more particularly, it concerns a method of and an apparatus for supporting a withdrawing bolt and head as it withdraws a cast strand from the continuous casting mold. Further, the invention is especially directed to arcuate, deflecting and vertical continuous casting plants.

In continuous casting operations, special care must be taken in commencing the casting operation because of the molten condition of the core within the casting as it is withdrawn from the mold. Prior to commencing the casting operations from the continuous casting mold, which mold is open at its top and its-bottom, a withdrawing head and bolt is positioned with the head inserted into the bottom end of the mold and the head has a cross-section which fits closely within the bottom opening within the mold. The means for withdrawing the casting or strand from the mold is located at some distance from the outlet of the mold. In order to start withdrawing the strand from the mold, the bolt portion of the withdrawing head and bolt extends from the head to the withdrawing means and this length may be as much as ten meters or more. in effect, the bolt portion acts as an artificial or dummy casting in commencing the removal of the casting from the mold.

In a continuous casting plant where a large variety of sizes of molds are used, a corresponding number of withdrawing heads and bolts are required. The storage of the continuous casting molds when not in use involves a considerable investment in space as well as in high maintenance costs. To these costs must be added the corresponding investment in space and maintenance for the withdrawing heads and bolts. The size of these withdrawing heads and bolts dictates the size of a part of the continuous casting plant in which they are stored until they are used again. In an attempt to solve this problem, a single withdrawing head and bolt has been used which has the dimensions of the smallest casting cross-section to be produced. However, it is still necessary to provide the head portion of this piece of equipment with the dimensions of the outlet from the mold cavity in the continuous casting mold. The transition from the casting cross-section to the shape of the starting casting is represented by inclined surfaces, accordingly, the head part of the withdrawing head and bolt has a conical or tapered configuration. Conically shaped heads and bolts are less expensive than most of the members used for commencing the castings which have different cross-sections. The starting members for such continuous casting operations are favorable only in a very heavy form, that is when the weight of the withdrawing head and bolt is such that it causes the head and bolt to press against the radially outer side of the roller guide track utilized in arcuate continuous casting plants for guiding the casting from the mold. It is only when the withdrawing head and bolt has considerable weight that an orderly or effective feed from the mold can be provided. When a lighter withdrawing head and bolt is used, it will separate itself from the support arrangement and then will move back toward the support thereby causing an irregular or jerky transmission of the feeding or withdrawing force to the cast- During startup, there is the possibility that excessive loads will be placed on the casting as it is initially withdrawn from the mold with the result that the solid casting shell cannot stand the applied stress in the range of the secondary cooling zone so that the casting will be at least considerably damaged at the outset. Due to'irnproper removal, the leading end of the casting may develop either/or both internal and external defects so that it must be remelted for effective use. When this occurs the percentage yield from the casting operation is not only reduced but additional costs are involved in the special handling or treatment which must be given the casting. Under extreme circumstances, a strong pull on the casting can result in a rupture of its shell with its liquid core flowing outwardly through the rupture and contacting various parts of the casting plant. When such an accident occurs, the casting process must be stopped and the plant is taken out of operation for at least several hours if not for a period of days. Further, such an accident can entail considerable costs to the casting plant itself. When the casting process is discontinued, the melt ready to be used must be poured into standby casting molds and an unplanned change in the plant operation is necessary and must be effected without delay to avoid temperature losses in the metal being cast. Accordingly, the advantages gained by the use of the conical withdrawing heads and bolts is offset by the difficulties experienced in properly withdrawing the casting from the mold.

Therefore, it is the primary object of the present invention to effect the safe removal of the withdrawing head and bolt of a special typeincluding a conical head where the disadvantages and risks experienced in the past are overcome and the withdrawing head and bolt are adequately supported during removal against the development of any movement or forces which would have a deleterious effect on the casting. In accordance with the present invention, a withdrawing head and bolt of any cross-sectional dimension can be used as long as it is smaller than the cross-section of the casting to be removed from the mold and conducted along a supporting roller track which is adapted to the crosssection of the strand being cast. On the radially outer side of the support arrangement, that is where an arcuate casting plant is involved, the withdrawing head and bolt is supported against a fixed set of supporting rollers, while on the opposite surface adjustable pressure rollers contact the surface of the withdrawing head and bolt and maintain it in contact with the fixed supporting rollers. Due to the adjustable character of the pressure .rollers they can be withdrawn from contact as the head of the withdrawing head and bolt begins to pass the point of application of the pressure roller. In contrast to previously used methods, the thickness of the bolt portion of the withdrawing head and bolt plays, only a both the withdrawing head and bolt and the casting are located within the roller support arrangement and the transfer from the withdrawinghead to the casting can be effected without critical periods. In accordance with this withdrawing arrangement, the casting travels in an uniform, even manner and the load applied to it is also uniform in all sections without any peaks.

In accordance with the invention, the structure for carrying out the withdrawingoperation includes a supporting roller track set for the transverse cross-section of the continuous casting. On one side of the track a plurality of spaced rollers are arranged to support, first, the withdrawing head and bolt and, then, the casting, while on the opposite side in addition to the rollers for the casting, adjustable pressure rollers and/or frames are provided which can be positioned to contact the smallest cross-section of the withdrawing head and bolt. It is not important whether the adjustable pressure rollers are located in the secondary cooling zone or downstream from this zone. With the adjustable pressure rollers located in the supporting roller track downstream from the continuous casting mold it is possible to provide a practically effective manner of instituting the action of withdrawing the continuous casting from its mold.

The various features of novelty which characterize the invention are pointed out with'particularity in the claims annexed to and forming a part of this disclosure. For a better understanding of the invention, its operating advantages and specific objects attained by its use, reference should be has to the accompanying drawings and descriptive matter in which there are illustrated and described preferred embodiments of the invention.

BRIEF DESCRIPTION OF THE DRAWING The drawing is a schematic side view of an arcuate continuous casting plant.

DETAILED DESCRIPTION OF THE INVENTION In the drawing a continuous casting mold l is located at the upper end of an arcuate supporting roller track having a lower additional section 3 through which the continuous casting passes downwardly from the mold. The drawing displays the arrangement of the mold and supporting roller track arranged to commence the withdrawing action of the casting from the mold. At the lower end or downstream end of the additional section the continuous casting, pressure rollers and/or frames 9 are positioned at spaced locations intermediate to the ends of the roller track 2 and its additional section 3.

3 from the mold, a pair of driving rolls 4 are provided to be formed. On the radially outer side of the roller track-Z-and additional section 3, a row of spaced fixed rollers 8 are rigidly mounted and form a support for the starting bolt and subsequently serve to support the continuous casting as it is withdrawn downwardly from the mold 1 along the roller track. On the radially inner side of the roller track a plurality of rollers 7 are spaced for contact with the other face of the continuous casting as it moves through the roller track 2. If the withdrawing force from the rolls 4 was applied to the bolt portion 5 of the withdrawing head and bolt positioned between the rollers 7, and 8, the radially inner face of the bolt As the starting head and bolt withdraws the continuous casting from the mold, the pressure rollers 9 press the bolt portion 5 against the rollers 8 located along the opposite surface of the bolt portion. Further, the withdrawing bolt portionS can be moved in the opposite direction by the pressure rollers 9 in a particularly accurate manner for positioning it relative to the continuous casting mold l, a driving member 9a is associated with each pressure roller 9 for driving the withdrawing head and bolt along the supporting roller track in the direction opposite to the withdrawing direction and inserting it into the mold. However, as soon as the continuous casting is withdrawn from the mold and its leading end approaches the first one of the pressure'rollers 9, the rollers are set to the dimension of the continuous casting automatically by means of hydraulic pressure or by other means. After the leading end of the casting passes through the first one of the pressure rollers 9 the other pressure roller 9 remains in contact with the bolt portion 5 and as the continuous casting approaches the second pressure roller it also opens automatically by hydraulic pressure so that the continuous casting can pass between it and the oppositely disposed roller 8. This arrangement of, pressure rollers is highly suitable for transmitting a selected feeding force to the casting in the regions where the casting has only a thin shell forming its exterior surface. This is particularly true when the pressure rollers are driven.

While 'a specific embodiment of the invention has been shown and described in detail to illustrate the application of the inventive principles, it will be understood that the invention may be embodied otherwise without departing from such principles.

What is claimed is:

1. Apparatus for supporting a withdrawing head and bolt used in commencing the withdrawal of a continuous casting from a mold in an arcuate, deflecting or vertical continuous casting plant where the bolt portion of the withdrawing head and bolt has a cross-section and thickness dimension smaller than the corresponding cross-section and thickness dimension of the continuous casting where the thickness dimension is'the dimension between the supported surfaces of the continuous casting and the head portion of the withdrawing head and bolt is in engagement with the continuous casting and includes a supporting roller track set to receive the cross-section of the continuous casting, said supporting roller track includes a plurality of first rollers spaced apart in the direction of travel of the continuous casting and arranged to form a fixed support along one side of the continuous casting, and a plurality of second rollers spaced apart in the direction of travel of the continuous casting and arranged on the opposite side of said roller track from said first rollers in the direction of the thickness dimension of the continuous casting and said second rollers arranged to contact the opposite side of the continuous casting from the side contacting said first rollers, and a pair of driving rolls located at the downstream end of said roller track for withdrawing the withdrawing head and bolt and the continuous casting from the mold along said roller track, wherein the improvement comprises a plurality of pressure rollers spaced between at least certain of said second rollers and located on the same side of said roller track as said second rollers, said pressure rollers are adjustable in the direction toward said first rollers relative to the smallest cross-sectional area of the variable cross-sectional area of the withdrawing head and bolt and are positionable inwardly from said second rollers toward said first rollers for contacting and applying pressure directed toward said first rollers and against the bolt portion of the withdrawing head and end of the mold.

Claims (1)

1. Apparatus for supporting a withdrawing head and bolt used in commencing the withdrawal of a continuous casting from a mold in an arcuate, deflecting or vertical continuous casting plant where the bolt portion of the withdrawing head and bolt has a crosssection and thickness dimension smaller than the corresponding cross-section and thickness dimension of the continuous casting where the thickness dimension is the dimension between the supported surfaces of the continuous casting and the head portion of the withdrawing head and bolt is in engagement with the continuous casting and includes a supporting roller track set to receive the cross-section of the continuous casting, said supporting roller track includes a plurality of first rollers spaced apart in the direction of travel of the continuous casting and arranged to form a fixed support along one side of the continuous casting, and a plurality of second rollers spaced apart in the direction of travel of the continuous casting and arranged on the opposite side of said roller track from said first rollers in the direction of the thickness dimension of the continuous casting and said second rollers arranged to contact the opposite side of the continuous casting from the side contacting said first rollers, and a pair of driving rolls located at the downstream end of said roller track for withdrawing the withdrawing head and bolt and the continuous casting from the mold along said roller track, wherein the improvement comprises a plurality of pressure rollers spaced between at least certain of said second rollers and located on the same side of said roller track as said second rollers, said pressure rollers are adjustable in the direction toward said first rollers relative to the smallest cross-sectional area of the variable cross-sectional area of the withdrawing head and bolt and are positionable inwardly from said second rollers toward said first rollers for contacting and applying pressure directed toward said first rollers and against the bolt portion of the withdrawing head and bolt as it moves through said roller track, each said pressure roller being individually releasable for removing said pressure roller from contact with the withdrawing head as the head Portion of the withdrawing head and bolt begins to pass said pressure roller, and said pressure rollers including means for driving the withdrawing head and bolt along said supporting roller track in the direction opposite to the direction of withdrawal of the continuous casting for inserting the head portion of the withdrawing head and bolt into the outlet end of the mold.

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