JPH01150442A - Belt tension device in twin belt caster - Google Patents

Abstract

PURPOSE:To prevent the development of crack or depression in a cast slab by arranging shoulder rings as shiftable to shaft direction at both end parts of a driving pulley and stretching the belt to width direction through recessed peripheral groove in the ring. CONSTITUTION:The shoulder rings 32 having the recessed peripheral groove 32a are arranged at both end parts of driving pulley 5, and the pulley 5 and the rings 32 are engaged through spline 36. Further, the width direction tension device 18 to the lower belt 3 is arranged and the rock bearing 24 is pushed to recessed part 25a in a slider 25 and also slided to shaft direction of a backup roll 19. By this method, cooling shrinkage of the belt 3 is prevented and the tension is added to the width direction of the belt 3 in molten metal supplying part, and the development of heat strain is prevented. Therefore, the development of the crack or the depression in the product cast slab 12 is surely prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a one-way tensioning device for a water-cooled belt in a twin-belt caster.

[Conventional technology and its problems]

Recently, various proposals have been made to apply twin belt casters (track continuous casting equipment) used for casting non-ferrous metals to ferrous metals.

However, since ferrous metals generally have a higher melting temperature than non-ferrous metals, twin belt casters made of ferrous metals have problems with the hot water supply system, melting of the lower belt, and surface defects in the slab.

That is, as shown in FIG. 8 which shows the overall conceptual diagram of the twin belt caster 1 of -Ill,
The main part is composed of water-cooled upper and lower belts 2.3, and left and right dam blocks 6 provided on both sides parallel to the running direction of these belts 2.3.

Here, 4 is a lower drive pulley, 5 is a lower drive pulley,
7 is the dam block guide, 8 is the upper tension pulley, 9
10.10 is a belt tension device for the belt running direction, 11 is molten metal, 12 is a slab, and 19 is a backup roll.

And the lower belt 3 of the twin belt caster 1
If high-temperature molten metal (approximately 1550°C for molten steel) 11 is supplied onto the belt, melting damage will occur on the belt. , cooling water is sprayed 22 onto the back surface of the lower belt 3 by a cooling water nozzle 20 and an auxiliary cooling water nozzle 21 along the belt running direction. Therefore, when the molten gold IFEII is supplied onto the lower belt 3, a temperature difference instantly occurs in the lower belt 3 in the thickness direction and in the plane, and as a result, as shown in FIG. 3, thermal strain 13 occurs. That is, the lower belt 3 has an elongation X in the longitudinal direction and an elongation Y in the width direction.

To explain this in more detail, this phenomenon is caused by the molten metal 11
The part of the lower belt 3 that does not come into contact with the molten metal 11 of the lower belt 3 is generated to restrain the expansion of the contact part (see the width 40 of the slab in FIG. 2).
This occurs because the temperature on the side of the contact surface is approximately 100°C higher than the water-cooled side of the back surface, causing it to swell into a convex shape.

Due to the thermal strain 13 of the lower belt 3, the molten metal 11 receives external force from the thermal strain 13 in the initial stage of solidification, causing cracks and dents on the surface of the slab 12, and also causes the surface of the slab 12 and the lower belt to 3 is no longer in contact with the slab 12, voids are created, a local insulation state is created, and a non-uniform solidified structure is formed, causing the slab 12 to
This results in a significant deterioration of the quality of the product.

Therefore, several proposals have been introduced to solve this problem.

For example, Japanese Patent Application Laid-Open No. 50-89218 introduces a proposal to avoid instantaneous thermal distortion as much as possible by preheating the upper and lower belts.

However, as shown in Fig. 10, the back surface of the belt in an actual device is cooled even on the drive pulley, so even if the belt is preheated according to this proposal, the temperature of the belt immediately before the hot water supply section is almost the same as that before preheating. It will return to . The above publication also introduces a method of preheating the lower belt 3 by jetting steam instead of the cooling water sprayed from the auxiliary cooling water nozzle 21 in FIG. time, molten metal 1
1 overflows, the lower belt 3 may be melted and damaged, which is extremely dangerous.

In any case, as described in the above publication, even if the upper and lower belts 2.3 are heated in advance, due to the frictional resistance between the upper and lower belts 2.3 and the drive boob IJ 4.5 in the actual device, Most of the expansion of the upper and lower belts 2.3 in the width direction due to preheating is restrained, and they hardly expand (Xal in Figure 7).
), the belt 3 is shrunk by the spray 22 of the cooling water nozzle 20 (corresponding to Xa2 in FIG. 7), and the thermal strain 13 in the hot water supply section still cannot be resolved. In addition, preheating the upper and lower belts 2.3 alone cannot reduce the temperature difference in the thickness direction, and therefore is generally not suitable as a means for solving the above problem.

Furthermore, the elongation of the upper and lower belts 2.3 in the X direction in Fig. 9 is as follows:
It can be adjusted with the belt tensilon device 10.

On the other hand, JP-A-62-38744, JP-A-61-2
No. 79345 and Japanese Unexamined Patent Application Publication No. 193749/1987 propose devices for mechanically tensioning a belt in the width direction.

However, the belt width direction tensioning device introduced in these publications is a method of tensioning the straight part of the belt, and not a tensioning method from the part wrapped around the drive pulley.
Therefore, it cannot be sufficiently effective for actual equipment in which the cold frame immediately before the hot water supply section restricts expansion of the belt in the width direction.

[Means for solving problems]

The present invention was created to solve the problems of the prior art, and its gist consists of a pair of water-cooled belts, a belt that is sandwiched between these belts, parallel to the running direction, and A twin heel caster consisting of a pair of dam blocks provided on both sides, and a shoulder ring and an 8-shoulder ring provided at both ends of the drive pulley of the belt and movable in the axial direction. A belt of a twin belt caster, characterized in that the belt is tensioned in the width direction from immediately before hot water is supplied, by comprising a concave circumferential groove provided on the outer periphery of the belt, and means for pressing an end of the belt against the concave circumferential groove. It's in the tension device.

〔Example〕

DESCRIPTION OF THE PREFERRED EMBODIMENTS The structure and operation of the present invention will be explained in detail with reference to embodiments shown in the accompanying drawings. Fig. 1 is an overall conceptual diagram of an embodiment of the present invention, Fig. 2 is a view taken from arrow A in Fig. 1, Fig. 3 is a view taken from arrow B in Fig. 2, and Fig. 4 is a view taken from arrow C in Fig. 2. View, Figure 5 is D in Figure 4
The arrow view, FIG. 6 shows a partially enlarged detailed view of FIG. 4.

Therefore, this embodiment is a belt width direction tensioning device suitable for twin belt casters for slab casting.

In FIGS. 1 to 6, parts that are the same as those in the conventional example shown in FIG. 9 are designated by the same reference numerals, and their explanations will be omitted.

Reference numeral 16 denotes a rolling down device, and this rolling down device 16 presses a pair of left and right rolling down rolls 17 against the lower belt 3. Hereinafter, only one side of the pair of structures will be described. As shown in FIGS. 4 and 5, this rolling roll 17 is pressed against a concave circumferential groove 32a of a shoulder ring 32 fitted to the shoulder portion of the drive boob IJ 5. , so as to sandwich both ends of a steel lower belt 30 wrapped around the drive pulley 5. Note that the rolling down device 16 is supported by a caster frame 37 of the twin belt caster 1.

As shown in FIGS. 4 and 5, the drive boob I75 and the shoulder ring 32 are engaged by a spline 36, and the belt rotation torque transmitted from the drive device (not shown) to the drive pulley 5 is applied to the shoulder ring. 32 as well.

Moreover, as shown in FIG. 6, the shoulder ring 32 is
A large number of pistons 33 of a ram cylinder 35 are disposed circumferentially on the end face of the drive pulley 5, and the drive boob IJ 5 is slid in the axial direction of the drive pulley 5. Note that a piston 33 fixed to a shoulder ring 32 is fitted into the ram cylinder 35 via a seal 34.
Further, this ram cylinder 35 is connected to an appropriate hydraulic device via an oil passage 35a.

1B is a widthwise tensioning device, which is disposed immediately after the lower belt 3 leaves the drive pulley 5, as shown in FIGS. 2 and 3. The main parts of this width direction tensioning device 18 are composed of a plate-shaped tension frame 23, a lock bearing 24, a tension cylinder 29, and a slide bin 30.

The lock bearing 24 is disposed on the backup roll 19 and is pressed against a recess 25a on the outer periphery of a slider 25 loosely fitted to the shaft end 19a of the backup roll 19 via a bush 26.

The plate-shaped tension frame 23 is attached to the slide bin 30 of the bracket 38 extending from the caster frame 37.
The slide bin 3 is pivotally engaged with the slide bin 3.
The elongated hole 31 into which the roller 0 is fitted allows the backup roll 19 to move in the axial direction. This elongated hole 31 is bored in a bracket 39 suspended from the tension frame 23.

The slider 25 is the shaft end 19a of the backup roll 19.
It is possible to slide in the axial direction. Note that the shaft 28 fixed to the caster frame 37 has a shaft end 19a.
It is rotatably fitted through a bearing 27.

The preheating device 14 (see FIG. 1) for the upper and lower belts 2.3 is
This is arranged just before the upper and lower belts 2.3 are wound around the drive pulley 4.5.

Since this embodiment has the above configuration, the following operations are performed. That is, prior to the casting operation, a linear impression 15 is formed on the lower belt 3. In other words, the lower belt 3 is rotated in the driving direction using the rolling roll 17 of the rolling device 16 as shown in the third figure. Then, with this linear indentation 15 pressed against the concave circumferential groove 32a, the belt tension device 10 or drive pulley 5 is applied to the belt in the longitudinal direction. Moreover, due to the hydraulic action of the ram cylinder 35, the shoulder ring 32 is pushed outward by the piston 33, and as a result, tension is applied in the belt width direction.

Therefore, even if the lower belt 3, which has been thermally expanded in the belt width direction by the preheating device 14, is cooled at the drive pulley 5, the elasticity of the steel belt remains and the belt does not contract, resulting in the effect of preheating. Drive while maintaining this until just before the hot water supply section.

Next, in the hot water supply section, the lower belt 3 is given tension in the belt width direction by the width direction tensioning device 118, so that the thermal distortion 13 caused by contact with the molten metal 11 is reduced. That is, when the tension cylinder 29 is operated in the direction a in FIG. 3, the tension frame 23
The lower belt 3 swings around the slide pin 30 in the direction b and also slides in the direction C, so the lower belt 3 can be sandwiched between the lock bearing 24 and the slider 25 and tensioned in the belt width direction. Thermal strain 13 is reduced.

It goes without saying that the present invention can be applied not only to 11 diagonal twin belt casters but also to vertical twin belt casters, and the dam block may be of a fixed type.
Furthermore, there is no need for a preheating device.

〔Effect of the invention〕

According to the present invention, since the belt is tensioned in the belt width direction from the drive pulley immediately before the hot water supply section, restraint in the belt width direction by the cold frame immediately before the hot water supply section can be eliminated.

That is, in the graph showing the relationship between the belt and pulley friction in FIG. However, in the embodiment of the present invention, the piston 33 stretches the belt 3 in the belt width direction by Xa2, so that restraint in the belt width direction by the cold frame can be eliminated.

In addition, in FIG. 7, the right horizontal axis Xa is the elongation in the belt width direction,
The left horizontal axis xb represents the belt tension in the longitudinal direction, the upper vertical axis Ya represents the frictional resistance force on the boolean, the lower vertical axis yb represents the heating temperature of the belt, μ is the friction coefficient between the belt and the booli, and B
t is the belt thickness, Bw is the belt width, and Xal
indicates the dimension at which the belt shrinkage is restrained by the frictional resistance of the boot.

Therefore, the belt does not have a convex bulge, and the slab does not have cracks or dents, and the slab can be of good quality.

In addition, since the tension in the width direction of the belt is simply applied by pressing the end of the belt against the concave circumferential groove of the shoulder ring of the drive pulley, it is possible to
The belt does not have a complicated structure as in the one disclosed in Japanese Patent No. 44.

[Brief explanation of the drawing]

FIG. 1 is an overall conceptual diagram of an embodiment of the present invention, FIG. 2 is a view in the direction of arrow A in FIG. 1, FIG. 3 is a view in direction of arrow B in FIG. 2, and FIG.
Fig. 5 is a view taken from arrow D in Fig. 4, Fig. 6 is a partially enlarged detailed view of Fig. 4, Fig. 7 is a graph showing the relationship between belt and pulley friction resistance, etc. FIG. 8 is an overall conceptual diagram of a general twin belt caster, FIG. 9 is a diagram of belt thermal deformation, and FIG. 10 is a diagram of a conventional water cooling system. l...twin belt caster, 2...upper belt,
3...Lower belt, 4...Upper drive pulley, 5...
Lower drive pulley, 6...Dam block, 32...Shoulder ring, 32a...Concave circumferential groove. Agent Patent attorney Masanobu Kato (and 1 other person) Figure 9 Figure 10

Claims (1)

[Scope of Claims] A twin belt caster comprising a pair of water-cooled belts and a pair of dam blocks sandwiched between these belts and parallel to the running direction and provided on both sides of the belts, comprising: A shoulder ring provided at both ends of the drive pulley and movable in the axial direction; a concave circumferential groove provided on the outer periphery of the shoulder ring; and means for pressing the end of the belt against the concave circumferential groove. A belt tensioning device for a twin belt caster, characterized in that the belt is tensioned in the width direction immediately before hot water is supplied.