JPH0342152A - Method and apparatus for continuous roll-to-roll casting of directly cold-rolled thin metal products - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method and apparatus for roll-to-roll casting of thin metal products, particularly thin metal products such as copper strips or laminar sheets.

This casting method is used to cast thin products that can later be directly cold rolled.

In conventional technology roll-to-roll casting equipment, liquid metal is fed into the casting space. In this casting space there is a portion of the cylindrical wall of the roll located above a plane passing through the parallel axes of the roll, and a small side or side wall, approximately perpendicular to the axis of the roll and usually fixed. It is separated by an end wall.

During casting, the liquid metal comes into contact with the cooled cylindrical surface of the roll and gradually forms a solidified film, which moves with the rotation of the roll and passes through the nip of the roll, i.e., along the axis of the roll. They merge at the surface of the surface and are continuously pulled downward to form the final product.

Some of these installations are equipped with a type of fixed electrical board. This stationary plate is constituted by two longitudinal walls in fluid-tight contact with the roll and two end walls which extend upwardly from the smaller walls mentioned above or are formed by a portion thereof. These fixed bridge plates are hereinafter referred to as "dams" because they are similar to fixed mold equipment or mold uprights for accommodating risers placed in mold equipment. This "dam" is used when casting between rolls.
It determines the area on the roll surface where the cast metal solidifies, and serves to ensure uniform solidification regardless of the height of the metal in the dam. Also, since the meniscus of the liquid metal is no longer in contact with the roll surface, the risk of impurities floating on the meniscus being carried into the metal is greatly reduced.

However, many problems remain in order to finally obtain a product that can be directly cold rolled. Thus, one of the desirable properties of a flat product to be cold rolled is that it be slightly overhanging (convex) in the transverse direction. For example, in the case of a sheet several millimeters thick, by initially overhanging it by a few tens of microns, the thickness of the steel plate after rolling can be made constant; It is known that in the case of hollow materials at least sufficient cross sections can be achieved.

Problem to be Solved by the Invention The main problem to be solved by the invention is therefore to produce a product with an overhang in the cast state.

SUMMARY OF THE INVENTION The object of the invention is to provide two mutually parallel
The method consists of continuous casting of liquid metal between rolls having book axes and being driven to rotate in opposite directions.

The characteristics of the present invention are that the generatrix is curved in the heated state and the diameter is 4Ill! Use at least ■ rolls whose center part is slightly smaller than both ends in one line direction, and apply the liquid metal to the walls of the rolls with an arc length that is longer in the center part than in both ends. At the point of contact.

As can be seen from the following description, the method of the present invention provides a longer contact time between the cold wall of the roll and the metal in the axially central region of the roll than in the end regions of the roll, so that the roll A method of obtaining a product in which the entire cross section is solidified in the nip region of the rolls and has a desired slight warp (bulge) by increasing the thickness of the solidified skin formed at both ends and at the center of the roll. be. This warpage corresponds to the depressions on the roll surface.

Through actual experiments, the present inventor discovered that the contact time between the roll and the gold powder, and therefore the length of the contact arc (arc length), has a great effect on the solidified skin.

For example, if the final thickness is 2 mm and the contact arc length is 600 m
If this arc length is changed by 50 mm in a cast product of 50 mm, all other conditions being the same, the thickness of the solidified skin will be approximately 50 μm.
A difference of m occurs. Therefore, the present inventor took advantage of this characteristic and utilized the relationship between the y1 distance measured from the longitudinal axis and the desired thickness of the product, in other words, the "concavity" of the roll surface was determined as a function. We considered obtaining the desired warpage (overhang) by making the length of the contact arc between the roll and the metal a constant distance from the vertical center plane perpendicular to the axis of the roll.

The invention is further directed to an apparatus for casting between two rolls with cooled walls. The device of the present invention is characterized in that the generatrix of at least one roll is curved in the heated state, and its diameter is slightly smaller at the center than at both ends in the axial direction; The central part has a longer arc length than both ends, and means is provided for bringing it into contact with at least the wall of the upper roll.

Said means preferably consist of a longitudinal wall of the dam, the lower edge of said wall being in substantial contact with the roll wall above the nip between the rolls, and the line of contact between the lower edge and the roll. is preferably a curve.

In other words, the arc length of the roll surface between the contact line and the nip is longer at the center of the longitudinal wall than at both ends.

In a special embodiment of the invention, the longitudinal wall of the dam is flat and has a chamfer formed at its lower edge, the angle of the surface of the chamfer being from both ends of the wall to the center. It is increasing towards the end.

In another special embodiment of the invention, the longitudinal walls of the dam are recessed towards the inside of the dam.

As is clear from the above description, by using the apparatus of the present invention, the method of the present invention can be carried out in a simple and practical manner, and the height of the liquid metal during casting can be adjusted between the dam and the roll. It can be maintained above the contact line.

Other features and advantages of the present invention will become more apparent from the following description of embodiments with reference to the accompanying drawings.

In addition, in the drawings, the roll "
Although the illustration emphasizes the "dent" and degree of overhang (warpage) of the product, in reality, these "dents" and degree of overhang are on the order of several tens of microns.

Example 1 FIG. 1 shows two rolls 1.
The equipment for continuous casting between 2 and 3 is shown.

Roll 1.2 is slightly "caved". That is, the generatrix 11.12 of the roll 1.2 is a perfect straight line if fL <
, it is curved and warped, the degree of curvature approximately corresponding to the value of the desired degree of overhang of the cast product. These rolls are driven in rotation in opposite directions in the direction of arrow 13 and their walls are cooled. Also, in order to compensate for diameter changes in the heated state due to expansion at the desired temperature at the start of casting (this expansion is generally not uniform over the length of the roll), The indentation of the roll can be different from the desired degree of warpage of the product, and can be greater than the degree of warpage of the product.

The dam, made of fire-resistant material, has two vertical walls 31 and a 21-piece end [32]. ,)ru. 'The slave wall 31 is parallel to the roll axis and its lower end 33 is held in contact with each roll with as little functional play as possible. In the illustrated embodiment, the two end walls 32 also close off the casting space 4 delimited by the roll surface portion in the area above the nip, located in a horizontal plane P passing through the axis of the roll. It consists of

In the present invention, a chamfered portion 34 is formed at the lower end edge of the vertical wall 31, and the degree of chamfering of this chamfered portion 34 is determined from both ends of the vertical wall 31 toward the center. It's getting bigger and bigger. Therefore, the line of contact 35 between each longitudinal wall and its corresponding roll is curved, so that the chamfered portion 34 is recessed. This chamfer is clearly illustrated in FIG. Figure 2 a is
This is a cross-sectional view at both ends of the vertical wall 31, and FIG. 2 is a cross-sectional view at the center of the wall 31. The length of the arc 6 where the cast metal 6 contacts the cooling wall of the roll at the center of the roll is:
It will be appreciated that the end of the roll is longer than the length of the arc 7 in contact with the cooling wall.

During casting, liquid metal is injected into the dam and fills the casting space 4. The level of liquid metal is adjusted to be above the contact line 35 between the dam and the roll. As the roll rotates, due to the difference in the length of the contact arc, the contact distance between the roll wall and the metal is longer in the center of the roll, resulting in the filling of the solidified skin of the resulting product. The thickness is thicker at the center than at the ends. The skins meet at nip 5 to produce a final product having the desired curvature (degree of bulge) as illustrated in Figure 4a. In this drawing, product 8
are formed on each roll.

It is composed of each epidermis, which has 8 parts. The final product includes
It can be seen that there is no discontinuity between these areas.

FIG. 4 illustrates in a similar manner a cross-section of a product manufactured by an apparatus according to another embodiment of the present invention. In this embodiment, only one roll has a recess, and only the vertical dam wall in contact with this roll has a chamfered portion as described above, and the generatrix of the other roll is a straight line; The longitudinal dam wall corresponding to the other roll is flat up to the line of contact with this roll. In this case, the thickness of the skin 9' formed on the other roll is constant over its entire length, and the thickness of only the skin 9''' formed on the one roll is at the center. The actual dimensions of this overhang are small, so that the "indentation" of one of the rolls and the corresponding chamfer of the longitudinal dam wall increase simultaneously, in other words, substantially As long as it is doubled, the asymmetry described above has no effect on the final product 9, which has the same overhang as the overhang of the product 8 described above. The advantage of this embodiment is that only one roll needs to be machined with a recess and only one dam longitudinal wall needs to be machined with a chamfer.

Theoretically, in order to ensure that the functional gap between the longitudinal wall 31 and the roll remains constant over the entire length, the lower end of the longitudinal wall 31 should be It is necessary to create a curve that corresponds to the "concavity".

However, this "indentation" is actually quite small, so even if this lower edge is made straight, there is little risk of liquid metal entering the functional gap, which makes the dam easier to manufacture. Conversely, as already mentioned, in order to vary the solidification thickness to produce the desired overhang in the cast product, and yet to solidify the product uniformly in the area of the nip 5, it is necessary to ensure that the contact at which skin solidification occurs It is necessary to increase the length of the arc.

As an example, the values of the chamfer in an experimental setup for casting a 2 mm thick strip with a bow of about 50 μm are shown below.

The invention is not limited to the above-described device shown by way of example. According to the present invention, as shown in FIG. Ru. In this embodiment, the longitudinal "lunar wall" of the dam is not curved, and the desired shape is achieved by curving the contact curve 35' between the dam and the roll. The length is changed to a contact arc.

Also, in order to limit the length of the contact arc at the ends of the rolls, instead of the dams mentioned above, any means capable of confining the liquid metal in the desired geometry, e.g. horizontal walls or diagonal It is also possible to use walls or other means to prevent contact with the piece of cast gold.

[Brief explanation of drawings]

FIG. 1 is a conceptual perspective view of an apparatus for casting between rolls with a dam, with some parts shown in cross-section. 2a and b are cross-sectional views perpendicular to the axis of the rolls at the ends and in the middle of the device described above, and FIG. 3 is a view similar to FIG. 1 of another embodiment of the invention. 3 and b: Sections of the products obtained when two and one dam walls according to the invention are used. (Main reference numbers) 1.2 Roll 5 Nip 8.9 Product 13 Rotation direction 33 Lower edge 35 Contact line 3 Dam 6.7・Contact arc 11.12... Bus line 31.32... Wall 34... Chamfer part agent

Claims (5)

[Claims] (1) A method of continuous casting of liquid metal between rolls having mutually parallel axes with cooled walls and driven to rotate in opposite directions, in which the generating line is curved in the heated state and the diameter is using at least one roll whose central portion is slightly smaller than its axial ends, and contacting the liquid metal with the wall of the roll over an arcuate length that is longer at the central portion than at the ends; A method characterized by: (2) In an apparatus for casting between two rolls with cooled walls, the generatrix of at least one roll is curved in the heated state and its diameter is greater than the center at both axial ends. 2. A device characterized in that the parts of the roll are slightly smaller and are provided with means for bringing the liquid metal into contact with the wall of at least one of the rolls at a greater arcuate length in the central part than in the ends. . (3) said means consist of a longitudinal wall (31) of the dam (3), the lower edge (33) of said wall being in substantial contact with the roll wall above the nip (5) between the rolls; 3. Device according to claim 2, characterized in that the line of contact (35, 35') between the lower edge and the roll is curved. (4) The longitudinal wall (31) of the dam is flat, and a chamfered portion (34) is formed at its lower edge, and the angle of the surface of this chamfered portion (34) is set at both ends of the wall. 4. A device according to claim 3, characterized in that the device increases from the central part to the central part. 5. The apparatus of claim 3, wherein the longitudinal walls of the dam are concave toward the inside of the dam.