JPS61232003A - Rolling method for clad material - Google Patents

Abstract

PURPOSE:To decrease the protrusion arising from the rolling of a clad material by forming preformed parts each having a parallel part and taper by local rolling to the front and rear ends of the clad material prior to rolling of the entire part then subjecting the material to the rolling over the entire part. CONSTITUTION:The clad material in a hot state is thinly rolled from the thick state of a plate thickness with a good yield in this method. The general material 2 side is more likely to elongate as compared to SUS1 and therefore the material is ironed by rolling rolls 3, 4 to generate a projection 32 when the clad material is successively rolled by the rolls 3, 4. The generation of such projection results in the decreased yield. The preformed parts each having the parallel part L0 and the tapered part by local rolling are thereupon provided to the front and rear end of the clad material prior to the rolling over the entire part and thereafter the rolling over the entire part is executed. As far as the preformed parts are provided thereto, the preformed parts restrain the projection even if the material is going to project in the stage of rolling the central part. The rolling with the decreased projection is thus made possible.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention particularly relates to a method of rolling a cladding material in a hot state with a good yield and rolling the cladding material into a thinner sheet than a thick sheet.

[Background of the invention]

A typical example of the rad material as shown in FIG. 2 is a material in which 5US1 and general steel 2 are laminated together.

SUS' is expensive, but it can be manufactured at a lower cost than if the entire plate thickness were made of SUS, and SUS is resistant to surface corrosion, so it is possible to make it extremely thin and maintain the strength with general steel. It is expected to be in great demand as a material in the future. In addition to the general steel and SUS materials, various types of cladding materials have been considered, such as Inconel and steel, depending on the purpose.

Such materials are usually processed using two reversible rolling mills in one
A slab with a thickness of 250~loo+am is repeatedly rolled in forward and reverse directions, and then reduced in thickness to a product thickness of 5~50+sm.

Plate width is 1000~420011m, plate thickness is 10m~50m
It is rolled at a high temperature of 1100°C to 750°C.

In SUS cladding material, the thickness of SO5 is about 10 to 30% of the total thickness.

When the rudd material is rolled in this manner, a protrusion of 30° 31 occurs at the leading and trailing ends in the rolling direction as shown in FIG. This is - compared to the variable resistance of SUS material of 23 kg/■12.
This is because the shell material has a low weight of 14 kg/i+n', which is about half as low, making it difficult for the SUS material to stretch.

The sum of the amounts of protrusion W1 and W2 increases in proportion to the thickness of the rolled material (slab), as shown in FIG.

When the cause of this was investigated, it was found that it was due to the following reason.

That is, in FIG. 4, when the cladding material is rolled by the rolling rolls 3 and 4, the one-shell material 2 side tends to elongate with respect to 5 USI, so this is squeezed by the rolling rolls 3.4, causing an overhang 32. This is to make it happen. This portion has to be cut out after rolling, reducing yield.

[Eighth aspect of the invention] The present invention provides a method for rolling a cladding material, which reduces protrusion during rolling of the cladding material and improves the yield.

[A lecture on invention]

In the present invention, as shown in FIG. 6, before rolling the entire clad material, the front and rear ends of the cladding material are provided with a parallel portion L0 and a taper, k,
A preforming section is provided by local rolling, and then the whole is rolled. This preforming is performed in the direction in which the rolled material is advanced toward the rolls, and the rolling extension is small, so the squeezing phenomenon shown in Figure 4 does not occur, and this rolling is based on the principle that almost no protrusion occurs with this rolling alone. It is.

In Fig. 6, it was found that if a pre-braking is provided, even if the central part tries to protrude during rolling, this preformed part will restrain the protrusion, making it possible to roll with less protrusion. did.

Ideally, the rolling thickness k of the preformed part should be equal to the product thickness, but as shown in Figure 3, the thinner the plate, the less the protrusion, so the amount of protrusion is proportional to the amount of preforming. This has the effect of reducing the amount of

If the length of the parallel portion L0 in FIG. 6 is approximately equal to or longer than the plate thickness H as shown in 711f, a sufficient effect for preventing extrusion can be obtained.

In addition, if the radius of curvature R1, R, of the part where the plate thickness changes from H to H in Fig. 6 is small, during the thickness reduction rolling for the first overall length, this part will change to the plate width B as shown in Fig. 8. , abnormal width bulge ΔB1. It was found that ΔB2 occurs.

In order to prevent this, R□ and R3 should have a large radius of curvature, but it is desirable that they have a gentle taper. Generally, the thickness of the rolled material and the diameter of the rolling rolls used are proportional, so R1, R in Fig. 6,
Abnormal plate width amount AB1. I investigated the relationship between AB2. This relationship is shown in FIG.

Assuming that R1 and R2 in FIG. 6 are equal, this is designated as R.

Assuming that the roll radius is R1, it can be seen that as R/R increases, the abnormal width amount AB1+ΔB3 decreases. It has also been found that good results can be obtained for this effect when R/R is set to 1 or more. In fact, a smooth taper will give better results than a single radius. The angle θ of this taper can be expressed as (a-h)/Lx in Fig. 6. In this way, changes in plate thickness will be averaged and smoothed in proportion to one R, so abnormal width will not occur. By becoming difficult.

As a technique similar to this, Japanese Patent Laid-Open No. 54-97559 is known. This method is used for the purpose of reducing fish tails that occur during width rolling during blooming. That is, the rolled material is advanced through rolling rolls to locally roll the leading and trailing ends, and then the rolled material is reversed to provide a preformed portion. - In this method, the boundary between the parallel part of the preform and the unrolled part inevitably becomes the radius of the roll, resulting in a large abnormal width lB, + AB as described above.

In view of the above points, in the present invention, as shown in FIG. From the state of b
, it opens smoothly to state c, and during this time,
The material is fed in the direction of the arrow shown by the solid line.First, after the material passes between the rolls, it is sent to the opposite end in the direction of the arrow shown by the dotted line and preformed using the same method as described above. This is what we do.

Although FIG. 5 shows that the upper and lower rolls 3 and 4 are opened at the same time, in reality, the same effect can be obtained if only one of the upper and lower rolls is opened.

[Embodiments of the invention]

FIG. 1 shows an embodiment of the present invention.

In FIG. 1, since it is difficult to extend the 5US1 side, the effect of the present invention is further expanded by using a roll 14 that is thinner than the roll 15 that rolls the lower general steel material 2 side.

An intermediate roll 13 and a lower work roll 15 contained within the stand 11 are driven by motors 20 and 22, respectively. The upper and lower rolls are supported by reinforcing rolls 12 and 16, respectively, and supported by an upper roll bearing box 41.

The roll position is set by a screw 10.

The rolled material is sent by a table roller 24 and rolls 14.15
Preformed by According to the command unit 21, the amount of oil from the high pressure oil source 20 is controlled by the servo valve 19 so that the preform shape is as shown in FIG.
While moving the piston 18 up and down, the upper rollers 15 and 16 are moved up and down to preform it into a predetermined shape.

After the preforming on one side is completed, the material is transferred to the other tape roller 25 side, so the material is fed back on this table and preformed on the end of the other side.

Although the present invention was carried out under hydraulic pressure as shown in FIG. 1, it may of course be carried out under electric screw pressure.

Further, in FIG. 6, the parallel parts 6 are parallel to each other, but the effect of the present invention can be obtained even if the parallel parts 6 are slightly inclined, but the effect of restraining protrusion is better when the parallel parts are as parallel as possible.

Further, although FIG. 1 shows an example of a five-high rolling mill using rolls of different diameters, the effects of the present invention can also be obtained using a four-high rolling mill or a two-high rolling mill of equal diameter.

〔Effect of the invention〕

1. Before rolling a clad material made of different metal materials, by providing a pre-formed part to reduce the plate thickness at the front or rear end of the clad material, the protrusion that occurs at the front or rear end of the material is reduced. I was able to do that.

2. By performing preforming by gradually changing the opening of the rolling rolls without stopping the material after parallel rolling during preforming, the boundary between the preformed parallel part and the unrolled part can be formed into a smooth tapered shape. was completed.

3. By making the radius of curvature of the upper boundary part at least equal to or larger than the roll radius, it was possible to reduce sheet width abnormalities during thinning rolling.

4. Using the present invention with rolls of different diameters, the hard side is made smaller in diameter.

By increasing the diameter of the soft side, better effects were obtained than when preforming was performed using rolls of equal diameter.

[Brief explanation of the drawing]

Figure 1 is a five-high rolling mill that is an embodiment of the present invention, Figure 2 is an explanatory diagram of the protrusion situation during rolling of cladding material, and Figure 3 is a
Fig. 4 is an explanatory diagram of the amount of protrusion in the same case as above, Fig. 4 is an explanatory diagram of the reason why protrusion occurs, Fig. 5 is an explanatory diagram of the preforming method using gradual opening rolls, and Fig. 6 is after the preforming performed according to the present invention. Slab situation diagram. Fig. 7 is a diagram showing the relationship between preforming length and protrusion amount, Fig. 8 is an explanatory diagram of abnormal width occurrence situation, and Fig. 9 is an abnormal width occurrence amount and boundary R.
FIG. 14...Small diameter work roll, 15...Large diameter work roll. 13... Intermediate roll, 12.16... Reinforcement roll. 22.23... Drive device. 01θ0 ゐ. 3ω Slab Rumor Prediction 72 Prediction 6 Diagram Prediction 90 Hiroshi.

Claims (1)

[Claims] 1. Prior to rolling to reduce the thickness of the clad material on which dissimilar metals are bonded together, preform rolling is performed on at least one side of the leading end or trailing end of the clad material in the rolling direction. A method of rolling cladding material that involves rolling the entire length of the cladding material to reduce its thickness. 2. In claim 1, the preforming performed on the front or rear end of the cladding material is carried out by holding the rolls of a rolling mill at a substantially constant gap, and then gradually opening the rolls. A method for rolling a cladding material, characterized by performing preforming. 3. In claim 2, the cladding material is preformed at the front end or rear end by making the radius of curvature of the boundary between the parallel part of the preformed part and the unrolled part of the cladding material larger than the roll radius. A method for rolling a cladding material, the method comprising: 4. Claim 1, characterized in that, in preforming the cladding material, the diameter of the roll that rolls the hard side of the cladding material is smaller than that of the roll that rolls the soft side of the cladding material. A method of rolling cladding material.