JPH04138884A - Method for controlling thickness of al/stainless steel clad plate at the time of manufacturing - Google Patents

Abstract

PURPOSE:To control the thickness at the time of manufacturing the clad plate of an Al alloy and stainless steel by rolling and cladding by regulating the heating temperature of the Al alloy. CONSTITUTION:In manufacturing the clad plate of the Al alloy and the stainless steel by rolling and cladding, a stainless steel coil 3 and an Al alloy coil 4 unwound from payoff reels 1 and 2 are continuously heated by electromagnetic induction heating devices 5 or 6 separately respectively for every material and then, both are superposed on each other and sent to a rolling mill 7. At this time, the heating temperature of the Al alloy coil 4 is regulated corresponding to variation of rolling load and frictional resistance between clad materials and between an Al alloy and rolling rolls is changed. Consequently, product thickness accuracy is improved and stability of joining can be maintained.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a method for controlling plate thickness when manufacturing a clad plate of Al or Al alloy and stainless steel by a rolling welding method.

<Prior art and its issues> Conventionally, in metal coil rolling, it has been believed that it is possible to precisely control the product plate thickness by adjusting the roll opening degree and tension, and in actual rolling operations, this method is generally used to control the plate thickness. controls have been implemented.

However, in the case of clad joint rolling of AI (hereinafter referred to as the general term including M alloy unless otherwise specified) and stainless steel, if we try to apply the roll opening and tension based on the conventional solid rolling technology mentioned above, It was pointed out that the problems shown in (81) and (b1) below occurred, and that rolling reduction cracking, poor bonding, etc. were likely to occur.

(a) Even if the roll opening degree is adjusted, regular changes in thickness cannot be realized, and the plate thickness is not stable.

For example, if you try to increase the thickness of a product and adjust the roll spacing in the direction of opening, the thickness will move in the direction of increase at the time of operation, but
A phenomenon occurs in which the thickness immediately returns to the initial thickness and an equilibrium state is reached. Furthermore, if the roll opening degree adjustment is frequently repeated, although the target thickness is achieved, the rolling becomes unstable due to non-uniform joining and squeezing, etc.

Even if the tension is adjusted, the thickness does not change in a regular manner, and the plate thickness is still unstable. That is,
Varying the strength of the tension to control the product board thickness,
Although a slight change in thickness is observed at the time of adjustment, it quickly returns to its initial state (thickness before adjustment) and reaches equilibrium.

Therefore, if the tension is increased, cutting of the material becomes a problem,
On the other hand, if it is too weak, problems such as aperture may occur.

In this way, in joint rolling of Af/stainless steel cuti-clad plates, controlling the plate thickness is extremely difficult and unstable, and when attempting to stabilize the plate thickness, the rolling joint becomes unstable, leading to a decrease in yield. Therefore, in actual work, it is necessary to prepare multiple AI base materials with various thicknesses and select the base material thicknesses to be combined according to the conditions to ensure stable bonding and appropriate product thickness. I was worried. Therefore, it is necessary to prepare in advance a large number of combination base materials in order to correspond to the plate thickness required by the user, and the preparation and storage of these materials also causes a considerable increase in costs.

For this reason, an object of the present invention is to perform clad rolling (
The aim was to establish an "AI/stainless steel cuti clad plate thickness control means" that can stably control the product plate thickness within a target range while ensuring sufficient stability of joint rolling.

(Means for Solving the Problems) In order to achieve the above object, the present inventors conducted extensive research while repeating numerous experiments, and as a result, they were able to obtain the following findings.

(a) The reason why plate thickness control methods based on conventional solid rolling technology do not work in Af/stainless steel cuti clad rolling is that ``Unlike solid rolling, in clad rolling (conventional), the material changes greatly depending on the heating temperature. The frictional resistance at the joint interface and the frictional resistance between the material (especially the M base material) and the rolling rolls sensitively affect the rolling reduction rate, and this is a major hindrance to controlling the plate thickness. In other words, when the roll opening degree is increased to increase the plate thickness, the rolling load decreases, but when the rolling load decreases, the frictional resistance at the interface of the clad base material (Ai) also decreases, resulting in a delay in the welding time. As a result, the rolling reduction rate hardly changes.

If this process is repeated, the frictional resistance at the bonding interface will drop below the limit necessary for bonding, resulting in poor bonding and drawing defects. In other words, while maintaining the load within a certain range, and adjusting the frictional resistance within a certain range)
Good clad rolling cannot be achieved unless the roll opening is widened.

(bl) However, as shown in Figure 1, the frictional resistance of M changes significantly as the heating temperature changes, so
When the heating temperature of the M base material is appropriately adjusted by Af/stainless steel cuti clad rolling, the frictional resistance between the bonding interface and the rolling roll and the AN base material changes accordingly. Therefore, the thickness of the product plate can be accurately controlled by adjusting the heating temperature of the M base material. For example, even when increasing the roll opening, if the heating temperature of the M base metal is increased accordingly, the frictional resistance will increase and the rolling load will be positive, eliminating the delay in joining time and ensuring an appropriate rolling reduction. This means that it is ensured.

The present invention has been made based on the above-mentioned findings and the like. ``When manufacturing a clad plate of Al or Al alloy and stainless steel by the rolling welding method, by adjusting the heating temperature of A1 or M alloy. The major feature is that it changes the abrasion resistance between the cladding materials and between the Al or M alloy and the rolling rolls, thereby accurately controlling the thickness of the product.

Although the above-mentioned plate thickness control method according to the present invention can be carried out independently, a good effect can be obtained, but it goes without saying that it may be carried out in combination with roll opening adjustment if necessary.

Next, the present invention will be specifically explained based on drawings showing examples of equipment for implementing the present invention.

FIG. 2 is a conceptual diagram illustrating an example of an apparatus used for Af/stainless steel cuticlad plate construction according to the present invention;
The payoff reels 1 and 2 are arranged on one side of the rolling mill 7 and the tension reel 8 is arranged on the opposite side, and the stainless steel coil 3 is heated between the rolling mill 7 and the payoff reels 1 and 2. The electromagnetic induction heating device 5 and the electromagnetic induction heating device 6 for heating the M coil 4 are shown.

Although FIG. 2 shows only an example of an apparatus for manufacturing a two-layer clad plate, it goes without saying that the number of cladding layers can be reduced as appropriate by adding a payoff reel and a heating device.

Now, in FIG. 2, the stainless steel coil 3 and the M coil 4 unwound from the payoff reel 1.2 are heated continuously by an electromagnetic induction heating device 5 or 6 separately for each material, and then both are heated. They are piled up and sent to the rolling mill 7.

At this time, the heating temperature of the M coil 4 is adjusted in response to variations in rolling load, thereby controlling the plate thickness.

Note that by heating each material using a separate electromagnetic induction heating device, it is possible to appropriately adjust the temperature for each material, and the heating time can also be extremely short.

The clad product coil that has been sent to the rolling mill 7 and bonded and rolled is then wound onto a tension reel 8 and sent to the next process.

Here, a method for increasing the thickness of the product board in the above-mentioned method of manufacturing kraft material will be described.

Usually, the heating temperature of the above cladding material is 300-500℃
(If the temperature is too low, it will cause a bonding failure; if it is too high, the M coil will be at risk of melting, and stainless steel coils will oxidize, causing a bonding failure.) Adjust the heating temperature in stages (1 stage is 10℃)
When the rolling force is increased (to an appropriate degree), the frictional resistance between the bonding interface and M and the roll increases accordingly, and the rolling load also increases regularly, so that the product plate thickness can be increased.

The mechanism by which the thickness of the product plate increases only by increasing the temperature of the M coil is as follows.

In other words, when the frictional resistance between the stainless steel and the M base material and the frictional resistance between the M base material and the roll increase due to a rise in the temperature of the coil, the M base material is likely to be caught in the rolling rolls and joined earlier, making it easier to stretch. The elongation tendency of the material is impeded. Resistance to this deformation appears as an increase in rolling load (applies elastic deformation to the rolling rolls in the direction of increasing the roll spacing), and as a result, the quality of the product plate becomes thicker. Of course, it is clear from the above description that this clad rolling is performed under a sufficient rolling load, and therefore there is no fear of poor bonding or the like.

In fact, a 0.6-thick 18Cr stainless steel coil and 2
When the clad rolling shown in Fig. 2 is carried out using a pure M coil with a thickness of fi as the cladding material, the pure M coil has a thickness of 40 mm.
If the temperature is increased by 10℃ from a heating temperature of around 0℃, 2
The plate thickness could be increased at a rate of ~3 m/100 wm, and no bonding defects occurred.

In addition, if the temperature increase of the M coil and roll opening adjustment are used together, the frictional resistance between the stainless steel and the M base material and the friction resistance between the M base material and the roll will increase due to the temperature increase of the Al coil. It is also possible to offset the increased rolling load by opening the rolls and perform control to keep the rolling load constant.

Furthermore, if the heating temperature of the M coil is further increased and the roll opening degree is increased (for example, 0.5 to 1 m/10
(approximately 0w), it is also possible to significantly increase the thickness of the product board while preventing poor bonding.

On the other hand, if you want to reduce the thickness of the product plate, you can use the opposite method. If you lower the heating temperature of the M coil or adjust it by reducing the roll opening, you can keep the rolling load constant. The product thickness can be adjusted to be thinner while maintaining rolling stability.

In addition, plate thickness control by temperature adjustment of the M base material according to the present invention may be carried out by setting conditions in advance before the work, or the setting conditions may be changed during craft rolling depending on the situation. It goes without saying that it may be implemented while changing the .

(Example) A pure M coil (plate thickness: 2, Oxm) equivalent to JIS Al100 and a stainless steel coil (plate thickness: 0.6 m) equivalent to 5US430 were used as the base material for the cladding.
An attempt was made to manufacture an Ai/stainless steel clad plate product by performing clad rolling using the equipment shown in the figure while adjusting the heating temperature of the M coil.

As a result, product thickness: 1.80 to 2.30 vs. wide range (product thickness: 2.0m, rolling reduction ratio is 23.1%), with high thickness accuracy of ±0.05m. It was confirmed that pJl/stainless steel clad plate products with good bonding conditions could be manufactured.

<Effects of the Invention> As explained above, according to the present invention, Aj! /In stainless steel clad plates (^), the accuracy of the product plate thickness is improved and the stability of the joint is ensured (
Conventionally, the rolling accuracy was approximately ±0.15m relative to the product plate thickness, but it has become possible to achieve less than ±0.05U, and we have been able to improve the yield rate by more than 15% within this range.) .

(B) It becomes possible to expand the range of product plate thickness using the same dimension M base material (conventionally, the product plate thickness that could be manufactured was limited by the plate thickness of the M base material, so the target product plate thickness Previously, the material thickness was selected according to the user's request for plate thickness, but now it is possible to obtain a good product even if M base materials of the same size are used as long as the difference is within a range of about 0.5 m. It is no longer necessary to prepare many combination base materials, resulting in a significant inventory source).

It can be said that the contribution to industry is extremely large, as it brings about excellent effects such as.

[Brief explanation of drawings]

FIG. 1 is a graph showing the relationship between temperature change and friction coefficient change for M and M-based alloys. FIG. 2 is a conceptual diagram illustrating an example of an apparatus used for AI/stainless steel cuticlad board construction according to the present invention. In the drawings: 1.2...Payoff reel. 3...Stainless steel coil. 4...M coil. 5.6...Electromagnetic induction heating device. 7...Rolling 11. 8...Tension reel. Applicant Nippon Stainless Co., Ltd.

Claims (1)

[Claims] When manufacturing a clad plate made of aluminum or aluminum alloy and stainless steel using the rolling welding method, by adjusting the heating temperature of aluminum or aluminum alloy, it is possible to reduce Al that is characterized by changing the abrasion resistance and thereby controlling the thickness of the product.
Or a method for controlling plate thickness during production of Al alloy/stainless steel clad plate.