JPS61199515A - Hot leveling method of two-ply clad metallic sheet - Google Patents

Abstract

PURPOSE:To obtain a cooled clad metallic sheet free from camber by hot leveling a two-ply clad metallic sheet in a hot state, where no temp. difference exists between both metals, and hot rolling it again in a state where the temp. difference is produced between both metals by forcible cooling the metal side of large heat shrinkage. CONSTITUTION:A two-ply metallic sheet is hot leveled into a flat shape by heating it without causing the temp. difference between both metals. Successively, a metal side of large heat shrinkage is forcibly cooled to hot level it again in a state, where the tamp. difference exists between both metals and a camber is produced. The product of the temp. of both metals, till both are cooled to an ordinary temp. and respective linear expansion coefficients becomes almost equal, and the two-ply metallic sheet is cooled from the flat state, produced by the second hot leveling, to an ordinary temp. without causing camber.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for hot straightening a two-layer clad metal plate.

[Prior art] A two-layer rad steel plate flute made of a composite material such as stainless steel or cupronickel and a base material such as carbon steel. As the temperature decreases, distortion or warping occurs in the width and length directions of the plate.

That is, as shown in FIG.
It consists of two plates IA and IB with different coefficients of linear expansion. Therefore, when the steel plate 1 undergoes a cooling process, it curves so that the plate material IA, which has a large coefficient of linear expansion and a large amount of shrinkage, is on the inside, causing distortion or warping.

In response to this problem, the present applicant has proposed a method for straightening warpage of 271 clad steel sheets as disclosed in Japanese Patent Application Laid-Open No. 511-42122, and has achieved results.

That is, the method according to JP-A-58-42122 is as follows:
When straightening a rolled clad steel plate in a hot straightening machine, by forcibly cooling the steel plate side with a large amount of heat shrinkage before or during hot straightening, the temperature difference between the side of the steel plate with a large amount of heat shrinkage and the side of the steel plate with a small amount of heat shrinkage is created. This causes a state in which the same amount of warpage as after cooling occurs, and then the product in this state is flattened using a hot leveler or the like, thereby making it possible to prevent warpage after cooling to room temperature.

[Problem to be Solved by the Invention 1] However, in reality, clad steel sheets begin to warp as soon as they are cooled immediately after hot rolling.
1" - According to Japanese Patent Application Publication H!; 11-42122, "During forced cooling, it is difficult to uniformly supply cooling water jetted from a rudder, etc. to the spray in the width and length directions of the steel plate. . Further, clad steel plates often have internal distortion due to processing history such as hot rolling.

Therefore, when using the above conventional hot straightening method,
It is difficult to provide a sufficient straightening effect to a clad steel plate, and it is difficult to straighten the shape of the clad steel plate so that it is flat after being cooled to room temperature.

An object of the present invention is to perform sufficient warpage correction on a clad metal plate.

[Means for Solving the Problems] The present invention provides a hot straightening method for a 2R clad metal plate consisting of a base material and a laminate, in which a temperature difference is actively applied between the two metals of the metal plate. After hot straightening the metal plate, the metal side of the metal plate with a large amount of thermal contraction is forcedly cooled, thereby creating a temperature between the two metals. It is designed for hot straightening.

[Function] According to the present invention, after the clad metal plate is flattened to remove the distortion caused by the pre-processing, a straightening operation that involves forced cooling is performed. This makes it possible to uniformly supply the cooling fluid in the width direction and length direction of the clad metal plate. In addition, under the condition where the influence of internal distortion from pre-processing is removed, the metal side with a large amount of thermal contraction is corrected and cooled using the cooling fluid, and the same amount of warp as after cooling is realized in advance, and the item in this state is flattened. This will be corrected. Therefore, it becomes possible to perform sufficient warpage correction on the clad metal plate.

[Example] FIG. 1 is a layout diagram showing an example of a correction device used for implementing the present invention. In FIG. 1, 111 hot rolling mill,
12 is a first correction device, and 13 is a second correction device. Second
The straightening device 13 includes cooling fluid supply means, such as a ladder, to the cooling spray between the straightening rollers. Hot rolling mill 11
and the first straightening device 12 or the second straightening device 13 are separated by a distance, and the clad steel plate l rolled by the hot rolling mill 11 is conveyed by the distance shown in FIG. This results in warping as shown in the figure.

Therefore, in the present invention, the first straightening device 12 first applies hot straightening to the clad steel plate l without actively creating a temperature difference between the base material and the laminate material of the clad steel plate l. 0th order: By using the second straightening device 13, the metal side of the clad steel plate 1 with a large amount of heat shrinkage is forcibly cooled by a cooling spray using a ladder or the like, thereby creating a temperature difference between the base material and the laminate material. Under certain conditions, it is used as hot straightening.

FIG. 3 is a diagram showing the relationship between the elapsed time, the amount of warpage, and the average temperature of the Clarade steel sheet 1 subjected to various straightening methods. A is the case where the specimen is allowed to cool after hot rolling, and the warpage after cooling to room temperature is maximum. B, Shimasu with normal hot straightening without forced cooling cj±1 song V,
This is a case of hot straightening accompanied by forced cooling according to Bunkan Sho 5-42122, and if forced cooling and restraint are not appropriate, warpage will remain after cooling to room temperature. d is the case according to the present invention, and it is observed that the warpage after cooling to room temperature is extremely small.

That is, according to the present invention, after flattening the clad steel plate 1 and removing the distortion caused by the pre-processing, a straightening operation that involves forced cooling is performed. As a result, the clad steel plate l
It becomes possible to supply cooling fluid uniformly in the width direction and length direction. In addition, under the condition where the influence of internal distortion from previous processing is removed, the metal side with a large amount of thermal contraction is forcibly cooled by the cooling fluid, and the same amount of warp as after cooling is realized in advance, and the item in this state is It will be corrected to be flat. This makes it possible to perform sufficient warpage correction on the clad steel sheet l.

In addition, in carrying out the present invention, the hot straightening that should be applied in the preliminary stage of hot straightening that involves forced cooling of the second straightening device 13 is performed only by the second straightening device 13 without using the first straightening device 12. It is also possible to do this by. In that case, first, hot straightening is applied to the clad steel plate l without operating the ladder to the cooling spray of the second straightening device 13, and then the cooling spray of the second straightening device 13 is applied. Hot straightening is performed on the clad steel plate 1 while cooling the clad steel plate 1 while operating a ladder or the like.

Hereinafter, specific implementation results of the present invention will be explained.

The laminated material is stainless steel, the base material is carbon steel, the total thickness of the plate is 201mm, and the cladding ratio (thickness of the composite material/total thickness of the plate) is 30.
%, the stainless clad steel sheet was subjected to the straightening method A described in JP-A-59-42122 and the straightening method B according to the present invention.

Here, the clad steel sheet obtained by hot rolling is flat immediately after rolling, but during the cooling process until it reaches the hot straightening machine, the stainless steel side, which has a large amount of heat shrinkage, is placed on the inside. ■It causes some degree of warping.

In the straightening method A disclosed in JP-A-59-42122, a clad steel plate, which is at an entrance temperature of 750°C on the entrance side of a straightening machine, is subjected to a 3-noise process that involves cooling one side of the clad steel plate with a spray lag. By straightening, the temperature of the stainless steel on the bottom side is 550℃, and the temperature of the carbon steel on the top side is 850℃.
Straightening was completed at the outlet temperature. The above-mentioned clad steel plate was flat during the straightening process, reversed (-) warp due to reheating after the straightening was completed, and then (+) 5 ha of warp remained at room temperature after being allowed to cool for nine months.

On the other hand, in the straightening method B based on the present invention, the clad steel plate, which is at an entrance temperature of 770° C., is first straightened in three passes on the entrance side of the first straightening device 12, and then the flattened primary and second The clad steel plate, which is at an entry temperature of 740°C on the entry side of the straightening device 13, is straightened in three passes with cooling of one side of the clad steel plate by a spray lug, so that the temperature of the stainless steel on the bottom side is 540°C, and the temperature on the top side is 540°C. Straightening was completed when the temperature of the carbon steel on the exit side was 640°C. The above-mentioned clad steel plate is straightened by the first straightening device 12 to remove the warp caused by cooling after rolling and to equalize the residual stress, thereby improving the effect of subsequent straightening accompanied by forced cooling by the second straightening device 13. It becomes possible to make it larger. Therefore, although a large warp appears due to reheating after straightening, the negative (-) warp gradually decreases after 7 d of cooling, and it is possible to finally achieve a warp state close to zero.

In addition, FIG. 4 shows the results obtained by the straightening device arrangement including both the first straightening device 12 and the second straightening device 13 shown in FIG. When the present invention is implemented, although the occurrence of reverse (-) warping due to recuperation is delayed, it is possible to obtain the same effect as shown in FIG. 4 as a result.

[Effects of the Invention] As described above, the present invention provides a method for hot straightening a two-layer clad metal plate consisting of a base material and a laminate, in which a temperature difference is actively created between the two metals of the metal plate. After the metal plate is hot-straightened, the metal plate is hot-straightened under conditions that create a temperature difference between the two metals due to the gold. Therefore, it becomes possible to perform sufficient warpage correction on the clad metal plate.

[Brief explanation of drawings]

FIG. 1 shows an example of an orthodontic device used in carrying out the present invention. ttm, Figure 2 is an end view showing the warped state of the clad steel plate, Figure 3 is a line drawing showing the relationship between elapsed time, amount of warpage, and average temperature of the clad steel plate subjected to various straightening methods, and Figure 4 is the book. FIG. 3 is a diagram showing a concrete implementation result of the invention.
・ 1... Clad steel plate, 11... Hot rolling mill, 12.
...first correction device, 13...second correction device. Agent Patent Attorney Osamu Shiokawa Figure 1 Figure 4

Claims (1)

[Claims] (1) In a hot straightening method for a two-layer clad metal plate consisting of a base material and a cladding material, the metal plate is hot straightened without actively creating a temperature difference between the two metals of the metal plate. After that, the metal side of the metal plate having a large amount of thermal contraction is forcibly cooled to create a temperature difference between the two metals, and the metal plate is hot-straightened. Hot straightening method for metal plates.