JPH0818042B2 - Multi-layer pack rolling method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention is an assembly for producing a wide and thin material (5 mm or less) of non-ferrous metal such as pure Ti or alloy Ti and high alloy steel by hot rolling. The present invention relates to a method for rolling a multi-layer pack of a laminated rolling material.

[Conventional technology]

A laminated rolling method (pack rolling method) has been conventionally used as a manufacturing technique for hard-to-work materials or wide thin materials such as alloy Ti and high alloy steel.

The pack rolling method is to stack one or more core materials (materials to be rolled) whose surface is coated with a release agent, and cover the top and bottom with covers.
It is a method of manufacturing a thin material by surrounding a periphery with a spacer and rolling a laminated and rolled material assembled by welding in a hot state.

In general, the material produced by such a pack rolling method is a high-grade material, and a small-quantity, high-mix production system is required.

However, in this pack rolling method, a lot of man-hours are required for packing, post-rolling treatment and the like, and a step other than rolling becomes a bottleneck as a method for producing various thickness products and various materials.

Therefore, in the pack rolling method, only the same size and the same material are manufactured in one pack.

It is considered that this is because the research on temperature, deformation, and behavior in the multi-layer pack rolling has not been conducted at all, and thus rolling defects due to the multi-layer rolling occur.

[Problems to be solved by the invention]

In the pack rolling method of the present invention, many steps are required for packing, treatment after rolling, and the like, and steps other than rolling are a bottleneck in manufacturing a wide variety of rolled materials. It is an object of the present invention to provide a multi-layer pack rolling method in which a wide variety of products can be obtained by stacking rolled materials having different plate thicknesses and / or different materials in the same pack.

[Means for solving problems]

The present invention, core materials having different plate thicknesses coated with a release agent on the surface are laminated in three or more layers so that the combination of plate thicknesses is symmetrical in the plate thickness direction, and the deformation resistance above and below the core material when rolling It is a multi-layer pack rolling method in which a laminated rolling material that is covered with a cover material that is the same size as the cover material, is surrounded by spacers made of the same material as the cover material, and is hot-rolled is assembled by welding. The core materials of different materials coated with are laminated in three or more layers so that the combination of materials is symmetrical in the plate thickness direction, and the upper and lower sides of the core material are covered with a cover material whose deformation resistance is equal to or smaller than that of the core material during rolling, This is a multi-layer pack rolling method in which the surroundings are surrounded by a spacer made of the same material as the cover material, and the laminated rolled material assembled by welding is hot rolled, and the combination of different core thicknesses is symmetrical in the thickness direction. 3 layers or more to be Was a multi-layer pack rolling method.

[Action]

As a result of many experiments and analyzes concerning pack rolling, the following was found.

When three or more core materials having the same size and the same material are stacked, the laminated rolled material cools from the outside during rolling, so that the outer core material 1 ′ of the laminated core materials is cooler than the inner core material 1.

FIG. 2 shows a temperature change when a laminated rolling material in which three core materials are stacked is rolled.

As shown in FIG. 2, such a temperature difference occurs in any laminated rolled material.

Since the deformation resistance changes depending on the temperature as shown in FIG. 3, the deformation resistances of the inner core material and the outer core material differ by the temperature difference generated in the core material. Due to this deformation resistance difference, the rolling reduction of the inner core material becomes larger than the rolling reduction of the outer core material, and the finished plate thickness of the inner core material becomes smaller than the finished plate thickness of the outer core material.

Therefore, by utilizing this property, in pack rolling of three or more layers of core material, core materials with different thicknesses coated with a release agent on the surface are laminated so that the combination of thicknesses is symmetrical in the thickness direction. As a result, the deformation resistance becomes symmetrical in the wall thickness direction because the lamination interface exists at the position symmetrical in the wall thickness direction. As a result, the deformation of the core material becomes symmetrical in the wall thickness direction. It is possible to prevent the occurrence of shape defects, warpage, etc. due to the difference in elongation. Even if core materials of different materials (deformation resistance) are used, three or more layers of core materials of different materials are laminated so that the combination of materials is symmetrical in the plate thickness direction, and the temperature decreases and the deformation resistance The deformation of the core material is made symmetrical in the thickness direction by ensuring that the outer core material with a large deformation and the inner core material with a high temperature and a low deformation resistance have the same deformation resistance value. , And the deformation resistance between the core materials changes so as to be equal, it is possible to prevent the occurrence of shape defects, warpage and the like due to the difference in elongation between the core materials during rolling. Therefore, it is possible to manufacture a wide variety of plates in one pack without the occurrence of shape defects or the like due to the difference in elongation between core materials during rolling.

Furthermore, even in pack rolling of three or more layers with different core materials or different plate thicknesses from each other, three or more layers are laminated so that the material or the combination of material and plate thickness is symmetrical in the plate thickness direction. Of the outer core material whose deformation resistance has increased and the deformation resistance has increased, and the inner core material whose temperature is high and whose deformation resistance has decreased have the same deformation resistance value Are symmetrical, and when the plate thickness is different, the deformation resistance between the core materials changes so that they are the same, and since the laminated interface can also exist at symmetrical positions in the thickness direction, Since symmetry can be ensured, simultaneous rolling of different thickness materials and different thickness materials is possible without warpage during rolling.

〔Example〕

Next, examples of the present invention will be described. FIG. 1 is a cross-sectional view showing the structure of a laminated rolling material according to the multilayer pack rolling method of the present invention. In the figure, 1 and 1'are core materials, 2 are cover materials, 3 are spacers, and 4 are welded portions. Then, when the core materials 1, 1 ′ having a release agent applied to the surfaces thereof have different plate thicknesses, the combination of the plate thicknesses is laminated so as to be symmetrical in the plate thickness direction.

When the materials of the core materials 1 and 1'having the release material coated on the surfaces are different, the materials are laminated so that the combinations of the materials are symmetrical in the plate thickness direction.

Further, when the plate materials and the material of the core material 1, 1 ′ having the surface coated with the release material are different, the combination of the plate thickness and the material may be laminated so as to be symmetrical in the plate thickness direction.
Hereinafter, the Ti material will be described as an example in this embodiment.

Here, the core material 1 is a three-layer Ti plate, and a release agent is applied to the surface of each Ti plate to prevent the Ti plates from adhering to each other and the Ti plate and the steel plate from sticking to each other by rolling. The upper and lower sides of the core material 1 are sandwiched by a cover material 2 made of steel or pure iron having a small deformation resistance during rolling, and the surrounding area is surrounded by a spacer 3 made of the same material as the cover material 2. The cover material 2 and the spacers 3 are welded over the entire circumference to prevent the cover material 2 from peeling off during rolling and breaking of the laminated rolled material. The laminated rolled material is filled with air or other gas, or in a vacuum atmosphere.

(1) Rolling with different thickness Cover material: SS41, Core material: 6A1-4VTi alloy Heating temperature: 900 ℃, Roll diameter: 1200mmφ Material size: Top and bottom of cover material: 18.6mm t × 2000w × 2500l Two outer core materials: 14.6 mm t Core material inside 1 sheet: 7.6 mm t Rolling condition: Roll a total pack thickness of 74 mm to 15 mm t in 10 passes.

The target plate thicknesses are 3.0 mm and 1.5 mm, and the above material dimensions were obtained from the deformation resistance difference by temperature analysis.

As a result of rolling, 3.1 mm t and 1.5 mm t plates could be manufactured.
For the time being, we tried to obtain 3.0t and 1.5t in a two-layer pack, but from the early stage of rolling, a large warp occurred with the side with the thicker plate being the outside, and rolling was impossible.

(2) Rolling of different materials Pure Ti has different deformation resistance depending on the oxygen content
There are three standards.

JIS class 3 shows about 1.3 times more hot deformation resistance than JIS class 2.
Therefore, in a three-layer pack, one JIS3 type thin plate and two JIS2 type thin plates were manufactured under the following conditions.

Cover material: Ultra low carbon steel, Core material: Inner pure Ti JIS Class 3: Outer pure Ti JIS Class 2 Heating temperature: 825 ℃, Roll diameter: 1200mmφ Material size: Cover material 18.5mm t x 2000w x 2500l Core material 12.0mm t Rolling condition: The total pack thickness of 73 mm is rolled to 15 mm t in 10 passes.

According to these conditions, 2.5 mm t pure Ti JIS 3 class and 2 class plates
It was manufactured by pack rolling. In the above-mentioned three-layer rolling, by making the inner core material and the outer core material different in plate thickness, it is possible to efficiently manufacture different materials having different wall thicknesses at the same time.

〔The invention's effect〕

According to the multi-layer pack rolling method of the present invention, products of various materials and plate thicknesses can be rolled by one pack rolling, and an effect such as effective means for small-quantity multi-product production can be obtained.

[Brief description of drawings]

FIG. 1 is a cross-sectional explanatory view showing the structure of a laminated rolling material according to the multilayer pack rolling method of the present invention, and FIG. 2 is an explanation showing temperature changes when rolling a laminated rolling material in which three core materials are stacked. FIG. 3 and FIG. 3 are graphs showing the relationship between Ti-6Al-4V deformation resistance and rolling temperature. In the figure, 1,1 ': core material, 2: cover material, 3: spacer, 4:
It is a welded part.

Claims (3)

[Claims] 1. A core material having a different thickness of a plate coated with a release agent is laminated in three or more layers so that the combination of the plate thicknesses is symmetrical in the plate thickness direction, and the upper and lower portions thereof have deformation resistance during hot rolling. A multi-layer pack rolling method comprising: covering a cover material having a size equal to or smaller than that of a core material, surrounding the same with a spacer made of the same material as the cover material, and welding and rolling a laminated rolling material to hot rolling. 2. A core material having different materials coated with a release agent on the surface is laminated in three or more layers so that the combination of the materials is symmetrical in the plate thickness direction, and the upper and lower portions of the core material have a deformation resistance during hot rolling. A multi-layer pack rolling method comprising rolling a laminated rolling material, which is covered with a cover material having the following size, surrounded by a spacer made of the same material as the cover material, and assembled by welding, while hot rolling. 3. A core material having a different thickness and material coated with a release agent on the surface is laminated in three or more layers such that the combination of the thickness and the material is symmetrical in the thickness direction, and the upper and lower sides of the core material have a deformation resistance. A multi-layered structure characterized by covering with a cover material of a size equal to or smaller than the core material during hot rolling, surrounding it with a spacer made of the same material as the cover material, and rolling the laminated rolled material assembled by welding into hot. Pack rolling method.