JPH07108403B2 - Multi-layer pack rolling method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention provides a multi-layer 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. Pack rolling method More specifically, it relates to a method for assembling laminated rolling materials.

[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 cover materials.
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 order to improve the rolling efficiency or to manufacture a thinner material, it becomes necessary to make the core material multilayer. However, when the core material has three or more layers, a temperature difference occurs between the core materials (higher temperature in the central part of the laminated material), which causes a difference in deformation resistance between the core materials, resulting in a difference in rolled finished plate thickness and a pressure difference. There is also a difference in length.

For this reason, the material length is regulated to the shortest length after rolling and the product thickness is regulated to the thinnest finishing pressure, so that the rolling yield decreases and the number of grinding processes for adjusting the plate pressure increases significantly. It will increase the cost.

[Problems to be solved by the invention]

An object of the present invention is to provide a multi-layer pack rolling method for improving the plate pressure accuracy between core materials in the multi-layer lamination rolling method, improving the yield, and reducing the number of refining steps.

[Means for solving problems]

The present invention, three or more core material coated with a release agent on the surface is laminated, the upper and lower sides are covered with a cover material, surrounded by a spacer, and the laminated rolled material assembled by welding is rolled hot, In the method for producing a thin material, a multilayer pack rolling method is characterized in that the inner core material among the core materials is made thicker and the finished plate thickness is adjusted.

[Action]

FIG. 1 shows the structure of the laminated rolled material in cross section. In the figure, 1: 1 ′ core material, 2: cover material, 3: spacer, and 4: welded portion.

In the text below, Ti material will be described as an example. The names of laminated rolled materials used below are as shown in FIG.

Here, the core materials 1, 1 ′ are three or more pieces of Ti, and a release agent is applied to the surface of each Ti plate to prevent the Ti and the Ti from sticking to each other due to rolling. The top and bottom of the core material 1 are sandwiched by a cover material 2 made of steel or pure iron, and the periphery thereof is surrounded by a spacer 3 made of the same material as the cover material 2. Cover material 2 and spacer 3
Welds over the entire circumference to prevent the cover material 2 from peeling off during rolling and breaking of the laminated rolling material. The laminated rolled material is filled with air or other gas, or in a vacuum atmosphere.

If there are two core materials, the rolling condition will be vertically symmetrical, so 2
Since the core materials of one sheet are deformed in the same manner and finished with the same plate thickness, there is no problem in plate thickness accuracy.

When three or more core materials are stacked, the laminated rolled material cools from the outside during rolling, so that the outer core material 1 ′ of the stacked 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, in order to prevent variations in the finished thickness of the core material in laminated rolling, the thickness of the inner core material before rolling may be increased and the finished thicknesses may be adjusted.

Next, examples of the present invention will be described.

〔Example〕

An example of manufacturing a 2.5 mm 6Al-4VTi alloy plate by three-layer pack rolling will be described. In that case, cover material: SS41, core material 6A: l-4VTi alloy Heating temperature: 900 ℃, Roll diameter: 1200mmφ Material size: 2000 × 2500 Rolling conditions: 10 passes, finishing to 15mm, and further pack composition The following test example (1) and test example (2) were performed.

Test example (1) Pack composition covers material thickness: 18.6 mm t, core material thickness: core material
All 1,1 were set to 12.0 mm t.

Test Example (2) The pack composition was set to cover material thickness: 18.6 mm t, core material thickness: core material 1 (inner side): 12.8 mm t. Core material 1 '(outer side): 12.0 mm t.

In the test example (1), three-layer pack rolling with the same core material plate thickness was performed as in the conventional case, and in the test example (2), the inner core material plate thickness was increased by the method of the present invention.

The optimum thickness difference is calculated by obtaining the difference in elongation from the deformation resistance ratio between the core materials in each pass by the temperature analysis as shown in FIG.

The results of the thickness of each core material after rolling are shown below.

Test Example (1) Core Material 1 2.40 mm, Core Material 1'2.55 mm Test Example (2) Core Material 1 2.50 mm, Core Material 1'2.50 mm From the above, according to the present invention, three core materials have plate thickness deviations. I was able to solve it. Similar results were obtained for the rolling length.

〔The invention's effect〕

The multilayer pack rolling method of the present invention has the following effects.

(1) The plate thickness accuracy is improved and the yield is improved accordingly,
Cost reduction and lack of length are resolved.

(2) The grinding process for adjusting the plate thickness can be omitted.

[Brief description of drawings]

FIG. 1 is a cross-sectional explanatory view showing a laminated rolling material structure of the present invention, FIG. 2 is an explanatory view showing a temperature change when a laminated rolling material in which three core materials are stacked is rolled, and FIG. Ti-6Al
It is a relational graph of -4V deformation resistance and rolling temperature. In the figure, 1,1 ': core material, 2: cover material, 3: spacer, 4:
It is a welded part.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Takashi Arizumi 1-2-1, Marunouchi, Chiyoda-ku, Tokyo Nihon Steel Pipe Co., Ltd. (56) References JP-A-48-86762 (JP, A)

Claims (1)

[Claims] 1. A laminated rolling material obtained by laminating three or more core materials each having a release agent applied on the surface thereof, covering the upper and lower sides thereof with a cover material, surrounding the periphery with spacers, and welding and assembling the laminated rolling material. In the method for producing a thin material, a multilayer pack rolling method characterized in that the inner core material of the core materials has a larger material thickness and a finished plate thickness.