JPH02211902A - Hot rolling method of aluminum - Google Patents

Abstract

PURPOSE:To prevent a defective bite and to allow the rolling of a work under high pressure by using work rolls formed by subjecting the surface of the cylindrical bodies of the rolls to hard chrome plating to a specific thickness. CONSTITUTION:The work rolls formed by subjecting the surfaces of the cylindrical bodies thereof to the hard chrome plating at >=5mu thickness are used. The degradation of the surface roughness is prevented and the defective bite, roll slip, etc., are prevented. The frequency of roll changes is decreased and the man-hours for the work are decreased.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for hot rolling aluminum using work rolls plated with hard chrome.

[Prior art] Current work rolls used for hot rolling aluminum are made of special forged steel, for example, and have a hardness of H.
9 is about 70, and special cast iron has a hardness H of 7.
It is about 8. As described above, in the hot rolling of aluminum, the surface roughness (Ra) of rolls made of special forged steel or special cast iron is determined.

However, when rolling a large number of DI cans (Lightning processed by drawing and ironing) or hard aluminum plates such as AA5182, the surface roughness Ra will be 0.3 to 0.4.
When the zero surface roughness decreases, there is a problem that poor biting and roll slip occur.

In addition, in the hot rolling of aluminum, aluminum and its oxides adhere to the work roll surface and cause surface defects on the rolled plate, so there is also the problem that the deposits must be removed with a brush roll. .

[Problem to be solved by the invention] The present invention is an aluminum (
This method provides a hot rolling method for rolls (including alloys), and is characterized by the use of work rolls that are chromium plated to increase hardness and improve wear resistance.

[Means for Solving the Problems] The present invention is based on various studies conducted in view of the above-mentioned circumstances, and it has been discovered that hard chrome plating may be applied to the surface of the body of the work roll.

In the present invention, hard chrome plating of 5μ or more (preferably 5 to 15μ) is applied to the surface of a commonly used work roll, that is, the chest surface. If it is thinner than 5μ, the abrasion resistance effect will be small, and if it is thinner than 15μ, the abrasion resistance effect will not change, so it is not practical! Use a forged steel or R-made roll as a work roll with a desirable f of 5μ or less,
A large number of rolls of AA5182 were rolled using this work roll, which was plated with hard chrome to a thickness of 5 to 15 μm, but there was no decrease in surface roughness, and there were no problems such as poor biting or roll slip.

In addition, although the adhesion of aluminum and its oxides to the rolls was generally small, when the thickness of the hard chrome plating was less than 5 μm, problems such as poor biting and roll slip occurred due to a decrease in surface roughness. Furthermore, those coated with hard chrome plating of 15μ or more showed no decrease in surface roughness and had no problems such as poor biting or roll slip.

[Effects of the Invention] The present invention uses a roll whose body surface is coated with hard chrome plating with a thickness of 5μ or more, and since the roll surface roughness does not decrease, defective biting can be prevented.
And can work under high pressure. Furthermore, the number of times the rolls are polished can be reduced, and the frequency of roll replacement can be reduced. In addition, the number of work steps can be reduced by reducing the number of roll checks and recombinations.

Claims (1)

[Claims] A method for hot rolling aluminum, characterized in that when hot rolling an aluminum plate, a work roll whose body surface is coated with hard chrome plating with a thickness of 5μ or more is used.