Method for laminating aluminum for fine-grain applications

Abstract

The present invention describes an aluminum rolling method comprising a stage a) of hot rolling at an initial temperature ranging from 450 to 500° C. up to a final temperature ranging from 360 to 400° C., obtaining an aluminum sheet with a thickness between 8 and 12 mm; and a stage b) of cold rolling wherein rolling passes at a temperature ranging from 75 to 120° C. are intercalated with an intermediate sub-stage of heat treatment at a temperature ranging from 340 to 390° C., until obtaining an aluminum sheet with a final thickness between 0.3 and 1 mm. Another object of the invention is the rolled aluminum obtained from the method explained in the present application and its use in manufacturing containers for the cosmetic and perfume industry.

Claims

1. An aluminum rolling method comprising a stage a) of hot rolling and a stage b) of cold rolling an aluminum sheet: in the stage a) of hot rolling, the temperature decreases from an initial temperature ranging from 450 to 500° C. to a final temperature ranging from 360 to 400° C., obtaining a hot rolled aluminum sheet with a thickness ranging from 8 to 12 mm; and in the stage b) of cold rolling, rolling passes at a temperature ranging from 75 to 120° C. are intercalated with an intermediate sub-stage of heat treatment at a temperature ranging from 340 to 390° C., until obtaining a cold rolled aluminum sheet with a final thickness ranging from 0.3 to 1.0 mm; wherein the intermediate sub-stage of heat treatment is carried out for a period ranging from 3 to 5 hours, the aluminum rolling method further comprising, after the stage b) of cold rolling: a heat treatment at a temperature ranging from 220 to 260° C. of the cold rolled aluminum sheet for a period of 4 to 6 hours; wherein an aluminum in the aluminum sheet is selected from pure aluminum and an aluminum alloy comprising magnesium as the main alloying compound; and wherein a reduction in the thickness from 45% to 75% is achieved in the final hot rolling pass, and after the hot rolling stage, a grain structure is totally recrystallized with a grain size between 50 and 90 μm measured by the grain intercept method ASTM E-112-88, and wherein each one of the stages comprises several rolling passes through a system of rollers.

2. The aluminum rolling method of claim 1, wherein in the hot rolling stage a), the temperature decreases from a temperature of 500° C. to a final temperature of 380° C., obtaining an aluminum sheet with a thickness of 10 mm; and in the cold rolling stage b), rolling passes at a temperature of 75° C. are intercalated with the intermediate sub-stage of heat treatment at a temperature of 350° C. for 4 hours.

3. The aluminium rolling method according to claim 1, wherein the aluminum sheet is used for manufacturing a container for the cosmetic and perfume industry.

4. The aluminum rolling method of claim 1, wherein the intermediate sub-stage of heat treatment is carried out with an aluminum sheet having a thickness between 3 and 5 mm.

Description

DESCRIPTION OF THE FIGURES

(1) FIG. 1: Grain structure obtained after the hot rolling stage according to the standard procedure (FIG. 1a) and according to the aluminum rolling method described in this patent application (FIG. 1b).

(2) FIG. 2: 3D grain structure obtained by the standard procedure (FIG. 2a) and by means of the aluminum rolling method described in this patent application (FIG. 2b).

EXAMPLES

Example 1: Aluminum Rolling Method

(3) First, a system of rollers is heated to an initial temperature of 500° C. Once this temperature is reached, an aluminum sheet with an initial thickness of 600 mm is passed through the roller system. This rolling process is repeated 15 to 20 times, progressively decreasing the temperature of the system until reaching a final temperature of 380° C., obtaining an aluminum sheet with a thickness of 10 mm.

(4) Once the established thickness is reached, the aluminum sheet is transferred in the form of a coil to another system of rollers which work at a lower temperature, approximately 75° C., and the aluminum sheet obtained in the previous stage is passed through this cold rolling system of rollers. This rolling process is done successively until obtaining a thickness of 4 mm.

(5) Then, the aluminum sheet obtained in the form of a coil is subjected to an intermediate sub-stage of heat treatment at a temperature of 350° C. In order to carry out the intermediate heat treatment (total intermediate annealing) the aluminum coil is heated in an oven until reaching a temperature of 350° C., and is then maintained for 4 hours at this temperature. After this time period, it is removed from the oven and left to cool until reaching a temperature of approximately 70° C.

(6) Then the aluminum sheet is passed through the roller system at a temperature of 75° C. until obtaining a sheet with the final desired thickness: from 1 mm to 0.3 mm.

(7) Lastly, the aluminum sheet obtained by the method previously described is subjected to heat treatment at a temperature of 260° C. for a period of 5 hours. To carry out this treatment, the aluminum sheet coils are introduced in an oven and heated until reaching the established temperature. This temperature interval is then maintained for a period of 5 hours.