Method for heat treating a rolling stock made of a heat-treatable aluminum alloy

Abstract

A method and an apparatus are shown for heat treating a rolling stock (3), particularly a strip, made of an age-hardenable aluminium alloy, particularly an alloy of the 6000 series, wherein the rolling stock (3) in the process of passing through an apparatus (1) is fed to a solution annealing operation and a quenching operation, and in a subsequent step the rolling stock (3) is subjected to hot exposure for age hardening. In order to provide advantageous conditions for the method it is proposed that in a first step during the hot exposure the rolling stock (3) which is in the process of passing through the apparatus (1) is heated, whereupon in a further step the heated rolling stock (3) is further subjected to the hot exposure.

Description

1. FIELD OF THE INVENTION[0001]The invention relates to a method for heat treating a rolling stock, particularly a strip, made of an age-hardenable aluminium alloy, particularly an alloy of the 6000 series, wherein the rolling stock in the process of passing through an apparatus is fed to a solution annealing operation and a quenching operation, and in a subsequent step the rolling stock is subjected to hot exposure for age hardening.2. DESCRIPTION OF THE PRIOR ART[0002]In order to change the material properties of a strip made of an age-hardenable aluminium alloy, or to enable age-hardening of the same, a method is known from the state of the art (DE 24 46 828 B2) in which the strip is solutionized, then quenched and subsequently subjected to hot exposure. Various temperature and time information is known for such hot exposure, which also includes a two-step hot exposure of the strip rolled up into a coil, namely with the help of a bell-type annealing furnace and with the help of a...

AI Technical Summary

Benefits of technology

[0007]If the rolling stock which is in the process of passing through the apparatus is heated during hot exposure as a first step and if thereupon the heated rolling stock is further subjected to hot exposure, it was surprisingly noticed that the material properties of the age-hardenable aluminium alloy can be leveled out with respect to its variance at least in sections over the length of the rolling stock. Examinations of the material of age-hardenable aluminium alloys of the 6000 series have shown that the known process variance in the heat treatment of these alloys can be reduced, by means which the invention especially stands out as compared with other known methods. Especially these alloys of the 6000 series in particular seem to respond to the method in accordance with the invention such as the 6061 (AlMg1SiCu) and 6082 (AlSi1MgMn) alloys. It can thus be seen that as a result the consolidation values are not only leveled out over the length of the rolling stock but can also be improved. An additional factor is that the duration of the further hot exposure of the rolling stock can be reduced, so that a reduced energy input can be expected in addition to an increase in the production capacity. The rolling stock can thus already be prepared during the passage for subsequent age hardening or it can already be begun at this point, with the rolling stock heated in the passage being subjected in the hot state to a further hot exposure or age hardening and is thus completed. The known negative effects of intermediate storage from quenching to age hardening can advantageously be avoided. Moreover, the heat or supplied energy from the first step of hot exposure can at least partly be used for further hot exposure. The method in accordance with the invention for age hardening can thus be more efficient and also cost-effective in its entirety in comparison with known methods. A large variety of known temperatures from the state of the art can be used for age hardening, which temperatures can be between 120 and 250 degrees Celsius.

[0017]Moreover, the constructional conditions can be improved when the other parts of the device for hot exposure of the rolling stock are arranged separate from the apparatus.

Problems solved by technology

The disadvantage in the known methods for hot exposure is that in addition to the comparatively high energy costs which are caused by the comparatively long duration of hot exposure, there are comparatively considerably deviating properties of the material also over the length of the strip.

Such process variances in particular do not represent any quality feature of the strip, leading to disadvantages in competition.

Stabilization annealing does not offer any advantages in hot exposure for hot age-hardening.

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