DE1279940B - Process for heat treatment of thermosetting strips and sheets made of aluminum alloys with a copper content of less than 1 percent - Google Patents

Description

FEDERAL REPUBLIC OF GERMANY GERMAN 40S7 ¥ W PATENTAMT Int. Cl .:

C22f

EDITORIAL

German class: 4Od -1/04

Number: 1279 940

File number: P 12 79 940.5-24 (Sch 35916)

Filing date: October 7, 1964

Opening day: October 10, 1968

The invention relates to the heat treatment of strips and sheets made of thermosetting Aluminum alloys with a copper content below 1%.

The process is particularly suitable for aluminum-magnesium-silicon alloys (AlMgSi), but also for low-alloy aluminum-zinc-magnesium alloys (AlZnMg).

AlMgSi alloys are to be understood here as having a composition within the following Limits lies:

Mg 0.3 to 1.5%

Si 0.2 to 1.6%

Remainder aluminum

these alloys have the following additions included individually or in groups:

Mn up to 1.0% Ti up to 0.2%

Cr up to 0.4% Zn up to 0.2%

Fe up to 0.5% Cu up to 1% ^ao

The base metal consists of aluminum of commercially available purity (metallurgical aluminum according to DIN 1712, Sheet 1, with a purity of 99 to 99.8% and pure aluminum according to Sheet 3, with a purity of as 98 to 99.8%) or made of aluminum of high or very high purity (refined aluminum).

The alloys AlMgSi 1, AlMgSi 0.5, E-AlMgSi are an example of such alloys DIN 1725, sheet 1, p. 4, and the American alloys 6011, 6061 and 6063 according to the alloy list of the Aluminum Association, New York, »Registration record of aluminum association alloy designations and chemical composition limits for wrought aluminum alloys ”, revised September 1, 1963.

The AlZnMg alloys in question here essentially have the following composition:

Zinc 3.5 to 5%

Magnesium 0.5 to 1.5%

Copper less than 1.0%

and can have further additions of z. B, manganese, chromium or a. contain. Because of their relatively deep Mg content, these alloys can match the AlZnMg 3 and AlZnMgCu alloys DIN 1725, sheet 1, p. 6, are referred to as low-alloy alloys.

The trend in the heat treatment of sheet metal and strips is moving more and more towards continuous processes. In other words: the heat treatment is carried out in continuous furnaces by means of heat treatment processes
thermosetting strips and sheets
Aluminum alloys with a copper content
less than 1 percent

Applicant:

Swiss Aluminum A. G., Chippis

(Switzerland)

Representative:

Dipl.-Chem. Dr. phil. E. Jung, patent attorney,

8000 Munich 23, Siegesstr. 26th

Named as inventor:

Dr. rer. nat. Dietrich Altenpohl, Feldmeilen;

Dr. se. nat. Heinrich Zoller,

Dipl.-Ing. Hans-Michael Cohen, Sierre (Switzerland)

Claimed priority:

Switzerland of August 27, 1964 (11 243)

guided. With a given throughput, the length of the annealing section is determined by the time it takes semi-finished product to be glowed must be kept at the required temperature. As with getting longer Annealing section as costs increase, a short annealing section is desirable for economic reasons. Technical reasons also speak in favor of the shortest possible length of the heating zones in a continuous furnace, because the handling of the material to be annealed is more difficult in long furnaces and thus increased There is a risk of damage to the surfaces of the annealing material. Any measure that is a shortening the annealing time necessary to achieve the required annealing effect, thus represents represents a technical advance.

According to the known prior art (Y. Bresson and P. Guesno, Rev. Metall. (1961), pp. 345 to 350) cold-rolled sheets or strips of AlMgSiI with a thickness of 3 mm and below for at least two minutes in one Continuous furnace kept at solution annealing ^{temperature (545 φ 10 0} C) and then quenched. This treatment requires a length of the annealing space of a little more than 10 m, with sheets of 2 mm

809 620/349

3 4

Thickness and less the throughput speed should not be less than 380 ⁰ C. This is followed by between 3 and 5 m / min, lies. Compared to the immediate quenching in water after the last speeds that occur during cold rolling and during hot rolling pass. The hot rolled plate will be obtained for example hot rolling, is cold rolled one pass way to 1 mm. Then closes speed of 5 m / min, and under very 5 is a solution heat treatment at, for example, 530 ⁰ C (small metal. The difference is particularly disadvantageous in temperature) in a continuous furnace, whose Heizder treatment of bands. zones have a length of 10 m. The pass-through

The invention now enables a substantial speed of 30 m / min., I.e. H. the whole

Increase in this throughput speed and annealing time is therefore 20 seconds, of which

provides an economical production of warm io 10 seconds for heating to temperature and

Hardenable strips and sheets made of essentially an additional 10 seconds to keep them at temperature

Borrowed copper-free, hardenable aluminum alloy needed. The subsequent quenching takes place with

struggles. Cold air or water. Finally the tapes

The subject of the invention is a method for (or sheets) artificially aged at 160 ° C. for 14 hours.

Production of thermosetting tapes and sheets 15 The tapes produced in this way were as follows

of about 2 mm thickness and less from aluminum - strength values determined:

alloys with a copper content of less than 1 ° / p> σ 0 2 = 28 2 kp / mm ²

being homogenized rolling ingots hot rolled, the _ff '_ 32 ^ kp / mm ⁸

Hot rolled plates from temperatures above 35O ⁰ C _{3 σ} _ iqqoi

preferably above 400 ⁰ C, to temperatures below 20 HB 5 = 10/2 10l'kp / mm ²

200 ⁰ C, preferably to room temperature, in less'

than 2 minutes, preferably in less than 1 minute, to the by the method according to the invention deterred and then to show progress achieved by at least 20%, this is further developed be cold rolled; the cold-rolled strips and the one from "Revue de Motallurgie", are finally annealed in a continuous furnace solution-25 April 1961, p. 345 to 350, known processes and deterred. The ribbons obtained in this way were similar.

(or sheet metal) can finally be cold or preferential The tests were carried out as follows:

wisely artificially aged. Rolling bars made of an AlMgSiI-

During hot rolling, the rolling speed alloy is 1.02% Si, 0.83% Mg (i.e. 1.31%

Density selected and maintained in such a way that because of the 30 Mg ₂ Si), 0.27% Fe, 0.02% Cu, 0.32% Mn.

due to the deformation resistance occurring heat ingot homogenization 540 ° C

the temperature of the rolled stock is not below 350, before ^e ° for 16 hours

preferably does not fall below 400 ° C. Hot rolling ^{temperature 525 0} C (beginning) -

The inventive method has the advantage of 445 ° C (end)

so that the homogeneous hot rolled plate thickness produced in the rolling ingot is 10 mm

Gerugezustand is largely preserved. That has

As a result, in a further work step, two lots were formed from these plates,

cold-rolled strip having a thickness of 3 mm and with which the following experiments were carried out

less, preferably from 1.5 to 0.1 mm, only were:

a few seconds, e.g. B. 5 to 10 seconds 4 ° l _os ι.

needs to be in a solution annealing temperature , ' , "" _n , "^ ,, _,., ..

heated continuous furnace those homogeneous supply £ * "£ Jf ^ _n f? ^{ate. d} _c ^{em? a? d} ^ ^{k ae jj)}

stand to reach, after quenching and cold- ^Man } ^ ^dl _f ^e ^ «en * ™ ^Sta f ^ύ ™ ^ η dl5Sunden

or artificial aging according to the usual method ?, ^{400 to} i °°. ξ. ί ^ ^1. ^ (pay attention to the

ren obtained strength values results. With another 45 cooling speed of a roll of tape).

Words: the tape treated according to the invention (or lot 2:

Sheet metal) can be through a homogenization furnace (treatment according to the invention Drive through the length at one speed)

pull that, as described below with reference to comparative Man the plates allowed to air from the hot experiments shown, is higher in any case to cool than the so-rolling temperature to 400 ⁰ C and deters with known methods to achieve the same _s i _e then in water.
Strength values in each case applicable maximum speed. The resulting increase in through- The plates of both lots were then cold-rolled to sheet metal of the set brings a corresponding increase in the host thickness of 0.5 mm. From the sheet metal with itself. The test rods according to the invention were produced, all of which were subjected to the same drive, preferably for heat treatment, namely: suitable for strips. However, it is possible to _heat-treat the strips L at 54 ο ° ₀ ;
cut into lengths before cold rolling or before or after solution annealing and continuously treat sheets as 2. quenching in water within 5 seconds. 60 after removal from the solution annealing furnace;

The method according to the invention is assumed to be a third of 16 hours artificial aging at 160 ° C.
Example explained:

When processing AlMgSi 1, different solution heat treatment was used for both lots.

Rolling ingots initially 6 hours at 500 ⁰ C (metal times - between 5 and 150 seconds (dwell

temperature). This is followed by the warm ^{- 65 at 540 0} C) - applied to the influence of this

roll at an initial temperature of 500 ° C to size on the material properties, in particular

a thickness of 7 mm, for example. The aim is to increase the tensile strength of both lots in the case of test rods

Determine the final temperature after the end of hot rolling. The artificial aging was in each case

indirect, d. H. started within less than 5 minutes after quenching.

The subsequent tearing tests showed:

1. The fact, known per se, that the annealing time influences the tensile strength ctb. There were in both cases, depending on the annealing time if tensile strengths of 34 to 39 kgf / mm ² achieved with longer annealing times to higher strength values resulted.

2. The superiority of the method according to the invention:

A certain tensile strength is obtained with test bars from lot 2 after a much shorter one Solution annealing time reached.

Cooling conditions of the Lot 2
from 400 ⁰ C Seconds Time savings
compared to the 38 Hot rolled plate deterred 5 State of 40 Aspired Loose
slow (invention 9 technology 38 / LUGGAGE cooled down according to) 20th 35 (State of Solution annealing times 44 33 Technology) Seconds 140 Seconds * U If 8th 3 kp / inm * 15th 6th 36.5 32 12th 37 68 24 37.5 210 70 38 38.5

The comparative tests clearly show that the hot rolled plates are quenched allows a time gain in the solution annealing of the finished strip, which under the conditions of the experiment is 33 to 40%.

This effect is even more pronounced in the case of more highly charged alloys.

The time savings mentioned may look modest at first glance. However, they fall sharply important if the solution heat treatment is carried out in a continuous furnace and especially if higher strength values are aimed for. There is then the option of either making the furnace shorter to build (reduction of investment costs) or the throughput of the furnace with the same length raise.

An industrial plant is known in which the hot-rolled strip is sprayed before being rolled up is cooled. The cooling of the strip when it leaves the hot rolling mill of this plant ha but not the task of maintaining a homogeneous state, only the handling of the tape to facilitate. This is because no hardenable aluminum alloys are used in this system rolled, but exclusively pure aluminum and the non-hardenable aluminum alloy AlMn. Through publications about this system (see e.g. the promotional leaflet »Continuous Strip Mill at

ίο Rogerstone «, published a few years ago by Northern Aluminum Co. Ltd.) the idea has by no means been suggested after hot rolling quenched plates of hardenable aluminum alloys for the manufacture of tapes and To use sheet metal by cold rolling and heat treatment in a continuous furnace. The invention is consequently based on a combination with a surprising effect.

Claims (3)

Patent claims: 1. Process for the heat treatment of hardenable strips and sheets of about 2 mm thickness and less made of aluminum alloys with a copper content of less than 1%> whereby a homogenized rolling ingot is hot-rolled and the hot-rolled plate is cold-rolled by at least 20%, the cold-rolled strip is then annealed and quenched in a continuous furnace is, characterized in that the hot rolled plate immediately following the hot rolling from temperatures above 350 ⁰ C, preferably above 400 ⁰ C, to temperatures below 200 ⁰ C, preferably to room temperature, in less than 2 minutes, preferably in less than 1 minute , is deterred. 2. The method according to claim 1, characterized in that the hot rolled plates between the quenching and the cold rolling are stored in the usual way. 3. The method according to claim 1 and 2, characterized in that the hot rolling speed is selected and observed that due to the occurring due to the deformation resistance of heat, the temperature of the rolled stock not 35O ⁰ C, preferably not below 400 ⁰ C, falls. Considered publications:
Revue de Metallurgie, April 1961, pp. 345 to 350. 309 620/349 9.58 © Bundesdruckerei Berlin