DE970155C - Process for the production of objects from cold aging AlZnMg alloys - Google Patents

Description

Process for the production of objects from cold-hardenable A1ZnMg alloys In the chip-free deformation of metals, z. B. the manufacture of aircraft parts from semi-finished products, several, often contradicting requirements are placed on the material posed. For easy deformability during processing, a low, for the material savings through the use of the lowest possible material thickness a high deformation resistance is desired. For hardenable materials, which have sufficient flow resistance through a heat treatment consisting of Annealing, quenching and hardening, as opposed to being preserved, offers itself materials to be hardened by cold working the possibility of meeting the two requirements at the same time to meet the fact that the processing in the soft-annealed state made and only on the finished workpiece due to the hardening a high flow resistance is produced.

However, this method causes difficulties in the case of bulky and, those parts that prevent undesirable changes in shape of the deterrent from not be very exposed to high temperatures. In this case you walk a lot so that annealing and quenching are carried out prior to shaping. Then she has to Processing and shaping of the semi-finished products carried out as soon as possible after quenching before the flow resistance has risen too high due to the onset of hardening and the deformability has decreased too much. One disadvantage of this method is in the requirement of early processing after quenching. So @ must z. B. Aluminum-copper-magnesium alloy rivets within about 4 hours to be beaten to the deterrent.

For further hardening of aluminum-zinc alloys, including magnesium to form MgZn and other elements such as beryllium, silicon, Copper, according to one known suggestion, is used after annealing and quenching for the purpose of self-payment a storage at higher. Temperatures carried out. Storage at this temperature can take place immediately after quenching after intermediate storage at room temperature or after complete storage at room temperature. Depending on your requirements, alloys with different strengths and elongations can be obtained will.

It is also known to use an aluminum-zinc alloy rivet Cold storage to delay the hardening of the rivets after quenching to achieve. The curing is carried out on ice and at room temperature. the Deformation of age-hardenable alloys, is carried out in the soft-annealed state, after which the finished part is homogenized, quenched and tempered. With bulky Objects that cannot withstand the homogenizing annealing will be deformed placed between deterrence and tempering.

These known methods have the common disadvantage that d the quenched alloys age too quickly at room temperatures and too hard and become difficult to deform.

The invention completely eliminates these drawbacks. this is achieved in that in aluminum-zinc-magnesium alloys between the Quenching, homogenizing and cold working, an intermediate treatment is switched on at a temperature which is so high that on the one hand a Hardening does not take place and on the other hand the hardenability is not v e, rlo, rengeh, t, to delay hardening before deformation.

The intermediate storage temperature is kept between 100 and 140 ° C. Quenching temperatures of 36o to 40o ° C are assigned to these temperatures.

According to the invention, curing can also be carried out at room temperature or initiated and continued at high temperatures.

In experiments with hardenable aluminum alloys with a simultaneous Zinc and magnesium content, there was now the possibility described in the following, which was previously not known for hardenable aluminum alloys: one is frightened z. Legs. Alloy with 4.2% zinc, i, ß ° / o. Magnesium, 0.50 / a silicon and r 0/0 Manganese, the remainder of aluminum, from d.65 ° C in water, occurs when stored at room temperature or increased temperature, an increase in the flow resistance. So get through Tempering at i40 ° C for 21/2 days, the hardness of 53 kg / mm2 immediately after quenching to i05 kg / mm2. The same increase in hardness can be achieved by tempering at z. B. 100 ° Achieve C by extending the starting time accordingly. Set the quenching temperature drops to 300 ° C, storage at i40 ° C does not result in any significant hardening a, while curing at lower temperatures, e.g. B. at room temperature or 100 ° C, is not influenced. If the quenching temperature is further reduced at about 36o ° C there is no noticeable increase in hardness even after storage at 100 ° C more one, without d.ass curing at lower temperatures, for example at room temperature or 75 ° C is influenced :. The increase in hardness. is thus almost prevented after quenching from temperatures below 36o ° C at 100 ° C or higher storage temperature etc.

Experiments have now surprisingly continued to show that after Carrying out this storage the possibility of hardening at a lower storage temperature still exists. So if you bring the stored at 140 or 100 ° C etc. and as a result lower quenching temperature at this temperature on non-hardening samples temperatures lower than 140 or 100 ° C, e.g. B. to room temperature, so occurs now curing at this temperature. This method of temporary storage at higher temperature after: suitable quenching offers the possibility of unwanted hardening after quenching; z. B. at room temperature to to delay at an appropriate time.

The process is particularly applicable to wrought aluminum alloys, which contain zinc and magnesium and possibly additives of other metals.

Claims (3)

PATENT CLAIMS: i. Process for the production of objects cold age hardenable Al Zn Mg alloys by cold working between quenching of homogenization temperature and the hardening treatment, with delay curing before deformation at temperatures other than room temperature is temporarily stored, characterized in that the intermediate storage temperatures between ioo and i40 ° C be maintained at these temperatures Quenching temperatures of 36o to 400 ° C are to be assigned. 2. The method according to claim i, characterized in that, ß the curing carried out below room temperature will. 3. The method according to claim i, characterized in that the curing is initiated below room temperature and is continued at higher tempering temperatures. Considered publications .: German Patent Specifications Nos. 526 266, 499 424; Material Handbook non-ferrous metals, 1936, H. i, p. 2; Matthaes, Metallkunde magazine, 1938, pp. 238 to 244.