DE1215941B - Process for improving the mechanical properties of semi-finished products made of beryllium or beryllium alloys - Google Patents

Description

FEDERAL REPUBLIC OF GERMANY

GERMAN

PATENT OFFICE

EDITORIAL

Int. CL:

Number:
File number:
Registration date:
Display day:

C22f

German KL: 40 d - 1/16

1215 941
C34063VI a / 40d
October 9, 1964
May 5th 1966

The invention relates to a method for improvement the mechanical properties of semi-finished products made of beryllium or beryllium alloys. In particular the inventive method has a favorable influence on the yield strength and the Elongation at break to the goal.

Beryllium and its alloys are used in a variety of ways. As part of a processing the common deformation methods are common. Known in this context is the Treatment of the metal at temperatures between 300 and 400 ° C resulting in plastic deformation relieved.

Beryllium and its alloys are widely used in the manufacture of sleeves for Nuclear reactor fuel elements. These and other nuclear applications are associated with high mechanical loads. Above all, it is essential for this to be the yield point of the material when it is warm and to improve its elongation at break.

The method according to the invention achieves this goal by a combined thermal and mechanical Treatment of semi-finished products made of beryllium or its alloys. It is that that Semi-finished product brought to a temperature between 550 and 800 ° C, preferably to 600 ° C, a weak permanent deformation from below the critical deformation in the case in question Subject to temperature lying magnitude, in the deformed state until the internal ones are equalized Tensions are kept at the elevated temperature and then cooled.

The deformation can take place through tension, pressure, torsion or bending.

The thermal mechanical treatment mentioned causes a change in the structure of the beryllium and its mechanical properties.

An example of the treatment of a beryllium sheet is to explain the method according to the invention whose initial values determined by tensile tests can be found in Table 1 are: Table 1

Test temperature Yield strength 0.2% Elongation at break ⁰ C kg / mm ² ° / o 25th 35 2 100 27 8th 200 20th 20th 500 11 18th 600 4th 10

Method of improving the mechanical
Properties of semi-finished products made from beryllium or beryllium alloys

Applicant:

Commissariat a l'Energie Atomique, Paris

Representative:

Dipl.-Ing. R. Beetz and Dipl, -Ing. K, Lamprecht,
Patent Attorneys, Munich 22, Steinsdorfstr. 10

Named as inventor:

Jose Mallen, Paris;

Michel Weisz, Orsay, Seine-et-Oise (France)

Claimed priority:

France 10 October 1963 (950 126) - -

The sheet metal is brought to a temperature of 600 ° C and undergoes a length deformation due to the tensile effect of 0.2%. The deformation will last for about 15 minutes at this temperature maintain. The metal needs this time to completely equalize or reduce the tension Experienced.

After this treatment, the properties of the beryllium sheet are found to be the same Conditions were determined like the starting values listed in Table 1 and those listed in Table 2 are.

Table 2

Test temperature 40 25th Yield strength Q, 2 ° / o Elongation at break ⁰ C 100 kg / mm ² % 200 500 35 4th 45 600 23 14th 14th 34 12th 26th 8th 50

A comparison of the two tables shows that the elongation at break of the machined Metal is increased over the entire temperature range and has finally quintupled at 600 ° C; at 600 ° C, the value of the yield point has doubled compared to the original value.

609 567/423

It should be noted at this point that the phase or stage of complete relaxation (relaxation of tension) represents an essential inventive feature of this treatment; becomes this condition not satisfied, the properties of beryllium are not improved.

The treatment which is the subject of the present invention can be carried out in various structural states Use: after drawing, extrusion or rolling, if necessary after recrystallization with or without prior heat treatment.

The method according to the invention can be applied industrially to various types of products, but in particular on tubes for the manufacture of sleeves for nuclear reactors.

The method according to the invention can in particular be used for straightening preprocessed, extruded or welded pipes can be used. Such straightening can be achieved by tensile force under the following conditions be effected:

a) The deformation stress must adapt to the required deformation and e.g. achieved by a screw arrangement, but not by a resilient force;

b) the temperature and duration of the treatment depend on a single factor; namely, to achieve a complete relaxation of the internal stresses initially generated;

c) the deformation to be effected in this case must be a compromise between that for straightening of the pipe required and that in each individual case through previous tests to be determined, optimal "compensation" - represent deformation.

Claims (5)

Patent claims: 1. Process for improving the mechanical properties, in particular the yield point and the elongation at break, of semi-finished products made of beryllium or beryllium alloys, thereby characterized in that the semi-finished product is brought to a temperature between 550 and 800 ° C, a weak permanent one Deformation below the critical deformation at the relevant temperature Subject to size, in the deformed state until the internal stresses are equalized is kept at the elevated temperature and then cooled. 2. The method according to claim 1, characterized in that the permanent deformation done by train. 3. The method according to claim 1, characterized in that the permanent deformation done by pressure. 4. The method according to claim 1, characterized in that the permanent deformation by torsion. 5. The method according to claim 1, characterized in that the permanent deformation done by bending. Considered publications:
U.S. Patent No. 2,872,363.