SU1599700A1 - Method of preparing samples from brittle non-metal materials for testing for single-axle compression - Google Patents

Abstract

This invention relates to compressive strength testing of materials. The method consists in the manufacture of metal (steel) holders 2 in the form of hollow cylinders and supports 3, their quenching, subsequent heating to the recrystallization temperature of the outer mating end edges of the supports 3 and holders 2, as well as the annular zone 6 in the holder 2, one of the boundaries of which located at the level of the edge of the cylindrical sample 1, grinding the heat-treated mating parts, fixing the clips 2 and the corresponding supports 3 on the end zones of the cylindrical sample 1 with the help of glue to the combination of the outer ends of the clips 2 and the supports 3 in the same plane. In this case, annular plastic zones 5 are formed on the outer face planes of the modular system. When loading sample 1, circular plastic zones 5 and 6 ensure uniform plastic deformation of the supports 3 and holders 2, which allows for the creation of stresses close to the limiting ones in sample 1 receive an equilibrium state along the length of its working part. 2 Il.

Description

3 15997PO The invention relates to the testing of strength of materials under I compression and can be used for; preparing for uniaxial compression tests of cylindrical specimens of brittle non-metallic materials such as inorganic glass, glass or ceramic.

The purpose of the invention is to increase the reliability of the test results: by reducing the concentration of the stress-: research institutes arising on the edge in the face; at the stage prior to the formation of longitudinal cracks in it,

FIG. 1 shows a sample placed in the cage with supports; in fig. 2 - heating scheme.

15 on the plastic zone 5; P (0.19-0.2l) d; P 1.9-2.1 mm; P is the depth of heating of the additional plastic zone 6; P (0.12-0.16) d; P 1.2-1.6 mm; M - ring height

Sample, 1 of technical glass 20 6 ;. M (1.9-2.1) P; M 2,3-rki SZT-1 with a diameter of 10.00 mm with te 3.4 mm.

Surface roughness H, 0.32-- Example, Pre-before 0.63 μm is placed in the cage 2 of the installation on the sample 1, the external salts 40X, hardened to the AL 30-32. On the strapped end edges of the hardened ends of sample 1, supports 3, 25 clips 2 and supports 3 are subjected to heating made of 40X steel, also heat-treated to HPC. C 30-32. Chamfers 4 are filled on the inner supporting edges of the clips 2. Oboy1-1y 2 and the supports 3 are fixed on the sample 1 with the help

thirty

to 1043–1073 K to a depth P of 1.9 mm. Heating is carried out by high-frequency currents using an HDTV generator with a power of 10 kBt. The frequency of the supply current is determined from the ratio

thirty

40

adhesive composition D-9. containing the following components, wt.% g epoxy-resin EL-16 76.2; .sch butylftolatR

8.6; polyethylene polyamine 7.6; acetone 7.6. On the outer end edges of each casing 2 and the supports 3 there are annular plastic zones 5. Additional annular plastic zones 6 are located in the opening of the cage at the level of the edges of the cylindrical image.

. 1. 1. Sample 1 is equipped with resistors (not shown).

The heating system contains a single-water cooled inductor 7. The inductor 7 is made in the form of a copper tube 45 with a wall thickness of 1.8 mm and is connected to an HDTV generator (not shown). In addition, metal plates 8 are mounted on the yoke 2 to limit the zone of exposure to an HDTV slot 9. 0 Temperature control was performed with a pyrometer aid (not shown),

The dimensions of sample 1, holder 2 and support 3 were selected in accordance with the empido 1043-1073 K to a depth P, which is: 1.9 mm. Heating is carried out by high-frequency currents using an HDTV generator with a power of 10 kBt. The frequency of the supply current is determined from the ratio

Wholesale

(Hz),

where P is the depth of the heated layer. For a sample with a diameter of 10.00 mm; P 1.9 mm; frequency P (3263 Hz. R) In this case, the C-shaped inductor is used to heat the edges, since this form reduces the likelihood of overheating of the edges. Similarly, the parameters are set. Lamellar zones 6j: P, 0.13 mm; P 1.3 mm; M 1.9 P,; M 2.5 mm.

The heating mode is chosen empirically With inductor 7 at a frequency fooT of 4770 Hz, a radiated power of 3 kW and a minimum gap between the inductor and the holder 1.5-2, О mM, the time delay at 1043-1073 K was 3-5 s. Temperature control was carried out using a Smotrich type pyrometer.

After air cooling to

The formulas: d — diameter of the ci-room temperature of the casing 2 and the optical sample 1, d 10.00 ± ry 3 is subjected to polishing to a roughness of 10.05 mm; L is the length of sample 1, (T. 3.0d), L 30, OOtO, 06 mm; D is the outer diameter of the holder 2 (D - 3,2),

vatosti mating surfaces of the wallpaper 2 and support 3Rd 1.00-0.63 microns. Then they are fixed on sample 1 at

ABOUT

P 32.2 mm; L, - the length of the national system (L, 4,0d), I ,, 40,00 mm; h, - thawing support 3 (h, 0.5d),

t J i sample depth (h.j 0,5d), hj 5.0 mm; b the thick walls of the hollow cylinder of the holder 2 (L 1,1d) ,, b 11.00 mm; F - chamfer size 4 (F 0,2dx60 °),

  2; d5, is the initial gap between the lateral surface of sample 1 and the holder 2; h, 0.1 is the initial gap between the end face of sample 1 and the end face of support 3; ,,, 0.05 mm; P - the depth of the plastic zone 5; P (0.19-0.2l) d; P 1.9-2.1 mm; P is the depth of heating of the additional plastic zone 6; P (0.12-0.16) d; P 1.2-1.6 mm; M - ring height

 6; M (1.9-2.1) P; M 2.3-3.4 mm.

Example. Before being installed on sample 1, the outer mating end edges of hardened holders 2 and supports 3 are heated.

R

to 1043–1073 K at a depth P, which is: 1.9 mm. Heating is carried out by high-frequency currents using an HDTV generator with a power of 10 kBt. The frequency of the supply current is determined from the ratio

Wholesale

(Hz),

where P is the depth of the heated layer. For a sample with a diameter of 10.00 mm; P 1.9 mm; frequency P (3263 Hz. R) In this case, the C-shaped inductor is used to heat the edges, since this form reduces the likelihood of overheating of the edges. Similarly, the parameters are set. Lamellar zones 6j: P, 0.13 mm; P 1.3 mm; M 1.9 P,; M 2.5 mm.

The heating mode is chosen empirically With inductor 7 at a frequency fooT of 4770 Hz, a radiated power of 3 kW and a minimum gap between the inductor and the holder 1.5-2, О mM, the time delay at 1043-1073 K was 3-5 s. Temperature control was carried out using a Smotrich type pyrometer.

After air cooling to

room temperature of the cage 2 and the support 3 is subjected to grinding to rough

vatosti mating surfaces of the wallpaper 2 and support 3Rd 1.00-0.63 microns. Then they are fixed on sample 1 at

oMODw adhesive composition. Lp create high-quality gluing together the connected elements forcibly with the help of clamps are pressed against each other with silicon 50-60Н for the time of polymerization of glue, which at 290-295 K is 20-24 hours. Further samples are placed in a heating cabinet, where at 353 K they are heated - live for 8 hours, then cool with thermostat.

A collection system comprising sample 1, rigidly mounted in cages 2 with supports 3, is placed between the support plates of the test set-press (not shown) and subjected sample 1 to testing for uniaxial compression until fracture. At the same time, the maximum value of the temporal characteristic of technical glass SET-1 under uniaxial compression is determined.

In the process of loading, uniform plastic deformation of the supports 3 and the clips 2 takes place due to the unloading of their solid zones in the annular plastic zones 5 until the moment of the appearance of longitudinal cracks in the sample 1 (before the stresses in the source material being followed 6). After that, in sample 1, zones of high concentration of stresses are practically not formed due to the presence of additional plastic zones 6. P15 and loading a series of 10 identical samples significantly increases the reliability of the results — the destruction of the sample occurs only in the working area, the magnitude of the values is 1407-1620 IPa, the average value is 1525 MPa, the coefficient-: the coefficient of variation is 5.9% and on average is 12% higher than that of the samples prepared for testing using the prototype method .

five

0

five

0

five

0

Compared with the prototype; method of sample preparation; - to tests it allows to increase the reliability of test results for uniaxial short-term compression of samples from high-strength brittle non-metallic materials by reducing the concentration of stresses in the torus, new areas of the sample at stresses in the material close to the limit, strength and almost uniform plastic deformation of the force bearing elements — supports and clamps — by creating annular plastic zones in the force-transmitting elements,

The table shows the values of the limiting bearing capacity of a sample of technical glass of the mark СЭТ-1: during short-term tests on

 uniaxial compression

Claims (1)

Invention Formula The method of preparing samples of brittle nonmetallic materials for uniaxial compression tests according to auth, sv, P 1493921, characterized in that, in order to increase the reliability of the tests, the annular zone in the opening of the holder is further subjected to induction heating to the recrystallization temperature, and one of the boundaries is annular the zones are positioned at the level of the edge of the 1tshindric sample, and the heating depth P is selected from the ratio P (0.12-0.16) d, and the height M of the annular zone is determined from the ratio M (1.9-2.1). ,, where d is the diameter of the cylindrical sample. A cylindrical sample (d 10 mm; L 30 mm P 0, 1.9 mm) prepared according to the prototype method The same sample (P 0.19d 1.9 mm) prepared by the proposed method (plastic zone depth P, 0.13d 1.3 mm, its height is M 1.9 mm; P, 2.5 mm) 1364 1272-1446 5.9 1525 1407-1620 5.9 FIG. g