SU1350534A1 - Method of producing specimen for determining strength of welded joints - Google Patents

Abstract

The invention relates to a testing technique and can be used in making samples to determine the strength of welded joints. In order to improve the accuracy of determining the strength of a welded joint by taking into account the effect of residual welding stresses due to shrinkage of the weld metal, two plates I and 2 are used. Plate I has a rectangular shape, and at plate 2 the weld edge 3 is inclined at an angle to the weld edge 4 plates I. On the edges to be welded 3 and 4, on the side opposite to the top of the corner, grooves 5 and 6 are made into which the insert 7 is installed without a gap. Then plates I and 2 are joined together by a weld 8, starting welding from the top of the corner p WITH . The specimen is loaded through holes 9 and 10. The residual stresses due to shrinkage of the weld metal do not change the deformed state of the specimen due to the rigid liner 7. This improves the accuracy of determining the strength of the welded joint and changes the geometry of the weld and specimen. to simulate the stress state during repair and assembly welding of statically indefinable structures, such as pressure vessels. I il. (I ate with a joint venture About ate with 4 - / g

Description

one

The invention relates to the study of the strength properties of materials and joints and can be used in the manufacture of samples to determine the strength of welded joints.

The purpose of the invention is to improve the accuracy of determining the strength of a welded joint by taking into account the effect of residual welding stresses due to shrinkage of the weld metal.

 The drawing shows a sample for determining strength.

The sample is made as follows.

Two plates 1 and 2 are used, of which the plate 1 has a rectangular shape, and the plate 2 has a welded edge 3 inclined at an angle of about (30-45 to the welded edge 4 of plate I, which corresponds to the actual cutting used in production. On the welded edges 3 and 4 on the side opposite to the apex of the angle o (, grooves 5 and 6 are made into which insert 7 is installed without a gap. Then plates 1 and 2 are joined together by a weld 8, starting welding from the top of the angle t between the edges 3 and 4.

To determine the strength of the welded joint, the specimen is secured in the grips of the loading device with studs inserted into the holes 9 and 10.

Residual stresses due to shrinkage of the weld metal do not change the deformed state of the specimen due to the rigid contribution of 7.: Example. The sample was made of steel 22 K. The total length of the sample in assembled form is 350 mm, the height is 90 mm, the width of the working part of the plates is 60 mm, the width of the gripping part of the plates is 35 mm. One plate was rectangular, the second plate had a beveled edge at an angle of 30 °. The insert was also made of steel 22 K, length 70 mm, height 10 mm, width 60 mm. Pastasins were interconnected by a weld of 60 mm length (sample width) and a height of 20 mm. Welding was carried out by manual arc welding with Rasni 13/55 electrodes with a diameter of 4 mm in 8 passes, the welding conditions were consistent with the standard for these electrodes.

1350534 .2,

In comparison, a similar specimen was made with the same dimensions and the same welded pin, but without the insertion.

After welding, the sample was placed in the grips of the loading device, secured with studs inserted into the holes, loaded and released under load.

During testing, the sample without the liner was destroyed after 48 h, and the sample with the liner after 10 h. The load in both cases was the same.

15 When measuring residual welding stresses on a specimen without a CifipoAJi H. insertion, 45 MPa,. 98 MPa, and on the sample with the contribution pf: o (ol, N. 137 MPa, inonepef,

20 189 MPa. This shows that the sample with the liner is longitudinal. increases by 3 times and none. by 2 times and approaches the residual welding voltage that occurs

25 in a real construction (equal to 0.8–0.9 of the level of residual stresses in a real construction). The insertion of residual welding stresses contributes to the liner, since

When a weld is superimposed as a result of its shrinkage during cooling of the joint, compressive stresses occur at the points of contact of the liner with the edges of the plates. Due to the fact that the volume shrinkage

35 is constrained, the weld metal tending to be compressed during the cooling (shrinking) process is in the stretched state. This makes it possible to increase the accuracy of determining the strength of a welded joint and simulate by changing the geometry of the weld and the sample and changing the loading force of the stress state during repair and assembly welding of statically non-separable structures, such as pressure vessels.

Claims (1)

,; Invention Formula . A method of making a sample for determining the strength of welded joints, according to which two plates, one of which is rectangular in shape and the edge of the other plate being welded, is inclined at an angle to the welded edge of the first plate, is joined between welding from the top of the angle between the ends, characterized in that, in order to increase the accuracy 31350534 determining the strength by taking into account the edges of the plates from the side, counteracting the residual welding parameters — the apex of the corner, due to the shrinkage of the metal, the welds into which the weld is installed without a gap, before welding, insert a liner onto the weld.