SU952939A1 - Method for making adhesive welded joints of metal - Google Patents

Description

The invention relates to the manufacture of glued-welded joints made by fusion welding methods.

It is known that in the manufacture of glued-welded joints, the method of welding over film adhesive is used, which makes it possible to cure the adhesive layer in any position and eliminates the release of volatile and unevenness of the layer of adhesive over the thickness 1.

The disadvantages of the welding method with adhesive film are the laboriousness of the process, the need to complicate the welding mode, high pressure during curing.

Closest to the proposed invention is a method for manufacturing glued-welded joints, carried out by fusion welding methods, by which parts are welded, and then after cooling parts are applied to the weld seams, polymer adhesive coatings 21.

The disadvantages of this method; are the difficulty or impossibility of applying adhesives of hot curing, due to the impossibility of heating the entire welded joint after welding, the spreading of the adhesive when applied

its seams of complex geometric shape and, as a result, the instability of increasing the cyclic properties of welded joints.

The purpose of the invention is to increase the cyclic strength of welded joints.

This goal is achieved by the fact that in the manufacture of glued-welded joints

10 metal glue is deposited in the process of welding on the areas of crystalline weld of the weld with a temperature of 0.4-0.8 of the value of the melting temperature of the metal of the jointed parts.

After the welding arc has passed in a certain place, the melting of the parts to be joined occurs, and then the molten metal begins to crystallize in this place, and the surface temperature of the weld decreases relatively slowly. For example, in argon arc welding

25 tungsten electrode on alternating current of parts made of aluminum of 1420 alloy, with a thickness of 1.5-2.5 mm, temperature decrease from 560-520 to 100-200 ° C occurs in 7-15 minutes.

During this time, due to the high temperature, it is largely time to undergo polymerization processes in a thin adhesive layer.

The technology of manufacturing glued-welded joints from aluminum alloy 1420 with a thickness of 2 mm is as follows.

The surface of the parts is prepared for welding using any known chemical or mechanical method, and immediately before welding, the edges of the joint are cleaned with a scraper. The parts are then welded in direct current polarity. The welding speed is 18 m / h, the arc voltage is 12 V, the welding current is 120 A. During the welding process, VK-18 glue is applied 10 mm from the rear edge of the welding pool from a polyethylene syringe with a steel nozzle and pneumatic feed. The temperature of the weld sections in this place is 490 + 10 ° С, i.e. is 0.75 from the melting point of the aluminum alloy 1420. At this temperature, the applied adhesive begins to polymerize very quickly, forming an even adhesive layer on the surface of the weld. Glue is applied at the rate of 250 g / m. Tables 1 and 2 show the comparative results of cyclic tests of welded specimens without coatings and with adhesive coatings — glues-welded specimens.

It is clear from Tables B. that the degree of increase in the durability of the samples is determined primarily by the grade of the alloy and the method of manufacturing the welded joints.

Table 1

636

9.87 52.1 250

Under low-cycle loading (Table 1), the number of cycles is up to. destruction of glues-welded specimens manufactured by the proposed method from titanium. When tested for fatigue strength (Table 2), the number of cycles until the adhesive-welded specimens manufactured by the proposed method are 1.5-3.2 times more than by the known method .

36.41

15.6 63.4

71., 54

alloy OT4-1, 3.7 times more than welded and more than 2 times more than glueswelded, made by a known method.

Table 2 65 The proposed method for the manufacture of glued-welded joints makes it possible to increase the cyclic strength of glues-welded joints by increasing adhesion and the possibility of using hot-melt adhesives by 1.5-3.

times, and also opens up the possibility for applying to the weld seams such adhesive compositions as film or powder, which, in contact with the heated seam, instantly melt and create a uniform adhesive seam.

Claims (2)

1. Kardashov D.A., Synthetic adhesives. M., Himi, 1962, p. 2. Authors certificate of the USSR (240895, cl. C 21 D 9/50, 1969 (prototype).