SU1602645A1 - Method of producing plate-type heat exchangers - Google Patents

Abstract

The invention relates to the manufacture of welded-heat exchangers and can be used in any industry. The purpose of the invention is to preserve the integrity of the joints and increase the tightness of the welds. When welding the collector caps 1 with the weld package, 2 parts containing the joints are melted to a depth not exceeding L / N, where L is the length of the weld pool 5

N is the maximum number of solder joints 3 per length L. The filler wire 4 is shifted from the center of the weld pool to the part containing the solder joints by an amount equal to 0.5 (BD), where B is the width of the weld pool, D - diameter filler wire. The filler wire material is chosen with a melting point not exceeding the brazing temperature. The method allows to preserve the integrity of the soldered joints during welding of the heat exchanger. 2 ill., 1 tab.

Description

1

The invention relates to the manufacture of heat exchangers and can be used in any part of the industry in the manufacture of welded plate heat exchangers.

The purpose of the invention is to preserve the integrity of the joints and increase the tightness of the welds.

Fig. 1 shows the scheme for implementing the method (welding scheme); FIG. 2 shows the connection of a steam package of a plate heat exchanger with a collector cap.

carried out as follows

/

Way

Before welding part 1, which does not contain soldered joints, with part 2, which has solder joints 3, the non-consumable electrode is displaced from the joint, ensuring the melting of part 2 to a depth not exceeding 1 / n, where 1 is the length of the welding bath, n is the maximum number of solder joints per length 1. Then the welding current is switched on and after the formation of the bath, welding at the speed V and filing wire 4 is started simultaneously and shifting it. from the center of the weld pool to the part 2 by an amount equal to 0.5 (B-d), where B is the width of the weld pool, d is the diameter of the filler wire.

The length and width of the weld pool, the optimum diameter of the welding wire, as well as, if required, the amount of electrode displacement from the joint is determined when testing the welding conditions on the samples. In this case, in a number of cases, in order to obtain high-quality weld formation, welding is performed in positions other than the bottom.

Restrictions on the depth of fusion of a part containing solder joints of 1 / n, where 1 is the length of the weld pool, and n is the maximum number of solids joints per length t, which ensures falling. soldering into the weld pool in amounts not forming lnkvatsionnyh zones, which lead to the formation of so cracks ,.

The required depth of fusion of the part containing solder joints is provided both by welding modes and by displacement of the electrode from the joint.

Offset filler wire from the center of the weld pool in the direction of the des

five

0 5 30

35 40

45 50

hoists containing solder joints, by an amount equal to 0.5 (Bd), where B is the width of the welding wire, d is the diameter of the filler wire, allows to provide in the weld fusion zone with solder joints a temperature close to melting temperature of the filler wire.

The choice of the filler wire with a melting point not exceeding the working temperature of the soldering was caused by the fact that it was experimentally established that after the formation of the bath, it was necessary to ensure a temperature in the weld fusion joint zone that does not exceed the working temperature of the soldering. Only in this case it is possible to provide such a temperature of the heat flow in the soldered joint, at which the integrity of the soldered joint is not disturbed.

Thus, the choice of filler wire with a certain melting point and its supply to the weld pool strictly at the fusion boundary prevents the solder from melting outside the weld pool.

Primer p. Argon-arc welding was performed using a non-consumable electrode with a filler wire. packages of heat exchangers with collector Krish: kami. The material of the packages and manifold covers is Amts aluminum alloy, the joint type is lap-joint, the filler wire grade is AK-5 (T PA 625-630 ° C), diameter is 2.00 mm. When soldering the packages, SIL-0 solder was used, the working temperature of the soldering was 630 ± 5 ° C. Welding was performed in automatic mode: 1 210-220 A} m / h; bushing feed rate55

Vc & 12

Noah wire m / h.

Under the indicated modes and overlapping joint type, the length of the welding bath (1) was 12 mm, width (B) 8 mm. The maximum number of solder joints (p) per length (1) was 6 joints. Exodus from of this, the depth of fusion of the package was 2 mm, which was achieved by displacing the electrode to the collector plate by 2 mm. In this case, the welding wire was displaced from the center of the bath towards the part by 3 mm.

For comparison, welding was performed using other filler materials and at different depth of cladding and displacement of the filler wire. Packages were soldered in all cases with the arrival of SIL-0 at 630i5 C. Welding modes were unchanged,. The depth of the package melting was regulated by the electrode displacement.

After welding, heat exchangers were subjected to external examination, leak tests and metallographic-CMM studies.

The test results are shown in the table.

The proposed welding method can significantly increase the tightness of welded joints in the manufacture of welded plate heat exchangers.

Claims (1)

Invention Formula A method of manufacturing plate heat exchangers mainly from Q five  aluminum alloys, in which parts obtained by soldering are connected to parts that do not contain solder joints, arc welding with a non-consumable electrode with filler wire, characterized in that, in order to preserve the integrity of solder joints and improve the tightness of welded joints parts containing solder joints are melted to a depth not exceeding 1 / n, where 1 is the weld pool length, mm; n is the number of soldered joints per liter 1; at the same time, the filler wire is displaced from the sva-axis. a solid bath in the direction of the part containing solder joints by 0.5 (B – d), where B is the width of the weld pool, mm; d is the diameter of the filler g. I wire, mm; and the filler wire material is chosen with a melting point not exceeding the brazing temperature. FIG. 2