SU1742001A1 - Fusion welding method - Google Patents

Abstract

Usage: mechanical engineering, manufacture of heat exchangers, containing intersecting welded and soldered joints. Essence: jump-like movement of the heat source during fusion welding in the areas of transverse joints. The movement starts from the border of the weld seam. The displacement amplitude is chosen from the ratio i B - (VCB t.), Mm, where B is the width of the weld seam, mm; VCB - welding speed, mm / s; t is the jump time, Ј. (0.1-0.5) s. The site adjacent to the weld seam is led by a source of energy tilted to the welding speed vector over time T. 3 ill., 1 tab.

Description

(54) METHOD OF WELDING BY MELTING

The invention relates to fusion welding (argon-arc, electron-beam, light beam, laser) and can be used in all industries in the manufacture of pas welded plate heat exchangers.

A known method of manufacturing plate heat exchangers in which parts obtained by soldering are connected to parts not containing solder joints by arc welding with displacing the non-consumable electrode from the joint towards the base metal and melting the solder part to a depth not exceeding l / n, where I is the length of the weld pool, mm; n is the number of soldered joints per length I.

This method does not allow high-quality welding of thin-walled joints intersecting the seams. Under the action of arc heat, the weld seam melts and solder flows out. The construction loses tightness.

There is a known method of laser welding, in which the heat input is controlled over the joints. At the radius and in the corners of the part being welded, the welding speed is changed.

The disadvantage of this method is the absence of regulated mode parameters that prevent overheating of the joints.

There is a method of fusion welding, in which the heating source is hoppingXJ

4 S

Noah is periodically moved along the joints in the direction of the welding speed vector to change the heat input.

The disadvantage of this method is the absence of regulated mode parameters, which prevent the melting of specified areas (for example, a weld seam) and a decrease in the quality of joints. After a spasmodic movement of the source to the cold joint at the beginning of this area, lack of penetration is formed.

The purpose of the invention is to improve the quality of welded joints on thin-walled structures with intersecting welded and soldered joints.

This goal is achieved by the fact that in the fusion welding method, in which the heating source abruptly and periodically moves along the joints in the direction of the welding speed vector, the spasmodic movement of the heating source begins at the boundary of the weld, and the deviation amplitude is chosen from

, l B- (VCB t), mm,

where B is the width of the weld seam, mm; Yev.- welding speed, mm / s; t-time jump-like movement of the heating source, equal to 0.1-0.5 s, while the deviation of the heating source is stopped after a period of time equal to T -yr-, s.

VCB

The application of the invention will improve the quality of welded joints. Elimination of molten solder into the weld seam and cracking is excluded. Solder leakage from the weld seam is prevented and the structural integrity is lost. Lack of penetration and surface defects in areas of intermittent seams are eliminated.

FIG. 1 shows a diagram of the cross-section of the weld seam and the welded joint; in fig. 2 is a section A-A in FIG. one; in fig. 3 is a view B in FIG. one.

The method consists in fusion welding with a constant speed of the heating source of the joint 1 crossing the seams 2, the formation of welds 3 along the joints between the grooves 2, At the boundary 4 of the weld seam 2, the heating source (arc or beam) abruptly A constant speed is moved a distance smaller than the width of the weld seam I B- (VCB t), mm, where B is the width of the weld seam, mm; VCB - welding speed, mm / s; t is the travel time in the VCB direction. FIG. 3 move from t. A to t. W. Inclined in the direction of the vector of welding (CSS) heat source

weld the joint 1 for a time T B / Shev and form a weld area of length B (section BK). Then, the heat source deviation is instantly stopped, it is oriented to the non-deflected position, and the formation of a seam begins again from T. B, i.e. the initial part of the joint from the weld seam at the length B, the heating source melts twice.

The time t of the hopping movement of the heating source is chosen to be (0.1-0.5) s. The optimal value of t depends on the welding speed VCB, the power of the source and its density in the heating spot and width

of the joint seam B. With an increase in VCB, the power of the heating source and its density, the optimal value of t decreases. At t 0.1 s in the range of minimum VCa 10–12 m / h, the welded edges do not melt on the section of the weld seam. At t 0.5 s

in the VCB range of 40-45 m / h, the solder melts from the thermal cycle of welding and flows out of the weld seam. In the section of the weld abutment AB, the weld is formed at less than in the section

base metal, heat input, since the speed of movement of the heating source is several times higher than the optimal VCB. Abrupt movement of the heat source from m. A with amplitude i B - C

provides the beginning of the formation of the weld at the interface of the weld (t. B). If you deviate the heat source from m. A to the distance I B, then the formation of a seam begins at a certain distance from the boundary

the weld seam (m. E) and the segment C between the points BE are unmelted. Taking into account that the segment C VCB t, and specifying the time t and the speed VCe, determine the optimal amplitude I, at which

The weld is formed at the edge of the weld seam (T. B).

Due to the unsteady welding process at the BC site, an inclined heat source cannot completely melt the junction 1. At the beginning of the section, lacks of welds are formed. Repeated welding of the section of the BC with a heating source oriented normally to the surface to be welded caused a defect.

PRI me R. Packages of heat exchangers of size 400-200x100 mm were soldered with solder solder SI L-0 at T 630 ° C from a set of plates and corrugations of aluminum alloy AMts. The distance between the seams is 14 mm and their width is 6 mm. The packages are welded together in sections of argon-arc and electron-beam welding on the upper plates with a thickness of 1.2 mm. Argon arc welding mode: alternating current, St. 50-55 A, 11d 12 V. Electron-beam welding mode: l 31 ± 1 mA, and 25 kV peak. Also, collector covers made of AMts sheet 3 mm thick are welded to the ends of the welded sections with an overlap seam. Argon-arc welding mode: St. 150-160 A, UA 13-14 V, filler wire d 2 mm. Electron-beam welding mode: l 50 ± 2 mA, UycK 25 kV. When passing through a weld seam, the welding arc or beam at the interface of the weld seam was deflected by a transverse magnetic field with a strength of 0.015-0.6 T. The rate of deviation of the heating source is regulated by the strength of the magnetic field. The arc is observed visually. In electron beam welding, the inclusion, exposure and deflection of the magnetic field is carried out automatically according to a predetermined program. For this purpose, the programmer of the mode of the jump-like movement of the beam is made. Switching on and off the magnetic field is carried out using a time relay.

The table shows experimental data on the welding of heat exchanger packages in this method, where it is shown that, at T B / VCB, no leaks in the weld seams are present. At T B / VCB, leaks along the weld seams are revealed; the solder melts and flows out. At T B / VCe, non-welds of the joint in the initial section and leaks along the weld were revealed.

Optimum VCB is chosen in the range of 10-45 m / h. The width of the weld seam B is known and chosen at least 3.8 mm from the condition of the structural strength of the joint. 00 06

0,0k

0.015

0.085

eleven

11 11 11

here choose the optimal value of time T. The optimal time interval t 0.1-0.5 with selected experimentally. At t 0.1 eV of the minimum VCB range, the welded edges do not melt on the section of the weld seam. At t 0.5 s in the range of maximum VCB, solder melts from the heat cycle of welding and flows out of the seam.

The use of the fusion welding method makes it possible to increase the tightness of the paired structures by 10 times.

Claims (1)

Invention Formula The method of fusion welding of predominantly thin-walled structures containing intersecting welded and soldered joints, in which the heating source is abruptly and periodically moved along the weld joints intersected by transverse fused seams in the direction of the welding speed vector, characterized in that compounds, the jump-like movement of the heating source starts at the interface of the stitch, and the amplitude of the deviation is chosen from I B - (VCB -t), mm, where B is the width of the weld seam, mm; VCB welding speed, mm / s; t is the jump time of the heat source Ј (0.1-0.5) s, at the same time, the welding of the area adjacent to the weld seam is carried out by the energy source inclined to the welding speed vector during the time T B / VCe. ,one 0.5 2 0.5, 5 0.5 05 0.6 3.9 2.8 0, b 5, b TV che Heat trap seams Melting weld edges absent Formation satisfactory, no leaks, no projections That he Heat traces That we Neproaara and t-chi seam Formation of udoelet credentials, no leaks, lack of penetration That we are the same Melting weld edges absent 3.3 6 6 3.3 6 6 0, 0.1 0.1 0.1 0.1 1 Table continuation 3.5 3.9 Heat trap seams Leaks, weld leaks Heat trap seams Also Nelrovary, leaks on the weld Fie.2 Vieb Fig.Z