Method of welding by electron beam

FIELD: process engineering.

SUBSTANCE: method may be used for making critical welded structures in machine building. Parts of be welded are arranged with clearance. Adding material is fed into said clearance. Grooves and adding material are washed by electron beam and common molten pool is produced. Clearance width is selected proceeding from the condition 1.1d≤h≤1.2d, where h is clearance width and d is adding material diameter.

EFFECT: higher quality of welded joints.

3 dwg

 

The invention relates to mechanical engineering and can be used in the production technology responsible welded structures.

The known method of multilayer electron beam welding (Ed. mon. The USSR №1530381 on CL VC 15/00, publ. 23.12.1989) non-ferromagnetic metals, in which welding is carried out in a narrow gap width of 2-8 mm feeding filler wire to the weld pool each layer, thus carry out periodic transverse oscillations of the electron beam relative to the neutral position with a frequency of 1-1000 Hz only within a narrow gap and ensure the interaction of the beam with the side walls of the gap. For this gap to form an alternating magnetic field of 0.5-25 MT, and the electron emitter located outside of this field.

The disadvantages of this method of multilayer electron beam welding with filler wire is the formation of defects in the form of incomplete fusion between the layers, the occurrence of significant angular deformation when welding large thickness due to repeated heat exposure, contributing to the tendency to the formation of defects such as cracks and reduce the corrosion resistance of the weld metal.

Closest to the present invention is a method of welding (RF patent №2298465 class VC 15/00, UK 28/02, publ. 10.05.2007), consisting in penetration stylevalue details of the electron beam and creating a magnetic field for forming the desired geometry of the electron beam and channel penetration. When this electron beam is directed to the front plane of the welded details under the entrance angle α, the value of which is chosen equal to 0°<α<90°, skip the current along the junction and deflect the beam from the bottom up so that the exit angle of the electron beam β, relative to the back plane of the welded parts is equal to the angle of entry of the electron beam α, and the points of entry and exit of the electron beam of the welded parts are in the same horizontal plane.

In this welding method, the problem of retaining weld pool is solved by reducing metrostations pressure and increasing pressure from the forces of surface tension, but when the periodic oscillations of the beam parameters due to the interaction with pairs of metal and the surface plasma equilibrium melt may be disrupted, causing them to leak and the formation of defects such as cavities.

An object of the invention is to improve the quality of welded joints.

The solution of the technical problem is achieved by the known method of electron beam welding, which consists in creating the magnetic field, the formation of the desired geometry of the electron beam directed to the front plane of the workpiece at an acute angle of entry of α, and the deviation in thickness of the workpiece upward at an acute angle of the output beam β relative to the rear is th plane of the welded parts, set the parts to be welded with a gap, which serves filler material, upravlyaut edges and filler material and form a common bath, the width of the gap is selected from the condition 1,1d≤h≤1,2d, where h is the gap width, d is the diameter of the filler material.

When you create a local magnetic field in the region of action of the electron beam across the thickness of the welded joint details vector of the magnetic induction perpendicular to the velocity vector of the electrons and the plane of the joint of the welded parts, thus, the electron Lorentz force, changing the direction of their movement so that the electrons will move along a curved trajectory. Thus there is a possibility by controlling the angle at the entrance to the metal and changes the configuration of the magnetic field to control the shape of the channel penetration.

When electron beam welding on the liquid metal welded bath acts metrostations pressure, the pressure of the reaction of the vapor recoil and pressure from the forces of surface tension, and at a horizontal arrangement welded bath first and second seek to push the melt from the channel, and the pressure from the forces of surface tension keeps the weld pool. In the case of welding in a gap of 1...1.5 mm feed filler material is reduced metrostations pressure. Also going on is it lowering the temperature and density of steam, consequently, the pressure reduction reaction of the vapor recoil and increasing pressure from the forces of surface tension. The main advantage of this method is the possibility of controlling the feed of the filler material, at which there is no overflow of the welding bath and escaping from her liquid metal.

The invention is illustrated by drawings. 1 shows a diagram of the process of formation of the weld pool with the participation of the filler material, figure 2 - joint welded parts, figure 3 shows a diagram for the implementation of the proposed welding method.

The circuit that implements the method of welding, contains an electron-beam gun 1, the parts to be welded 2, the movement of parts 3, table 4, the axis of the electron beam 5, the filler material 6, the weld seam 7, the weld pool 8.

When implementing the proposed method creates a magnetic field perpendicular to the junction of the welded parts. Electron beam gun 1 is installed at an angle α to the front plane of the workpiece 2, selected from the conditions 0°<α<90°, and deny it on the part thickness up at the acute angle of the output beam β relative to the back plane of the workpiece 2, with the parts to be welded 2 sets with a narrow gap of the h value. Electron beam 5 from the electron gun 1 is directed in a narrow gap welded de the Aley 2, moreover, the electrons have a curved trajectory through the entire thickness of the workpiece 2. Then move the parts to be welded 2 with velocity VStby the transfer mechanism 3, is fed into the gap of the workpiece 2, a filler material 6, for example a wire of diameter d and are welding. In the result of melting of the filler material 6 and the edges of the workpiece 2 is formed General welding bath 8 contained in a curved channel penetration, which then crystallizes and is formed weld seam 7.

The width of the gap between the welded parts h is chosen based on the possibility of a free supply of filler material on the one hand and to minimize the amount of filler material needed to fill the gap. Thus, on the basis of admission to the shape and dimensions of the welding wire, the width of the gap is selected within 1,1d≤h≤1,2d.

The use of the proposed method of welding allows to obtain high-quality welded joint without defects such formation that extends its technological capabilities.

The method of electron beam welding, which includes the creation of a magnetic field, the formation of the desired geometry of the electron beam, the beam direction to the front plane of the workpiece at an acute angle of entry of α and the deviation in thickness of the workpiece from below upon the acute angle of the output beam β relative to the back plane of the welded parts, characterized in that the parts to be welded set with a gap, which serves filler material, upravlyaut edges and filler material by an electron beam and form a common weld pool, while the width of the gap is chosen from the condition 1,1d≤h≤1,2d, where h is the gap width, d is the diameter of the filler material.



 

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