RU2635637C1 - Method of electron-beam welding of parts - Google Patents

Abstract

FIELD: electricity.

SUBSTANCE: invention can be used for butt joints of titanium alloys with through penetration with width of up to 15 mm. The method includes cutting the welded edges of the welding parts with the execution of an additional projection with a reference point on one of the parts from its outer side, installing the parts butt-to-butt on the welded edges, aiming the electron beam on the mentioned reference point with the location of its axis in the joint plane of the parts and simultaneously melting the additional projection and the welded edges of parts with the electron beam. The welded edges are made at right angle to the outer surface of the parts. The additional projection is made with a cross-section in the form of a rectangle with the location of its center in the plane of the welded edge of the part, wherein the reference point is made in the form of a graduation mark located in the plane of the welded edge of the part and transverse slits with depth to the plane of the welded edge of the part are made on the projection.

EFFECT: reducing the labour intensity of processing parts for welding and improving the quality of welded seams.

4 dwg

Description

The invention relates to methods for electron beam welding of parts and can be used in electron beam welding of butt joints of titanium alloys with through penetration up to a thickness of 15 mm

A known method of forming the junction of parts connected by electron beam welding [RF patent for the invention No. 2527566, IPC VK 15/00].

The method consists in the formation of an allowance of one of the parts removed by machining after welding the joint at the vertical position of the beam of the lining located in the root of the welded joint, having a thickness and a width of 0.5-0.35 and 0.10-0.15 respectively joint thickness. This method provides high-quality welded joints in the root of the welds, but does not guarantee the absence of external defects, such as undercuts, underestimation of the reinforcement of the weld due to the large opening of the penetration channel in the root and leakage of molten metal from the weld pool, this method requires after welding, mechanical work to remove the lining, which increases the complexity and duration of the product manufacturing cycle as a whole.

The closest to the invention in technical essence and the achieved effect is a method of electron beam welding of pipes [RF patent for the invention No. 2285599, IPC V23K 15/02], in which the edges of the parts are cut: an annular protrusion with a transverse is performed on the side surface of one of the pipes section in the form of an isosceles triangle, the apex of one of the corners of the base of which is located on the outer edge of the pipe.

The end face at this end of the pipe is cut at an angle inside the pipe to the inner edge of the end, which when turning is performed shifted along the axis inward of the pipe from the end by half the base of the protrusion. The end of the other pipe is cut at an angle outside the pipe to the inner edge, shifted outward by the same amount. Then the pipes are joined, after which the electron beam is directed to the top of the triangular filler protrusion, which is the reference point for the beam, and the filler protrusion and pipe ends are simultaneously melted in one revolution of the joint by the concentrated electron beam.

The disadvantages of this method are:

- high complexity in achieving precision tuning of the electron beam to the top of the filler triangular protrusion. A slight transverse displacement of the electron beam relative to the weld, which may be due to both an error in the adjustment of the electron beam to the top of the filler protrusion and a deviation of the very top of the protrusion relative to the root of the weld due to inaccurate machining of the edges for welding, which leads to displacement of the weld from the necessary junction plane of the welded parts and, as a result, to the formation of zones with lack of fusion, which reduce the quality and strength of welds;

- the high complexity of the machining of the technological protrusion, due to the high requirements for the precision parameters of the filler protrusion, cutting the ends of the pipes at one angle;

- there may be defects in the assembly of parts for welding, such as a wedge-shaped gap between the edges to be welded, leading to a misalignment of the axes of the parts to be welded, which is caused by possible errors when cutting pipe ends at the same angle;

- with this method, the plane of the welded edges is located at an angle to the axis of the electron beam. This angle is a critical parameter in obtaining high-quality welded joints, since in most cases it leads to the appearance of zones with lack of penetration in the welds along the joint thickness, which significantly reduce the strength of welded joints.

Common features for the prototype and the claimed invention are: cutting the edges of the parts to be welded to be welded with a filler protrusion on one of the parts on the outside, setting the butt end-to-end along the edges to be welded, aiming the electron beam at said landmark with its axis in the joint plane parts and simultaneous electron beam melting of the filler protrusion and the welded edges of the parts.

The problem to which the claimed invention is directed is to reduce the complexity of the method of electron beam welding, improve the quality of assembly of parts for welding, improve the quality of welds in terms of defects such as lack of fusion, understatement of the weld from the front side.

When solving the tasks achieved the following technical result:

- the ability to visually assess the accuracy of the location of the landmark for pointing the electron beam to the plane of the joint and assess the absence of a gap between the welded edges;

- ensuring the accuracy of tuning the electron beam to the junction plane along the reference line due to the possibility of a visual assessment of the accuracy of the location of the applied reference point relative to the junction plane of the edges to be welded and the possibility of adjusting the beam position relative to the reference point to the detected offset value, if any, from the junction plane, which eliminates lack of fusion due to inaccurate adjustment of the electron beam to the plane of the junction of the welded edges;

- improving the quality of welds, reducing the complexity of cutting welded edges.

The technical result is achieved by the fact that in the electron-beam method of welding parts, including cutting the welded edges of the parts for welding with the execution on one of the parts from its outer side of the filler protrusion with a landmark, the installation of parts butt-welded along the edges, aiming the electron beam at the said landmark with by the location of its axis in the plane of the junction of the parts and the simultaneous melting of the filler protrusion and the welded edges of the parts by the electron beam, the welded edges are performed at right angles to the outside on the surface of the parts, the filler protrusion is made with a cross-section in the form of a rectangle with its center located in the plane of the welded edge of the part, while the landmark is made in the form of risks located in the plane of the welded edge of the part, and transverse cuts are made on the protrusion depth to the plane of the welded edge of the part for the possibility of a visual assessment of the location of the landmark relative to the plane of the junction of the welded edges and to assess the absence of a gap between the welded edges.

The claimed technical solution meets the criteria of novelty and inventive step, because it has distinctive features from the prototype, is characterized by a new combination and sequence of essential features, which allows using the invention to solve the tasks and get a new technical result compared to the identified analogues and prototype.

The method is illustrated by drawings.

In fig. Fig. 1 shows the parts to be welded, in Fig. 2 - the welded edges of the parts prepared for assembly-welding, in fig. 3 - parts in the assembly for welding, in fig. 4 - weld after welding parts.

The method is as follows.

The body (Fig. 1) was welded from VT-23 titanium alloy, consisting of two flanges 1 and one shell 2, the diameter in the welding zone was 400 mm, and the thickness of the welded edges was S = 5 mm (Fig. 2) as follows.

We performed machining (cutting) of the welded edges 3 and 4 (Fig. 2), in which the welded edges 3 and 4 were made at right angles to the outer surface of the parts. On the outside of the flanges 1, a filler protrusion was made with a cross section in the form of a rectangle 5 with the location of its center in the plane of the welded edge of the part. On protrusion 5, a landmark was performed in the form of risks 6 with a depth of N = 0.5 mm and an opening angle of γ = 60 °, located in the plane of the welded edge 4 of the part (Fig. 2). The thickness and width of the filler protrusion 5 is chosen by a method known to a person skilled in the art and can be performed, for example, as described in the closest analogue, RU 2285599, description, p. 5.

Based on the given geometrical parameters of the weld (the width of the weld L = 8 + 2 mm and the gain g = 1 ± 0.5 mm), the thickness and width of filler protrusion 5 were previously determined. In order to ensure high-quality formation of the weld and guarantee compensation for the loss of molten metal Welded samples of parts, and then finally determined the thickness, width of the protrusion 5 and welding modes. The following dimensions of filler protrusion 5, optimal for a given welded joint, were determined: thickness H = 1 mm ± 0.1 mm, width B = 4 mm ± 0.2 mm, offset of the protrusion from the plane of the welded edges K = 2 mm ± 0.1 mm, welding modes: current strength 130 ± 5 mA, voltage - 30 ± 1 kV, welding speed - 30 ± 2 m / h. Before assembly, to visually assess the gap between the welded edges 3 and 4 after joining the parts and the accuracy of the location of the risk landmark 6, the electron beam is guided to the joint plane 7 (Fig. 3) on the filler protrusion 5 from its butt 8 (Fig. 3) in four evenly spaced along the entire length of the joint 7 places, the control transverse slots 9 (Fig. 3) were made with a width of F = 1.5 mm and a depth of up to the plane of the welded edge 4 on the flange 1. Next, through the slots the welded parts 1 and 2 were butt-welded 7 weld to full contact edges 3 and 4 (Fig. 3), through slots 9 in the technological shoulder 5, a visual assessment was made of the location of the landmark — risks 6 relative to the joint plane 7 of the edges to be welded and the absence of a gap between the edges to be welded, the assembled assembly was installed in the welding chamber, vacuum was pumped out , pointed the electron beam at the reference point - risk 6 on the technological shoulder 5 of the seam No. 1 with the location of its axis in the joint plane of 7 parts (Fig. 1) and welded the weld No. 1 with simultaneous melting of the filler protrusion 5 and melting of the welded edges 3 and 4 to their entire thickness S with through penetration.

After welding the weld No. 1, the weld No. 2 was welded in the same way (Fig. 1). As a result of welding, welds were obtained that have a high-quality formation of the front side of the weld without underestimation (Fig. 4) (weld width L = 8 + 2 mm, reinforcement g = 1 ± 0.5 mm). Before carrying out X-ray inspection of welds by means of ball machining, the melt was cleaned flush with the base metal. According to the results of X-ray inspection, the absence of lack of fusion was recorded and the quality of the welds corresponds to category I OST92-1114.

The claimed method of electron beam welding in comparison with the prototype allows to reduce the complexity of machining parts for welding, to improve the quality of assembly of welded joints before welding, the quality of welds.

Claims (1)

A method of electron beam welding of parts, including cutting the welded edges of the parts for welding with performing a filler protrusion on one of the parts from its outer side, setting the butt end-to-end along the welded edges, guiding the electron beam to said landmark with its axis in the plane of the parts junction and the simultaneous melting of the electron beam filler protrusion and the welded edges of the parts, characterized in that the welded edges are performed at right angles to the outer surface of the parts, the filler protrusion is made with a cross-section in the form of a rectangle with its center in the plane of the welded edge of the part, while the landmark is in the form of risks located in the plane of the welded edge of the part, and the protrusion is made of transverse cuts with a depth of up to the plane of the welded edge of the part for visual assessment the location of the landmark relative to the plane of the junction of the welded edges and assess the absence of a gap between the welded edges.

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