SU966999A1 - Method of electric arc hard facing - Google Patents

Abstract

1. ELECTRIC METHOD; ORGANIZING, in which a ribbon electrode is inserted into the arc burning zone and a relative oscillatory movement of the ribbon end by the electrode foot and weld weld is performed, in order to reduce the heating of the part and allow for its subsequent processing by reducing the thickness of the deposited layer by reducing the intensity of the electrode melting, the surfacing is performed with cooling of the end of the ribbon electrode at a current density of 0.5 5, 0 A / mm and the speed of the said oscillatory voltage 0.03 0, 18 m / s, and the amplitude of this movement is determined in accordance with the dependence A

Description

The invention relates to the field of metalworking, in particular, to methods of electric arc surfacing of parts surfaces, and can be used both for restoring worn parts and for applying wear-resistant coatings on new parts. It is most expedient to use this invention when surfacing parts that overheat is undesirable, especially when surfacing parts with low wear.

The known method of electric arc surfacing, providing a small thickness of the deposited layer. In this method, electric-arc welding of the surfaces of parts is carried out by relative movement of the surface of the part and the core non-meltable (tungsten) electrode oscillating across the filler tape of small thickness up to 1 mm, which is introduced into the burning zone of the arc by constant contact with the weld surface fj .

This method, even with a small thickness of the deposited layer (0.2 mm), does not eliminate the undesirable overheating of parts due to the fact that this method causes the arc power to be much larger than necessary to melt the filler tape, and the cooling of parts is applied It is almost impossible, since the stability of the arc and gas saturation of the process is disturbed.

There is a known method of electric arc surfacing, in which a ribbon electrode is introduced into the arc burning zone without its constant contact with the weld surface and a relative oscillatory movement of the end of the ribbon electrode and the weld surface is carried out by giving the end of the electrode oscillatory movement in its feed direction (2J .

In this method, the deposition is carried out at a current density of 125-250 A / mm of the speed of the said oscillatory movement O, 3 m / s, and the amplitude of this movement is chosen by a much greater thickness of the tape electrode, so that A Ь 5b, where L is the thickness of the belt electrode. The thickness of the deposited layer is 4-12 times as thick as the electrode and is 1-5 4 mm.

This method does not provide a small thickness of the deposited layer, as described above, however, it can be applied liquid cooling of the part, which reduces its heating. At the same time, they try to avoid cooling.

the end of the electrode, since this reduces the intensity of its melting, which is undesirable in this method, since it reduces the deposition rate.

The purpose of the invention is to reduce the heating of the part and the allowance for its subsequent processing by reducing the thickness of the deposited layer by reducing the melting intensity of the electrode.

This is achieved in that way. The electric arc surfacing, in which a ribbon electrode is introduced into the arc burning zone without its constant contact with the weld surface, is carried out by relative oscillatory displacement of the ribbon electrode tip and the surface being welded, the surfacing is performed with the end of the ribbon electrode cooled. at a current density of 0.5-5 A / mm and a speed of the said oscillatory movement of 0.03-0.18 m / s, and the amplitude of this movement is determined in accordance with the dependence A (0.03-1.0) 1) where b is the TOL of the ribbon electrode.

The lower speed of oscillatory movement, the smaller amplitude of this movement, the non-constant contact of the electrode with the weld surface make it possible to obtain a stable arc at a lower current density, which exists during the period when the electrode does not contact the weld surface.

Less current density provides less heat in the electric arc.

Less heat release reduces the intensity of the electrode melt. In this case, the molten metal in the form of microportions is transferred to the surface of the part during the contact of the end of the electrode with the weld surface, forming a weld layer of small thickness, which reduces the allowance for the subsequent processing of the part and reduces its heating.

The cooling of the end of the ribbon electrode must also be carried out to reduce the intensity of its melting and to obtain the aforementioned microportions, and not to reduce heating of the part, the part in this case may not be cooled at all.

If the current density, the speed of the said oscillatory displacement, and the amplitude of this displacement within the specified limits are not observed, the quality of formation of the deposited layer deteriorates sharply.

Another difference is that said oscillatory movement is carried out in a direction perpendicular to the plane of the ribbon electrode.

This improves the conditions for the transfer of metal micro portions from the electrode to the weld surface, and therefore improves the quality of the weld layer.

The drawing shows a schematic diagram of the invention.

The deposition is carried out as follows.

The item 1 is rotated, the tape electrode 2 is introduced into the burning zone of arc 3 without its constant contact with the weld surface 4, relative oscillatory movement of the electrode end and the weld surface is performed by moving the electrode end in the direction perpendicular to the plane of the electrode end. In the process of surfacing, the end of the electrode is cooled.

The shaft with a diameter of 50 microns is rotated at a frequency of 0.1 rpm (the drive is not shown in the drawing. As the electrode, a MarkK LS-70KhZMN sintered ribbon with a cross section of 30x1 mm2 is used. A voltage of 11 V is maintained at the arc. The end of the electrode is at 4 mm, cooled by water through the pipe 5. The current to the electrode is carried out using tires 6. The electrode 2 is fed by rollers 7, and its oscillatory movement is carried out

using the crank crank rod (not shown) ..

The following are specific examples of the method implementation, tabulated.

As can be seen from the table, the thickness of the deposited layer can be 5-10 times less than the thickness of the electrode tape, which is 1 mm thick, while the arc power is small,

0 since current flow rate is very small (10–200 times less than that of the prototype method).

In all the above cases, surfacing occurred with good quality of formation of the deposited layer.

five

The present invention compared with the method using not. a melting electrode, and a prototype method reduces the detail coverage. According to Wed introduction with the method of the prototype

This invention, in addition, allows to obtain a weld layer with a thickness of 5–20 times less, which significantly reduces the allowance for the subsequent b treatment.

five

Saving from the use of the proposed invention is achieved by reducing the complexity of the work. On the subsequent processing of parts, reducing the consumption of electrical metal

0 and electricity. According to preliminary calculations, 1 dm of the surface being deposited saves 0,151 rubles.

Claims (2)

1. METHOD OF ELECTRIC ARC FILLING, in which a tape electrode is introduced into the arc burning zone and relative vibrational movement of the end of the tape electrode and the weld bead is carried out so that, in order to reduce the heating of the part and allowance for its subsequent processing by reducing the thickness deposited layer by reducing the intensity of the molten electrode, surfacing is performed with cooling of the end of the tape electrode at a current density of 0.5 5.0 A / mm ² and the speed of the aforementioned oscillatory movement of 0.03 0.18 m / s, and the amplitude of this non-displacement is determined in accordance with the dependence 2. The slope and vibrational movement are carried out in the direction perpendicular to the plane of the end of the tape electrode.