RU2307009C1 - Electric-contact welding on method - Google Patents

Abstract

FIELD: restoration of worn parts by means of electric-contact welding processes with use of additive materials such as steel wires, belts and powders.

SUBSTANCE: method comprises steps of pressing additive wire to surface of shaft; heating it till plastic state by means of high-power short time period electric current pulses and upsetting with use of welding -on roller; forming continuous metallic coating by welding on to restored surface welding lands mutually overlapped along length and width; placing protection belt in the form of endless ring made of highly electrically conducting and thermally conducting metal such as copper between additive wire and working surface of welding-on roller. It allows significantly reduce contact stresses in electrode metal.

EFFECT: lowered wear degree of tool with use of such method.

1 dwg, 1 ex

Description

The invention relates to the field of welding and surfacing and can be used in the restoration of worn parts by electrocontact methods using filler materials in the form of steel wires, tapes and powder materials.

The prototype of the invention is a method of electrical contact surfacing, in which a filler wire is pressed onto the shaft surface, heated to a plastic state by powerful, short-term current pulses, deposited by the force of the weld roller and form a continuous metal coating by welding to the weld surface overlapping each other along the length and width of the welded areas [ one].

The disadvantage of this method is the low wear resistance of the working surface of the weld roller. Due to the plastic deformation of the electrode metal due to repeated exposure to temperature and pressure of the filler wire, an annular wear groove is formed on the cylindrical working surface of the surfacing roller. When surfacing with a worn-out surfacing roller, the deformation of the filler metal deteriorates and, accordingly, the quality of the welded joint decreases. Therefore, the fusing roller must be constantly refilled by grooving its working surface on a lathe, which leads to a quick failure of the roller, and reduces the productivity of the operator-builder. For the manufacture of rollers are used expensive non-ferrous metals and alloys.

The invention allows to obtain a new technical effect, which consists in increasing the wear resistance of the working surface of the weld roller.

This technical effect is achieved by the fact that between the filler wire and the working surface of the surfacing roller is placed a protective tape made of highly electrical and heat-conducting metal, such as copper, made in the form of an endless ring.

The drawing shows a diagram of the surfacing of the shaft using a protective tape.

The circuit includes a fusing roller 1, a protective tape 2, filler wire 3, a shaft 4 and guide rollers 5.

The method is as follows.

A filler wire 3 is pressed with force F to the surface of the deposited shaft 4. A protective tape 2 made of highly electrically and thermally conductive metal is placed between the filler wire 3 and the working cylindrical surface of the deposited roller 1. During surfacing, the shaft 4 is rotated, which leads to the filler wire 3 being pulled into the welded joint formation zone, the movement of the protective tape 2 made in the form of an endless ring covering the rotating surfacing roller 1 and the guide rollers 5. The protective tape 2 and the guide rollers 5 are mounted on the support the surfacing installation and simultaneously with the fusing roller 1 during surfacing move along the axis of the shaft 4. The welding force F is perceived by the working surface of the fusing roller 1 through the protective tape 2, which is repeatedly lower compresses contact stresses in the electrode metal and reduces its wear.

It is recommended that the protective tape 2 be made of copper foil with a thickness of 0.3 ... 0.6 mm and wider than the thickness of the overlay roller 1. By sliding the tape 2 along the axis of the roller 1, it can increase its service life. Worn protective tape 2 is easy to replace.

An example implementation of the method. The shafts were fused with spring wire Np-30HGSA GOST 10543-63 with a diameter of 1.8 mm by a fusing roller with a diameter of 300 mm, a width of 12 mm, made of hot-rolled copper. Surfacing was carried out without the use of a protective tape and through a copper protective tape 0.5 mm thick, 25 mm wide, 1300 mm long, rolled up into an endless ring. Surfacing mode: the actual value of the surfacing current I = 7.2 kA, the force on the roller F = 1.4 kN, the peripheral shaft rotation speed υ _О = 0.025 mm / s, the current pulse duration t _И = 0.04 s, the pause duration t _П = 0.08 s After 1.5 hours of machine time during surfacing without a protective tape, a wear groove 0.3 mm deep formed on the working surface of the surfacing roller. The machine time during surfacing until the protective tape was completely worn out was 5 hours; no noticeable signs of wear of the working surface of the surfacing roller were detected.

Thus, the use of a protective tape significantly increases the tool life.

The source of information

1. Klimenko Yu.V. Contact deposition. M., Metallurgy, 1978, p. 8.

Claims (1)

The method of electrical contact surfacing, in which a filler wire is pressed against the shaft surface, is heated to a plastic state by powerful, short-term current pulses, precipitated by the force of the weld roller and a continuous metal coating is formed by welding to the weld surface overlapping each other in length and width of the welded areas, characterized in that between the filler wire and the working surface of the surfacing roller, a protective tape of high-electrical and heat-conducting metal is placed, for example p copper formed in the shape of an endless ring.