SU542603A1 - The method of resistance butt welding - Google Patents

Description

one

The invention relates to resistance butt welding and is used primarily for welding parts of a carbon section from carbon and low alloy steels.

Known methods of contact flash butt welding include the fact that a moving product in the process of fusion, along with the main translational movement, is reported to oscillate along a direction with a frequency of at least 1 Hz and a vibration amplitude of not more than 1 mm I. One of its main disadvantages is a large welding allowance and the complexity of implementation in welding machines.

The closest to the invention according to the technical essence and the achieved result is a resistance welding method consisting of heating the ends of parts and precipitates 2. In this method, parts are heated by flowing electric current through previously tightly compressed ends.

Heating of the ends of the parts occurs in a wide area. Compression of parts along their axes is usually done either with a constant force, or with an increasing force towards the end of heating. The compressive force of the parts is removed after the current is turned off.

When using this method of welding with co-motivation, an unfavorable factor during heating is its unevenness over the cross section of the parts to be welded, which is primarily caused by the randomness of the location of physical contact points. As a result, the quality of the welds is unstable. The purpose of the invention is to reduce the allowance

on welding n improving the quality of the welded

connections by ensuring uniform

heating temperatures of the ends in a short timed duck.

To do this, according to the proposed method, the end-heating of the ends of the parts is performed in the mode

resistance at return-posting

displacement of one of the parts with a frequency

not less than 5 Hz.

The process of welding is as follows. After the parts in the jaws of the welding maschina, the iHOMy latch with simultaneous switching on of the welding current is given a reciprocating movement with a specific frequency. Going on

Heated parts. During the reciprocating movements, at each successive mixing, the places of contact change, and new areas are heated by a passing electric current. Thanks to the return and repair movement and change

of contact points, the contact resistance of the component is maintained at a sufficiently high level, which contributes to a more intensive heating of the ends and the edge zone.

However, with a frequency of reciprocating movements of less than 5 Hz, it is impossible to heat parts with the required characteristics in terms of the degree of uniformity of heating of the end surfaces. At a frequency of reciprocating non-repetition: at least 5 Hz, the contact points change so quickly that the heating of the end surfaces to the end of the welding process is uniform with the temperature equal to the melting point. After the end of the heating allowance, the precipitation is switched on, the reciprocating movements are stopped and the welding current is switched off. This completes the welding process.

Details of low carbon steel with a diameter of 20 mm were welded by the proposed method in 3.5 seconds with a welding allowance of 3 mm. The weld mode was next. The holding time of the parts in the reduced state during one pulse of reciprocating movement was 0.06 sec, and the pause time was 0.02 sec. Compressive force at preheating was 30 kgf, specific force of precipitation 1.5-2.0 kgf / mm. The frequency of reciprocating movements was 12.5 Hz.

The proposed method was welded parts of low carbon steel with a diameter of 40 mm in 8.5 seconds with a total (heating and sludge) welding allowance of 7 mm. The frequency of reciprocating movements was 6.25 Hz, the dwell time of the parts in the reduced state was 0.14 seconds, the pause time was 0.02 seconds. The compression force during heating is 60 kgf, the specific force of the draft is 1.0-1.5 kgf / mm.

The proposed method allows material savings by reducing the welding allowance.

Comparative data on welding allowances for the proposed method, as well as recommended ones are given in the table.

Claims (2)

1. Auth. St. L 226052, M.C. 23K 11/04, 1968 2. Kabanov, N. S. Slepak, E. Sh., “Butt welding technology, M,” Mashinostroenie, 1970, p. 48-49.