SU1692785A1 - Method of welding by arc rotatable in magnetic field - Google Patents

Abstract

The invention relates to the technology of arc welding, rotating in a magnetic field, and can be used for welding pipes, hollow shafts and other products. The purpose of the invention is to improve the quality of welding and stabilize the heating process. Between the welded ends of the pipes excite an arc, which is rotated in a magnetic field. After the edges are heated to the plastic state, the welding current is increased and the precipitate is conducted. The moment when the edges reach the plastic state is determined by the change in the size of the arc gap. The arc gap can be determined from the voltage across the arc. With an increase in stability4 of the process and quality of welded joints, the method simplifies the equipment used to control the process and allows expanding the range of materials to be welded, 1 hp f-ly. o w o

Description

The welding method relates to arc welding, rotating in a magnetic field, and can be used to connect closed sections of pipes, hollow shafts, and other products.

The aim of the invention is to improve the quality of welding by controlling the temperature expansion of products, leading to a reduction in the arc gap and simplification of equipment.

The essence of the method is as follows.

The minimum arc voltage corresponding to the beginning of the melting of their ends is experimentally determined with one gap between the products being welded. The voltage change of the rotating arc occurs mainly due to the linear expansion (elongation) of the pipe ends.

when they are heated and reduce the arc gap. Upon reaching the minimum voltage value corresponding to the beginning of the melting of the ends of the welded parts, increase the welding current (forcing) and produce pipe slumping.

Example. Weldable pipes with a diameter of 57 mm and a wall thickness of 5 mm from Steel 20 were installed in machine clamps with a gap of 2.0 mm and the machines were fixed with power devices. The electromagnets distance to the pipe end was 12 mm radial induction at the center of the gap 100 mT. In the gap, a rotating arc was excited by a fused jumper. After a delay of 1-2 seconds to stabilize the rotational speed for 5 seconds, a welding current of 250 A was maintained and the voltage across the arc was measured. Upon reaching this voltage of 21 V, an increased current value of 1000 A was turned on, and after a time of 0.2 s, a draft was carried out, and as a result, a welded joint was obtained. The shortening of the pipes after precipitation was 6.5 mm. Compression was carried out at a speed of at least 150 mm / s with a force of 60000 N. The total welding time was 12 s. Welding a batch of 57x5 pipes in the specified mode showed that when the gap between the pipes was installed with sufficient accuracy (2.0 ± 0.2 mm), the quality of the joints was high and was, by main indicators, at the level of the base metal.

With an increase in process stability and quality of welded joints, the method simplifies the process control equipment used and allows expanding the range of materials to be welded.

Claims (2)

1. A method of welding by an arc rotating in a magnetic field, in which the edges to be welded is heated to the plastic state, controls the moment of reaching the plastic state, then an increase in the welding current and draft are performed, characterized in that heating process by improving the accuracy of determining when the edges reach the plastic state, as a parameter to determine when the edges reach the plastic state, the change in The arc gap during the heating process. 2. A method according to claim 1, characterized in that the arc gap is determined by the voltage across the arc.