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Welding technology

“SHTORM-ITS”: MECHANIZATION AND AUTOMATION OF WELDING PROCESSES DURING ASSEMBLING

The quality of welding joints, which are made during assembling, influence a lot on the strength, workability and safety of the whole welded construction. Most of the joints are made manually. The contemporary line of welding equipment development is directed on the decrease of “human factor” risk. Therefore the use of devices for welding torches moving becomes a highly important step towards the increase of effectiveness.

During 30-40s of the last century there was a rash transfer from riveted to welding constructions by industrial engineering and bridge engineering. The main factor was the replacement of manual arc welding by submerged arc welding, which resulted in the improvement of the welds quality and output of welding process. However, such method of welding is applicable mainly in the shop conditions at the manufacture of separate parts of building and bridge constructions. The exception is made for fillet and butt welds, which are produced by manual and MIG/MAG welding. The process of welding of such joints in shop and assembling conditions can be automated by using the devices for welding torches moving.

The new developments among such equipment are devices of NOBORUDER series (Fig. 1), which are able to move the torches of almost any semi-automated welders, and are meant for producing welds in any attitude positions. Thus, a welding operator has an instrument that can if necessary replace the manual and semi-automatic welding into automated (horizontal and vertical welds, hard-to-reach places), for this it is only needed to fix the torch in the moving device.

An important peculiarity is the following: a constant magnet is built-in inside the moving device with the help of which it is fixed and held on the workpiece itself.

At the same time the carriage itself is based on 4 driving non-magnet wheels with the constant air-gap between the magnet and the workpiece (equal to 6,5 mm) and can be easily moved with the given welding speed both in horizontal and vertical ways. The width of joint can be set by torch adjusting handle; the speed of vibration frequency is set on the operation box. The joint formation can be controlled by setting and adjusting of temporary delays of the vibration at the end and central positions of the torch. To start the welding it is only needed to set the welding speed, vibration frequency and amplitude with the adjusters during the “test” mode and to press the “start” button. The correction of the settings can be made during the welding process. Such construction of the device allows carrying the automated welding of horizontal and vertical butt and fillet in top-bottom and bottom-top directions. The usage of transverse vibration mechanism provides the width of the vertical weld (the filling of the butt weld) up to 15 mm at one run (with the amplitude of torch transverse vibration of 25 mm). Tracking on the joint can be carried out by the following ways: at welding of flat butt horizontal and vertical joints – by using magnet guide rails, by roller sensor on V-shaped grooving of the joint; at welding of fillet joints – by using guide thrust rollers. A self-propelled carriage is so easy-in-operate, that no special training is needed. All the mechanisms are supplied with limit switches and one operator can use several machines at one time in order to increase the effectiveness.

The NOBORUDER series also includes different modifications of welding tractors:

• for simultaneous two-sided welding at T-shaped joint, for example, welding of orthotropic constructions in the sphere of bridge engineering;
• for one-sided twin-arc welding (“tandem”) of fillet horizontal joints – one-run welding of wide fillet welds with;
• for welding of constructions with a smooth compound curvature;
• for welding of nonmagnetic materials (the mechanism is supplied with a vacuum device for fixing on the workpiece) – for welding of reservoirs or stainless steel constructions
• for welding in hard-to-reach and constrained places, as well as more complicated modifications, which provide different vibration moving s of the torch during top-bottom, circle or triangle welding.

The weight of a self-propelled carriage, depending on modification, is only 6-10 kg, that allows lifting it up by one hand. The set includes one torch for semi-automatic welding, which can be connected up to practically any welding machine. However, the operating experience of such devices shows, that the most qualitative formation of the welds is achieved by using modern inverter machines (http://www.ewm.ru/), which reacts extremely fast to the changeable parameters of the torch transverse vibration.

The above-described equipment permits to mechanize and to automatize almost completely the process of welding in any attitude positions (except overhead position welding) both in shop conditions and at reservoirs assembling. Thereby, the output of welding process is increased considerably; the quality of welds is also increased and becomes stable.

The skilled technicians of “Shtorm-ITS” Ltd will help to look into all variety of welding tractors, to adapt them for certain conditions and to select the welding modes.

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