Two new innovations have been added to Polysoude’s TIGer high speed cladding solution: the Reclining Welding Lance for accessing bore diameters down to 150 mm; and Patch Mode, for cladding areas that cannot be described easily in geometric terms.
Using a 1.2 mm diameter single wire, the TIGer process can deliver weld overlay speeds of up to 2 000 mm/min.
For many years. the French company Polysoude has enjoyed an excellent reputation in the area of weld overlay cladding. Process controllers, power sources, mechanical system components and cladding lances are the result of continues improvement and close cooperation with end users.
In 2013 Polysoude introduced the unique TIGer technology, a modified TIG hot wire process. The two TIG arcs generated by the bi-cathodic torch are controlled to form one single arc with characteristics that differ significantly from an ordinary TIG arc. The enhanced energy concentration allows remarkably improved melting rates, whereas low dilution between the weld and base metal helps to meet the strict requirements of today’s cladding standards and guidelines.
Originally, TIGer cladding lances were made for circular or longitudinal cladding of the inside or outside of cylindrical bodies. However, the outstanding performance of the TIGer process, especially when mounted on a CNC machine, has created the demand to handle more complex workpiece geometries.
For the design of a cladding lance a lot of technical marginal conditions have to be taken into consideration, such as the welding position, which depends on the orientation of the workpiece; the shape and size of the surface which has to be clad; the characteristics of the machines that hold and lead the lance on its trajectories – column and boom equipment, longitudinal seam welders, gantry devices, etc.
Based on a comprehensive analysis of all related problems, Polysoude has developed a torch that can be configured to meet most of the technical requirements, the reclining welding lance for the TIGer process
The reclining welding lance is composed of a beam that allows the cladding lance to be mounted on the right- or left-hand side, and an adjustable, modular and symmetrical torch bloc. A bore diameter of only 150 mm is sufficient to introduce the lance, while the length of the clad area can be up to 1.0 m.
The torch bloc is adjustable in whatever axis by means of an Allen key, the two torches can be reclined independently of one another so that the optimum configuration for each particular cladding task becomes possible.
Within the duty cycle of the torch with two welding arcs, one per electrode with an intensity of up to 2×300 A can be applied, complemented by a hot wire current of up to 140 A.
For easy set-up of the lance, the so-called preferred positions P1, P2 and P3 are indicated on the different components. To fit the desired application, the indicated reference points on the torch bloc and the used sector have to be aligned.
In the same manner the wire guide is mounted on a setting ring to ease the finding of the best position for correct wire impact. The modular design of the reclining TIGer torch is perfect for cladding in tilted position, the orientation of electrodes and wire impact can be different so cladding in reverse directions becomes possible.
Components for high temperatures or high pressure are often equipped with flanges which need to be sealed with circular metallic joints. The grooves in the flanges are filled using weld overlay cladding, after which the entire surface is clad with a corrosion-resistant alloy. The final geometry and surface quality are obtained by machining.
Patch mode for difficult geometries
For cladding equipment with CNC machines such as the Polyclad CN, Polysoude has introduced a function named ‘Patch’ which is useful for areas which cannot be described easily in geometric terms. The function is based on torch trajectory control and may be applied for the cold and hot wire TIG process as well as for the TIGer technology. The choice of ‘Teaching’ simplifies the specification of the geometric zone to be clad.
The relevant surface area is clad by means of a cycle where the torch is moving back and forth, with indexed forward and reverse movements of the welding torch.
The shape of each surface can be specified using four coordinate points, which can be established by position-based teaching or by directly entering of the relative coordinates.
The combination of a reclining TIGer lance with the Patch mode considerably simplifies the programming of complex workpiece geometries, which were often areas only accessible by manual welding. It enables almost all workpiece geometries, from simple cylinder bodies to complex and difficult to access shapes to be programmed and clad automatically.
