PTA stands for Plasma Transferred Arc and is a continuous welding process that is used in metallic coating of exposed areas to improve surface properties.
With minimal heat impact, the process melts both base and additive materials and thus achieves complete metallic bonding. At the same time, the layer becomes completely free of pores and slag. The method provides very clean welds of high quality while the impact on the base material is minimal.
The number of layers has no limit and the method can therefore be used both for repairs (many layers for major damage) and for surface coating in new production.
As a method, PTA welding differs from traditional welding in that the arc is efficient and thin. This reduces the heat input to the piece, while minimizing the heat-affected zone (HAZ). The method also makes it possible to efficiently weld carbides and stellites, for example on valve surfaces and wear sleeves.
The great advantage of PTA, compared to conventional welding methods (MIG / MAG, TIG, MMA etc.), is that the energy can be controlled much better. This means that less base material needs to be melted to obtain a good weld, which results in considerably much less mixing and cleaner welds.
Although the temperature may be higher in the melt, the total heat into the goods is significantly lower. It provides a significant reduction in shape changes.
In addition, PTA is a continuous process, which means that the heat is evenly distributed and thus further reduces movements in the workpiece. Thanks to the PTA’s high performance, materials that are otherwise difficult to weld can be coated with good results. This method is therefore most often used for hard facing. Typical applications are wear sleeves, valves, nozzles, hydraulic cylinders, rollers and laminating rollers, industrial knives and blades etc.