Plasma powder build-up welding

This article or the following section is not adequately provided with supporting documents ( e.g. individual evidence ). Information without sufficient evidence could be removed soon. Please help Wikipedia by researching the information and including good evidence.

The plasma arc welding (also: PTA process "Plasma Transferred-Arc") is a thermal coating process for the surface treatment, which is the beginning of the 20th Century by the current JG group was invented. In this welding process , which is primarily used for surfacing wear and corrosion-resistant layers on a base material, a protective layer is metallurgically bonded to the base material (e.g. low-alloy steel, stainless steel, cast iron, bronze, nickel-based superalloys).

Working principle

With PTA build-up welding, the workpiece surface of the workpiece to be protected is melted with a plasma arc . The plasma is generated with the aid of a plasma gas (e.g. argon , helium ) through an arc between the cathode and anode. The resulting high-density plasma arc serves as a heat source and a metal powder is used as an application material. The powder is heated in a plasma jet and applied to the workpiece surface. Here it melts completely in the melt pool on the substrate.

The entire process takes place in the atmosphere of a protective gas (e.g. an argon-hydrogen mixture).

Advantages of the procedure

The PTA process enables low dilution (5-10%), a small heat-affected zone, a high application rate (up to 20 kg / h) and a real metallurgical bond between the substrate and the layer. Due to the additional material in powder form, which is easier to manufacture than z. B. welding rods or wires, almost any materials and material combinations in all hardness ranges can be applied.

The process is convincing due to the high degree of automation and therefore high reproducibility of the welds. The mainly used build-up welding powders can be classified as nickel- based , cobalt-based and iron-based alloys .