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Wednesday, May 17, 2006 - 2:10 PM
EAP3.2

PTA Surfacing – Carbide Containing Coatings for Highest Abrasive Wear Conditions

U. Morkramer, R. F. Moll, M. Oechsle, A. Kirsten, Sulzer Metco WOKA GmbH, Barchfeld, Germany

Among the surfacing processes Plasma Transferred Arc welding (PTA) is known as an excellent coating process. The use of powder shaped materials guarantees highest flexibility in the design of welding materials. Especially if strong requirements are posed on abrasive wear resistance of coated components mechanical blends of matrix materials and wear resistant carbides are used. The standard material to increase abrasive wear resistance is tungsten carbide. However the drastically price increase in tungsten containing materials forces users and suppliers to look for alternatives. Therefore new materials with other carbides like chromium carbide have to be developed.

Based on a brief description of the materials mainly applied to date the influencing factors on the coating structure and wear properties are described. The investigations are focused on Nickel based alloys and tungsten carbide as reinforcing elements. New developments in tungsten carbide as well as chromium carbide containing materials are presented. Their wear behavior is characterized and discussed under economical considerations.


Summary: Tungsten and chromium carbide containing materials have been developed and applied by PTA. They were investigated regarding weldability and wear resistance. The results show that highest abrasive wear resistance can be achieved with combinations of Nickel base alloys and tailored mixtures of tungsten carbides. Although chromium carbide containing coatings cannot compete in wear resistance they can be an economical alternative if the price of tungsten carbide remains high.