Method for controlling the microstructure of a laser metal formed hard layer

摘要

It is disclosed a method of applying a coating ( 12 ) with a controlled laser metal forming process. A light source with a specific power and a signal capturing apparatus is moved over an article ( 1 ) to form locally a melt pool ( 7 ) on the surface ( 5 ) of the article ( 1 ) to which a coating powder ( 8 ) is injected. An optical signal ( 13 ) is captured from the melt pool ( 7 ), and the monitored optical signal ( 13 ) is used for the determination of the temperature and temperature fluctuations of the melt pool ( 7 ). Furthermore, a control system ( 16 ) is used to adjust at least one process parameter such as the power of the light source to obtain desired melt pool properties. Subsequently the melt pool ( 7 ) solidifies. The high degree of control over the microstructure provides an efficient tool for generating laser metal formed hard coatings ( 12 ) with optimised wear properties.