Tribology of Hard Coatings Alloys Deposited by Thermal Methods: Applications to Industrial Components

CONDE, RAÚL HORACIO; CARR, GUSTAVO EDUARDO

San Diego, California, EEUU

Conferencia; The International Conference On Metallurgical Coatings And Thin Films ICMCTF 2008; 2008

AVS (American Vacuum Society) Science And Technology of Materials, Interfases and Processing

In most of seamless tube making industries, the service life of mandrels used for rotary forging is less than 350 perforation events, despite in some cases the tool lasts longer than 1000 perforations. Being the first of a series of hot working steps, an improvement during the piercing multiplies the benefits throughout the whole manufacturing process. Mandrels are cast in three metal bases: iron, nickel and cobalt, but lower costs support the use of iron base alloys, mostly when larger mandrel diameters are required. Mandrels life is usually improved by the controlled growth, at high temperature, of a hard oxide film. The research reported in this work is related to the protective oxide films grown on mandrels for seamless tube rotary forging1. A laboratory scale equipment has been entirely designed and built at INTEMA in order to study mandrels wear during rotary piercing of steel billets. Hard coatings oxides grown under controlled atmosphere on mandrels surface were tested by this equipment, reproducing the same wear conditions observed at industrial scale. Wear and oxide film evolution were studied by optical microscopy and energy-dispersive X-ray spectroscopy. Acquired data from lab-scale piercing experiments were analyzed using neural networks (self organizing maps) in order to find out relationships among 22 process parameters and oxide film characteristics. It is suggested that this method of analysis could be applied to any industrial component under multivariable hard coating wear situations.