G1100-1-3 Effects of the iron content to the sliding properties of the cobalt-based "Stellite"

Abstract

Stellite is the hard-facing material specified in AWS as CoCr-A. The alloy has the good anti-corrosion, anti-wear and anti-erosion properties. Therefore, the alloy is generally used as the valve's seat materials on the pipe-line of the plants. Stellite are used to be welded by gas-welding. Recently, there are tendency to adopt TIG or PTA welding methods. By these methods, iron-dilutions occur due to the un-proper welding conditions. This study has been done to clarify the effects of iron to the sliding properties of the alloy. The allowable iron contents are discussed to obtain the good pressure tightness of the gate valve.