A COMPARATIVE STUDY OF HARDFACING TECHNOLOGIES APPLIED FOR INCREASING THE WEAR RESISTANCE OF MUD PUMP VALVES.

The drilling process requires the transportation of the drilling fluid (mud) loaded with high abrasive materials like sand and rock cuttings. The drilling mud is transported through the close running clearance of the valve opening at high flow velocities, producing high abrasive wear within a short period of time. As the drilling process makes it impossible to operate the pump at lower speed in order to reduce the flow velocity through the valves, the valve protection against abrasive wear can be realized by the following actions: – designing the valve to control the flow stream, avoiding abrupt changes in flow direction, close clearances and turbulent flow; – using abrasive wear resisting materials by applying hardfacing technologies, such as case hardening, cladding by weld overlays and coating by thermal spray techniques. This article is based on a comparative investigation of these methods for protection of the valve seat's working surface, operating under abrasive wear conditions. The comparison is based on the analysis of microstructure and hardness obtained by applying different hardfacing technologies. [ABSTRACT FROM AUTHOR]