Recent Progress in Coating Developments for Power, Oil & Gas, and Mining

Khelfaoui, Fadila

Valve components are hardfaced to reduce friction, wear and corrosion thus enhancing their in-service life. The increasing demand of severe service applications have pushed the limits of these commonly used materials. This presentation will focus on three main challenges and provide an update on the status of current developments:

1 Power

Materials are the key to develop advanced processes operating at temperature up to 760°C and sustained pressure up to 4500 psi. Pressure vessel materials may fail due to creep, oxidation, and erosion.

Stellite 6 (cobalt-based alloy) is the benchmark hardfacing. However, the latest results tend to indicate that it is not suitable above 600°C. An alternative hardfacing will be required for Advanced Ultra-Supercritical steam generators.

New Ni- and Co- based alloys are being developed. Their chemistry, which accounts for their excellent dry-running properties makes them very suitable for use in adhesive wear combined with high temperature of 800°C.

We present the methodology that has been developed to explore the effects of elevated temperature on the tribological behavior of those advanced material, with the goal of capturing the basis for the specification, design, fabrication, operation, and maintenance of valves for A-USC steam power plants.

2) Oil & Gas

We present the methodology that has been developed to explore the effects of coking and sulfidation corrosion on the tribological behavior, with the goal of developing a wear-resistant surface treatment, to prevent scale and coke build-up caused by different classes of heavy oil, including in Coker and Ebullated Bed applications.

3) Mining

The thermal sprayed ceramic coatings have enhanced the life span of in-service equipment, including metal-seated ball valves (MSBV’s) in HPAL and POx services. The most recent advancements in ceramic materials and metallurgically bonded hardfacing solutions suitable for the operating conditions of the valves are presented, including our latest coating, VEL-8.