Corrosion resistant laser coatings for hydraulic piston rods

Abstract

Hydraulic piston rods on oil & gas drilling platforms, hydro-power stations, chemical plants and underground mines are exposed to sever e tribo-corrosive conditions under static and dynamic mechanical loads. Piston rods made of carbon, quenched & tempered and stainless steels are frequently surface coated with methods such as thermal spraying, hard chrome plating and overlay welding. Unfortunately, several premature failures have been reported particularly in marine applications due to insufficient coating properties. Laser cladding has recently drawn lot of attention in this field thanks to high coating quality and improvements in productivity. In this study, several potential Fe-, Ni-and Co-based alloys were laser clad on carbon and quenched & tempered steels. Their corrosion and mechanical performances were studied in long-term salt spray, immersion, hardness, abrasive wear and 4-point bending fatigue tests. Most of the laser coatings outperformed hard chrome in corrosion properties but hardness values were somewhat lower. Fatigue performance was strongly dependent on coating material.Hydraulic piston rods on oil & gas drilling platforms, hydro-power stations, chemical plants and underground mines are exposed to sever e tribo-corrosive conditions under static and dynamic mechanical loads. Piston rods made of carbon, quenched & tempered and stainless steels are frequently surface coated with methods such as thermal spraying, hard chrome plating and overlay welding. Unfortunately, several premature failures have been reported particularly in marine applications due to insufficient coating properties. Laser cladding has recently drawn lot of attention in this field thanks to high coating quality and improvements in productivity. In this study, several potential Fe-, Ni-and Co-based alloys were laser clad on carbon and quenched & tempered steels. Their corrosion and mechanical performances were studied in long-term salt spray, immersion, hardness, abrasive wear and 4-point bending fatigue tests. Most of the laser coatings outperformed hard chrome in corrosion properties but hardness values...