Worn valve spindles & seats (Normal Steel or Nimonic Type) are machined down to sound material, and rebuilt with recommended materials by specialised welding process/Plasma Transfer Arc techniques . Worn valve stems are restored to the original by chromium plating or thermal spray processes.
Cast iron valve housing are often exposed to material loss at the exhaust gas passage from burning & cold corrosion. The corrosion is due to the formation of excessive sulphuric acid during cooling interval of the main engine. These affected areas are built up with nickel overlays by our skilled welders. The final stage by grinding to smooth profile is critical as this will enable efficient gas flow to the exhaust manifold, with minimum turbulence.
DMS worldwide Exchange Program offers client the convenience of exchanging their worn piston crown, cylinder cover, exhaust valve spindle and seat with our reconditioned ones at no extra cost. This arrangement contributes to substantial cost & time savings for the clients/ships.
Defects to be removed by grinding to sound material.Dye check to ensure no crack.Rebuild up by MIG welding with backing plate acc. to LR’s approved WPS.Repaired areas are grinded, polished and dye check.
To enhance our specialised marine engineering services, we have now established service teams for onboard repair works.The services include main/auxiliary engine & turbocharger overhaul, hydraulic equipment service & repair, pipe renewal and others.
On-site welding and machining of worn-out bores.Line boring of engine bed plates and bearing pockets, turbine bearing pockets, etc.Removal of broken studs by drilling and machining.Vertical boring on bearing pockets, pintle housings and rudder bearing housings.Cylinder block liner landing face machining.
DMS has been successful in combining welding techniques with chromium plating process for the reconditioning of worn steel piston crowns of both slow & medium speed enginesPiston skirts are refurbished by replacing the worn rider bands and final machining to the original specifications.
Main Engine cylinder covers with burnt eroded and cracked areas can be effectively rectified by welding & machining. If required , machining of entire combustion surface to reach & remove all internal cracks can be carried out and rebuilt by submerged arc welding & machining as per DMI approved procedures . Auxiliary Engine cylinder heads work scope include grinding & renewal of valve seat rings & valve spindles, welding or modification (sleeve insert), machining and dismantling/assembling of accessories.
