High temperature corrosion is always a trouble when it comes to marine diesel engine’s exhaust passages. The most important component which suffers from high temperature corrosion is the exhaust valves and spindles. Poor quality fuel and low load operation invites bigger trouble against the normal trouble free operation of a marine diesel engine.
Mitsubishi Heavy Industries Marine Machinery & Engine Co., Ltd. (MHI-MME), apply DSA 760,which is developed by DAIDO STEEL Co., Ltd , to the exhaust valve for UE engine to achieve the lifetime extension and higher reliability under low speed operation of 2 strokes diesel engines.
The exhaust valve made of DSA 760 was verified that it has high corrosion resistance compared with NIMONIC one by verification examination on vessel with large bore sized UE engine for abt. 1.5 years. DSA 760 exhaust valve will be commercialized to satisfy the customer needs for low speed operation.
This DSA 760 is the heat-resistant alloy which added chromium and aluminum in proper balance to nickel. And It also has the high temperature strength compared with existing the heat-resistant alloy and the resistance of the high temperature corrosion, which become a problem by diesel engine.
It is estimated that the wear rate of combustion surface decreases about 60%, and a lifetime extends about 2.5 times, as a result of verification examination.
MHI-MME will continue to propose various new technology development and high reliability measures to enhance seagoing energy efficiency and environmental preservation efforts.
- DSA 760 is an abbreviation for Daido Super Alloy No.760. DSAⓇ is a registered trademark of Daido Steel Co., Ltd.
Source: MHI MME