The two stroke diesel engine has been continually optimized since its invention more than a century ago. One of the ways to increase fuel efficiency further is to increase the compression ratio, and thereby the temperature in the combustion chamber. Because of this, and the composition of the fuel used, exhaust valve spindles in marine diesel engines are subjected to high temperatures and stresses as well as molten salt induced corrosion. To investigate candidate materials for future designs which will involve the HIP process, a spindle with Ni superalloy material samples inserted in a HIPd Ni49Cr1Nb matrix has been produced, and put into service for 2,200 hours allowing a unique in-situ corrosion test. 10 high Cr alloys have been tested this way. The corrosion appearance is found to be a factor of not only the chemical composition but also the production method. HIPd material with high Cr content and low content of Fe and Mo is found to be the best choice for hot corrosion resistance.
Proceedings of the 2011 International Conference on Hot Isostatic Pressing, 2011
Corrosion test; HIP; Exhaust valve spindle; Hot corrosion
Main Research Area:
HIP'11 - International Conference on Hot Isostatic Pressing 2011