In Situ Laser Build-Up Welding of Shipboard Crankshafts

Abstract

Renovation of marine diesel engine crankshaft main and crankpin journals surfaces is usually done when ships engine is undergoing repairs. Often heavy working conditions and intensive wear accompanied with lubrication failures require a complete renovation of these worn-out surfaces. In most of the cases these repairs are done in the workshop, by removing crankshaft from engine and subsequently performing journal grinding. Where it is necessary also various types of build-up operations are carried out. Final technical requirements for these repairs are demanding: fine surface quality, geometrical accuracy and high surface roughness (texture) parameters have to be ensured. Although available technologies are able to deliver these results, they are very expensive, time consuming and usually can be done only in workshop conditions by highly sophisticated and expensive grinding machinery. This article describes novel technology which has been developed to perform crankshaft crankpin journal surfaces grinding operations directly in engine housing. Furthermore, a comprehensive study of laser build-up techniques and their potential applications for marine crankshaft specifics is outlined. Study confirmed that previously adopted grinding platform can be extended to laser cladding technology. It suites well shipboard crankshaft surface renovation needs and opens an entirely new industrial application dimension to the laser cladding technologies. Combination of these in-situ grinding and laser cladding technologies can bring considerable economic benefits and save the valuable marine diesel engine repair time.