Thermal shocks on an electrolytic chromium coating in a solar furnace

The electrodeposited chromium coatings are currently used to protect surfaces in many industrial cases, such as rolling-mills, landing gear, jack rod or gun barrels. in the latter case, an important thermal effect is superimposed to the frictional one, bringing to the coating flake off This paper presents a part of a more extended study of the damages induced in gun tubes. It deals with thermal shock resistance analysis of uncoated and chromium coated steel samples. Its aim is to reproduce and study the main damage types observed at the inner surface of gun tubes by using the DCE solar furnace in Odeillo (France). In a real weapon shooting, the thermal pulse can reach nux levels as high as 50 kW/cm(2) in an extremely brief time (about 10ms). These thermal conditions cannot be simulated at the focus of a solar furnace, so we have to determine the couple of parameters (flux level and duration) creating the same damage on the samples.