Six Sigma in metallurgy

Six Sigma is a data driven process improvement methodology based on DMAIC cycle (Define – Measure-Analyze – Improve – Control). This methodology can be applied successfully in Metallurgy.
Here is an example of successfully Six Sigma project used to decrease number of ball bearings blocking in stands in a rolling mill. The ball bearings used in stands of the mill have diameters reaching nearly 1 meter, are very expensive and their replacement times exceed 4 hours. The key indicator which give the performance of the process was the down time caused by these blockages (D).