At one point in time the “Bosch Fuel Systems” location in Kentwood, Michigan, USA boasted what was probably the largest plasma nitriding location in the world (Source; the late David Pye who knew as much or more about plasma nitriding as anybody in the world). 

 

At one point in time this location had 12 “Ipsen” plasma nitride furnaces, 2 “Eltro” plasma nitriding  furnaces, 4 “Kloeckner” plasma nitride furnaces, 3 “Ipsen” 10-bar gas quench furnaces, 3 “Surface Combustion” vacuum oil-quench furnaces, 5 “Surface Combustion” vacuum temper furnaces and 1 “Ipsen” vacuum temper furnace.

 

As of a couple of months ago the final two Ipsen plasma nitriding furnaces were scrapped which means the end of an era for plasma nitriding at this location. Perhaps a shame but the world keeps changing.

 

As a footnote to this story this location would have ranked as one of the “15 Largest Single Location Captive Heat Treats in North America” as ranked by “The Monty Heat Treat News”.