Korfax at Light's Hope Chapel in the Eastern Plaguelands will make Dreadnaught Legplates if you bring him the following items: 1 Desecrated Legplates, 20 Wartorn Plate Scraps, 4 Arcanite Bars and 3 Cured Rugged Hides.
During your battles with the Scourge in Naxxramas, should you come across desecrated battlements and wartorn plate scraps, return them to me and I shall craft for you a piece of armor worn by heroes.
Exellent <name> !
, you got everything just as i asked and now i can make a Dreadnaught Legplates.
The entirety of this quest happens at Eastern Plaguelands