Innovative Surface Modification for High Strength Steel Alloys to Enhance Corrosion Resistance

High strength steel components on Navy aircraft are prone to corrosive effects of the sea water environment during long term use. Innovative low cost surface modification approaches can significantly improve the corrosion resistance of high strength steels without reducing their mechanical properties and wear resistance. An important component on the JSF is the Weapons Bay Door Drive System made from Pyrowear 675 alloy. The Phase I effort demonstrated that two low temperature carburizing processes (Swagelok SAT-12 Process and Bodycote Kolsterizing Process) can be successfully applied to martensitic stainless steels, such as Pyrowear 675 and Custom 465. These low temperature carburization processes produced surface hardnesses in excess of HRC 70 and about a 200-500% increase in wear resistance. The use of low temperature carburization processes could have a major impact on the cost and performance of components on various aircraft platforms including the JSF. The Phase II effort will apply the two low temperature carburizing processes to these alloys on actual JSF components. Work on the low temperature carburizing of 300M steel and optimization of the current carburizing process for Pyrowear 675 alloy used in the Weapons Bay Drive Door System will also be done.