Development of Hydrogen Embrittlement Test Methods Which Reflect Realistic Maintenance Scenarios

This paper compares several different test methods used to test maintenance chemicals for potential to induce hydrogen embrittlement in high-strength steel. The program was structured to accomplish three main objectives with regard to hydrogen embrittlement testing: 1) compare various test methods used to qualify maintenance chemicals, 2) compare various coatings used to protect high-strength steel parts such as landing gear, and 3) compare various high-strength steel substrates specified for aircraft landing gear. The coatings selected included electrodeposited cadmium (baseline), ion vapor deposited (IVD) aluminum, SermeTel 984, and Zinc-Nickel plate. Substrates tested included AISI 4340 (260-280 ksi HT), 300M (280-300 ksi HT), and AerMet 100 (minimum 290 ksi HT).