How do you prevent hydrogen embrittlement in high-strength steel components?

Hydrogen embrittlement is loss of ductility/strength due to absorbed hydrogen. Mechanism: Hydrogen diffuses to high-stress regions (crack tips), Weakens atomic bonds, enables crack propagation at lower loads, Time-dependent failure. Susceptibility: High-strength steels (>180 ksi UTS), Tempered martensite most susceptible, Stress (applied or residual), and Environment (electroplating, corrosion, hydrogen gas). Sources: Processing - Pickling, electroplating, welding; In-service - Corrosion (cathodic hydrogen evolution), and Hydrogen environment (fuel systems). Prevention: Material selection - Limit strength level, resistant microstructures; Processing - Bake after plating (4+ hours at 375F within 4 hours of plating), Avoid hydrogen-generating processes; Protection - Barrier coatings to prevent hydrogen entry; and Design - Minimize stress concentrations. Testing: Slow strain rate testing, Sustained load testing in environment, and Incremental step loading. Specifications require baking (AMS 2759/9). High-strength fasteners and landing gear particularly vulnerable. Strict process controls essential.