Hydrogen Embrittlement Cracking of 17-4 Stainless Steel

 

Nomarski intereference contrast photograph of the microstructure of a 17-4PH stainless steel sleeve bearing overlayed with sintered tungsten carbide. A hydrogen embrittlement crack has initiated at the overlay/base metal interface. A mechanical crack in the overlay permitted access of a corrosive downhole environment to the 17-4PH stainless steel base metal. Vilellla's etch. (~65X)