Studs used in a turbo pump were made from0.35C-1.5Ni-1.0Cr-0.2Mo steel, quenched and tempered to 400 HVhardness, cadmium-plated and baked at 200°C for 2 h. The studs usedin a turbo pump failed after 3 months of assembly. A fractograph ofa failed stud revealed a predominantly intergranular mode mixedwith ductile failure features. Increasing the baking time to 12 hconsidering the low diffusivity of hydrogen across the relativelyimpervious cadmium coating solved the problem. Explain the causeand mode of this failure.
