The Relation Between Degssing Baking Treatment and Fracture Taughness of Cadmium-plated High-Strength Steel

The cadmium plated high-strength steel 35CrMnSiA was studied using modified WOL and cantilever beam specimens.The hydrogen content in cadmium coating was determined as well as the content in steel. The cadmium plating is enriched with hydrogen.The degassing at 200℃ through bright, nonporous coating is very slow.Hydrogen content in the steel increases first during baking and reaches its maximum at about 2-2.5 hours, then decreases slawly.The delayed fracture properties of the steel depend on its hydrogen content.When the hydrogen content in steel is at its maximum, the KIscc of the steel reaches its minimum and da/dt reachs its maximum.In order to improve the mechanical prorepties, its necessary to take a prolonged degassing baking treatment.