Hydrogen effect on properties and fracture of steel with different structure

The effect has been studied of hydrogen upon the strength and the plastic characteristics, and the peculiarities of failure of samples from chromium-nickel steels, such as the 30KhGN steel of various structures, under prolonged action of tensile stresses (slow loading). It is shown that hydrogen exerts a most adverse effect upon the structure of martensite, particularly at small amounts. Fractures of hydrogenated and nonhydrogenated samples with sorbite structure are compared. The failure of a hydrogenated steel of sorbite structure occurs according to a cleavage mechanism. For equal hydrogen contents, samples with martensite structure break up in a more brittle manner than those with a sorbite structure. When castings possess various types of structure and have a high hydrogen content, cracks nucleate in the first place in martensite type structures