Hydrogen influence on structural strength of low-alloyed (40 ГФ, 40ГФ, 40ГMФ, 40ГCMФ) steels

T. Loladze, G.Shimbor, Kh. Ananiashvili, L. Kotiashvili, V. Kopaleishvili (Georgian Technical University)

ABSTRACT

Accelerated, simplified methodology for defining hydrogen influence on structural strength of low-alloyed 40ГТ, 40ГФ, 40ГMФ, and 40ГCMФ, steels after their holding in hydrogen containing corrosive medium for certain period of time was elaborated.

It is established that as a result of hydrogen saturation of steel coupons for 24 hours strength parameters (s_y, s_B) are increased and plasticity (d, j) and real fracture stress (S_k) are lowered.

Hydrogen saturation process is reversible – after weathering properties of hydrogen saturated coupons are restored; Lowering sulphur content down to 0,015% significantly reduces negative hydrogen influence and it is enhanced by normalization after hot–rolling. It is also shown that cold working intensifies negative influence of hydrogen on steel properties.