HYDROGEN-INDUCED DELAYED CRACKINGOF T-250 MARAGING STEEL

摘要

Hydrogen induced delayed cracking (HIDC) of T-250 maraging steel in air has been studied.rnThe results show that HIDC can occur in air with RH≥30%. The arrested threshold stress intensityrnfactor of HIDC, KIH(MPam1/2), decreases linearly with increasing natural logarithm of hydrogenrnconcentration, C(ppm), I.e. KIH=49.5-26.1lnC. The threshold stress intensity factor of HIDC initiatingrnfrom notch tip in humid air, KIH(ρ), increase with increasing the square root of notch radius ρ, as ρ>ρ0=rn0.08 mm, I.e. KIH(ρ> 0.08 mm)=-32.7+244.9√ρ , however, when ρ≤ρ0, KIH(ρ≤ 0.08 mm)=KIH =37.5rnMpam1/2.