Hydrogen embrittlement susceptibility and permeability of two ultra-high strength steels

The effect of aging treatment on hydrogen embrittlement of PH 13-8 Mo steel was investigated by tensile tests. The specimens were electrochemically hydrogen-charged in 0.5 mol/L NaOH solution with 1 g/L CH4N2S at room temperature for 24 h, and then were tensioned to fracture at different tensile rates. The results show that hydrogen slightly increases the tensile strength of the steel at high tensile rate (20 mm/min), but decreases the tensile strength at low tensile rate (0.5 mm/min and 0.03 mm/min). In the range of temperature from 540 °C to 750 °C, the specimen aged at 650 °C has the highest resistance to hydrogen embrittlement, which can be attributed to reverted austenite. At tensile rate of 0.03 mm/min, the SEM fractograph reveals quasi-cleavage and intergranular fracture mode for hydrogen-charged specimens aged at 540 °C, 600 °C,700 °C and 750 °C while dimple-type fracture mode for hydrogen-charged specimens aged at 650 °C.

Effect of aging treatment on hydrogen embrittlement of PH 13-8 Mo martensite stainless steel

Stress corrosion cracking and fatigue crack growth behavior were determined in 17-4 PH stainless steel under various metallurgical conditions, including the H900 (482°C/1 h), H1025 (552°C/4 h) aging and laser surface annealing treatments. Peak-aged (H900) specimens locally irradiated by laser beam consisted of a portion of composite region (CR), in which comprised of soft laser-annealed (LA) zones on the outer surfaces and the hard base metal in between. Slow extension rate tensile tests were performed at room temperature in a saturated H 2 S solution to evaluate the hydrogen embrittlement susceptibility of various specimens. H900 specimens show an obvious improvement in impact toughness after irradiating by laser. Regardless of testing environments, H900 specimens exhibited better tensile properties than the other specimens. Experimental results also indicated that H900 specimens had the highest fatigue crack growth rates among the specimens, particularly at low stress intensity factor range. The retardation of crack growth in the region ahead of the CR in the LA specimens was rather pronounced. For compact tension specimens tested in gaseous hydrogen, enhanced crack growth was correlated with quasi-cleavage fracture in contrast to transgranular fatigue fracture in air.

Embrittlement of laser surface-annealed 17-4 PH stainless steel

The influence of aging treatments on sulfide stress corrosion cracking of PH 13-8 Mo steel welds

Gaseous hydrogen embrittlement of PH 13-8 Mo steel

Sulfide stress cracking case histories of 12Cr and 17-4PH stainless steel tubing hangers are presented along with the results of NACE Standard TM0177 laboratory tests performed on the fail...

D. R. Canfield

Papers

Sulfide Stress Cracking Failures of 12Cr and 17-4PH Stainless Steel Wellhead Equipment