Author: Publisher:
ISBN:
Category :
Languages : en
Pages : 0
Book Description
The Effects of Hydrogen on the Fracture Toughness Properties of Upset Welded Stainless Steel
Author: The Effects of Hydrogen, Tritium, and Heat Treatment on the Deformation and Fracture Toughness Properties of Stainless Steel
Author: Publisher:
ISBN:
Category :
Languages : en
Pages :
Book Description
The deformation and fracture toughness properties of forged stainless steels pre-charged with tritium were compared to the deformation and fracture toughness properties of the same steels heat treated at 773 K or 873 K and precharged with hydrogen. Forged stainless steels pre-charged with tritium exhibit an aging effect: Fracture toughness values decrease with aging time after precharging because of the increase in concentration of helium from tritium decay. This study shows that forged stainless steels given a prior heat treatment and then pre-charged with hydrogen also exhibit an aging effect: Fracture toughness values decrease with increasing time at temperature. A microstructural analysis showed that the fracture toughness reduction in the heat-treated steels was due to patches of recrystallized grains that form within the forged matrix during the heat treatment. The combination of hydrogen and the patches of recrystallized grains resulted in more deformation twinning. Heavy deformation twinning on multiple slip planes was typical for the hydrogen-charged samples; whereas, in the non-charged samples, less twinning was observed and was generally limited to one slip plane. Similar effects occur in tritium pre-charged steels, but the deformation twinning is brought on by the hardening associated with decay helium bubbles in the microstructure.
HYDROGEN EFFECTS ON THE FRACTURE TOUGHNESS PROPERTIES OF FORGED STAINLESS STEELS.
Author: Publisher:
ISBN:
Category :
Languages : en
Pages :
Book Description
The effect of hydrogen on the fracture toughness properties of Types 304L, 316L and 21-6-9 forged stainless steels was investigated. Fracture toughness samples were fabricated from forward-extruded forgings. Samples were uniformly saturated with hydrogen after exposure to hydrogen gas at 34 MPa or 69 and 623 K prior to testing. The fracture toughness properties were characterized by measuring the J-R behavior at ambient temperature in air. The results show that the hydrogen-charged steels have fracture toughness values that were about 50-60% of the values measured for the unexposed steels. The reduction in fracture toughness was accompanied by a change in fracture appearance. Both uncharged and hydrogen-charged samples failed by microvoid nucleation and coalescence, but the fracture surfaces of the hydrogen-charged steels had smaller microvoids. Type 316L stainless steel had the highest fracture toughness properties and the greatest resistance to hydrogen degradation.
The Effects of High Pressure, High Temperature Hydrogen on Steel
Author: Ellis E. FletcherPublisher:
ISBN:
Category : Steel
Languages : en
Pages : 82
Book Description
This report deals with the deleterious effects of hydrogen gas on steel at elevated temperatures and/or pressures. Hydrogen attack on steels is manifest as decarburization, intergranular fissuring, or blistering. These conditions result in lowered tensile strength, ductility, and impact strength. The reaction of hydrogen with iron carbide to form methane is probably the most important chemical reaction involved in the attack on steel by hydrogen. Attack of steel at elevated temperatures and pressures is limited or prevented by the following measures: (1) use of steel alloyed with strong carbide-forming elements, (2) use of liners of resistant alloy steels, and (3) substitution of resistant nonferrous alloys.
HYDROGEN EFFECTS ON FRACTURE TOUGHNESS OF TYPE 316L STAINLESS STEEL FROM 175 K TO 425 K.
Author: Publisher:
ISBN:
Category :
Languages : en
Pages :
Book Description
The effects of hydrogen on the fracture-toughness properties of Type 316L stainless steel from 175 K to 425 K were measured. Fracture-toughness samples were fabricated from Type 316L stainless steel forgings and hydrogen-charged with hydrogen at 34 MPa and 623 K for two weeks prior to testing. The effect of hydrogen on the J-Integral vs. crack extension behavior was measured at various temperatures by fracturing non-charged and hydrogen-charged samples in an environmental chamber. Hydrogen-charged steels had lower toughness values than non-charged ones, but still retained good toughness properties. The fracture-toughness values of hydrogen-charged samples tested near ambient temperature were about 70% of non-charged values. For hydrogen-charged samples tested at 225 K and 425 K, the fracture-toughness values were 50% of the non-charged values. In all cases, fracture occurred by microvoid nucleation and coalescence, although the hydrogen-charged samples had smaller and more closely spaced microvoids. The results suggest that hydrogen effects on toughness are greater at 225 K than they are at ambient temperature because of strain-induced martensite formation. At 425 K, the hydrogen effects on toughness are greater than they are at ambient temperature because of the higher mobility of hydrogen.
Fracture Toughness of Hydrogen Embrittled Welds and Heat Affected Zones in Stainless Steel
Author: Scientific and Technical Aerospace Reports
Author: Effects of Hydrogen Gas on Metals at Ambient Temperature
Author: James Edward CampbellPublisher:
ISBN:
Category : Alloys
Languages : en
Pages : 30
Book Description
On the basis of the information available, steels(ferritic, martensitic, and bainitic), nickel-base alloys, and titanium alloys become embrittled in pure-hydrogen-gas environments at ambient temperature. The embrittling effect is detected by making tension tests on sharp-notched specimens in an environment of high-purity hydrogen gas and, for comparison, tests on similar specimens in an inert gas at the same temperature and pressure. If the material is embrittled by hydrogen, its notch tensile strength will be reduced. The effect is more pronounced as the hydrogen-gas pressure is increased, but in some cases the embrittling effect has been observed at 1 atmosphere of pressure. The effect is more pronounced for the high-strength steels and high-strength nickel and titanium alloys than for the low-strength alloys. In unnotched specimens exposed to a pure-hydrogen environmental, hydrogen embrittlement manifiests itself as a decrease in ductility. Results of tests on stable austenitic stainless steels such as Types 310 and 316, or certain aluminum alloys such as 6061-T6, 2219-T6, and 7075-T73, and beryllium copper indicate that there is no significant evidence of embrittlement of these alloys in hydrogen gas at pressures up to 10,000psi.
Effects of Absorbed Hydrogen on Fracture Toughness of Welded SA516 Grade-70 Steel
Author: Mohamad Haidir MaslanPublisher:
ISBN:
Category : Pressure vessels
Languages : en
Pages : 64
Book Description
Author: