Showing papers on "Austenitic stainless steel published in 1992"
AeA1
TL;DR: In this article, the authors used two high purity model alloys, one of which was doped with sulphur, and laser surface melting of the alloys to detect and follow the evolution of anodic current transients (unstable micropits).
277 citations
TL;DR: In this article, nanocrystalline (grain size approximately 25 nm) stainless steel films were prepared by sputter-depositing the conventional 304 type stainless steel on glass substrates.
Abstract: Nanocrystalline (grain size approximately 25 nm) stainless steel films were prepared by sputter-depositing the conventional 304 type stainless steel on glass substrates. Despite the same chemical composition, the breakdown potential (Eb) of the sputtered stainless steel films is found to be approximately 850 mV higher than that of the conventional material. Also, the breakdown potentials of the sputtered nanocrystalline stainless steel films are close to those of the amorphous FeCr18Ni9W11 and FeCr10P13C7 alloys reported in the literature. The high corrosion resistance of the sputtered films is attributed to the smaller grain size of the films.
118 citations
TL;DR: In this article, the authors used X-ray photoelectron spectroscopy (XPS) measurements and the sputter depth profiles of the implanted material for a fixed time in order to reach a well-defined point on the nitrogen depth profile.
114 citations
86 citations
TL;DR: In this article, three regimes of serrated flow were identified as low temperature type A (LT-A), high temperature type C (HT-A) and high temperature types C (Ht-C) for a 15Cr15Ni titanium-modified austenitic stainless steel.
Abstract: Serrated flow in a 15Cr15Ni titanium-modified austenitic stainless steel has been investigated at a wide range of temperatures (300–1023 K) and strain rates (10−5−10−2s−1). Three regimes of serrated flow have been identified as low temperature type A (LT-A), high temperature type A (HT-A) and high temperature type C (HT-C). Different methods suggested in the literature for the determination of activation energy, Q were employed and Q was obtained aas 115 ± 9, 140 ± 7 and 178 ± 7 kJ/mol for LT-A, Ht-A and HT-C regimes respectively. Based on the Q values, the mechanisms responsible for the three regimes of serrated flow were identified as vacancy migration for LT-A, C (or N) as controlling diffusing species to form a pair with vacancy causing Schoeck-Seeger locking for HT-A regime and interaction of Ti with C (or N) for HT-C regime. Titanium was found to influence the serrated flow in all regimes.
74 citations
TL;DR: In this paper, the effects of modification with oversized elements (Ti, Zr, Hf, V, Nb or Ta) on radiation-induced grain boundary segregation (RIS) in austenitic stainless steels were studied by means of electron irradiation in an HVEM and analytical electron microscopy.
71 citations
61 citations
TL;DR: In this paper, the idea of microstructural barriers to the propagation of short stress corrosion cracks was developed; a simple statistical model, based on a jump probability to cross a barrier, was developed for crack advance.
58 citations
TL;DR: The acoustic emission response of a low-carbon type 304 stainless steel (SS) (UNS S30400) during pitting and transgranular stress corrosion cracking (TGSCC) has been measured.
Abstract: The acoustic emission (AE) response of a low-carbon type 304 stainless steel (SS) (UNS S30400) during pitting and transgranular stress corrosion cracking (TGSCC) has been measured. Tests w...
55 citations
TL;DR: In this paper, the effect of Cu on the anodic dissolution behavior of stainless steel in acidic 3.5% NaCl solution at 80°C was studied by electrochemical and AES techniques.
50 citations
TL;DR: The influence of Cu additions on the electrochemical and corrosion behavior of 18-8 austenitic stainless steel was investigated in this paper, where both potentiodynamic polarization curves and potential decay curves, which were dependent upon the Cu content and the dissolved oxygen in the solution tested, were determined in both de-aerated and aerated 0.1 M H 2 SO 4 solution.
TL;DR: In this paper, Raman spectroscopy was used to identify corrosion layers on stainless steels, polarized at the pitting potential in alkaline solutions containing chloride, and the inner layer was formed by tetravalent molybdate.
Abstract: Corrosion layers grown on stainless steels (AISI 302, 316), polarized at the pitting potential in alkaline solutions containing chloride, were identified by Raman spectroscopy. Several binary alloys such as Fe-10Ni, Fe-6Mo, and Fe-18Cr, were studied to separate the influence of the different alloy elements. A comparison was also made with the layers formed on these alloys by voltametric cycling (which allows the thickening of the passive layer), the anodic reverse potential being in this case below the pitting potential. The parts played by the two main elements, Cr and Mo, are described. After the passivity breakdown, i.e., once the chromia layer has broken down, the inner layer is formed by tetravalent molybdate, the pitting initiation being related to the passage of Mo from valency6+ to valency4+. In the outer green rust layer, bichromate ions fill the sites available for Cl− and then slow down the ingress of chloride.
TL;DR: In this paper, the effect of aging on the precipitation of grain boundary phases in three austenitic stainless steels (AISI 347, 347AP, and an experimental steel stabilized with hafnium) was investigated.
Abstract: The effect of aging on the precipitation of grain boundary phases in three austenitic stainless steels (AISI 347, 347AP, and an experimental steel stabilized with hafnium) was investigated. Aging was performed both on bulk steels as well as on samples which were subjected to a thermal treatment to simulate the coarse grain region of the heat affected zone (HAZ) during welding. Aging of the bulk steels at 866 K for 8000 hours resulted in the precipitation of Cr23C6 carbides, σ, and Fe2Nb phases; the propensity for precipitation was least for the hafnium-stabilized steel. Weld simulation of the HAZ resulted in dissolution of the phases present in the as-received 347 and 347AP steels, leading to grain coarsening. Subsequent aging caused extensive grain boundary Cr23C6 carbides and inhomogeneous matrix precipitation. In addition, steel 347AP formed a precipitate free zone (PFZ) along the grain boundaries. The steel containing hafnium showed the best microstructural stability to aging and welding.
Journal Article•
TL;DR: In this article, the formation of microstructures across cladding interfaces was examined with an emphasis on the fused region as-welded and after postweld heat treatment (PWHT).
Abstract: The formation of microstructures across cladding interfaces was examined with an emphasis on the fused region as-welded and after postweld heat treatment (PWHT). The strip submerged arc and shielded metal arc welding processes were used to deposit austenitic stainless steel and nickel-alloy consumables on to 2 1/4 Cr-1 Mo steel. Optical and electron microscopy were employed, with energy dispersive x-ray and electron probe microanalysis for examining major alloying elements and carbon. The observations were related to the results of hardness, bend and crack tip opening displacement (CTOD) toughness testing
TL;DR: In this paper, solution-annealed (SA) and 25% cold-worked (CW) prime-candidate-alloy (PCA) austenitic stainless steel were irradiated in ORR in spectrally-tailored experiments specially designed to produce fusion-relevant He/dpa ratios.
TL;DR: The intrinsic susceptibility of stainless steels to corrosive attack by barnacles is a widely recognized phenomenon as discussed by the authors, and it usually manifests itself in crevices, corresponding to the ba...
Abstract: The intrinsic susceptibility of stainless steels to corrosive attack by barnacles is a widely recognized phenomenon. Corrosion usually manifests itself in crevices, corresponding to the ba...
TL;DR: In this paper, the effect of aging on the microstructural stability of Alloy D9 was studied as a function of the amount of cold work and the Larson-Miller parameter.
TL;DR: An attempt was made to modify the surface microstructure of a sensitized austenitic stainless steel, without affecting the bulk properties, using laser surface melting techniques as mentioned in this paper, which indicated an improvement in the intergranular corrosion resistance.
Abstract: An attempt was made to modify the surface microstructure of a sensitized austenitic stainless steel, without affecting the bulk properties, using laser surface melting techniques. AISI type 316 stainless steel specimens sensitized at 923 K for 20 hr were laser surface melted using a pulsed ruby laser at 6 J energy. Two successive pulses were given to ensure uniform melting and homogenization. The melted layers were characterized by small angle X- ray diffraction and scanning electron microscopy. Intergranular corrosion tests were carried out on the melted region as per ASTM A262 practice A (etch test) and electrochemical potentiokinetic reactivation test. The results indicated an improvement in the intergranular corrosion resistance after laser surface melting. The results are explained on the basis of homogeneous and nonsensitized microstructure obtained at the surface after laser surface melting. It is concluded that laser surface melting can be used as an in situ method to increase the life of a sensitized component by modifying the surface microstructure.
TL;DR: In this paper, a tensile curve of solution annealed and cold-worked 316 and PCA type austenitic stainless steels were irradiated in the HFIR, HFR and R2 reactors, to 3.1-10.9 dpa at 523 K.
TL;DR: Although case histories reflecting engineers' experiences with chloride-induced stress corrosion cracking of austenitic stainless steels in water, are multifold, this source of informatio... as discussed by the authors.
Abstract: Although case histories, reflecting engineers' experiences with chloride-induced stress corrosion cracking of austenitic stainless steels in water, are multifold, this source of informatio...
Journal Article•
TL;DR: In this paper, solution-annealed and cold-worked austenitic stainless steels with nitrogen contents from 0.5 to 1.0 wt% exhibit highly desirable combinations of strength and fracture toughness.
Abstract: Solution-annealed and cold-worked austenitic stainless steels with nitrogen contents from 0.5 to 1.0 wt% exhibit highly desirable combinations of strength and fracture toughness. This article illustrates their corrosion resistance in water and salt water, along with quantitative correlations concerning pitting corrosion, crevice corrosion, and stress corrosion cracking
TL;DR: In this paper, the authors present a procedure for estimating the duration of a creep crack from a knowledge only of the stress rupture properties and creep ductility of a material and compare the results with experimental data on type 316L stainless steel at 600°C and a 1% CrMoV low alloy steel at 550°C.
Abstract: An incubation period is often observed prior to the onset of creep crack growth. This paper presents a procedure for estimating its duration from a knowledge only of the stress rupture properties and creep ductility of a material. Comparisons are made with experimental data on type 316L stainless steel at 600°C and a 1% CrMoV low alloy steel at 550°C. It is shown that good agreement is achieved when allowance for a build up of damage in a process zone at the crack tip during the early stages of cracking is incorporated into the analysis.
TL;DR: The diffusion and permeation behavior of tritium through the films of TiC and TiN + TiC coated on surface of 316L stainless steel by chemical vapour deposition has been described as mentioned in this paper.
TL;DR: In this article, a phenomenological modelling based on a decomposition of the specimen into three different parts is proposed, which allows simple predictions of the behaviour of the residual stresses in the case of various metallic materials on two different substrates.
Abstract: Laser surface treatments induce, like any other surface treatment, thermal gradients and hence residual stresses. In the present work, these stresses are determined in the case of coatings of various metallic materials on two different substrates: a low carbon steel and an austenitic stainless steel. Qualitative analysis of experimental results is performed by using a phenomenological modelling based on a decomposition of the specimen into three different parts. A generalization is proposed, which allows simple predictions of the behaviour.
TL;DR: In this paper, laser surface melting was used to desensitize the surface layer of sensitized 304 stainless steel and the degree of sensitization was determined quantitatively for sensitized and sensitized then laser surface melted samples from the modified ASTM-262 practice E test.
Abstract: Laser surface melting was used to desensitize the surface layer of sensitized 304 stainless steel. The degree of sensitization was determined quantitatively for sensitized and sensitized then laser surface melted samples from the modified ASTM-262 practice E test to be 45% and 0%, respectively. Grain-boundary melting which occurs in the heat-affected zone is believed to contribute the desensitization in the solid. X-ray diffraction results did not show any phase transformation in the melted layer or in the heat-affected zone. The results of the tensile tests indicate that sensitized stainless steel regains its corrosion resistance properties and, in addition, its mechanical properties seem to be enhanced by the laser surface melting.
TL;DR: In this article, the relationship between the crack paths and the underlying microstructure was investigated for annealed and cold-rolled (CR) 304 stainless steels that had been tested in a deaerated 3.5 pct NaCl solution, air, and vacuum.
Abstract: To assist in the understanding of micromechanisms for corrosion fatigue crack growth in metastable austenitic steels, the relationships between the crack paths and the underlying microstructure were investigated for annealed and cold-rolled (CR) 304 stainless steels that had been tested in a deaerated 3.5 pct NaCl solution, air, and vacuum. Corrosion fatigue in the deleterious environments (3.5 pct NaCl and air) was brittle and occurred primarily by {001}γ and other unidentified, quasi-cleavage (QC), accompanied by preferential cracking along {111}γ twin and grain boundaries. In contrast, fatigue cracking in vacuum was ductile, fully transgranular, and noncrystallographic. Transformation to alpha prime (α′-) martensite by fatigue was found to be essentially complete in the CR steel, which contained e-martensite, and in the annealed steel tested in vacuum, but was substantially less in the annealed steel tested in air and 3.5 pct NaCl solution. These results, taken in conjunction with the crack growth and electrochemical reaction data, support hydrogen embrittlement (HE) as the mechanism for corrosion fatigue crack growth in 304 stainless steels in 3.5 pct NaCl solution. Martensitic transformation appears not to be the only responsible factor for embrittlement. Other microstructural components, such as twin and grain boundaries, slip bands, and cold work-induced lattice defects, may play more important roles in enhancing crack growth rates.
TL;DR: In this article, surface enhanced Raman spectroscopy (SERS) was carried out on AISI 316 stainless steel to identify the species present on the electrode surface as a function of potential.
Abstract: This paper reports on potentiodynamic polarization curves measured by Type AISI 304 and 316 stainless steels in 0.15M NaCl solution at 4, 20, and 40[degrees]C. The pitting potentials decreased with increasing temperature. A positive effect on the inhibition of passivity breakdown was found in the presence of molybdenum. Surface enhanced Raman spectroscopy (SERS) was carried out on AISI 316 stainless steel to identify the species present on the electrode surface as a function of potential. Results indicate the corrosion films to be highly disordered and most likely to consist of a mixture of the oxides and hydroxides of the component elements of the stainless steel. The potential dependence of the spectra may reflect the behavior of iron, which is the most abundant component in the alloy and most probably in the film.
Patent•
13 Oct 1992
TL;DR: A low-nickel austenitic stainless alloy containing about 16.5 to about 17.5% chromium, 6.4 to about 8.0% manganese, 2.0 to less than about 3.0%, copper, 0.15% by weight carbon, less about about 0.2% nitrogen, and 0.1% silicon.
Abstract: An low-nickel austenitic stainless alloy containing about 16.5 to about 17.5% by weight chromium; about 6.4 to about 8.0% by weight manganese; about 2.5 to about 5.0% by weight nickel; about 2.0 to less than about 3.0% by weight copper; less than about 0.15% by weight carbon; less than about 0.2% by weight nitrogen; less than about 1% by weight silicon; and the balance essentially iron with incidental impurities.
TL;DR: In this article, a series of model alloys, based on the commercial 20Cr-25Ni-Nb stainless steel, have been irradiated in an HVEM using 1 MeV electrons, at temperatures between 250 and 500°C, to doses ranging from 0.6 to 7.2 dpa.