High Performance Super-Austenitic Surface Alloy Using Plasma Coating and Laser Treatment

1997 ◽  
Author(s):  
A.S. Khanna ◽  
K. Sridhar ◽  
M.B. Deshmukh
Keyword(s):  
Stainless Steel ◽  
Stainless Steels ◽  
Crevice Corrosion ◽  
High Performance ◽  
Plasma Coating ◽  
Offshore Structures ◽  
304 Stainless Steel ◽  
Delta Ferrite ◽  
Mo Content ◽  
Type 304

Abstract Stainless Steels are required for many applications for ship building as well as for offshore structures such as oil exploration. AISI type 304 stainless steel is not very suitable for such applications as it has a strong tendency for pitting and crevice corrosion. Even type 316 and 317 stainless steels which have respectively 2.5 and 3.5% Mo are not very effective in these environments. Commercially available stainless steels, viz., Avesta 254 SMO is being employed for such applications because of its strong resistance to pitting and crevice corrosion. This is mainly because of high Mo concentration (6.5%). Such steels are not only costly but are prone to form deleterious phases such as delta ferrite and sigma during welding or other heat treatment operations. Hence, an alternative technique to restrict Mo at the surface is needed. In the present work, surface alloys consisting of an austenitic stainless steel with Mo content as high as 10-12% have been formed on stainless steel type 304 substrates. These steels show enhanced passivity and strong resistance to pitting corrosion.

OUTOKUMPU TYPE 630

Alloy Digest ◽  
2016 ◽  
Vol 65 (2) ◽  
Keyword(s):  
Fracture Toughness ◽  
Stainless Steel ◽  
Corrosion Resistance ◽  
Physical Properties ◽  
High Performance ◽  
High Strength ◽  
Heat Treating ◽  
304 Stainless Steel ◽  
Type 304 ◽  
Type 304 Stainless Steel

Abstract Outokumpu Type 630 is a martensitic age hardenable alloy of composition 17Cr-4Ni. The alloy has high strength and corrosion resistance similar to that of Type 304 stainless steel. This datasheet provides information on composition, physical properties, hardness, and tensile properties as well as fracture toughness. It also includes information on corrosion resistance as well as forming, heat treating, and joining. Filing Code: SS-1238. Producer or source: Outokumpu High Performance Stainless.

Susceptibility of 304 Stainless Steel to Crevice Corrosion in Electrochemically Active Fluids

CORROSION ◽  
10.5006/3324 ◽  
2020 ◽  
Vol 76 (4) ◽  
pp. 424-435
Author(s):  
Abinaya Kamaraj ◽  
Johann Wilhelm Erning
Keyword(s):  
Stainless Steel ◽  
Crevice Corrosion ◽  
Chloride Concentration ◽  
304 Stainless Steel ◽  
Water Composition ◽  
Polyether Ether Ketone ◽  
Electrochemically Active ◽  
Ether Ketone ◽  
Type 304 ◽  
Type 304 Stainless Steel

The susceptibility of Type 304 stainless steel (SS) to crevice corrosion upon contacting with electrochemically active fluids was investigated using exposure tests and stepwise potentiostatic polarization. Crevice materials made of 304 SS and polyether ether ketone (PEEK) were focused on in this study. The combined influence of oxidant and chloride concentration on crevice corrosion was examined in detail in the two types of crevice combinations (304 SS-to-PEEK and 304 SS-to-304 SS). The 304 SS specimens were strongly susceptible to crevice corrosion when coupled with 304 SS. Even at a low concentration of 5 mg/L free chlorine and 150 mg/L chloride, which is below nominal dilutions in beverage industries, the examined specimens underwent crevice corrosion in both crevices. The effect of water composition on crevice corrosion was also studied, indicating high susceptibility of 304 SS to crevice corrosion in low pH (pH ≤ 5) solutions. The corroded surface morphology was analyzed using scanning electron microscope, energy dispersive x-ray, and confocal microscope.

Precipitation Behavior of M23C6 Carbides in Type 304 Stainless Steel Containing Delta Ferrite

2012 ◽  
Vol 18 (S2) ◽  
pp. 1352-1353 ◽  
Author(s):  
B. Miller
Keyword(s):  
Stainless Steel ◽  
304 Stainless Steel ◽  
Precipitation Behavior ◽  
Delta Ferrite ◽  
Type 304 ◽  
Type 304 Stainless Steel ◽  
M23c6 Carbides

Extended abstract of a paper presented at Microscopy and Microanalysis 2012 in Phoenix, Arizona, USA, July 29 – August 2, 2012.

Molybdenum solubility differences in MC phases formed in titanium and niobium modified austenitic stainless steels determined using AEM

1984 ◽  
Vol 42 ◽  
pp. 496-497
Author(s):  
P. J. Maziasz
Keyword(s):  
Stainless Steel ◽  
Corrosion Resistance ◽  
Elevated Temperature ◽  
Stainless Steels ◽  
Austenitic Stainless Steels ◽  
304 Stainless Steel ◽  
Elevated Temperature Strength ◽  
Helium Embrittlement ◽  
Type 304 ◽  
Type 304 Stainless Steel

Molybdenum is added to improve elevated temperature strength and corrosion resistance for type 316 compared to type 304 stainless steel. Strong carbide forming elements, like titanium and niobium, are also added to these steels to improve creep strength and reduce stress corrosion cracking, as well as to improve resistance to irradiation induced swelling and helium embrittlement. This work shows that fairly pure TiC and NbC form in Ti- and Nb- stabilized versions of type 304 stainless steel (types 321 and 347, respectively); however, the Ti-rich MC dissolves Mo considerably whereas the NbC remains compositionally quite pure when these phases form in Ti- and Nb- modified type 316 stainless steels, respectively.

Effects of Chloride, Bromide, and Thiosulfate Ions on the Critical Conditions for Crevice Corrosion of Several Stainless Alloys as a Material for Geological Disposal Packages for Nuclear Waste

1992 ◽  
Vol 294 ◽  
Author(s):  
Guen Nakayama ◽  
Hisao Wakamatsu ◽  
Masatsune Akashi
Keyword(s):  
Stainless Steel ◽  
Nuclear Waste ◽  
Crevice Corrosion ◽  
304 Stainless Steel ◽  
Critical Conditions ◽  
Geological Disposal ◽  
Steel Type ◽  
316 Stainless Steel ◽  
Type 304 ◽  
Type 304 Stainless Steel

ABSTRACTIn addition to mild steel, several stainless alloys are being proposed as materials for packages for geological disposal of high-level nuclear waste. When buried deep underground, the greatest detriment to the integrity of packages made of these alloys is localized corrosion, for which critical conditions for initiation of crevice corrosion in chloride environments, with or without other ions, need be precisely known.Crevice corrosion behavior of Type 304 stainless steel, Type 316 stainless steel, Alloy 825, Ti-Gr.1, and Ti-Gr.12 in solutions containing ions of chloride, bromide (these two for their ordinary presence in natural waters), or thiosulphate (this for the likelihood of microbially influenced corrosion) to varying concentrations have been empirically examined. All of these alloys exhibit much the same concentration dependency of crevice corrosion sensitivity for chloride and bromide ions, while Type 304 stainless steel is particularly sensitive to the thiosulphate ion. The region of insensitivity for chloride ion is wider in the increasing order of Type 304 stainless steel, Type 316 stainless steel, Ti-Gr. 1, and Ti-Gr. 12, with that of Alloy 825 lying somewhere in between.

Intergranular Corrosion of Nonsensitized Austenitic Stainless Steels — 1. Environmental Variables

CORROSION ◽  
1965 ◽  
Vol 21 (7) ◽  
pp. 235-244 ◽  
Author(s):  
J. S. ARMIJO
Keyword(s):  
Stainless Steel ◽  
Grain Boundary ◽  
Stainless Steels ◽  
Intergranular Corrosion ◽  
304 Stainless Steel ◽  
Intergranular Attack ◽  
Corrosion Reaction ◽  
Stress Levels ◽  
Type 304 ◽  
Type 304 Stainless Steel

Abstract Intergranular corrosion of nonsensitized stainless steels is reviewed, with emphasis on corrosion experienced in nitric-dichrornate solutions. Electrical resistance changes occurring during corrosion of Type 304 stainless ' steel in nitric-dichromate solutions are used to measure the rate of intergranular attack. Effects of HN03 concentration, Cr+6 concentration, temperature and stress on the intergranular corrosion reaction have been studied. The over-all corrosion reaction is found to consist of an incubation period, followed by a penetration period in which the rate of intergranular dissolution is linear. Measured activation energies for incubation and penetration periods are identical. The effect of applied stress is to increase both incubation and penetration rates. Low stress levels have greatest effect on the incubation rate, while high stress levels have greatest effect on the penetration rate. Appreciable grain boundary hardening is observed in nonsensitized Type 304 stainless steel. The grain boundary hardening is attributed to adsorbed impurities at grain boundaries. This segregation presents another variable which may be important in this type of intergranular attack.

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