Enhancement of the Resistance to Localized Corrosion of Type 304 Borated Stainless Steels through Hot Rolling

The pitting corrosion resistance and passive behavior of type 304 borated stainless steels (Febalance–18Cr–12Ni–1.5Mn–(0.19, 0.78, and 1.76 wt %)B) manufactured through conventional ingot metallurgy were investigated. The alloys were composed of an austenitic matrix and Cr2B phase, and the volume fraction of Cr2B increased from 1.68 to 22.66 vol % as the B content increased from 0.19 to 1.76 wt %. Potentiodynamic polarization tests measured in aqueous NaCl solutions revealed that the pitting corrosion resistance was reduced as the B content increased and the pits were initiated at the matrix adjacent to the Cr2B phase. It was found that the reduced resistance to pitting corrosion by B addition was due to the formation of more defective and thinner passive film and increased pit initiation sites in the matrix.

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General and Localized Corrosion of Austenitic and Borated Stainless Steels in Simulated Concentrated Ground Waters

Transportation, Storage, and Disposal of Radioactive Materials ◽

10.1115/pvp2004-2792 ◽

2004 ◽

Author(s):

David V. Fix ◽

John C. Estill ◽

Lana L. Wong ◽

Rau´l B. Rebak

Keyword(s):

Corrosion Resistance ◽

Ground Water ◽

Stainless Steels ◽

Nuclear Industry ◽

Localized Corrosion ◽

Spent Fuel ◽

Ground Waters ◽

Fuel Storage ◽

Type 304 ◽

Control Rods

Boron containing stainless steels are used in the nuclear industry for applications such as spent fuel storage, control rods and shielding. It was of interest to compare the corrosion resistance of three borated stainless steels with standard austenitic alloy materials such as type 304 and 316 stainless steels. Tests were conducted in three simulated concentrated ground waters at 90°C. Results show that the borated stainless were less resistant to corrosion than the witness austenitic materials. An acidic concentrated ground water was more aggressive than an alkaline concentrated ground water.

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Effects of Overall Grain Boundary Nature on Localized Corrosion in Austenitic Stainless Steels

Materials Science Forum ◽

10.4028/www.scientific.net/msf.467-470.813 ◽

2004 ◽

Vol 467-470 ◽

pp. 813-818 ◽

Cited By ~ 9

Author(s):

D.N. Wasnik ◽

Vivekanand Kain ◽

I. Samajdar ◽

Bert Verlinden ◽

P.K. De

Keyword(s):

Stainless Steel ◽

Grain Boundary ◽

Cold Rolling ◽

Grain Boundaries ◽

Stainless Steels ◽

Intergranular Corrosion ◽

Localized Corrosion ◽

Mechanical Processing ◽

Type 316L ◽

Type 304

Thermo-mechanical processing of type 304 and type 316L stainless steels done by (a) cold rolling to a reduction in thickness of 20 to 80 percent and (b) solution annealing to obtain a medium size of grains led to a considerable improvement in resistance to both sensitization and intergranular corrosion. The nature of the resultant grain boundaries was examined in a scanning electron microscope using orientation imaging microscopy in electron back scattered diffraction mode. Fraction of random and special grain boundaries were established for each set of thermo-mechanical processing. After appropriate sensitization treatments, the degrees of sensitization of these stainless steels were evaluated by double loop electrochemical potentiokinetic reactivation tests. Standard ASTM tests were used to evaluate susceptibility to intergranular corrosion (IGC) and intergranular stress corrosion cracking (IGSCC). These studies showed that a particular combination of thermomechanical processing led to formation of over 75 percent random grain boundaries in the steels and this imparted resistance to sensitization and to IGC and IGSCC. This opens a new concept in grain boundary (GB) engineering of a high fraction of random GB increasing the resistance to localized corrosion like IGC and IGSCC. Textural studies were carried out with the help of X-ray and MTM-FHM software. It showed significant change of texture in type 304 stainless steel, while no change in the texture of type 316L stainless steel after cold rolling and annealing.

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Strain-induced martensite effects on transgranular carbide precipitation in type 304 stainless steels

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100087331 ◽

1991 ◽

Vol 49 ◽

pp. 604-605

Author(s):

A.H. Advani ◽

L.E. Murr ◽

D. Matlock

Keyword(s):

Heat Treatment ◽

Grain Boundary ◽

Stress Corrosion Cracking ◽

Stainless Steels ◽

Deformation Twin ◽

Austenitic Stainless Steels ◽

Carbide Precipitation ◽

Strain Induced Martensite ◽

Type 304

Thermomechanically induced strain is a key variable producing accelerated carbide precipitation, sensitization and stress corrosion cracking in austenitic stainless steels (SS). Recent work has indicated that higher levels of strain (above 20%) also produce transgranular (TG) carbide precipitation and corrosion simultaneous with the grain boundary phenomenon in 316 SS. Transgranular precipitates were noted to form primarily on deformation twin-fault planes and their intersections in 316 SS.Briant has indicated that TG precipitation in 316 SS is significantly different from 304 SS due to the formation of strain-induced martensite on 304 SS, though an understanding of the role of martensite on the process has not been developed. This study is concerned with evaluating the effects of strain and strain-induced martensite on TG carbide precipitation in 304 SS. The study was performed on samples of a 0.051%C-304 SS deformed to 33% followed by heat treatment at 670°C for 1 h.

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CARPENTER STAINLESS 304+B

Alloy Digest ◽

10.31399/asm.ad.ss0121 ◽

1961 ◽

Vol 10 (9) ◽

Keyword(s):

Fracture Toughness ◽

Cross Section ◽

Stainless Steels ◽

Austenitic Stainless Steels ◽

Heat Treating ◽

Neutron Absorption ◽

Absorption Cross ◽

Type 304 ◽

Conventional Type ◽

Neutron Absorption Cross Section

Abstract Carpenter Stainless 304+B is similar to conventional Type 304 with the addition of boron to give it a much higher thermal neutron absorption cross-section than other austenitic stainless steels. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties as well as fracture toughness. It also includes information on corrosion resistance as well as forming, heat treating, machining, joining, and surface treatment. Filing Code: SS-121. Producer or source: Carpenter.

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