Influences of Aging Precipitation on Corrosion Resistance of 18Cr-18Mn-2Mo-0.77N HNS

Influences of aging precipitation of Cr2N and Chi (χ) phases on the resistance to pitting corrosion and intergranular corrosion of 18Cr-18Mn-2Mo-0.77N high nitrogen steel (HNS) as a type of fundamental and structural materials were investigated using scanning electron microscopy (SEM), X-ray diffraction (XRD) pattern and electrochemical methods. Intergranular, cellular Cr2N and χ phases precipitate gradually along grain boundaries and inward grains. The volume fraction of precipitation presents a C-curve with a nose temperature of 850°C during 2h aging treatment. The solution-treated (ST) HNS exhibits the highest pitting corrosion potential because of high nitrogen content in steel, and especially no precipitation. The pitting corrosion resistance of aged HNS decreases because of the formation of aging precipitation which results in the depletion of Cr and Mo in the matrix. The pitting corrosion potentials firstly decrease then increase as the same tendency as the amount of precipitation expect 850°C and 900°C. Double loop electrochemical potentiokinetic reaction (DL-EPR) results show that the change tendency of IGC susceptibility is well consistent with the amount of precipitation of aged HNS for 2h at various temperatures. With prolonging the aging time at 850°C, aged HNS presents more obviously intergranular sensitization due to the formation of aging precipitation which results in the depletion of Cr and Mo.

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Influences of Nitrogen Content and Aging Precipitates on Pitting Corrosion Resistance Properties of High Nitrogen Austenitic Stainless Steel

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.448-453.102 ◽

2013 ◽

Vol 448-453 ◽

pp. 102-106

Author(s):

Zu Rui Zhang ◽

Zhen Ye Zhao ◽

Chun Zhi Li ◽

Zhou Hua Jiang ◽

Hua Bing Li

Keyword(s):

Stainless Steel ◽

Corrosion Resistance ◽

Austenitic Stainless Steel ◽

Nitrogen Content ◽

Pitting Corrosion ◽

Corrosion Potential ◽

High Nitrogen ◽

Pitting Corrosion Resistance ◽

The Matrix ◽

Nose Temperature

This study is concerning the influences of nitrogen content and aging precipitates on pitting corrosion resistance properties of high nitrogen austenitic stainless steel (HNS) through potentiodynamic polarization method. The microstructure of aged HNS is analized by scanning electron microscopy (SEM). The main results obtained are as follow: the formation of intergranular, cellular Cr2N and intermetallic χ precipitates makes the depletion of Cr and Mo in the matrix and deteriorates the resistance to pitting corrosion in aged specimens. Cr2N starts to precipitate in the form of lamellar structure to cellular precipitates, the pitting corrosion drops to about 0 VSCE. HNSs perform the same tendency that the pitting corrosion potential firstly decreases then increases and reduce to the minimum value at nose temperature. All the pitting corrosion potential of HNS-B aged for 2h at different temperature presents more than that of HNS-A. The pitting corrosion resistance is mainly controlled by nitrogen content before great precipitates of cellular Cr2N and intermetallic χ phase rich in Cr and Mo. It is also mainly controlled by the content and the type of precipitates after great precipitates of cellular Cr2N.

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Investigation of the Localized Corrosion and Passive Behavior of Type 304 Stainless Steels with 0.2–1.8 wt % B

Materials ◽

10.3390/ma11112097 ◽

2018 ◽

Vol 11 (11) ◽

pp. 2097 ◽

Cited By ~ 5

Author(s):

Heon-Young Ha ◽

Jae Jang ◽

Tae-Ho Lee ◽

Chihyoung Won ◽

Chang-Hoon Lee ◽

...

Keyword(s):

Corrosion Resistance ◽

Pitting Corrosion ◽

Stainless Steels ◽

Volume Fraction ◽

Localized Corrosion ◽

Ingot Metallurgy ◽

Passive Behavior ◽

Pitting Corrosion Resistance ◽

The Matrix ◽

Type 304

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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Friction welding of a nickel free high nitrogen steel: influence of forge force on microstructure, mechanical properties and pitting corrosion resistance

Journal of Materials Research and Technology ◽

10.1016/j.jmrt.2013.12.001 ◽

2014 ◽

Vol 3 (1) ◽

pp. 90-100 ◽

Cited By ~ 19

Author(s):

Mrityunjoy Hazra ◽

Kotipalli Srinivasa Rao ◽

Gankidi Madhusudhan Reddy

Keyword(s):

Mechanical Properties ◽

Corrosion Resistance ◽

Pitting Corrosion ◽

Friction Welding ◽

High Nitrogen Steel ◽

High Nitrogen ◽

Pitting Corrosion Resistance ◽

Nitrogen Steel

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NIROSTA 4429

Alloy Digest ◽

10.31399/asm.ad.ss0787 ◽

2000 ◽

Vol 49 (5) ◽

Keyword(s):

Stainless Steel ◽

Corrosion Resistance ◽

High Temperature ◽

Pitting Corrosion ◽

Intergranular Corrosion ◽

Heat Treating ◽

Low Carbon ◽

High Nitrogen ◽

Temperature Performance ◽

Pitting Corrosion Resistance

Abstract Nirosta 4429 is a low-carbon, high-nitrogen version of type 316 stainless steel. The low carbon imparts intergranular corrosion resistance while the nitrogen imparts both higher strength and some increased pitting corrosion resistance. It is recommended for use as welded parts that need not or cannot be annealed after welding. This datasheet provides information on composition, physical properties, elasticity, and tensile properties. It also includes information on high temperature performance and corrosion resistance as well as forming, heat treating, and joining. Filing Code: SS-787. Producer or source: ThyssenKrupp Nirosta.

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La corrosion par piqûres d'aciers inoxydables austéno-ferritiques dans l'eau de mer synthétique

Matériaux & Techniques ◽

10.1051/mattech/199684060023s ◽

1996 ◽

Vol 84 ◽

pp. 23-30

Author(s):

I. Trigui ◽

H. Sidhom ◽

C. Braham ◽

J. Lédion

Keyword(s):

Corrosion Resistance ◽

Pitting Corrosion ◽

Sea Water ◽

Phase Behaviour ◽

High Nitrogen ◽

Electrochemical Tests ◽

Analysis Techniques ◽

Pitting Corrosion Resistance ◽

Nitrogen Contents ◽

Image Analysis Techniques

Duplex stainless steels crevice and pitting corrosion resistance in synthetic sea water is studied. Conventional electrochemical tests and image analysis techniques are used. Three commercial steels are examined. The forged material has the best behaviour, whereas cast materials, in spite of their high nitrogen contents, have a lower corrosion resistance. Micrographic studies show a good correlation between pittings distribution and inclusions distribution and reveal that gamma phase behaviour is more affected by inclusions. The metallurgic purity of products seems to be the most important parameter in this type of corrosion. Consequently, the PREN index is questionable in pitting corrosion grading of these steels because it does not take into acount the inclusions effect.

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