scholarly journals Decrease in Pitting Corrosion Resistance of Extra-High-Purity Type 316 Stainless-Steel by Cu2+ in NaCl

Metals ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 511
Author(s):  
Takahito Aoyama ◽  
Hiroaki Ogawa ◽  
Chiaki Kato ◽  
Fumiyoshi Ueno
Keyword(s):  
Stainless Steel ◽  
Corrosion Resistance ◽  
Passive Film ◽  
Pitting Corrosion ◽  
High Purity ◽  
Film Formation ◽  
Bulk Solution ◽  
Potential Region ◽  
316 Stainless Steel ◽  
Pitting Corrosion Resistance

The effect of Cu2+ in bulk solution on pitting corrosion resistance of extra-high-purity type 316 stainless-steel was investigated. Pitting occurred in 0.1 M NaCl-1 mM CuCl2, whereas pitting was not initiated in 0.1 M NaCl. Although deposition of Cu2+ on the surface occurred regardless of a potential region in 0.1 M NaCl-1 mM CuCl2, Cu2+ in bulk solution had no influence on the passive film formation. The decrease in pitting corrosion resistance in 0.1 M NaCl-1 mM CuCl2 resulted from the deposited Cu or Cu compound and continuous supply of Cu2+ on the surface.

scholarly journals The Pitting Corrosion Behavior of the Austenitic Stainless Steel 308L-316L Welded Joint

Metals ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 1258
Author(s):  
Jinshan He ◽  
Shiguang Xu ◽  
Wenxin Ti ◽  
Yaolei Han ◽  
Jinna Mei ◽  
...  
Keyword(s):  
Stainless Steel ◽  
Corrosion Resistance ◽  
Statistical Analysis ◽  
Austenitic Stainless Steel ◽  
Passive Film ◽  
Pitting Corrosion ◽  
Welded Joint ◽  
Weld Zone ◽  
Electrochemical Tests ◽  
Pitting Corrosion Resistance

The pitting corrosion resistance of the austenitic stainless steel 308L-316L welded joint was investigated by electrochemical tests. It is found that the weld zone was the most critical for pits to initiate in the welded joint due to relatively instable passive film with few Mo and inhomogeneous passive film induced by multiple (Mn, Al, and Si) oxides and continuous network of 13.94 vol.% δ ferrites. By statistical analysis, 53.8% pits initiated at (Mn, Al, and Si) oxides, 23.0% in austenite, and 23.2% at interface between ferrite and austenite. In addition, heat-affected zone was prone to have pitting corrosion compared with the base metal since residual strain was much higher in the region.

The Influence of Cold Working on Semiconducting Properties of Passive Film and Pitting Corrosion Resistance of High Nitrogen Austenitic Stainless Steel

2011 ◽  
Vol 415-417 ◽  
pp. 784-788
Author(s):  
Li Wei Xu ◽  
Hua Bing Li ◽  
Qi Feng Ma ◽  
Zhou Hua Jiang ◽  
Dong Ping Zhan
Keyword(s):  
Stainless Steel ◽  
Corrosion Resistance ◽  
Austenitic Stainless Steel ◽  
Cold Rolling ◽  
Passive Film ◽  
Pitting Corrosion ◽  
High Nitrogen ◽  
Pitting Corrosion Resistance ◽  
Semiconducting Properties ◽  
Rolling Deformation

The effect of cold working on semiconducting properties of passive film and pitting corrosion resistance of 19Cr-18Mn-2Mo-0.9N high nitrogen austenitic stainless were investigated by anodic polarization, AC impedance and capacitance measurement methods. With increasing the cold rolling deformation ranging from 0% to 60%, the passive region of high nitrogen austenitic stainless steel decreases, and the corrosion potential, EIS radius and polarization resistance all decreases. The Mott-Schottky result indicates that the pitting corrosion resistance deteriorates with increment of cold rolling deformation. The results show that the passive films formed on high nitrogen austenitic stainless steel with different cold rolling deformation behave as n-type semiconductors. With increasing the cold rolling deformation grade, the donor density (ND) increases, but the thickness of the space-charge layer (W) decreases. The decreasing of the thickness of space-charge layer with increment of cold rolling deformation is attributed to the inceasing defect which deteriorates the stability of the passive film.

scholarly journals Understanding the Efficacy of Concentrated Interstitial Carbon in Enhancing the Pitting Corrosion Resistance of Stainless Steel

2021 ◽  
Author(s):  
Tianshu Li ◽  
Szu-Chia Chien ◽  
Zhe Ren ◽  
Wolfgang Windl ◽  
Frank Ernst ◽  
...  
Keyword(s):  
Stainless Steel ◽  
Corrosion Resistance ◽  
Dissolution Rate ◽  
Passive Film ◽  
Pitting Corrosion ◽  
Covalent Bonds ◽  
Interstitial Carbon ◽  
Metal Atoms ◽  
Pitting Corrosion Resistance ◽  
Metal Metal

Abstract By introducing a high fraction of interstitial carbon through low temperature carburization, the pitting corrosion resistance of austenitic stainless steel can be significantly improved. Previous work attributed this enhancement to the improvement of passive film properties. However, we show here that interstitial carbon actually weakens the passive film on stainless steel. In fact, the enhancement in pitting resistance is a result of carbon reducing the metal dissolution rate in a local pit environment by many orders of magnitude, which extremely decreases the growth stability of a pit and prevents it from transitioning into stable growth. Electronic structure calculations show that carbon bonds to the metal atoms and that the metal–carbon bonds are 1.6 to 2.0 times stronger than the metal–metal bonds. Different from prior theories, we show that the significant increase of pitting resistance originates from the formation of covalent bonds between interstitial carbon and its neighboring metal atoms, resulting in a significantly reduced dissolution rate. This study indicates a new strategy for the design of corrosion resistant alloys, namely alloying with concentrated interstitials that form strong bonds with the matrix atoms.

NIROSTA 4429

Alloy Digest ◽  
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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