The Effect of Trace Boron Element on Local Corrosion Resistance of Casted 0.04C-16Cr Ferritic Stainless Steel

2011 ◽  
Vol 415-417 ◽  
pp. 800-806 ◽  
Author(s):  
Tie Ming Guo ◽  
Ding Cang Zhang ◽  
Zhi Hui ◽  
Chang Song Han ◽  
Li Ming Zhao
Keyword(s):  
Stainless Steel ◽  
Corrosion Resistance ◽  
Nitric Acid ◽  
Corrosion Rate ◽  
Ferritic Stainless Steel ◽  
Pitting Corrosion ◽  
Intergranular Corrosion ◽  
Corrosion Potential ◽  
Chloride Ions ◽  
Curve Method

0.04C-16Cr and 0.04C-16Cr containing 26ppm B ferritic stainless steels were smelted by using a vacuum induction furnace. Then 65% boiling nitric acid method and the electrochemical potentiokinetic reactivation method (EPR) were used to research their intergranular corrosion sensitivity. Meanwhile, electrochemical test method (Tafel polarization curve method, the anode circular polarization curve method) and chemical immersion method were used to research their pitting corrosion resistance. The results showed that the corrosion rate of 0.04 C-16Cr stainless steel containing 26ppm B in 65% boiling nitric acid is lower than that of 0.04 C-16Cr stainless steel. The reactivation rate of 0.04C-16Cr containing 26ppm B in dilute sulphuric acid medium significantly reduced compared with that of 0.04C-16Cr. The pitting corrosion potential, self-corrosion potential and the value of (Eb-Ep) of the stainless steel containing with 26ppm B in chlorideions medium reduced, while the corrosion rate increased compared with the stainless steel without B addition. It indicates that trace boron addition improves the intergranular corrosion resistance and repair ability of the passive film of the 0.04C-16Cr ferritic stainless steel after pitting corrosion process in chloride ions medium, but it also promotes the pitting corrosion tendency of the steel. Besides, introduction B to 0.04C-16Cr ferritic stainless steel reduces the steel’s corrosion resistance in active dissolved zone and promotes its intergranular corrosion tendency in chloride ions medium. The electrochemical characteristics of local corrosion are consistent with the results of chemical immersion test.

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.

Research on the Failure Mechanism of Pitting Corrosion of the 304 Stainless Steel in Chloride Ions Environment

2012 ◽  
Vol 502 ◽  
pp. 12-16
Author(s):  
Yi Pan ◽  
Rong Fa Chen ◽  
Du Xiong Wang ◽  
Guo Sheng Cai ◽  
Xian Liang Zhang ◽  
...  
Keyword(s):  
Stainless Steel ◽  
Corrosion Rate ◽  
Failure Mechanism ◽  
Pitting Corrosion ◽  
Chloride Ion ◽  
Chloride Ions ◽  
304 Stainless Steel ◽  
Cr Content ◽  
Experiment Method ◽  
Ion Impact

The Mechanism of 304 Stainless Steel Pitting Corrosion Was Researched in Chloride Ions Environment. the Metallographic Microstructure of Areas near the Pitting Corrosion and Far Away from the Pitting Corrosion Were Observed by the Metallographic Experiment；Cr Content of the Sample Was Determined by EDXRF, to Prove Chloride Ion Impact on the Element Cr of 304 Stainless Steel. Finally, Corrosion Rate of Specimens Was Determined by Piecewise Experiment Method to Prove Otherness for Corrosion Rate in Different Period of 304 Stainless Steel in Chloride Ions Environment.

Difference of Corrosion Characteristics of the Welding Zone between Laser and TIG Welding

2010 ◽  
Vol 146-147 ◽  
pp. 899-903
Author(s):  
Kyung Man Moon ◽  
Yun Hae Kim ◽  
Myung Hoon Lee
Keyword(s):  
Stainless Steel ◽  
Corrosion Resistance ◽  
Laser Welding ◽  
Heat Exchangers ◽  
Intergranular Corrosion ◽  
Corrosion Potential ◽  
Corrosion Current ◽  
Tig Welding ◽  
Chromium Depletion ◽  
Welding Zone

Two kinds of welding methods were performed on 22APU stainless steel: laser welding and TIG welding. In this case, the differences of the corrosion characteristics of the welded zones between the two welding methods mentioned above were investigated with electrochemical methods such as the measurement of corrosion potential, polarization curves, cyclic voltammogram, etc. The Vickers hardness of all welded zones (WM:Weld Metal, HAZ:Heat-Affected Zone, BM:Base Metal) was relatively higher for the laser welding than for the TIG welding. Furthermore, the laser welding method’s corrosion current densities in all welding zones were also observed to have a lower value compared to TIG welding. In particular, the corrosion current density of BM, regardless of the welding method, was the lowest value among all other welding zones. Intergranular corrosion was not observed at the corroded surface of all laser-welded welding zones; however, it was observed at the TIG-welded WM and HAZ welding zones, which suggests that chromium depletion due to the formation of chromium carbide occurs on the WM and HAZ which are in the range of sensitization temperatures, therefore the zones can easily be corroded with a more active anode. Consequently, we can see that corrosion resistance of all welding zones of 22APU stainless steel may be improved by the use of laser welding. Keywords: Laser welding, TIG welding, Corrosion potential, Weld metal, Heat affected zone, Polarization curves, Chromium depletion1.Introduction In recent years, use of austenitic stainless steel, which has a high corrosion resistance, has been increasing due to the development of industries, such as atomic energy, aerospace, petro chemical, etc. When stainless steel was welded for numerous kinds of structures, intergranular corrosion would often be observed at the area surrounding the welding zone due to chromium depletion; in addition, there are numerous papers which have investigated both general corrosion and intergranular corrosion[1-6]. However, there are few experimental results on the effect of corrosion control at the welding zones when laser or TIG welding are used for the purpose of constructing heat exchangers with 22 APU stainless steel. Although laser welding is more expensive than TIG welding, laser welding is often used instead of TIG welding for the production of heat exchangers. Consequently, it has been suggested that, from a long-term point of view, laser welding is more economic than TIG welding. In this study, when TIG and laser welding are performed on the stainless steel, the differences of the corrosion characteristics in the welding zone was investigated with electrochemical methods. The experimental results are therefore expected to provide useful reference data for the appreciation of mechanical and corrosion characteristics in the welding zones.

Corrosion Resistance of 9 - 15% Cr ODS Steels and its Comparison with Austenitic Stainless Steel

2013 ◽  
Vol 794 ◽  
pp. 575-582 ◽  
Author(s):  
S. Ningshen ◽  
M. Sakairi ◽  
K. Sukuki ◽  
S. Ukai
Keyword(s):  
Stainless Steel ◽  
Corrosion Resistance ◽  
Corrosion Rate ◽  
Passive Film ◽  
Intergranular Corrosion ◽  
High Performance ◽  
304L Stainless Steel ◽  
Corrosion Attack ◽  
Ods Steel ◽  
Ods Steels

An oxide dispersion strengthened steels are one of the most promising high temperatures, and high performance advanced structural material being developed for future fast reactors and high-temperature Generation IV reactors. In the present work, the corrosion resistance and its correlation with the passive film compositions of 11% Cr F/M and 9-15% Cr (with Zr or Hf) ODS steels is examined and compared with AISI type 304L stainless steel in boiling 60 - 62% (~13 M) HNO3. The corrosion rate measured in 62% HNO3 for 240 h of 11% Cr F/M, 9% Cr and 15% Cr (Zr) ODS steels show high corrosion rate. On the other hand, low corrosion rate was observed in 304L stainless steel (0. 21 to 23 mm y-1). However, severe intergranular corrosion attack was revealed in type 304L SS after 240 h exposure, but none in ODS steels. Such an intergranular corrosion attack seen in type 304L stainless steel is undesirable. On the contrary, low corrosion rate (0.04 0.15 mm y-1) of 15% Cr (Hf) ODS steel in 3 M, 6 M and 9 M HNO3, comparable to that of type 304L stainless steel was observed. The improved corrosion resistance of 15% Cr (Hf) ODS steel was attributed to enrich (20 at. %) and protective Al2O3 layer formation in addition to Cr2O3 in the passive film.

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