scholarly journals Novel Formation of Ferrite in Ingot of 0Cr17Ni4Cu4Nb Stainless Steel

2018 ◽  
Author(s):  
Fei Han ◽  
Haicheng Yu ◽  
Jeffrey Dessau ◽  
Xianghai Chen
Keyword(s):  
Stainless Steel ◽  
Corrosion Resistance ◽  
Mushy Zone ◽  
Mechanical Stability ◽  
Ferrite Formation ◽  
Significant Difference ◽  
Central Segregation ◽  
The Difference ◽  
Steel Ingots ◽  
Zone Temperature

Ferrite body is the origin of crack and corrosion initiation of steels. Distribution and density of ferrite in seven steel ingots were examined by light optical microscopy and computational modeling in the study to explore the correlation of ferrite formation to chemical composition and mushy zone temperature in ingot forming. The central segregation phenomenon in ferrite distribution was observed in all the examined steel specimens except 0Cr17Ni4Cu4Nb stainless steel. No significant difference was found in distribution and density of ferrite amongst zones of the surface, ½ radius and core in neither risers nor tails of 0Cr17Ni4Cu4Nb ingots. Additionally, fewer ferrite was found in 0Cr17Ni4Cu4Nb compared to other examined steels. The difference of ferrite formation in 0Cr17Ni4Cu4Nb elicited a debate on the traditional models explicating ferrite formation. Considering the compelling advantages in mechanical strength, plasticity and corrosion resistance, further investigation on the unusual ferrite formation in 0Cr17Ni4Cu4Nb would help understand the mechanism to improve steel quality. In summary, we observed that ferrite formation in steel was correlated with mushy zone temperature. The advantages of 0Crl7Ni4Cu4Nb in corrosion resistance and mechanical stability could be resulted from that fewer ferrites formed and distributed in a scattered manner in microstructure of the steel.

scholarly journals Novel formation of Ferrite in Ingot of 0Cr17Ni4Cu4Nb Stainless Steel

2018 ◽  
Vol 2 (3) ◽  
pp. 44
Author(s):  
Fei Han ◽  
Haicheng Yu ◽  
Jeffrey Dessau ◽  
Xianghai Chen
Keyword(s):  
Stainless Steel ◽  
Corrosion Resistance ◽  
Mushy Zone ◽  
Mechanical Stability ◽  
Ferrite Formation ◽  
Significant Difference ◽  
Central Segregation ◽  
The Difference ◽  
Steel Ingots ◽  
Zone Temperature

The ferrite body is the origin of crack and corrosion initiation of steels. Distribution and density of ferrite in seven steel ingots were examined by light optical microscopy and computational modeling, in the study, to explore the correlation of ferrite formation to chemical composition and the mushy zone temperature in ingot forming. The central segregation phenomenon in ferrite distribution was observed in all the examined steel specimens, except 0Cr17Ni4Cu4Nb stainless steel. No significant difference was found in the distribution and density of ferrite among zones of the surface, ½ radius, and core in neither the risers nor tails of 0Cr17Ni4Cu4Nb ingots. Additionally, fewer ferrites were found in 0Cr17Ni4Cu4Nb compared to other examined steels. The difference of ferrite formation in 0Cr17Ni4Cu4Nb elicited a debate on the traditional models explicating ferrite formation. Considering the compelling advantages in mechanical strength, plasticity, and corrosion resistance, further investigation on the unusual ferrite formation in 0Cr17Ni4Cu4Nb would help understand the mechanism to improve steel quality. In summary, we observed that ferrite formation in steel was correlated with the mushy zone temperature. The advantages of 0Crl7Ni4Cu4Nb in corrosion resistance and mechanical stability could be the result of fewer ferrites being formed and distributed in a scattered manner in the microstructure of the steel.

scholarly journals Bizarreness of Ferrite Formation in Ingot of 0Cr17Ni4Cu4Nb Stainless Steel 

2018 ◽  
Author(s):  
Fei Han ◽  
Haicheng Yu ◽  
Jeffrey Dessau ◽  
Xianghai Chen
Keyword(s):  
Stainless Steel ◽  
Mushy Zone ◽  
Chemical Components ◽  
Ferrite Formation ◽  
Corrosion Initiation ◽  
Significant Difference ◽  
Central Segregation ◽  
Segregation Phenomenon ◽  
Steel Ingots ◽  
Zone Temperature

Ferrite body is the origin of crack and corrosion initiation of steels. Distribution and density of ferrite in seven steel ingots were examined by light optical microscopy and computational modeling in the study to explore the correlation of ferrite formation to chemical composition and mushy zone temperature in ingot forming. The central segregation phenomenon in ferrite distribution was observed in all the examined steel specimens except 0Cr17Ni4Cu4Nb stainless steel. No significant difference was found in distribution and density of ferrite amongst zones of the surface, ½ radius and core in neither riser nor tail of 0Cr17Ni4Cu4Nb ingot. Additionally, fewer ferrite was found in 0Cr17Ni4Cu4Nb compared to other examined steels. The bizarreness of ferrite formation observed in 0Cr17Ni4Cu4Nb elicited a debate on the traditional concepts explicating ferrite formation. Considering the compelling advantage in the mechanical strength, plasticity and corrosion resistance, further investigation on the unusual ferrite forming occurrence in 0Cr17Ni4Cu4Nb would help develop steels with improved quality. In summary, we observed that ferrite formation was correlated to mushy zone temperature, Cr:Fe and Cu:Fe ratios. We originally assume that Fe, the major component of steel could play an unrecognized role via proportion to other chemical components in ferrite formation.

scholarly journals Comparison of Mechanical Stability of Elastic Titanium, Nickel-Titanium, and Stainless Steel Nails Used in the Fixation of Diaphyseal Long Bone Fractures

Materials ◽  
2018 ◽  
Vol 11 (11) ◽  
pp. 2159 ◽  
Author(s):  
Pei-Yuan Lee ◽  
Yen-Nien Chen ◽  
Jin-Jia Hu ◽  
Chih-Han Chang
Keyword(s):  
Stainless Steel ◽  
Mechanical Stability ◽  
Fe Simulation ◽  
Bone Fractures ◽  
Nickel Titanium ◽  
Long Bone ◽  
Bone Modeling ◽  
Long Bone Fractures ◽  
Elastic Nails ◽  
The Difference

Elastic nails made of the nickel-titanium shape memory alloy (Nitinol) have been reported to control bone modeling in animal studies. However, the mechanical stability of the Nitinol nail in the fixation of long bone fractures remains unclear. This study compared mechanical stability among nails made of three materials, namely Nitinol, titanium, and stainless steel, in the fixation of long bone fractures. These three materials had identical shapes (arc length: π/2 and radius: 260 mm). A cylindrical sawbone with a 10-mm gap and fixed with two C-shaped elastic nails was used to examine the stability of the nails. A finite element (FE) model was developed based on the sawbone model. The end cap for elastic nails was not used in the sawbone test but was considered based on a constraint equation in FE simulation. The results of stability tests appeared to depend on the presence or absence of the end cap. In the sawbone test, the titanium nail yielded a higher ultimate force against the applied load than did the stainless steel and Nitinol nails before the gap completely closed; the difference in linear stiffness between the nails was nonsignificant. In FE simulation, the titanium nail produced smaller gap shortening than did stainless steel and Nitinol nails without the end cap; the difference in gap shortening between the nails was minor with the end cap. The titanium elastic nail should be a better choice in managing diaphyseal long bone fractures when the end cap is not used. For Nitinol and stainless steel nails, the end cap should be used to stop the nail from dropping out and to stabilize the fractured bone.

scholarly journals Improving the Corrosion Resistance of AISI 316L Steel for Semiconductor Piping by Controlled Delta-Ferrite Content

2022 ◽  
Vol 60 (1) ◽  
pp. 46-52
Author(s):  
Young Woo Seo ◽  
Chan Yang Kim ◽  
Bo Kyung Seo ◽  
Won Sub Chung
Keyword(s):  
Stainless Steel ◽  
Corrosion Resistance ◽  
316L Stainless Steel ◽  
Sem Analysis ◽  
Ferrite Content ◽  
Aisi 316L ◽  
Delta Ferrite ◽  
Aisi 316L Stainless Steel ◽  
316L Steel ◽  
The Difference

This study evaluated changes in delta-ferrite content depending on the preheating of AISI 316L stainless steel. We also determined the reasons for the variation in delta-ferrite content, which affects corrosion resistance. Changes in delta-ferrite content after preheating was confirmed using a Feritscope, and the microstructure was analyzed using optical microscopy (OM). We found that the delta-ferrite microstructure size decreased when preheating time was increased at 1295 oC, and that the delta-ferrite content could be controlled through preheating. Potentiodynamic polarization test were carried out in NaCl (0.5 M) + H2SO4 (0.5 M) solution, and it was found that higher delta-ferrite content resulted in less corrosion potential and passive potential. To determine the cause, an analysis was conducted using energy-dispersive spectroscopy (EDS), which confirmed that higher delta-ferrite content led to weaker corrosion resistance, due to Cr degradation at the delta-ferrite and austenite boundaries. The degradation of Cr on the boundaries between austenite and delta-ferrite can be explained by the difference in the diffusion coefficient of Cr in the ferrite and austenite. A scanning electron microscopy (SEM) analysis of material used for actual semiconductor piping confirmed that corrosion begins at the delta-ferrite and austenite boundaries. These results confirm the need to control delta-ferrite content in AISI 316L stainless steel used for semiconductor piping.

Semiconductor properties of passive film and corrosion resistance of 2205 duplex stainless steel joint welded by laser hybrid welding

2019 ◽  
Vol 66 (3) ◽  
pp. 327-335 ◽  
Author(s):  
Guo Yi ◽  
Junhua Xu ◽  
Chuanbo Zheng
Keyword(s):  
Stainless Steel ◽  
Corrosion Resistance ◽  
Passive Film ◽  
Pitting Corrosion ◽  
Welded Joint ◽  
Hybrid Welding ◽  
Content Type ◽  
Laser Hybrid Welding ◽  
The Difference ◽  
Laser Hybrid

Purpose There are obvious differences in corrosion resistance of different 2205 welding joints with different ratios of austenite and ferrite, from the top to the bottom, the austenite content decreased gradually while the ferrite increased. In each region of welded joint, the pitting resistance number of ferrite is higher than that of austenite; pitting corrosion is more likely to occur in austenite phase first on the top region of the weld and in the secondary phase precipitates on the other regions of the weld. The fluctuation of the ratio of austenite and ferrite has a great influence on performance of passive film in 3.5 per cent NaCl solution. Design/methodology/approach To study the corrosion behavior of welded joint, the samples were obtained by laser hybrid welding. Pitting corrosion was studied in different area of welded joint. The Mott–Schottky curves of welded joints were measured to study the passive film on the different welded joint area. Findings Due to the difference of heat input and the limit of filler depth of the wire, the microstructure of duplex stainless steel laser welding joint has obvious difference in the thickness direction. In addition, there will be harmful secondary phase (such as chromium nitride and σphase) precipitates in the lower part of the joint. For the welded joint, the corrosion resistance decreases with the increase in the difference of the microstructure. Pitting corrosion usually takes the two phases as the nucleation point and grows up. The surface of 2205 duplex stainless steel laser hybrid welding joint cannot form a complete passive film in 3.5 per cent NaCl solution, and the more the ratios of austenite and ferrite deviate from equilibrium position (50:50), the worse the performance of passive film is. Originality/value In this paper, the authors attempt to establish the correlation between the semiconductor electronic properties of passive film and the difference of microstructures and the component in a joint welded by laser hybrid welding. The effect of passive film on the corrosion resistance of the weld was further investigated.

scholarly journals Effect of Nitrogen on the Corrosion Behavior of Austenitic Stainless Steel in Chloride Solutions

2015 ◽  
Vol 9 (11) ◽  
pp. 119 ◽  
Author(s):  
W. A. Ghanem ◽  
W. A. Hussein ◽  
S. N. Saeed ◽  
S. M. Bader ◽  
R. M. Abou Shahba
Keyword(s):  
Stainless Steel ◽  
Corrosion Resistance ◽  
Austenitic Stainless Steel ◽  
Electrochemical Impedance ◽  
Open Circuit ◽  
Localized Corrosion ◽  
Partial Replacement ◽  
General Corrosion ◽  
Heat Treated ◽  
The Difference

The effect of partial replacement of nickel with nitrogen on the corrosion resistance of newly designed austenitic stainless steel samples without and with heat treated was investigated in 3.5wt% and 5wt% NaCl solution using open-circuit, potentiodynamic, cyclic anodic polarization and electrochemical impedance spectroscopy techniques. The results showed that, passivation in sample 1 where the highest addition of nickel and low addition of nitrogen is different from that for sample 4 where the nitrogen is greatest and the nickel is reduced almost to the third comparing sample 1. The difference in responses of heat treated samples to localized and general corrosion could be attributed to the difference in their phase compositions. The appearance of ferrite phase for samples (2, 4, 5 and 6) after heat treatment resulted in lowering the general and localized corrosion resistance than as forged samples in contrast with samples 1 and 3, where they still pure austenite. The obtained results are confirmed by surface examination.

scholarly journals Selective Laser Melting of 316L Stainless Steel: Influence of Co-Cr-Mo-W Addition on Corrosion Resistance

Metals ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 597
Author(s):  
Bolin Li ◽  
Tingting Wang ◽  
Peizhen Li ◽  
Shenghai Wang ◽  
Li Wang
Keyword(s):  
Stainless Steel ◽  
Corrosion Resistance ◽  
Selective Laser Melting ◽  
Scanning Speed ◽  
Corrosion Current ◽  
Laser Melting ◽  
Two Samples ◽  
Order Of Magnitude ◽  
The Difference ◽  
Tensile Experiment

The selective laser melting (SLM) of o-Cr-Mo-W/316L composite with 10wt% Co-Cr-Mo-W addition to 316 L stainless steel (SS) powder is produced to explore it’s the corrosion behavior. The tensile experiment of SLM composites is also measured to investigate the difference between the two samples. The optimum parameters of SLM 316 L SS and it’s composite samples are obtained by adjusting laser power and scanning speed with the relative density of 99.04 ± 0.69 and 99.15 ± 0.43. The yield strength of samples is increased from 731.96 MPa to 784.09 MPa after doping, and no obvious crack or fracture failure in the tensile samples are observed, indicating that the excellent plasticity is still maintained. The corrosion resistance of samples is improved largely with an order of magnitude lower corrosion current density than that of 316 L SS and increasing of 277 mv of epit Ep. The addition of Cr element in the doped powder contributes to the formation of the passivated film containing Cr. The different pitting corrosion pit occurs mainly around the pre-existing pores of the powder and further extends outward to form pits with the increase of voltage.

Pitting corrosion of super martensitic stainless steel 00Cr13Ni5Mo2

2014 ◽  
Vol 61 (6) ◽  
pp. 387-394 ◽  
Author(s):  
J.L. Li ◽  
C.T. Qu ◽  
S.D. Zhu ◽  
L. Liu ◽  
Z.Q. Gao
Keyword(s):  
Stainless Steel ◽  
Corrosion Resistance ◽  
Pitting Corrosion ◽  
Martensitic Stainless Steel ◽  
Pitting Potential ◽  
Content Type ◽  
Pitting Corrosion Resistance ◽  
Super Martensitic Stainless Steel ◽  
The Difference ◽  
Made In

Purpose – The purpose of this study was to investigate the pitting resistance and assess the critical pitting temperature (CPT) of a super martensitic stainless steel, 00Cr13Ni5Mo2, made in China, considering especially the difference in the pitting corrosion resistance between the domestic super martensitic stainless steel and an imported one. Design/methodology/approach – Potentiodynamic sweep tests were applied to investigate the effects of four NaCl concentrations (weight per cent) of 1, 3.5, 9 and 17, and four testing temperatures of 30, 50, 75 and 90°C on the pitting resistance of the domestic super martensitic stainless steel in the presence of CO2. Potentiostatic sweep tests were utilized to determine the CPT. Furthermore, chemical immersion exposures, implemented according to the appropriate standard were used to evaluate the difference in the pitting corrosion resistance between the domestic super martensitic stainless steel and an imported one. In addition, the morphology of pits was analyzed using a scanning electron microscope. Finding – The pitting potential of the domestic super martensitic stainless steel decreased with an increase in NaCl concentration and temperature in the presence of CO2. The CPT of the domestic super martensitic stainless steel measured by potentiostatic polarization was 41.16°C. Two types of typical corrosion pits, closed pits formed at 35°C and open pits formed at 50°C, were observed. Furthermore, compared to the super martensitic stainless steel made in Japan, the domestic one was better in terms of pitting potential, corrosion rate and the density of the pits, but worse in terms of the depth of the pits, which may result in a risk of corrosion perforation of tubing and casings. Originality/value – The paper highlights that chloride ions, temperature and the presence of CO2 play an important role on the pitting resistance of super martensitic stainless steel.

Corrosion Resistance of Three 316 Stainless Steels

2014 ◽  
Vol 936 ◽  
pp. 1097-1101
Author(s):  
Jan Shu Lu ◽  
Qin Song Lu ◽  
Jin Xue
Keyword(s):  
Stainless Steel ◽  
Corrosion Resistance ◽  
Stainless Steels ◽  
316L Stainless Steel ◽  
Advanced Material ◽  
Good Corrosion Resistance ◽  
Corrosion Rates ◽  
The Difference

316L stainless steel is a well known advanced material for its good corrosion resistance in many aggressive situations. As the quality of different manufacturer of the stainless steel may vary in some degree, this paper studied the corrosion resistances of three 316L stainless steels which supplied by three manufacturers. The results show that the difference of the corrosion rates of the three 316L stainless steels in 5% H2SO4 or 3.5%NaCl solutions is one time in quantity. The reasons for the difference can be explained by compositional and metallographic factors.

scholarly journals The Difference of Corrosion Behavior in Initial Period for the Hot-Rolled and Cold-Rolled 2205 Duplex Stainless Steel

2018 ◽  
Author(s):  
Tao Gao ◽  
Jian Wang ◽  
Qi Sun ◽  
Peide Han
Keyword(s):  
Stainless Steel ◽  
Corrosion Resistance ◽  
Duplex Stainless Steel ◽  
Sigma Phase ◽  
Aging Treatment ◽  
Rolled Material ◽  
2205 Duplex Stainless Steel ◽  
Cold Rolled ◽  
The Difference ◽  
Hot Rolled

The precipitate phases often play an important influence on the corrosion resistance of 2205 Duplex stainless steel (DSS). In the presented paper, the microstructure and corrosion resistance in the hot-rolled and cold-rolled 2205 DSS aging for different time at 850 °C was investigated by XRD, SEM and potentiodynamic polarization. It has been found that the Chi(χ) phase and Sigm(σ) phase were precipitated in turn after aging treatment of hot-rolled and cold-rolled materials, but the precipitate amount in cold-rolled material is much more than that of hot-rolled samples. The corrosion resistance of the solution-annealed cold-rolled material is similar to the hot-rolled material, but the corrosion resistance of cold-rolled material with precipitate is weaker than that of hot-rolled material after aging treatment. Pitting initiates preferentially in the Cr-depleted region from σ phase in aged hot-rolled 2205, and severe selective corrosion occurs on sigma/ferrite interfaces aged for a long aged lime. However, the initiation of pitting corrosion may take place at the phase boundary, defect and martensite in the aged cold-rolled 2205. The σ phase is further selectively dissolved by electrochemical method to investigate the difference of microstructure and corrosion behavior in hot-rolled and cold-rolled 2205 duplex stainless steel.

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