Effect of CH4 Content on the Characteristics of Surface Layers of Low Temperature Plasma Nitrided 2205 Duplex Stainless Steel

2016 ◽  
Vol 879 ◽  
pp. 1074-1079 ◽  
Author(s):  
Insup Lee
Keyword(s):  
Stainless Steel ◽  
Corrosion Resistance ◽  
Duplex Stainless Steel ◽  
Layer Thickness ◽  
Plasma Nitriding ◽  
Surface Hardness ◽  
S Phase ◽  
Temperature Plasma ◽  
Phase Layer ◽  
2205 Duplex Stainless Steel

Plasma nitriding was performed on the 2205 duplex stainless steel samples at 400 V with a gas mixture of H2 and N2 for 15 hrs with changing N2 percent, temperature and adding various amounts of CH4. After treatment the behavior of the surface layer was investigated by optical microscopy, X-ray diffraction, GDOES analysis and micro-hardness testing. Potentiodynamic polarization test was also used to evaluate the corrosion resistance of the samples. With increasing both N2 percentage from 10% to 25% and nitriding temperature from 370°C to 430°C, the thickness of nitrogen expanded austenite (S-phase) layer and surface hardness increase up to 16 μm and 1200 HV0.1 at the treatment temperature of 430°C with 25% N2, but decreases the corrosion resistance due to the formation of Cr2N and γ`(Fe, Cr)4N. Thus in order to further increase the thickness of S-phase layer and the corrosion resistance, the influence of adding various amount of CH4 (1% to 5%) in the nitriding atmosphere was investigated. Adding CH4 in the nitriding atmosphere increases the layer thickness compared with that of nitrided sample. The highest thickness can be obtained at 1 % CH4, but addition of CH4 beyond 1 % slightly decreases the layer thickness. Moreover, when nitrided at 400°C with 10% N2 and 5% CH4 content, best corrosion behavior is obtained which also have around 10 μm layer thickness and about 870 HV0.1 surface hardness.

Effect of Gas Content and Treatment Temperature on the Characteristic of Surface Layers of Low Temperature Plasma Nitrided 316L Austenitic Stainless Steel

2018 ◽  
Vol 941 ◽  
pp. 1784-1789
Author(s):  
Insup Lee
Keyword(s):  
Stainless Steel ◽  
Corrosion Resistance ◽  
Surface Hardness ◽  
Treatment Temperature ◽  
S Phase ◽  
Gas Content ◽  
Low Temperature Plasma ◽  
Temperature Plasma ◽  
Phase Layer ◽  
316L Austenitic Stainless Steel

The effect of gas content and treatment temperature on the surface characteristics of hardened layers of low temperature plasma nitrided 316L Austenitic Stainless Steel was investigated. The process was performed at fixed processing time at 15Hr and changing the N2content from 10% to 25%, changing the treatment temperature from 370 °C to 430 °C. The surface hardness and the thickness of expanded austenite (S-Phase) layer increase with increasing both temperature and nitrogen content. At 430°C processing temperature and 25% N2content, the S-phase layer thickness increased up to 13 μm and surface hardness increased about 3.5 times of that of untreated sample which is 880 HV0.1(before treatment 250HV0.1hardness). However, the XRD pattern of the this sample shows the presence of γ'-(Fe,Cr)4N precipitation on the surface which is the reason for the increased corrosion current density that results in increased corrosion rate. Thus the corrosion resistance degrades and presents even worst behavior comparing that of before treatment. Therefore, for increasing the corrosion behavior, further research was conducted by fixing the N2content at 10% with changing the CH4content from 0% to 5%. The best results were found when treated at 430°C with 5% CH4content. At this condition the S-phase thickness increase to around 17μm and surface hardness (980 HV0.1) is improved about 3.9 times of the hardness of untreated one. This sample also showed superior corrosion resistance than the other treated samples and the untreated one due to much higher pitting potential.

EFFECT OF PLASMA NITRIDING TEMPERATURES ON CHARACTERISTICS OF AISI 201 AUSTENITIC STAINLESS STEEL

2016 ◽  
Vol 23 (01) ◽  
pp. 1550084 ◽  
Author(s):  
YUXIN GAO ◽  
SHAOMEI ZHENG
Keyword(s):  
Stainless Steel ◽  
Corrosion Resistance ◽  
Austenitic Stainless Steel ◽  
Plasma Nitriding ◽  
Nitrided Layer ◽  
Surface Hardness ◽  
Electrochemical Corrosion ◽  
S Phase ◽  
Phase Identification ◽  
Phase Layer

Samples of AISI 201 austenitic stainless steel were produced by plasma nitriding at 350[Formula: see text]C, 390[Formula: see text]C, 420[Formula: see text]C, 450[Formula: see text]C and 480[Formula: see text]C for 5[Formula: see text]h. Systematic characterization of the nitrided layer was carried out in terms of micrograph observations, phase identification, chemical composition depth profiling, surface microhardness measurements and electrochemical corrosion tests. The results show that the surface hardness and the layer thickness increased with increasing temperature. XRD indicated that a single S-phase layer was formed during low temperature ([Formula: see text][Formula: see text]420[Formula: see text]C), while Cr2N or CrN phase was formed besides S-phase when nitrided at 450[Formula: see text]C and 480[Formula: see text]C. The specimen treated at 390[Formula: see text]C presents a much enhanced corrosion resistance compared to the untreated substrate. The corrosion resistance deteriorated for samples treated above 450[Formula: see text]C due to the formation of chromium nitrides.

Low-Temperature Plasma Surface Modification of Medical Grade Austenitic Stainless Steel to Combat Wear and Corrosion

2008 ◽  
Vol 373-374 ◽  
pp. 296-299 ◽  
Author(s):  
Joseph P. Buhagiar ◽  
Han Shan Dong
Keyword(s):  
Stainless Steel ◽  
Corrosion Resistance ◽  
Austenitic Stainless Steel ◽  
Low Temperature ◽  
S Phase ◽  
Low Temperature Plasma ◽  
Temperature Plasma ◽  
Phase Layer ◽  
Wear And Corrosion ◽  
Medical Grade

The novel low temperature plasma alloying technique that simultaneously introduces both nitrogen and carbon into the surface of austenitic stainless steel has been used in the past to create a hybrid N-C S-Phase. This S-Phase layer boasts of high hardness and wear resistance without any detriment to corrosion resistance. In this study, the afore mentioned hybrid N-C S-Phase was successfully implemented in the surface of two medical grade austenitic stainless steels: ASTM F138 and F1586. At an optimum process temperature of 430°C a very hard, 20μm precipitate-free S-Phase layer was created. Anodic Polarization tests in Ringer’s solution showed that the corrosion resistance of this layer was similar to that of the untreated alloys. Both dry-wear and corrosion-wear (Ringer’s) behaviour of the surface treated alloys showed an improvement of more than 350% and 40% respectively when compared to the untreated material.

scholarly journals Combating the Tribo-Corrosion of LDX2404 Lean Duplex Stainless Steel by Low Temperature Plasma Nitriding

Lubricants ◽  
2018 ◽  
Vol 6 (4) ◽  
pp. 93 ◽  
Author(s):  
Xiaoying Li ◽  
Wenbo Dou ◽  
Linhai Tian ◽  
Hanshan Dong
Keyword(s):  
Stainless Steel ◽  
Low Temperature ◽  
Duplex Stainless Steel ◽  
Plasma Nitriding ◽  
Nitrided Layer ◽  
Surface Hardness ◽  
Electrochemical Corrosion ◽  
Treatment Temperature ◽  
Temperature Plasma ◽  
Lean Duplex Stainless Steel

A lean duplex stainless steel, LDX2404, was DC plasma nitrided under a range of treatment conditions. The microstructure characterisation evaluation of the treated samples revealed that a dense, super-hard surface layer can be produced by low-temperature (<450 °C) plasma treatments. The original austenite phase became S-phase and the ferrite phase was supersaturated with nitrogen and ε-Fe3N nitride precipitated from it. When plasma nitriding was carried out at above 450 °C, chromium nitrides precipitated in the surface nitrided layer. Compared to the untreated samples, the surface hardness of the lean duplex stainless steel (DSS) is increased up to four times. The dry wear resistance increased when increasing the treatment temperature. In contrast, the low-temperature treated samples showed the best performance in the electrochemical corrosion and corrosion-wear tests; the performance of the high temperature (>450 °C) plasma nitrided samples was found to be significantly worse than that of the untreated material.

scholarly journals Formation and Properties of Nitrocarburizing S-Phase on AISI 316L Stainless Steel-Based WC Composite Layers by Low-Temperature Plasma Nitriding

Metals ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 1538
Author(s):  
Shinichiro Adachi ◽  
Takuto Yamaguchi ◽  
Nobuhiro Ueda
Keyword(s):  
Stainless Steel ◽  
Corrosion Resistance ◽  
Low Temperature ◽  
Plasma Nitriding ◽  
S Phase ◽  
Low Temperature Plasma ◽  
Temperature Plasma ◽  
Composite Layers ◽  
Aisi 316 ◽  
Aisi 316 L

Stainless steel-based WC composite layers fabricated by a laser cladding technique, have strong mechanical strength. However, the wear resistance of WC composite layers is not sufficient for use in severe friction and wear environments, and the corrosion resistance is significantly reduced by the formation of secondary carbides. Low-temperature plasma nitriding and carburizing of austenitic stainless steels, treated at temperatures of less than 450 °C, can produce a supersaturated solid solution of nitrogen or carbon, known as the S-phase. The combined treatment of nitriding and carburizing can form a nitrocarburizing S-phase, which is characterized by a thick layer and superior cross-sectional hardness distribution. During the laser cladding process, free carbon was produced by the decomposition of WC particles. To achieve excellent wear and corrosion resistance, we attempted to use this free carbon to form a nitrocarburizing S-phase on AISI 316 L stainless steel-based WC composite layers by plasma nitriding alone. As a result, the thick nitrocarburizing S-phase was formed. The Vickers hardness of the S-phase ranged from 1200 to 1400 HV, and the hardness depth distribution became smoother. The corrosion resistance was also improved through increasing the pitting resistance equivalent numbers due to the nitrogen that dissolved in the AISI 316 L steel matrix.

Surface Modification of SS2205 Duplex Stainless Steel by Plasma Nitriding at Anodic Potential

2014 ◽  
Vol 881-883 ◽  
pp. 1263-1267 ◽  
Author(s):  
Shuo Zhao ◽  
Liang Wang ◽  
Jiu Jun Xu ◽  
Y. Shan
Keyword(s):  
Stainless Steel ◽  
Wear Resistance ◽  
Corrosion Resistance ◽  
Low Temperature ◽  
Duplex Stainless Steel ◽  
Plasma Nitriding ◽  
Nitrided Layer ◽  
Surface Hardness ◽  
Anodic Potential ◽  
Wear And Corrosion

The duplex stainless steel has better pitting corrosion resistance but lacks of hardness and wear resistance. Therefore, the low temperature nitriding treatment can be used to increase its hardness and wear resistance or to gain more perfect corrosion resistance. The plasma nitriding of SS2205 stainless steel was carried out at temperatures from 693k to 753k for 4 hours at anodic potential. The nitrided samples were analyzed by optical microscopy, X-ray diffraction, SEM-EDX analysis, microhardness testing, wear and corrosion evaluation. The XRD analysis of all treated samples showed that the nitrogen-expanded austenite phase was formed. Both α and γ phase of the substrate were transformed into γNduring plasma nitriding. Observing the nitrided layers formed on α and γ phase, the ones situated in the austenite were thinner than the ones in the ferrite. This phenomenon was more evident at low temperature, which confirmed that the nitrogen has a higher diffusion rate in the ferrite during plasma nitriding treatment. The surface hardness of nitrided layer was increased with the nitriding temperature. The highest hardness value obtained in this experiment was about 1300 HV0.05which was 4 times as the original sample (380 HV0.05). Furthermore, through the wear and corrosion property tests, it was shown that anodic plasma nitriding improved the wear resistance and corrosion resistance of the duplex stainless steel.

Microstructural evolution and mechanical integrity relationship of dissimilar metal welding between 2205 duplex stainless steel and composite bimetallic plates

2021 ◽  
pp. 095440622110036
Author(s):  
Changqing Ye ◽  
Weiguo Zhai ◽  
Guangyao Lu ◽  
Qingsong Liu ◽  
Liang Ni ◽  
...  
Keyword(s):  
Stainless Steel ◽  
Corrosion Resistance ◽  
Weld Metal ◽  
Duplex Stainless Steel ◽  
Intergranular Corrosion ◽  
Thermal Cycle ◽  
Filler Metal ◽  
2205 Duplex Stainless Steel ◽  
Welding Thermal Cycle ◽  
Intergranular Corrosion Resistance

In this paper, shielded metal arc welding on the dissimilar joint between 2205 duplex stainless steel and composite bimetallic plates (304 L stainless steel/10CrNi3MoV steel) with a filler metal E2209 was performed. Furthermore, the microstructure, phase, mechanical properties and intergranular corrosion resistance of the joints were investigated and element distributions of the interfaces were characterized. The results show that austenite transformed to ferrite under the influence of welding thermal cycle, and then a large amount of ferrite appeared in heat affected zone (HAZ) of 2205 duplex stainless steel. Coarse bainite grains were formed in HAZ of the 10CrNi3MoV steel near the fusion line with high temperature welding thermal cycle. Fine granular bainite was also generated in HAZ of 10CrNi3MoV steel due to the relatively short exposure time to the active temperature of grain growth. Local peak temperature near the base 10CrNi3MoV steel was still high enough to recrystallize the 10CrNi3MoV steel to form partial-recrystallization HAZ due to phase change. The filler metal was compatible with the three kinds of base materials. The thickness of the elemental diffusion interfaces layers was about 100 µm. The maximum microhardness value was obtained in the HAZ of 2205 duplex stainless steel (287 ± 14 HV), and the minimum one appeared in HAZ of SS304L (213 ± 5 HV). The maximum tensile strength of the welded joint was about 670 ± 6 MPa, and the tensile specimens fractured in ductile at matrix of the composite bimetallic plates. The impact energy of the weld metal and HAZ of the 10CrNi3MoV steel tested at –20 °C were 274 ± 6 J and 308 ± 5 J, respectively. Moreover, the intergranular corrosion resistance of the weldment including 304 L stainless steel, weld metal, HAZs and 2205 duplex stainless steel was in good agreement with the functional design requirements of materials corrosion resistance.

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