Effects of Aging Precipitates on the Mechanical and Corrosion Resistance Properties of 18Cr-18Mn-2Mo-0.96N Super High Nitrogen Austenitic Stainless Steel

2013 ◽  
Vol 395-396 ◽  
pp. 284-288 ◽  
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 ◽  
Aging Time ◽  
Volume Fraction ◽  
Charpy Impact ◽  
Optical Microscope ◽  
High Nitrogen ◽  
Effects Of Aging ◽  
The Impact

This paper investigates the effects of aging precipitates on the mechanical and corrosion resistance properties of 18Cr-18Mn-2Mo-0.96N super high nitrogen austenitic stainless steel (HNS) through Vickers hardness, Charpy impact, tensile and electrical chemical methods. The probable affected mechanism is discussed by optical microscope (OM) and transmission electron microscopy (TEM). The results are presented as follow: the initial TTP curve with 0.05% precipitates volume fraction presents C type which has a nose temperature at 850°C with an incubation period for 60s. The precipitates increase with prolonging aging time to 40%. The HV results of aged HNS present firstly decrease then increase, the relevant yield strength firstly increase then decrease with increasing the aging time. Meanwhile, the impact energy, ultimate tensile strength and elongation are deteriorated significantly because of the formation and growth of cellular Cr2N and χ phase with concomitant increased amount of intergranular Cr2N. The IGC susceptibility increases and the pitting corrosion potentials decrease because of the Cr, N and Mo depletion through the formation of intergranular, cellular Cr2N and intermetallic χ precipitates by aging treatments.

Investigation on Impact Energy of S30403 Austenitic Stainless Steel at Different Temperatures

2016 ◽  
Vol 138 (3) ◽  
Author(s):  
Zhiwei Chen ◽  
Caifu Qian ◽  
Guoyi Yang ◽  
Xiang Li
Keyword(s):  
Stainless Steel ◽  
Austenitic Stainless Steel ◽  
Cross Section ◽  
Test Temperature ◽  
Impact Energy ◽  
Welded Joint ◽  
Charpy Impact ◽  
Base Plate ◽  
Charpy Impact Energy ◽  
The Impact

In this paper, a series of impact tests on S30403 austenitic stainless steel at 20/−196/−269 °C were performed to determine the effects of cryogenic temperatures on the material properties. Both base plate and welded joint including weld and heat-affected zone were tested to obtain the Charpy impact energy KV2 and lateral expansion rate at the cross section. It was found that when the test temperature decreased from 20 °C to −196 °C or −269 °C, both the Charpy impact energy KV2 at the base plate and welded joint decreased drastically. Specifically, the impact energy KV2 decreased by 20% at the base plate and decreased by 54% at the welded joint from 20 °C to −196 °C, but the impact energy of base plate and welded joint did not decrease, even increased when test temperature decreased from −196 °C to −269 °C. Either at 20 °C or −196 °C, the impact energy KV2 with 5 × 10 × 55 mm3 specimens was about 0.53 times that of the 7.5 × 10 × 55 mm3 specimens, much lower than 2/3, the ratio of two specimens’ cross section areas.

scholarly journals Surface Modification of a Nickel-Free Austenitic Stainless Steel by Low-Temperature Nitriding

Metals ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 1845
Author(s):  
Francesca Borgioli ◽  
Emanuele Galvanetto ◽  
Tiberio Bacci
Keyword(s):  
Stainless Steel ◽  
Corrosion Resistance ◽  
Austenitic Stainless Steel ◽  
Low Temperature ◽  
Stainless Steels ◽  
Volume Fraction ◽  
Surface Hardness ◽  
Austenitic Stainless Steels ◽  
Surface Layers ◽  
Modified Surface

Low-temperature nitriding allows to improve surface hardening of austenitic stainless steels, maintaining or even increasing their corrosion resistance. The treatment conditions to be used in order to avoid the precipitation of large amounts of nitrides are strictly related to alloy composition. When nickel is substituted by manganese as an austenite forming element, the production of nitride-free modified surface layers becomes a challenge, since manganese is a nitride forming element while nickel is not. In this study, the effects of nitriding conditions on the characteristics of the modified surface layers obtained on an austenitic stainless steel having a high manganese content and a negligible nickel one, a so-called nickel-free austenitic stainless steel, were investigated. Microstructure, phase composition, surface microhardness, and corrosion behavior in 5% NaCl were evaluated. The obtained results suggest that the precipitation of a large volume fraction of nitrides can be avoided using treatment temperatures lower than those usually employed for nickel-containing austenitic stainless steels. Nitriding at 360 and 380 °C for duration up to 5 h allows to produce modified surface layers, consisting mainly of the so-called expanded austenite or gN, which increase surface hardness in comparison with the untreated steel. Using selected conditions, corrosion resistance can also be significantly improved.

scholarly journals Effects of High Temperature Aging Treatment on the Microstructure and Impact Toughness of Z2CND18-12N Austenitic Stainless Steel

Metals ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 1691
Author(s):  
Hui Zhang ◽  
Yanfeng Liu ◽  
Xian Zhai ◽  
Wenkai Xiao
Keyword(s):  
Stainless Steel ◽  
Austenitic Stainless Steel ◽  
Impact Toughness ◽  
Charpy Impact ◽  
Aging Treatment ◽  
Fracture Morphology ◽  
Charpy Impact Test ◽  
Scattered Electron ◽  
Σ Phase ◽  
Effects Of Aging

During the casting cooling process or the forging process, austenitic stainless steel will remain at around 800 °C for some time. During this period, precipitate particle behaviors in austenitic stainless steel (containing ferrite) will cause a reduction in ductility, which can lead to material cracking. In this study, the effects of aging at 800 °C on the microstructure, impact toughness and microhardness of Z2CND18-12N austenitic stainless steel were systematically investigated. The precipitation processes of the χ and σ phases were characterized by color metallography and back scattered electron (BSE) signals. The toughness was investigated by the Charpy impact test. After the aging treatment, the χ and σ phases precipitated successively in the ferrite, and as the aging duration increased, the χ-phase dissolved and the σ-phase precipitated along the austenite grain boundaries. These all lead to a decrease in toughness and an increase in microhardness. Finally, the relationship between fracture morphology and aging time is discussed herein, and a crack mechanism is given.

OUTOKUMPU FORTA H500

Alloy Digest ◽  
2018 ◽  
Vol 67 (2) ◽  
Keyword(s):  
Stainless Steel ◽  
Corrosion Resistance ◽  
Austenitic Stainless Steel ◽  
Physical Properties ◽  
Nitrogen Content ◽  
Tensile Properties ◽  
Work Hardening ◽  
Research Centre ◽  
High Nitrogen Content ◽  
High Nitrogen

Abstract Forta H500 is an austenitic stainless steel in which manganese replaces some of the nickel. Its high-nitrogen content adds strength. Grades Forta H800 and H1000 can be derived from the same composition by changing the degree of work hardening. This datasheet provides information on physical properties, hardness, elasticity, and tensile properties. It also includes information on corrosion resistance as well as forming and joining. Filing Code: SS-1278. Producer or source: Outokumpu Stainless AB, Avesta Research Centre.

Aging Precipitation Evolving Process and its Effects on Mechanical Properties of 0Cr21Ni6Mn9N Austenitic Stainless Steel

2015 ◽  
Vol 816 ◽  
pp. 255-261
Author(s):  
Na Yun Jiang ◽  
Fu Shun Liu
Keyword(s):  
Mechanical Properties ◽  
Stainless Steel ◽  
Electron Microscope ◽  
Austenitic Stainless Steel ◽  
Aging Time ◽  
Solution Treatment ◽  
Optical Microscope ◽  
Precipitation Process ◽  
Second Phase ◽  
Aging Precipitation

The solution treatment (ST) and the the second phase morphology changing duing the aging precipitation process of 0Cr21Ni6Mn9N austenitic stainless steel were investigated using optical microscope (OM), X-ray diffraction (XRD), scanning electron microscope (SEM) with EDS and transmission electron microscope (TEM). The results showed that the precipitation phase was Cr2N which initially nucleated along austenitic grain boundaries and then grew towards into the inner grains in strip morphology. Also, with the longer aging time the proportion of Cr2N increased. The mechanical properties of alloys with and without the presence of the precipitation Cr2N were also studied. It was observed that due to the exiting of the precipitation Cr2N, the strength of 2169N stainless steel reduced during a certain range of aging time, and then improved when the aging time reached to 48h, while the elongation decreased thoroughly.

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 Charpy Impact Behavior of a Novel Stainless Steel Powder Wire Mesh Composite Porous Plate

Materials ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 2924
Author(s):  
Chaozhong Li ◽  
Zhaoyao Zhou
Keyword(s):  
Stainless Steel ◽  
Impact Toughness ◽  
Volume Fraction ◽  
Sintering Temperature ◽  
Porous Plate ◽  
Charpy Impact ◽  
Wire Mesh ◽  
304 Stainless Steel ◽  
Powder Wire ◽  
The Impact

A novel powder wire mesh composite porous plate (PWMCPP) was fabricated with 304 stainless steel powders and wire mesh as raw materials by vacuum solid-state sintering process using self-developed composite rolling mill of powder and wire mesh. The effects of different mesh volume fractions, mesh diameters, and sintering temperatures on the pore structure and Charpy impact properties of PWMCPPs were studied. The results show that PWMCPPs have different shapes and sizes of micropores. Impact toughness of PWMCPPs decreases with increasing wire mesh volume fraction, and increases first and then decreases with increasing wire mesh diameter, and increases with increasing sintering temperature. Among them, the sintering temperature has the most obvious effect on the impact toughness of PWMCPPs, when the sintering temperature increased from 1160 °C to 1360 °C, the impact toughness increased from 39.54 J/cm2 to 72.95 J/cm2, with an increased ratio of 84.5%. The tearing between layers, the fracture of the metallurgical junction, and the fracture of wire mesh are the main mechanisms of impact fractures of the novel PWMCPPs.

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