scholarly journals Self-heating of metastable 304L austenitic stainless steel under cyclic loading: Influence of initial martensite volume fraction, testing temperature and pre-strain

2020 ◽  
Vol 151 ◽  
pp. 103596
Author(s):  
Behnaz Amini ◽  
Younes Demmouche ◽  
Mahmoud Barati ◽  
Guillaume Helbert ◽  
Shabnam Arbab Chirani ◽  
...  
Keyword(s):  
Stainless Steel ◽  
Cyclic Loading ◽  
Austenitic Stainless Steel ◽  
Volume Fraction ◽  
Testing Temperature ◽  
Martensite Volume Fraction ◽  
Self Heating

Corrosion of 310S Austenitic Stainless Steel in Simulated Rocket Combustion Gas

2018 ◽  
Vol 765 ◽  
pp. 155-159
Author(s):  
Tosapolporn Pornpibunsompop ◽  
Purit Thanakijkasem
Keyword(s):  
Stainless Steel ◽  
Austenitic Stainless Steel ◽  
Testing Temperature ◽  
Chemical Information ◽  
Metal Chlorides ◽  
Internal Corrosion ◽  
Combustion Gas ◽  
Wet Condition ◽  
External Corrosion ◽  
Peeling Off

High temperature corrosion of 310S austenitic stainless steel in simulated rocket combustion gas at 900 degree Celsius was investigated and discussed in this paper. 310S austenitic stainless steel was chosen because it was used for building some components of a rocket launcher. The corrosive atmosphere was prepared by mixing of hydrochloric acid and distilled water with 5.5 mole per liter then, boiling that solution and feeding into a corrosion testing chamber. The chamber was set up at 900 degree Celsius with duration 210 hrs. After testing, the corroded specimen was microscopically characterized by OM and SEM/EDS techniques. The corrosion layer was classified into three main sublayers: peeling-off scale, external corrosion sublayer, and internal corrosion sublayer. The local chemical information was analyzed by XRD (in case of peeling-off scale) and SEM/EDS (in case of external and internal corrosion sublayers). The peeling off scale mainly comprised Fe2O3and Fe21.3O32ferrous oxides because they needed much oxygen consumption to exist. In case of external and internal sublayers, there were a lot of pore tunnels and corrosion products. Chlorine and/or hydrogen chloride would penetrate through a passive film and, then, metal chlorides was formed on both external and internal corrosion sublayers. Metal chlorides would volatile because of their lower evaporation temperature than the testing temperature. Moreover, they were oxidized by oxygen in wet condition and resulted metal oxides mostly remaining on the external corrosion sublayer.

Magnetic Characterization of SUS316L Deformed by High Pressure Torsion

2011 ◽  
Vol 239-242 ◽  
pp. 1300-1303
Author(s):  
Hong Cai Wang ◽  
Minoru Umemoto ◽  
Innocent Shuro ◽  
Yoshikazu Todaka ◽  
Ho Hung Kuo
Keyword(s):  
Plastic Deformation ◽  
High Pressure ◽  
Stainless Steel ◽  
Phase Transformation ◽  
Austenitic Stainless Steel ◽  
Volume Fraction ◽  
High Pressure Torsion ◽  
Austenitic Matrix ◽  
Magnetic Characterization

SUS316L austenitic stainless steel was subjected to severe plastic deformation (SPD) by the method of high pressure torsion (HPT). From a fully austenitic matrix (γ), HPT resulted in phase transformation from g®a¢. The largest volume fraction of 70% a¢ was obtained at 0.2 revolutions per minute (rpm) while was limited to 3% at 5rpm. Pre-straining of g by HPT at 5rpm decreases the volume fraction of a¢ obtained by HPT at 0.2rpm. By HPT at 5rpm, a¢®g reverse transformation was observed for a¢ produced by HPT at 0.2rpm.

Effects of Deformation Mode on Resistivity Curve Used for Estimating Martensite Induced in Stainless Steel

2010 ◽  
Vol 638-642 ◽  
pp. 2992-2997 ◽  
Author(s):  
Hidefumi Date
Keyword(s):  
Stainless Steel ◽  
Austenitic Stainless Steel ◽  
Linear Relation ◽  
Volume Fraction ◽  
Tensile Deformation ◽  
Deformation Mode ◽  
Transformation Process ◽  
Martensite Formation ◽  
Austenitic Phase ◽  
Ε Phase

The martensite induced in three types of austenitic stainless steel, which indicate the different stability of the austenitic phase (γ), were estimated by the resistivity measured during the tensile deformation or compressive deformation at the temperatures 77, 187 and 293 K. The resistivity curves were strongly dependent on the deformation mode. The volume fraction of the martensite (α’) was also affected by the deformation mode. The ε phase, which is the precursor of the martensite and is induced from the commencement of the deformation, decreased the resistivity. However, lots of defects generated by the deformation-induced martensite increased the resistivity. The experimental facts and the results shown by the modified parallelepiped model suggested a complicated transformation process depending on each deformation mode. The results shown by the model also suggested a linear relation between the resistivity and the martensite volume at the region of the martensite formation. The fact denoted that the resistivity is mostly not controlled by the austenite, ε phase and martensite, but by the defects induced due to the deformation-induced martensite.

Effect of Hydrogenated Water on Fatigue Crack Growth for Austenitic Stainless Steel in Simulated BWR Water Environment

2004 ◽  
Author(s):  
Li H. Wang
Keyword(s):  
Stainless Steel ◽  
Fatigue Crack ◽  
Cyclic Loading ◽  
Austenitic Stainless Steel ◽  
Fatigue Crack Growth ◽  
Water Chemistry ◽  
Crack Growth ◽  
Growth Stage ◽  
Transgranular Fracture ◽  
Cyclic Loading Condition

Fatigue crack growth rates (FCGR) of sensitized austenitic stainless steel (SS) were measured in simulated BWR water at 288 °C using compact tension specimens under different cyclic loading modes, including saw-tooth, trapezoidal and constant loading pattern. This study tested sensitized SS in normal water chemistry (NWC) and hydrogen water chemistry (HWC) respectively, and attempted to clarify the effect of low electrochemical corrosion potential on the FCGR of sensitized stainless steel. Significant environment effects on FCGR of sensitized stainless steel were observed in both water chemistries when compared with air fatigue curve. The pronounced suppression effect of HWC on crack growth in statically sustained load was not observed in cyclic loading condition. ASME curve doesn’t seem to be conservative and could not bound all the FCGR data tested in this study. In contrast, all of the measured FCGR data were bound by the JSME disposition curve. PLEDGE model proposed by General Electric reasonably predicted the FCGR of sensitized SS in NWC, but underestimated the FCGR in HWC. ANL’s superposition model successfully estimated the FCGR measured in both water chemistries. The fractography exhibited transgranular fracture mode during the crack initiation and growth stage. No differences in the appearance of fracture surface were observed in HWC and NWC. Only in very high DO environments, the sensitized 304 SS exhibited the mixed mode of intergranular and transgranular during growth stage.

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.

Effect of martensite volume fraction on the mechanical behavior of an UNS S41003 dual-phase stainless steel

2020 ◽  
Vol 797 ◽  
pp. 140208
Author(s):  
Geraldo Lúcio de Faria ◽  
Leonardo Barbosa Godefroid ◽  
Isadora Pereira Nunes ◽  
José Carlos de Lacerda
Keyword(s):  
Stainless Steel ◽  
Mechanical Behavior ◽  
Volume Fraction ◽  
Dual Phase ◽  
Martensite Volume Fraction

Promoting Isothermal Martensite Formation by High Temperature Heat Treatments in a Precipitation Hardening Austenitic Stainless Steel

2011 ◽  
Vol 172-174 ◽  
pp. 166-171 ◽  
Author(s):  
David San Martín ◽  
Carlos García-Mateo
Keyword(s):  
Stainless Steel ◽  
Austenitic Stainless Steel ◽  
Precipitation Hardening ◽  
Volume Fraction ◽  
Solution Temperature ◽  
Continuous Heating ◽  
Martensite Formation ◽  
Delta Ferrite ◽  
Kinetic Measurements ◽  
Semi Empirical

This work investigates what phase transformations are taking place during a continuous heating as well as the influence of the solution temperature on the isothermal formation of martensite in a precipitation hardening semi-austenitic stainless steel. In previous studies in the stainless steel under investigation (12Cr-9Ni-4Mo-2Cu) only the isothermal mode of martensitic transformation has been experimentally detected. In this work it is shown that: 1) The AFtemperature is located around 1040 K; 2) The χ-phase present in the initial microstructure dissolves above ~1323 K; 3) above 1448 K the formation of delta ferrite is promoted at austenite grain boundaries; 4) the kinetics of isothermal martensite formation is strongly accelerated with increasing solution temperature. The kinetics has been monitored in-situ at room temperature by using high resolution dilatometry. A semi-empirical dilatometry model is used to convert the dilatometry signal into volume fraction of martensite transformed. The results are briefly compared with previous kinetic measurements under the influence of strong magnetic fields.

Phase Transformation and Annealing Behavior of SUS 304 Austenitic Stainless Steel Deformed by High Pressure Torsion

2010 ◽  
Vol 654-656 ◽  
pp. 334-337 ◽  
Author(s):  
Innocent Shuro ◽  
Minoru Umemoto ◽  
Yoshikazu Todaka ◽  
Seiji Yokoyama
Keyword(s):  
High Pressure ◽  
Stainless Steel ◽  
Phase Transformation ◽  
Austenitic Stainless Steel ◽  
Volume Fraction ◽  
High Pressure Torsion ◽  
Two Phase ◽  
Annealing Behavior ◽  
304 Austenitic Stainless Steel ◽  
Deformed State

SUS 304 austenitic stainless steel was subjected to severe plastic deformation (SPD) by the method of high pressure torsion (HPT). From a fully austenitic matrix (γ), HPT resulted in phase transformation to give a two phase structure of austenite (γ) and martensite (α') by the transformation γα'. The phase transformation was accompanied by an increase in hardness (Hv) from 1.6 GPa in the as annealed form to 5.4 GPa in the deformed state. Subsequent annealing in temperature range 250oC to 450oC resulted in an increase in both α' volume fraction and hardness (6.4 GPa). Annealing at 600oC resulted in a decrease in α' volume fraction hardness.

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