The Effect of Surface Self-Nanocrystallization on Low-Temperature Gas Carburization for AISI 316L Steel

2019 ◽  
Vol 795 ◽  
pp. 137-144
Author(s):  
Zhe Liu ◽  
Ya Wei Peng ◽  
Jian Ming Gong ◽  
Chao Ming Chen
Keyword(s):  
Stainless Steel ◽  
Elastic Modulus ◽  
Austenitic Stainless Steel ◽  
Low Temperature ◽  
Surface Hardness ◽  
Electron Probe Micro Analyzer ◽  
Gas Carburizing ◽  
316L Steel ◽  
Negative Effect ◽  
Effect Of Surface

In this work, the effect of surface self-nanocrystallization on low-temperature gas carburizing for AISI316L austenitic stainless steel has been studied. The surface ultrasonic rolling processing (SURP) was used to prepare nanostructured surface layers, and then the un-SURP and SURP samples were treated by LTGC at 470 °C for 10 h, 20 h and 30 h. In order to analyze the effect of surface self-nanocrystallization on low-temperature gas carburizing, optical microscopy (OM), atomic force microscope (AFM), scanning electron probe micro-analyzer (EPMA) and nano-indentation analyzer were used. The results show depth of SURP-induced plastic deformation layer was about 330 μm. Meanwhile, the surface hardness and elastic modulus were increased but the surface roughness decreased obviously after SURP. After low-temperature gas carburizing, according to the results of the thickness, carbon concentration, nano-hardness and elastic modulus of the carburized layer, the conclusion is that surface self-nanocrystallization carried by SURP has a negative effect on the low-temperature gas carburizing for AISI316L austenitic stainless steel and with the increase of carburizing time, the greater the adverse effect on carburizing.

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.

Plasma Carburizing and Post-Treatment of Austenitic Stainless Steel

2011 ◽  
Vol 228-229 ◽  
pp. 114-118 ◽  
Author(s):  
Shao Mei Zheng ◽  
Cheng Zhao
Keyword(s):  
Stainless Steel ◽  
Corrosion Resistance ◽  
Austenitic Stainless Steel ◽  
Low Temperature ◽  
Surface Hardness ◽  
Post Treatment ◽  
Surface Appearance ◽  
Black Film ◽  
316L Austenitic Stainless Steel ◽  
Plasma Carburizing

Plasma carburizing of AISI 316L austenitic stainless steel was carried out at low temperature to improve the surface hardness without degradation of its corrosion resistance. And the post-treatment, namely electrochemical surface brightening process was carried out to clear away a layer of thin black film on the plasma carburized samples and improve the surface quality of the hardened stainless steel. The surface appearance, roughness, microstructures, microhardness and corrosion resistance of the samples before and after brightening were analyzed and compared. Experimental results of plasma carburizing at low temperature showed that high-quality hardened layers can be produced at the appropriate process parameters.The electrochemical brightening process can be used as a post-treatment to restore the original color and further improve the corrosion resisitance of the plasma carburized stainless steel.

scholarly journals Application of Active-Screen Plasma Nitriding to an Austenitic Stainless Steel Small-Diameter Thin Pipe

Metals ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 366
Author(s):  
Kenzo Sumiya ◽  
Shinkichi Tokuyama ◽  
Akio Nishimoto ◽  
Junichi Fukui ◽  
Atsushi Nishiyama
Keyword(s):  
Stainless Steel ◽  
Corrosion Resistance ◽  
Austenitic Stainless Steel ◽  
Low Temperature ◽  
Plasma Nitriding ◽  
Small Diameter ◽  
Surface Hardness ◽  
Bending Rigidity ◽  
Nitriding Temperature ◽  
Active Screen Plasma Nitriding

Low-temperature active-screen plasma nitriding (ASPN) was applied in this study to improve the bending rigidity and corrosion resistance of a small-diameter thin pipe composed of austenitic stainless steel (SUS 304). The inner and outer diameters of the pipe were ϕ0.3 and ϕ0.4 mm, respectively, and the pipe length was 50 mm. The jig temperature was measured using a thermocouple and was adopted as the nitriding temperature because measuring the temperature of a small-diameter pipe is difficult. The nitriding temperature was varied from 578 to 638 K to investigate the effect of temperature on the nitriding layer and mechanical property. The nitriding layer thickness increased with an increase in nitriding temperature, reaching 15 μm at 638 K. The existence of expanded austenite (S phase) in this nitriding layer was revealed using the X-ray diffraction pattern. Moreover, the surface hardness increased with the nitriding temperature and took a maximum value of 1100 HV above 598 K. The bending load increased with an increase in the nitriding temperature in relation to the thicker nitriding layer and increased surface hardness. The nitrided samples did not corrode near the center, and corrosion was noted only near the tip at high nitriding temperatures of 618 and 638 K in a salt spray test. These results indicated that the bending rigidity of the small-diameter thin pipe composed of austenitic stainless steel was successfully improved using low-temperature ASPN while ensuring corrosion resistance.

Plasma Carburizing of AISI 316L Austenitic Stainless Steel at Low Temperature

2011 ◽  
Vol 214 ◽  
pp. 564-568 ◽  
Author(s):  
Shao Mei Zheng ◽  
Cheng Zhao
Keyword(s):  
Stainless Steel ◽  
Corrosion Resistance ◽  
Austenitic Stainless Steel ◽  
Low Temperature ◽  
Surface Hardness ◽  
Hardened Layer ◽  
Aisi 316L ◽  
Chromium Carbides ◽  
316L Austenitic Stainless Steel ◽  
Plasma Carburizing

Plasma carburizing of AISI 316L austenitic stainless steel was carried out at low temperature to improve the surface hardness without degradation of its corrosion resistance. The microstructure, surface hardness, phase composition and corrosion property of the hardened layer were analyzed. The experimental results show that high-quality hardened layers can be produced at the carburizing temperatures between 673 K and 773 K, which have not only high surface hardness and wear resistance, but also good corrosion resistance. All of the hardened layers display a precipitation-free structure or Sc phase. The chromium carbides began to precipitate in the hardened layer as soon as the carburizing temperature is higher than 823 K. The precipitation of chromium carbides will lead to deterioration in corrosion resistance of the hardened stainless steel.

scholarly journals Characteristic of Low Temperature Carburized Austenitic Stainless Steel

2018 ◽  
Vol 299 ◽  
pp. 012048
Author(s):  
Istiroyah ◽  
M A Pamungkas ◽  
G Saroja ◽  
M Ghufron ◽  
A M Juwono
Keyword(s):  
Stainless Steel ◽  
Austenitic Stainless Steel ◽  
Low Temperature
Sign in / Sign up

Export Citation Format

Share Document