Research of Microstructure and Properties of the 4Cr14Ni14W2Mo Steel with QPQ Salt-Bath Nitriding

2008 ◽  
Vol 373-374 ◽  
pp. 260-263 ◽  
Author(s):  
Guang Yao Xiong ◽  
Bo Lin He ◽  
Rui Zou
Keyword(s):  
Wear Resistance ◽  
Corrosion Resistance ◽  
Low Temperature ◽  
White Layer ◽  
Surface Hardness ◽  
Complex Salt ◽  
Salt Bath ◽  
Experimental Results ◽  
Process Time ◽  
High Production Rate

The wear-resistance, corrosion resistance, hardness can be greatly increased by using low temperature QPQ complex salt-bath treatment. And it is a new strengthening method without distortion in the treating process. The surface of 4Cr14Ni14W2Mo steel was treated using this method. The microstructure and depth of the treated surface for the steel were analyzed using SEM. The sliding wear resistance was tested on the M-2000 tester and the micro-hardness was tested using 401MVA microscopy hardness tester. The corrosion resistance was tested in the 5%NaCl water by using spraying method. The experimental results indicate that a certain depth of white layer and diffusion layer of the steel can be obtained by using low temperature QPQ complex salt-bath treatment. The nitriding compound layer with high hardness, superior wear resistance and stable microstructure, can also be obtained on the surface of the parts. The highest hardness in the surface is HV0.11012. The surface hardness is 2.8 times higher than that of inner part. The depth of white layer is from 10 to 12μm. The experimental results and applied results show that the low temperature QPQ complex salt-bath treatment has many advantages, such as fast nitriding speed, uniform heating, short process time, low treating temperature, small distortion, high production rate, low cost, stable nitriding quality no pollution and so on.

The Effect of QPQ Salt-Bath Nitriding on Microstructure and Wear Resistance of 3Cr2W8V Steel

2009 ◽  
Vol 628-629 ◽  
pp. 715-720 ◽  
Author(s):  
Bo Lin He ◽  
Ying Xia Yu ◽  
Jian Ping Shi
Keyword(s):  
Wear Resistance ◽  
Corrosion Resistance ◽  
Low Temperature ◽  
White Layer ◽  
Salt Bath ◽  
Experimental Results ◽  
Process Time ◽  
Scratch Hardness ◽  
High Production Rate ◽  
Salt Bath Nitriding

The wear resistance, corrosion resistance and hardness can be greatly increased by using low temperature QPQ salt-bath nitriding treatment. And it is a new strengthening method without distortion in the treating process. In this paper, 3Cr2W8V steel is dealt with QPQ salt-bath nitriding at 520°C, 540°C, 560°C and 2h, 4h, 6h, respectively. The treated surface microstructure was analyzed by using SEM. The depth of nitriding layer, scratch hardness and wear-resistance were tested for both QPQ salt-bath treated and untreated specimen. The corrosion resistance was tested in the 5%NaCl water by using spraying method. The experimental results indicate that a certain depth of white layer and diffusion layer of the steel can be obtained by using low temperature QPQ salt-bath nitriding treatment. The nitriding compound layer with high hardness, superior wear-resistance and stable microstructure can also be obtained on the surface of the parts. With increasing the temperature and the nitriding time, the depth of nitriding layer, scratch hardness and wear-resistance of 3Cr2W8V steel were greatly increased. Comparing with the untreated specimen, its hardness enhances 95.0%, wear resistance enhances 212.3%, anti-corrosion enhances 1288.9%. The experimental results show that the low temperature QPQ salt-bath nitriding treatment has many advantages, such as fast nitriding speed, uniform heating, short process time, low treating temperature, small distortion, high production rate, low cost, stable nitriding quality without pollution and so on.

The Effect of QPQ Salt-Bath Nitriding on Microstructure and Wear Resistance of 4Cr5MoSiV1 Steel

2010 ◽  
Vol 154-155 ◽  
pp. 57-60
Author(s):  
Ying Xia Yu ◽  
Bo Lin He ◽  
Jian Ping Shi
Keyword(s):  
Wear Resistance ◽  
Corrosion Resistance ◽  
Salt Bath ◽  
Experimental Results ◽  
Surface Microstructure ◽  
Nitriding Time ◽  
Scratch Hardness ◽  
Salt Bath Nitriding ◽  
Spraying Method

In this paper, 4Cr5MoSiV1 steel is dealt with by QPQ salt-bath nitriding at 520°C, 540°C, 560°C and for 2h、4h、6h, respectively. The treated surface microstructure was analyzed by using SEM. The depth of nitriding layer, scratch hardness and wear-resistance were tested for QPQ salt-bath nitriding technology. The corrosion resistance was tested in the 5%NaCl water by using spraying method. The experimental results indicate that with increasing the temperature and the nitriding time, the depth of nitriding layer, scratch hardness and wear-resistance of 4Cr5MoSiV1 steel were increased greatly. Comparing with the untreated specimen, its hardness enhances 196.73%, wear resistance enhances 349.65%, anti-corrosion enhances 943.10%. The die hardness, wear resistance and the corrosion resistance can be greatly improved by using the QPQ salt-bath nitriding technology.

Low Temperature Nitriding of a Martensitic Stainless Steel

2011 ◽  
Vol 312-315 ◽  
pp. 994-999 ◽  
Author(s):  
Riza Karadas ◽  
Ozgur Celik ◽  
Huseyin Cimenoglu
Keyword(s):  
Wear Resistance ◽  
Corrosion Resistance ◽  
Low Temperature ◽  
Stainless Steels ◽  
Martensitic Stainless Steel ◽  
Surface Hardness ◽  
Austenitic Stainless Steels ◽  
S Phase ◽  
Martensitic Stainless Steels ◽  
Wear And Corrosion

Nitriding is as an effective technique applied for many years to improve the surface hardness and wear resistance of low carbon and tool steels [1]. In the case of stainless steels, increase of surface hardness and wear resistance accompany by a drop in corrosion resistance due to the precipitation of CrN. In this respect, many attempts have been made to modify the surfaces of austenitic stainless steels to increase their surface hardness and wear resistance without scarifying the corrosion resistance [2-6]. It is finally concluded that, nitriding at temperatures lower than conventional nitriding process (which is generally about 550°C) has potentiality to produce a nitrogen expanded austenite (also known as S-phase), on the surface without formation of CrN. Due to the superb properties of the S-phase, the low temperature nitrided austenitic stainless steels exhibit very high surface hardness, a good wear resistance, and more importantly, an excellent corrosion resistance. Recently some attempts have been made to apply low temperature nitriding to martensitic stainless steels, which are widely used in the industries of medicine, food, mold and other civil areas [7-9]. In these works, where nitriding has been conducted by plasma processes, superior surface hardness, along with excellent wear and corrosion resistances have been reported for AISI 410 and AISI 420 grade martensitic stainless steels. This work focuses on low temperature gas nitriding of AISI 420 grade martensitic stainless steel in a fluidized bed reactor. In this respect the microstructures, phase compositions, hardness, wear and corrosion behaviours of the original and nitrided martensitic stainless steels have been compared.

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.

MODELING AND INVESTIGATION OF THE WEAR RESISTANCE OF SALT BATH NITRIDED AISI 4140 VIA ANN

2013 ◽  
Vol 20 (03n04) ◽  
pp. 1350033 ◽  
Author(s):  
ŞERAFETTIN EKINCI ◽  
AHMET AKDEMIR ◽  
HUMAR KAHRAMANLI
Keyword(s):  
Wear Resistance ◽  
Friction Coefficient ◽  
Surface Characterization ◽  
Wear Behavior ◽  
Surface Hardness ◽  
Salt Bath ◽  
Back Propagation Algorithm ◽  
Aisi 4140 Steel ◽  
Aisi 4140 ◽  
Sliding Distance

Nitriding is usually used to improve the surface properties of steel materials. In this way, the wear resistance of steels is improved. We conducted a series of studies in order to investigate the microstructural, mechanical and tribological properties of salt bath nitrided AISI 4140 steel. The present study has two parts. For the first phase, the tribological behavior of the AISI 4140 steel which was nitrided in sulfinuz salt bath (SBN) was compared to the behavior of the same steel which was untreated. After surface characterization using metallography, microhardness and sliding wear tests were performed on a block-on-cylinder machine in which carbonized AISI 52100 steel discs were used as the counter face. For the examined AISI 4140 steel samples with and without surface treatment, the evolution of both the friction coefficient and of the wear behavior were determined under various loads, at different sliding velocities and a total sliding distance of 1000 m. The test results showed that wear resistance increased with the nitriding process, friction coefficient decreased due to the sulfur in salt bath and friction coefficient depended systematically on surface hardness. For the second part of this study, four artificial neural network (ANN) models were designed to predict the weight loss and friction coefficient of the nitrided and unnitrided AISI 4140 steel. Load, velocity and sliding distance were used as input. Back-propagation algorithm was chosen for training the ANN. Statistical measurements of R2, MAE and RMSE were employed to evaluate the success of the systems. The results showed that all the systems produced successful results.

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.

Low-Temperature Carburization of the Ni-base Superalloy IN718: Improvements in Surface Hardness and Crevice Corrosion Resistance

2010 ◽  
Vol 41 (8) ◽  
pp. 2022-2032 ◽  
Author(s):  
Reza Sharghi-Moshtaghin ◽  
Harold Kahn ◽  
Yindong Ge ◽  
Xiaoting Gu ◽  
Farrel J. Martin ◽  
...  
Keyword(s):  
Corrosion Resistance ◽  
Low Temperature ◽  
Crevice Corrosion ◽  
Surface Hardness ◽  
Base Superalloy

Effect of Carburizing Atmosphere Proportion on Low Temperature Plasma Carburizing of Austenitic Stainless Steel

2014 ◽  
Vol 598 ◽  
pp. 90-93 ◽  
Author(s):  
Xing Sheng Tong ◽  
Ting Zhang ◽  
Wei Ye
Keyword(s):  
Stainless Steel ◽  
Wear Resistance ◽  
Corrosion Resistance ◽  
Friction Coefficient ◽  
Austenitic Stainless Steel ◽  
Low Temperature ◽  
Corrosion Rate ◽  
Low Temperature Plasma ◽  
Temperature Plasma ◽  
Plasma Carburizing

In this study, in order to explore a suitable method to obtain a better wear resistance and corrosion resistance of austenitic stainless steel, low temperature plasma carburizing technology has been studied. Research on the properties of austenitic stainless steel under different carburizing atmosphere proportion, with hardness, wear resistance and corrosion resistance as the properties characterization. The results shows that C3H8:H2=1:40 have better properties with the hardness of 950 HV0.05, the friction coefficient of about 0.25, which showed a better wear resistance. And also the corrosion rate of about 20.3g/m2·h showed a better corrosion resistance.

Effect of QPQ Salt Bath Oxidation on Corrosion Resistance

2006 ◽  
Vol 118 ◽  
pp. 209-214
Author(s):  
Yuan Hui Li ◽  
De Fu Luo ◽  
Shao Xu Wu
Keyword(s):  
Corrosion Resistance ◽  
Water Solution ◽  
Salt Spray ◽  
Complex Salt ◽  
Salt Bath ◽  
Neutral Solution ◽  
High Corrosion Resistance ◽  
Salt Bath Nitriding ◽  
Porous Area ◽  
Magnetite Film

The QPQ complex salt bath treatment is a type of surface technology which contains mainly salt bath nitriding and post-oxidizing processes. The effect of QPQ oxidizing temperature and duration on the corrosion resistance of QPQ treated specimens has been explored by immersion tests and salt spray tests in this paper. All the specimens were post-oxidized after being nitrided at 570! for 2 hours. The material used in this study were 1020 steel. In the immersion tests, the specimens were immersed in 3‰ H2O2 and 10% NaCl water solution. In the salt spray tests, specimens were salt spray tested using 5% NaCl neutral solution. From the experimental data, for high corrosion resistance, conclusions can be drawn:(1) appropriate temperature should be selected carefully in post-oxidizing stage .Too low or too high temperature would decrease the corrosion resistance. (2) The best post-oxidizing duration should generate magnetite film in porous area and should not collapse. (3) In second oxidizing stage, the porous area has been partly eliminated, so the duration should be less than the duration of post-oxidizing.

scholarly journals Effects of Surface Modification by Means of Low-Temperature Plasma Nitriding on Wetting and Corrosion Behavior of Austenitic Stainless Steel

Coatings ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 98 ◽  
Author(s):  
Francesca Borgioli ◽  
Emanuele Galvanetto ◽  
Tiberio Bacci
Keyword(s):  
Surface Tension ◽  
Contact Angle ◽  
Corrosion Resistance ◽  
Low Temperature ◽  
Surface Morphology ◽  
Corrosion Behavior ◽  
Sessile Drop ◽  
Plasma Nitriding ◽  
Surface Hardness ◽  
Temperature Plasma

Low-temperature nitriding of austenitic stainless steels produces modified surface layers, consisting mainly of the S phase, which improve surface hardness and corrosion resistance. Because of the localized plastic deformations, owing to modified layer formation, and ion bombardment occurring during the process itself, this treatment produces also modifications of surface morphology and roughness, which can affect wettability and corrosion behavior. In this study the effects of plasma nitriding, performed using different treatment conditions, on the surface morphology and roughness, and thus on wettability and corrosion resistance, of AISI 202 specimens with different initial finishings (2D and polished finishing) were investigated. Different probe liquids, having both high (bi-distilled water and solution of 3.5% NaCl) and low (ethanol and rapeseed oil) surface tension, were employed for assessing the wetting behavior with the sessile drop method. The contact angle values for water increased markedly when nitriding was performed on polished samples, while this increase was smaller for 2D samples, and on selected specimens a hydrophobic behavior was observed. Very low contact angle values were registered using low surface tension liquids, suggesting an oleophilic behavior. Corrosion resistance in a 5% NaCl solution was assessed, and it depended on the characteristics of the nitrided specimens.

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