QPQ Salt Bath Nitriding and Corrosion Resistance

2006 ◽  
Vol 118 ◽  
pp. 131-136 ◽  
Author(s):  
Yuan Hui Li ◽  
De Fu Luo ◽  
Shao Xu Wu
Keyword(s):  
Corrosion Resistance ◽  
Water Solution ◽  
Salt Spray ◽  
Complex Salt ◽  
Compound Layer ◽  
Salt Bath ◽  
Nitriding Temperature ◽  
Surface Strengthening ◽  
Higher Temperature ◽  
Salt Bath Nitriding

The QPQ complex salt bath treatment is a type of surface strengthening technology which contains mainly salt bath nitriding and salt bath post-oxidizing processes. The effect of nitriding temperature and duration on the corrosion resistance of QPQ treated specimens is explored by immersion tests and salt spray tests in this paper. The material used in this study was 1020 annealed 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 a 5% NaCl neutral solution. The data indicate that, when the nitriding duration is less than 2 hours at temperature below 590(phase change will exist when the nitriding temperature is above 590 according to Fe-N phase diagram) , the higher temperature of the salt bath nitriding , the specimens will have the higher corrosion resistance. In addition we have found that nitriding for too short a time generates a thin compound layer, and nitriding for too long generates too much porosity. Both will deteriorate the 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.

KINETICS ANALYSIS OF HIGHER TEMPERATURE SALT BATH NITRIDING FOR AISI 1045 STEEL

2016 ◽  
Vol 23 (06) ◽  
pp. 1650049 ◽  
Author(s):  
MINGYANG DAI ◽  
YAO CHEN ◽  
YATING CHAI ◽  
JING HU
Keyword(s):  
Compound Layer ◽  
Salt Bath ◽  
Micro Hardness ◽  
Kinetics Analysis ◽  
Cross Sectional ◽  
Aisi 1045 Steel ◽  
Aisi 1045 ◽  
Higher Temperature ◽  
1045 Steel ◽  
Salt Bath Nitriding

Rapid salt bath nitriding was conducted at higher temperature above 600[Formula: see text]C instead of normally used 560[Formula: see text]C for AISI 1045 steel. Optical microscopy (OM), X-ray diffraction (XRD) and micro-hardness tester were employed to characterize the microstructure, phase constituents and micro-hardness of the treated specimens. The results showed that salt bath nitriding at higher temperature could significantly increase the compound layer thickness and higher cross-sectional hardness can be obtained. Kinetics analysis illustrated that the nitrogen atoms diffusion coefficient was obviously increased with temperature, and the activation energy of nitrogen atom diffusion was decreased from 220[Formula: see text]kJ[Formula: see text]mol[Formula: see text] to 142[Formula: see text]kJ[Formula: see text]mol[Formula: see text].

scholarly journals THE INFLUENCE OF SALT BATH NITRIDING VARIABLES ON HARDNESS LAYER OF AISI 1045 STEEL

2016 ◽  
Vol 22 (3) ◽  
pp. 188
Author(s):  
Elhadj Ghelloudj ◽  
Hamid Djebaili ◽  
Mohamed Tahar Hannachi ◽  
Abdenour Saoudi ◽  
Bilal Daheche
Keyword(s):  
Compound Layer ◽  
Salt Bath ◽  
Case Depth ◽  
Nitriding Process ◽  
Hardness Profile ◽  
Aisi 1045 Steel ◽  
Aisi 1045 ◽  
Layer Increase ◽  
1045 Steel ◽  
Salt Bath Nitriding

<span>The aim of  this paper is to study and analyze the effects of a surface controlled salt bath nitriding on the microhardness of AISI 1045 steel. The nitriding process were implemented in salt bath component at ten different times (from 1 h to 10 h) when temperature was constant at (520ºC). The nitriding process repeated of another specimens at the same times but the temperature was (580ºC).The microstructure of surface layers was investigated by optical microscopy. Hardness profiles were measured with low-load hardness testing to determine the growth of the case depth after nitriding. Microhardness testing was carried out on samples to investigate the hardness profile at the transition from the compound to the diffusion layer. The microhardness of surface of nitrided sample at 520ºC and 580ºC was observed in the range of 318–430 HV0.3 and 329–421 HV0.3, respectively. Experimental results showed that the nitrides ε-Fe2-3(N,C) and γ’-Fe4(N,C) present in the compound layer increase the microhardness. It is found that salt bath nitriding parameters (time and temperature) improves the microhardness. </span>

scholarly journals COMPARISON OF SALT BATH PREOXIDATION AND AIR PREOXIDATION FOR SALT BATH NITRIDING

2019 ◽  
Vol 25 (2) ◽  
pp. 130
Author(s):  
Wenchen Mei ◽  
Jiqiang Wu ◽  
Mingyang Dai ◽  
Kunxia Wei ◽  
Jing Hu
Keyword(s):  
Compound Layer ◽  
Salt Bath ◽  
Micro Hardness ◽  
X Ray Diffraction ◽  
X Ray ◽  
Hardness Tester ◽  
Modified Surface ◽  
Salt Bath Nitriding ◽  
Modified Surface Layer

<p class="AMSmaintext1">Salt bath preoxidation was primarily conducted prior to salt bath nitriding, and the effect on salt bath nitriding was compared with that of conventional air preoxidation. Characterization of the modified surface layer was made by means of optical microscopy, scanning electron microscope (SEM), micro-hardness tester and x-ray diffraction (XRD). The results showed that the salt bath preoxidation could significantly enhance the nitriding efficiency. The thickness of compound layer was increased from 13.3μm to 20.8μm by salt bath preoxidation, more than 60% higher than that by conventional air preoxidation under the same salt bath nitriding parameters of 560℃ and 120min. Meanwhile, higher cross-section hardness and thicker effective hardening layer were obtained by salt bath preoxidation, and the enhancement mechanism of salt bath preoxidation was discussed.</p>

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.

scholarly journals Improving the Corrosion Resistance of Tin-bronze by Surface Modification

2021 ◽  
Vol 23 (09) ◽  
pp. 1270-1281
Author(s):  
Mahmoud Abbas ◽  
◽  
Rehab M. El-Maghraby ◽  
Esraa Hassan ◽  
Reda F. M. Elshaarawy ◽  
...  
Keyword(s):  
Contact Angle ◽  
Corrosion Resistance ◽  
Surface Modification ◽  
Water Solution ◽  
Salt Spray ◽  
Sol Gel ◽  
Distilled Water ◽  
Adhesion Test ◽  
X Ray ◽  
Tin Bronze

Bronze alloys are made of copper-based materials with another metal, usually tin. Many surface modification techniques such as chemical etching, oxidation, electro deposition and sol-gel could be employed to improve surface properties. The organic compound that was used in this study was extracted from chili peppers. FT-IR (Fourier-transform infrared) spectroscopy and UV (Ultraviolet) spectroscopy investigations were applied on the extracted compound and results showed that this compound is mainly capsaicin [N-(4-hydroxy-3-methoxybenzyl)-8-methylnon-trans-6-enamide) (HMMTE)]. Electrochemical deposition was employed under cell voltage equal to 30 volts in a two-electrodes cell where bronze was the anode and stainless steel was the cathode in a solution of 10 ml/L (HMMTE)/distilled-water. Modification of tin-bronze for 1 hr. in 10 ml/L HMMTE/ distilled water solution increased the contact angle from 48° to 132˚. Attension Biolin device (Model: Theta Optical Tensiometers) was used to measure the contact angle at ambient temperature. Electrochemical measurements revealed that a significant improvement in corrosion resistance of tin-bronze in 3.5% NaCl had been achieved. The corrosion rate of tin-bronze decreased from 10.22 mpy to 1.39 mpy. Surface morphology of the samples was investigated with scanning electron microscopy (SEN) and energy-dispersive X-ray (EDX). X-ray diffraction was employed to determined present phases. Surface investigations results confirmed that a layer of red cuprous oxide (Cu2O) was formed on the surface layer after modification which led to the improvement in corrosion resistance. Salt spray test was carried out using Alpha+ Salt Spray Testing Equipment for 13 days on the base and surface modified samples according to ASTM B117. A green layer from [CuCl2 and Cu46Cl24(OH)68-(H2O)4] was observed on the nonmodified specimen (could be patina and bronze disease) while the red layer [Cu2O] is still observed on the modified specimen. Adhesion test (using X-Cut Tape Adhesion test according to ASTM D3359) was also investigated.

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.

Enhanced corrosion resistance of Cr-Mn ASS by low temperature salt bath nitriding technique for the replacement of convectional Cr-Ni ASS

2019 ◽  
Vol 66 (4) ◽  
pp. 439-445 ◽  
Author(s):  
Vipin Tandon ◽  
Awanikumar P. Patil ◽  
Ramesh C. Rathod
Keyword(s):  
Corrosion Resistance ◽  
Low Temperature ◽  
Electrochemical Impedance ◽  
Electrochemical Techniques ◽  
Austenitic Stainless Steels ◽  
Salt Bath ◽  
Potassium Nitrate ◽  
Industrial Applications ◽  
Content Type ◽  
Salt Bath Nitriding

Purpose The purpose of this paper is to enhance the corrosion resistance of Cr-Mn austenitic stainless steel (ASS) via low temperature salt bath nitriding and to replace the convectional Cr-Ni ASS with newly developed enhanced corrosion resistive Cr-Mn ASS. Design/methodology/approach The low temperature salt bath nitriding was performed on Cr-Mn ASS at 450°C for 3 h in potassium nitrate salt bath. Findings The present paper compares the corrosion resistance of salt bath nitrided Cr-Mn ASS with convectional Cr-Ni ASSs (316 L and 304 L ASSs) in 3.5 per cent NaCl by electrochemical techniques. The electrochemical impedance spectroscopy result shows the increase in film resistance and potentiodynamic polarization results show the enhanced corrosion resistance of nitrided Cr-Mn ASS, which is almost equivalent to that of 316 L and 304 L ASSs. This is attributed to the formation of nitrogen supersaturated dense nitride layer. The present results therefore suggest that the nitrided Cr-Mn ASS may replace costly convectional Cr-Ni ASSs for commercial and industrial applications. Originality/value Ever-increasing price of nickel (Ni) is driving the industries to use Ni-free or low-Ni austenitic stainless steels (ASSs). But its corrosion resistance is relatively poor as compared to conventional Cr-Ni ASSs. However, its corrosion resistance can be improved by nitriding. The low temperature salt bath nitriding of Cr-Mn ASS and its electrochemical behavior in 3.5 per cent NaCl has not been studied. The present research paper is beneficial for industries to use low cost Cr-Mn, enhance its corrosion resistance and replace the use of costly conventional Cr-Ni ASSs.

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