Effect of Working Current on Microstructure and Properties of Cylinder Hardened by Plasma Beam at Junction of the Hardening Traces

2011 ◽  
Vol 314-316 ◽  
pp. 98-101
Author(s):  
Li Yang ◽  
Ying Huai Qiang ◽  
Fu Shan Chen ◽  
Yang Gao ◽  
Yun Tian Zhong
Keyword(s):  
Retained Austenite ◽  
Flake Graphite ◽  
Structure And Properties ◽  
Micro Hardness ◽  
Beam Hardening ◽  
X Ray ◽  
Plasma Beam ◽  
Hardness Tester ◽  
Large Gradient ◽  
Improve Wear Resistance

To improve wear resistance and service life of boron cast iron cylinder, plasma beam hardening on surface is adopted.Scanning electron microscope,X-ray diffractometer and micro-hardness tester is used to analyze the effect of working current on the structure and properties of plasma beam hardening layer at the junction of the hardening traces. The results show that the microstructure of hardening layer at the junction is hidden acicular martensite, retained austenite and flake graphite. With the increase of working current, the content of retained austenite decreases, the hardness and depth of the hardening layer increases. The highest hardness is not achieved at the surface of hardening layer but at the second-surface layer which has a certain distance to the surface. The uneven distribution of hardness in hardening layer leads to large gradient at the both sides of the highest hardness and the gradient decreases with the increase of working current.

Characterisation of WC-17Co and WC-9Ni HVOF Sprayed Cermet Coatings

2016 ◽  
Vol 840 ◽  
pp. 331-335
Author(s):  
Nur Amira Mohd Rabani ◽  
Zakiah Kamdi
Keyword(s):  
Steel Substrate ◽  
Optical Microscope ◽  
Binder Phase ◽  
High Porosity ◽  
Tungsten Carbides ◽  
Micro Hardness ◽  
X Ray Diffraction ◽  
X Ray ◽  
Hardness Tester ◽  
Vickers Micro Hardness

Cemented tungsten carbides have been paid much attention due its better mechanical properties with excellent combination of hardness and toughness characteristics. The hard WC particles in the coating provide hardness and wear resistance, while the ductile binder such as Co and Ni contribute to toughness and strength. WC-17wt.% Co and WC-9wt.% Ni powders have been sprayed by the HVOF method to form coatings approximately 300μm and 150μm thick onto AISI 1018 steel substrate. Both coatings have been prepared and supplied by an external vendor. The coatings were examined using optical microscope (OM), scanning electron microscope (SEM), and X-Ray diffraction (XRD). The hardness of both coatings were also measured using Vickers micro-hardness tester. The microstructure of the coatings has been analyzed and found to consist of WC, brittle W2C phase, metallic W phase, and amorphous binder phase of Co and Ni. It is found that WC-Ni has a higher hardness value compared to WC-Co due to high porosity distribution.

Influence of Rare Earth on the Properties of H13 Steel by the QPQ Salt-Bath Treatment

2010 ◽  
Vol 97-101 ◽  
pp. 1454-1458 ◽  
Author(s):  
Guang Yao Xiong ◽  
Ming Juan Zhao ◽  
Long Zhi Zhao ◽  
Zhang Jian
Keyword(s):  
Wear Resistance ◽  
Rare Earth ◽  
Sliding Wear ◽  
Salt Bath ◽  
Structure And Properties ◽  
Micro Hardness ◽  
H13 Steel ◽  
Hardness Tester ◽  
Different Content

The structure and properties of H13 steel treated by the QPQ Salt-bath treatment with different content of Rare Earth (RE) LaCO3 were studied. The surface of H13 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 results showed that the thickness and the wear resistance and the speed of nitriding was highly improved and the performance of nitriding layer and the nitriding structure was improved.

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>

Microstructures and Properties of W-26Re Alloy by SPS

2012 ◽  
Vol 236-237 ◽  
pp. 113-117
Author(s):  
Song Wang ◽  
Ming Xie
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Test Results ◽  
Micro Hardness ◽  
X Ray Diffraction ◽  
X Ray ◽  
Hardness Tester ◽  
Fine Grain ◽  
Plasma Sintering ◽  
Spark Plasma

W-26Re alloy was fabricated by spark plasma sintering (SPS) technology. The phases, microstructures and mechanical properties of the alloy were investigated by X-ray diffraction, optical light microscope, scanning electron microscope, energy dispersion spectroscope, digital display micro-hardness tester and tensile test. Results show that, using SPS technique can prepare W-26Re alloy with high density, fine grain and excellent mechanical properties. The relative density of W-26Re alloy was 96.2%. The main phases in the alloy were determined by the amount of (W) solid solution and the intermetallic  phases. The micro-hardness was 729HV, the ultimate tensile strength was 1680MPa, yield tensile strength was 1143MPa and elongation of alloy was 8.7%.

scholarly journals Yttria stabilized tetragonal zirconia ceramics: preparation, characterization and applicationspplications

2018 ◽  
Vol 53 (2) ◽  
pp. 111-116 ◽  
Author(s):  
N Sultana ◽  
K Bilkis ◽  
R Azad ◽  
MR Qadir ◽  
MA Gafur ◽  
...  
Keyword(s):  
Sintering Temperature ◽  
Tetragonal Zirconia ◽  
Micro Hardness ◽  
X Ray Diffraction ◽  
Zirconia Ceramics ◽  
X Ray ◽  
Hardness Tester ◽  
Maximum Value ◽  
Different Temperatures ◽  
Temperature Water

In this study, yttria stabilized tetragonal zirconia (YSTZ) ceramics were prepared and were sintered at different temperatures to find out the optimum sintering temperature for their better tetragonality and mechanical properties for their application as optical ferrule. Vicker’s hardness was performed by micro hardness tester and it was found to increase with the increase of sintering temperature to a maximum value, then it was decreased with higher sintering temperature. Water absorptivity and porosity were also seen to decrease as the densities of the specimens were increased. X-ray diffraction was employed to determine crystal structure of sintered samples. Surface morphology of the sintered samples was examined through field emission scanning electron microscope.Bangladesh J. Sci. Ind. Res.53(2), 111-116, 2018

Wear Resistance of Al2O3, Al2O3-40wt.%TiO2 Coatings Prepared by Plasma Spraying on H13 Hot-Worked Die Steel

2012 ◽  
Vol 538-541 ◽  
pp. 235-238 ◽  
Author(s):  
Ren Guo Song ◽  
Pu Hong Tang ◽  
Chao Wang ◽  
Guo Lu
Keyword(s):  
Wear Resistance ◽  
Plasma Spraying ◽  
Ceramic Coatings ◽  
Micro Hardness ◽  
X Ray Diffraction ◽  
Die Steel ◽  
X Ray ◽  
Hardness Tester ◽  
Plasma Sprayed ◽  
Scanning Electron

Al2O3 and Al2O3-40wt.%TiO2 ceramic coatings on H13 hot-worked die steel have been prepared by plasma spraying, and then the microstructure, micro-hardness as well as wear resistance of the prepared coatings have been investigated by means of x-ray diffraction (XRD), scanning electron microscope (SEM), Vickers hardness tester and ball-on-disk high temperature tribometer. The results showed that the plasma sprayed ceramic coatings are of higher hardness and wear resistance than H13 hot-worked die steel.

Properties of Al2O3-TiO2 Coating Prepared by Plasma Spraying with an Internally-Fed Powder System

2008 ◽  
Vol 368-372 ◽  
pp. 1274-1276
Author(s):  
Feng Zhou ◽  
Ying Qing Fu ◽  
Yang Gao
Keyword(s):  
Low Power ◽  
Plasma Spray ◽  
Thermal Spraying ◽  
Deposition Efficiency ◽  
Micro Hardness ◽  
X Ray Diffraction ◽  
Powder System ◽  
X Ray ◽  
Hardness Tester ◽  
Spray Dried

Alumina-titania (60: 40 by weight) coatings were prepared by low power plasma thermal spraying with two types of plasma spray systems: internally-fed and externally-fed powder system. The coatings were investigated by many techniques, respectively X-ray diffraction (XRD), scanning electron microscopy (SEM) and micro-hardness tester. It was found that the thickness of coatings by low power plasma spray with an internally-fed powder system is higher than that of the coatings with an externally-fed powder system. The internally-fed powder system not only decreases the loss of powder but also increases the deposition efficiency for more than 80%. To better qualify the characteristics of these coatings prepared from spray-dried powders, microhardness was also studied.

Effects of NiO Nanoparticles on Physical and Mechanical Properties of BNKT Lead-Free Ceramics

2017 ◽  
Vol 866 ◽  
pp. 282-286 ◽  
Author(s):  
Chatchai Kruea-In ◽  
Suchittra Inthong ◽  
Wilaiwan Leenakul
Keyword(s):  
Mechanical Properties ◽  
Physical And Mechanical Properties ◽  
Micro Hardness ◽  
Nio Nanoparticles ◽  
X Ray Diffraction ◽  
Solid State Reaction Technique ◽  
X Ray ◽  
Hardness Tester ◽  
Lead Free Ceramics ◽  
Vickers Micro Hardness

In this research, The effects of NiO nanoparticles on the physical and mechanical properties of Bi0.5(Na0.81,K0.19)0.5TiO3 (BNKT) were investigated. The ceramics were synthesized by solid state reaction technique. The powder of BNKT was calcined at 850 °C for 4 h. The ceramics of BNKT/x NiO vol.% ( i.e. x= 0.0, 1.0, 2.0 and 3.0) were sintered at 1000-1150 °C for 2 h for optimize condition. Densification, phase formation, microstructure and micro hardness of samples were characterized via Archimedes method, X-ray diffraction techniques (XRD), scanning electron microscope (SEM) and Vickers micro hardness tester. The X-ray diffraction analysis of the ceramics suggests that all samples exhibited a perovskite structure. Densification of samples tended to increase with increasing amount of NiO content with minimun at 1.0 vol.% NiO additive. The NiO additive influenced densification as well as the mechanical properties of the samples. The results of this research suggest that NiO nanoparticles have influence on physical and mechanical properties of BNKT ceramics.

Thermal Stability of Nickel Molybdenum Electrodeposits

2012 ◽  
Vol 576 ◽  
pp. 413-416
Author(s):  
Suryanto ◽  
Hanafi Ani Mohd
Keyword(s):  
Thermal Stability ◽  
Vacuum Furnace ◽  
Micro Hardness ◽  
Deposition Technique ◽  
X Ray Diffraction ◽  
Electro Deposition ◽  
X Ray ◽  
Hardness Tester ◽  
Thermal Stability Of ◽  
Temperature Crack

Thermal stability of nickel molybdenum electrodeposits was investigated. This investigation is important to show that electrodeposits can be used at elevated temperature and to understand electrodeposit behaviour as a function of temperature. Crack-free electrodeposits with up to 17 at% molybdenum were produced by the square pulse electro-deposition technique from a solution containing nickel sulphamate. The experiment was performed using vacuum furnace. Microstructure of deposits was investigated using microscope SEM, while the phase of deposits was studied using x-ray diffraction. Chemical composition of deposits was observed using energy dispersive x-ray analyzer and hardness of deposits was measured using micro hardness tester. The result shows that nickel molybdenum electrodeposits stable up to 400 oC. For 550 oC, grain growth was observed to start but the hardness of electrodeposits has no significant changed. Hardness analysis shows that hardness of electrodeposits does follow Hall Petch relationship.

Modelling of retained austenite in carburized layers

2004 ◽  
Vol 120 ◽  
pp. 121-128
Author(s):  
M. Przyłęcka ◽  
W. Gęstwa ◽  
G. E. Totten
Keyword(s):  
Phase Composition ◽  
Retained Austenite ◽  
Thermal Process ◽  
Impact Resistance ◽  
Residual Austenite ◽  
Structure And Properties ◽  
Micro Hardness ◽  
Steel Composition ◽  
Steel Alloys

In this paper, modelling of the phase composition of the carburized case produced on steel alloys containing chromium, manganese and nickel will be discussed. In particular, the effect of steel composition on the amount of retained austenite and carbide structure will be discussed. These microstrucures were selected because they exhibit the greatest influence on the correlation between structure and properties of hardened carburized case. The thermal process largely influences the formation of carbides quantity of residual austenite in structure of hardened carburized elements. Properties evaluated include: hardness, micro-hardness, and impact resistance. The model can be applied to carburized 20H (20Cr4), 15HN (17CrNi6-6) and 16HG (16MNCr5) steel although data for 20H (20Cr4) steel is provided here.

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