scholarly journals Effect of Gaseous carburizing thermochemical treatment on tribological behavior of Ti–6Al–4V alloy

2021 ◽  
Vol 15 (58) ◽  
pp. 179-190
Author(s):  
Fedaoui Kamel ◽  
Amar Talhi ◽  
Mohamed Zine Touhami
Keyword(s):  
Wear Resistance ◽  
Treatment Time ◽  
Surface Hardness ◽  
Thermochemical Treatment ◽  
Microscopic Analysis ◽  
Hardness Test ◽  
Indentation Load ◽  
Case Hardening ◽  
Resistance To Wear ◽  
Loss Of Mass

This study, concerns the improvement of the hardness and resistance to wear of the Ti-6Al-4V alloy surface by means of thermochemical treatment, for obtaining coatings on the Ti-6Al-4V alloy gives performance of resistance to wear phenomena. Three-thermochemical treatment time (2h, 4h, and 6h) was chosen for investigation of the effect of such treatment on this alloy. The hardness test under an indentation load of 50 gf with a Vickers pyramidal indenter revealed that the surface hardness is 335 Hv for the untreated samples. On the other hand the hardness reaches approximately 1500 Hv during gas cementation at 930 °C for variable times (2h, 4h, 6h) followed by quenching at 840 °C in an oil medium, which was accompanied by a significant improvement in wear resistance. The characterization of the modified surface layers was made by means of a microscopic analysis and by X-ray diffraction. The case-hardening made it possible to obtain a wear resistance greater than that of the alloy not treated, minimal loss of mass by dry friction and an improvement in roughness as well as a good coefficient of friction.

Surface Hardness Modify and Improve Wear Properties of EP\ NanoZrO2

2021 ◽  
Vol 19 (2) ◽  
pp. 77-82
Author(s):  
Fadhil K. Farhan ◽  
Aws Abbas Hussein ◽  
Ali Q. Tuama
Keyword(s):  
Wear Resistance ◽  
High Surface ◽  
Ceramic Powder ◽  
High Surface Area ◽  
Surface Hardness ◽  
Weight Ratio ◽  
Hardness Test ◽  
Wear Properties ◽  
Mechanical Mixing ◽  
Dioxide Powder

The liquid and mechanical mixing method was used in addition to ultrasound technology to prepare samples according to standard conditions. The percentage of cementing with ceramic powder was adopted from 1% to 4% as a weight ratio, and by using mixing drivers, nanocomposites were prepared depending on the theoretical density of the components. The velvet density was measured using Archimedes' method, and the results showed a successive improvement and increase in density with the weight ratio of addition. The results of the particulate hardness test showed a significant improvement in the results of the prepared nanostructures compared to the base sample (pure epoxy). With regard to the properties of wear resistance (wear modulus) using the screw-on-disk method, the cemented samples showed a higher wear resistance compared to the base sample. The results were interpreted based on the values of density and hardness in addition to the properties possessed by the ceramic powder of high surface area and average granular size of 32 nanometers through scanning electron microscopy. In this work, nanostructures based on (a polymer) supported with nanoscale zirconium dioxide powder were developed.

Effect of the Morphology, Size, Distribution and Homogeneity of Carbides and Matrix on Wear Resistance in High Cr-Alloys White Cast Iron

2021 ◽  
Vol 1016 ◽  
pp. 56-62
Author(s):  
Carlos Camurri ◽  
Jasmín Maril ◽  
Eric Romero
Keyword(s):  
Wear Resistance ◽  
Cast Iron ◽  
White Cast Iron ◽  
Wear Behavior ◽  
Hardness Test ◽  
Mining Equipment ◽  
Cast Irons ◽  
Loss Of Mass ◽  
Ultimate Purpose ◽  
Wear Tests

The aim of this work was to study the wear behavior of high-chromium white cast iron of families ASTM A-532 II (B, D) and III A, used in mining equipment, in order to establish relationships between the wear resistance, hardness and microstructure of the alloys, with the ultimate purpose of predicting their resistance to abrasion. Samples from these cast irons were subjected to mechanical wear tests by rotating drum, then their micro/macro hardness was measured and microstructure analyzed by optical and scanning electron microscopy .It was found that when the macroscopic hardness differences were significant there was a strong correlation between the hardness and the loss of mass due to abrasion-impact wear. By contrast, when the alloys had similar hardness, the wear resistance was determined by morphology, size, and the distribution and connectivity of carbides and matrix and therefore was not predictable by an only simple hardness test.

scholarly journals The Effect of Chip Binding on the Parameters of the Case-Hardened Layer of Tooth Surfaces for AMS 6308 Steel Gears Processed by Thermochemical Treatment

Materials ◽  
2021 ◽  
Vol 14 (5) ◽  
pp. 1155
Author(s):  
Robert Fularski ◽  
Ryszard Filip
Keyword(s):  
Mechanical Performance ◽  
Negative Impact ◽  
Gear Tooth ◽  
Surface Hardness ◽  
Thermochemical Treatment ◽  
Hardened Layer ◽  
Case Depth ◽  
Machining Process ◽  
Case Hardening ◽  
Power Skiving

The following article describes influence of pressure welded or bound chips to the gear tooth flank and/or the tooth root on a carburized case and surface layer hardness of Pyrowear 53 steel gears, machined by Power Skiving method. This paper is focused only on one factor, the chips generated while forming gear teeth by power skiving, which could result in local changes in the carburized case parameters as a negatively affecting point of mechanical performance of the carburized case. The chips, due to the specifics of the power skiving process and the kinematics of tooth forming, could be subject to the phenomena of pressure welding or binding of chips to the tooth. During the carburizing stage of the downstream manufacturing processes, the chips form a diffusion barrier, which ultimately could result in localized changes in the carburized case. This work was an attempt to answer the question of how and to what extent the chips affect the case hardening. Performed simulations of chips by a generating cupper “spots”, mentioned in the study, represent a new approach in connection with minimization of errors, which could appear during carbon case depth and case hardness analysis for typical chips, generated during the machining process—assurance that a complete chip was bound to the surface. Hardness correlation for zones, where the chip appears with areas free of chips, gives simple techniques for assessment. Performed tests increased the knowledge about the critical size of the chip—1.5 mm, which could affect the case hardening. Obtained experimental test results showed that the appearance of chip phenomena on the gear tooth might have a negative impact on a carburized case depth and hardened layer.

DILLIDUR 450V

Alloy Digest ◽  
2011 ◽  
Vol 60 (12) ◽  
Keyword(s):  
Fracture Toughness ◽  
Wear Resistance ◽  
Physical Properties ◽  
Tensile Properties ◽  
Room Temperature ◽  
Surface Hardness ◽  
Heat Treating ◽  
Hot Working ◽  
Resistant Steel ◽  
Bend Strength

Abstract Dillidur 450V is a water hardened wear-resistant steel with surface hardness at room temperature of 420-480 HB. The steel is easy to weld and bend. Hot working is not recommended. This datasheet provides information on composition, physical properties, hardness, tensile properties, and bend strength as well as fracture toughness. It also includes information on wear resistance as well as forming, heat treating, machining, and joining. Filing Code: SA-638. Producer or source: Dillinger Hütte GTS.

LUCEFIN GROUP 20NiCrMo2-2(1.6523), 20NiCrMoS2-2 (1.6526)

Alloy Digest ◽  
2020 ◽  
Vol 69 (12) ◽  
Keyword(s):  
Wear Resistance ◽  
Fatigue Strength ◽  
Physical Properties ◽  
Tensile Properties ◽  
Heat Treating ◽  
Medium Size ◽  
Case Hardening ◽  
Low Carbon ◽  
High Fatigue

Abstract Lucefin Group 20NiCrMo2-2 and 20NiCrMoS2-2 are low-carbon, Ni-Cr-Mo, alloy case-hardening steels that are used in the carburized or carbonitrided, and subsequently quench hardened and tempered, condition. These steels are, in general, used for medium-size case-hardened parts requiring high fatigue strength and wear resistance. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties. It also includes information on forming, heat treating, and joining. Filing Code: SA-866. Producer or source: Lucefin S.p.A..

LUCEFIN GROUP 16MnCr5 (1.7131), 16MnCrS5 (1.7139)

Alloy Digest ◽  
2020 ◽  
Vol 69 (8) ◽  
Keyword(s):  
Wear Resistance ◽  
Fatigue Strength ◽  
Physical Properties ◽  
Tensile Properties ◽  
Heat Treating ◽  
High Wear Resistance ◽  
Medium Size ◽  
Case Hardening ◽  
Low Carbon

Abstract Lucefin Group 16MnCr5 and 16MnCrS5 are low-carbon, 1.2Mn-1Cr, alloy case-hardening steels that are used in the carburized or carbonitrided, and subsequently quench hardened and tempered condition. In general, these steels are used for small and medium size parts requiring high wear resistance and fatigue strength. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties. It also includes information on forming, heat treating, machining, and joining. Filing Code: SA-864. Producer or Source: Lucefin S.p.A.

A Study of the Mechanical Role of Enamel and Dentin in Human Teeth

2012 ◽  
Author(s):  
Keyoung Jin Chun ◽  
Hyun Ho Choi ◽  
Jong Yeop Lee
Keyword(s):  
Surface Hardness ◽  
Mechanical Tests ◽  
Indentation Load ◽  
Bite Force ◽  
Compression Tests ◽  
Healthy Human ◽  
Human Teeth ◽  
Diamond Indenter ◽  
Dental Hard Tissues ◽  
Measured Hardness

The dental hard tissues of a tooth are combined of enamel and dentin together. The enamel protects the dentin and comes in direct contact with food during mastication. Bite force is expressed as compression force. The purpose of this study is to identify the primary roles of enamel and dentin during mastication by analyzing their mechanical properties and hardness. Healthy human teeth (age: 19.3 ± 4.1) were used as specimens for mechanical tests. The teeth, which underwent epoxy resin molding, were machine cut to make 10 enamel specimens, 10 dentin specimens and 10 enamel–dentin composite (ED) specimens of 1.2 mm × 1.2 mm × 3.0 mm (Width × Height × Length) in size. Compression tests were conducted using a micro-load system at 0.1 mm/min test speed. Teeth surface hardness (HV) was measured by a Vickers diamond indenter with a 300g indentation load. Data were obtained from 4 points on each enamel specimen and 4 points on each dentin specimen. The strain (%), stress (MPa) and modulus of elasticity (E, MPa) of the specimens were obtained from compression tests. The MAX. strain of the enamel, dentin and ED specimens were 4.5 ± 0.8 %, 11.9 ± 0.1 % and 8.7 ± 2.7 %, respectively. The MAX. stress of the enamel, dentin and ED specimens were 62.2 ± 23.8 MPa, 193.7 ± 30.6 MPa and 126.1 ± 54.6 MPa, respectively. The E values of the enamel, dentin and ED specimens were 1338.2 ± 307.9 MPa, 1653.7 ± 277.9 MPa and 1628.6 ± 482.7 MPa, respectively. The E of the dentin specimens was the highest and the E of the enamel specimens was the lowest, but the E values of all specimens was not significantly different in the T-test (P > 0.1). The measured hardness value of the enamel specimens (HV = 274.8 ± 18.1) was about 4.2 times higher than that of the dentin specimens (HV = 65.6 ± 3.9). Because of the values of MAX. stress and MAX. strain of the enamel specimens, the enamel specimens tended to fracture earlier than the dentin and ED specimens; therefore, enamel was considered to be more brittle than dentin and ED. Enamel is a harder tissue than dentin based on their measured hardness values. Therefore, enamel has a higher wear resistance, making it suitable for grinding and crushing, whereas dentin has a higher force function, making it suitable for abutment against bite force.

scholarly journals Effects of medications and laser on induced tooth movement and associated root resorption: four key points

2013 ◽  
Vol 18 (2) ◽  
pp. 4-7 ◽  
Author(s):  
Alberto Consolaro
Keyword(s):  
Laser Therapy ◽  
Tooth Movement ◽  
Root Resorption ◽  
Treatment Time ◽  
Microscopic Analysis ◽  
Experimental Models ◽  
Control Groups ◽  
Accurate Evaluation ◽  
Key Points ◽  
Test Treatment

The following four fundamental points on the use of experimental models will be described to ensure an accurate evaluation of the effects of medication and laser therapy on induced tooth movement and associated root resorption: (1) If the objective is to check the effect on root resorption, the forces experimentally applied must produce a lesion on the cementoblast layer in all specimens; (2) If the objective is to optimize induced tooth movement and reduce treatment time without side effects, the forces experimentally applied should not produce a lesion in the cementoblast layer in any specimen; (3) The laser therapy operator, the person administering medication and the person that places appliances should not know which animals will effectively receive the test treatment, and the control groups should receive placebo treatments; (4) CT and microscopic analysis of the specimens should be random, and the group to which the specimen belongs should not be identified to ensure that the person reading images and the pathologists are not influenced in their evaluation of phenomena. These measures will ensure that results are more reliable and easier to extrapolate to orthodontic clinical practice.

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.

Kinetic Study of the Growth of Hard Layers on a Low Carbon Steel

MRS Advances ◽  
2017 ◽  
Vol 2 (50) ◽  
pp. 2809-2817
Author(s):  
Daniel S. Huerta ◽  
E.D. García Bustos ◽  
D.V. Melo Máximo ◽  
M. Flores Martinez
Keyword(s):  
Carbon Steel ◽  
Treatment Time ◽  
Low Carbon Steel ◽  
Thermochemical Treatment ◽  
Low Carbon ◽  
X Ray Diffraction ◽  
Kinetic Growth ◽  
Steel Aisi ◽  
Growth Constants ◽  
Substrate Hardness

ABSTRACTIn the present work the kinetic growth is analyzed for a hard coating applied on a low carbon steel AISI 8620. A thermochemical treatment of bored with dehydrated paste at temperatures of 900, 950 and 1000 °C with a residence time of 2, 4, 6 and 8 h. The morphology and types of borides formed on the surface of the steel were evaluated by optical microscopy, scanning electron microscopy (SEM) and X-ray diffraction (XRD). The layer formed has a size of 20 to 113 μm which will be dependent on the process temperature, the treatment time and the alloy elements of the substrate. Hardness of 1493-1852 HV are presented for treatment times and temperatures established in this study. The kinetics of growth were determined and analyzed using a mathematical model of diffusion, evaluating the penetration of the biphasic layer that is determined as a function of the time and temperature of the thermochemical treatment (TCT). The results show the increase in the growth constants (k) with respect to the bored temperatures. The activity energy (Q) of the material AISI 8620 was also obtained.

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