Journal of Mechanical Engineering 56 (2010) 2

SV-JME-2-2010 in digital form »

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Editorial

 

Special issue: Quenching & Distortion

Biographical notes:
Prof. Dr. Janez Grum is Professor of Materials Science, Heat Treatment and Surface Engineering. He is also the Founder and Editor-in-Chief of a new journal, the Int. Journal of Microstructure and Materials Properties (IJMMP) and has been Editor of the Non-destructive Testing News issued by the Slovenian NDT Society. He has published more than 200 refereed journal papers and more than 400 conference papers. He published five books with several reprints and five book chapters at ASM, Marcel Dekker and Taylor & Francis publishers.
Dr. George E. Totten received his BS and MS degrees from Fairleigh Dickinson University in New Jersey and his PhD from New York University, USA. He is a Fellow of ASM International, SAE, ASTM and IFHTSE. He has co-authored approximately 30 books and over 500 patents and publications on various aspects of heat treatment, quenching, hydraulic, lubrication and tribology. He is a former President of the International Federation of Heat Treatment and Surface Engineering (IFHTSE). Currently, he is a Research Professor at Portland State University in Portland, Oregon, USA.
Dr. Imre Felde received his B.S. from Bánki Donát Polytechnic and M.S. from Eötvös Lóránd University of Sciences in Budapest, and his Ph.D. degree from Miskolc University. He works as a research fellow in Bay Zoltán Institute for Materials Science and Technology. He has published and co-authored more than 80 papers on various aspects of heat treatment, laser cladding, modeling of phase transformation, numerical simulation of laser material processing, and quenching.
In practical work, we often come across size modifications and distortions of mechanical parts subjected to various manufacturing technologies, primarily those operating at high ...

Guest editors:
Janez Grum
George E. Totten
Imre Felde

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Evaluation Of Hardening Performance of Cooling Media by Using Inverse Heat Conduction Methods and Property Prediction

Corresponding author - Imre Felde

Authors - Tamás Réti

Abstract

A sequential numerical method for characterization of hardening performance of quenchants applied for steel quenching is outlined here. This novel method is based on the specific processing of measured time–temperature samples performed as a result of cooling curve tests. As a function of surface temperature the heat transfer coefficient, characterises the heat transfer during cooling and is calculated using an iterative inverse algorithm. The heat transfer coefficient is used for the calculation of the microstructural constituents and the hardness profile of cylindrical samples of arbitrary diameters. The hardening performance of the media is evaluated by the estimated hardness of the specimen obtained by heat treatment.

Keywords - steel quenching, hardening performance, polymer quenchant, ISO 9950, inverse heat conduction problem, computer simulation

Paper's information

Strojniški vestnik - Journal of Mechanical Engineering 56(2010)2, 77-83 
UDC 621.785

 Evaluation Of Hardening Performance of Cooling Media by Using Inverse Heat Conduction Methods and Property Prediction (pdf)

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Extension of Isothermal Time-Temperature Parameters to Non-isothermal Conditions: Application to the Simulation of Rapid Tempering

Corresponding author - Tamas Reti

Avtorji - Imre Felde - Janez Grum - Rafael Colas - Gustavo Sanchez Sarmiento - Augusto Moita de Deus

Abstract

A phenomenological method for constructing non-isothermal, generalized time-temperature parameters (GTT parameters) is presented. An analysis of the relationship between the various traditional isothermal time-temperature parameters has verified that the generalized Dorn-parameter is regarded to be the sole non-isothermal complex parameter to which a rigorous, physically well-founded interpretation is attributed. Possible applications of GTT parameters are illustrated by examples concerning the prediction of hardness change in quenched steels during rapid tempering treatments.

Keywords - kinetic function, diffusion, steels, laser cladding, secondary hardening

Paper's information
Strojniški vestnik - Journal of Mechanical Engineering 56(2010)2, 84-92 
UDC 621.78.084

 Extension of Isothermal Time-Temperature Parameters to Non-isothermal Conditions: Application to the Simulation of Rapid Tempering (pdf)

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A Simulation of the Quenching Process for Predicting Temperature, Microstructure and Residual Stresses

Corresponding author - Caner Şimşir

Authors - C. Hakan Gür

Abstract

A finite element model capable of predicting the temperature history, evolution of microstructure and residual stresses in the quenching process is presented. Proposed model was integrated into Msc. Marc® software via user subroutines. Verification of the model was performed by X-ray diffraction residual stress measurements on a series of steel cylinders quenched.

Keywords - steel quenching, simulation, finite element method, microstructure, residual stress

Paper's information
Strojniški vestnik - Journal of Mechanical Engineering 56(2010)2, 93-103 
UDC 621.785

 A Simulation of the Quenching Process for Predicting Temperature, Microstructure and Residual Stresses (pdf)

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Prediction of Quench-Hardness within the Whole Volume of Axially-Symmetric Workpieces of any Shape

Corresponding author - Božidar Liščić

Authors - Saša Singer - Božo Smoljan

Abstract

A quench probe, based on temperature gradient method was used to measure and record cooling curves when quenching real axially symmetric workpieces of any complex shape in liquid quenchants. Calculation of relevant heat transfer coefficients (HTC) is based on the cooling curve measured just below surface of the cylindrical probe of 50 mm diameter. A 2-D computer program, based on the cooling time from 800 to 500°C (t8/5), and the Jominy hardenability curve of the steel grade in question, is used to predict the hardness distribution within the whole volume of the workpiece, all at once, which is a unique feature of this method.

Keywords - quenching, heat transfer coefficient, hardness prediction

Paper's information
Strojniški vestnik - Journal of Mechanical Engineering 56(2010)2, 104-114 
UDC 621.785

 Prediction of Quench-Hardness within the Whole Volume of Axially-Symmetric Workpieces of any Shape (pdf)

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Predictions of Mechanical Properties of Quenched and Tempered Steel

Corresponding author - Božo Smoljan

Authors - Dario Iljkić - Furio Traven

Abstract

Mechanical properties of quenched steel directly depend on the degree of quenched steel hardening. Fracture toughness and fatigue limit depend on microstructural constituents, and distribution of the usual intermetallic particles and non-metallic inclusions. Fatigue resistance of quenched and tempered steel is achieved by eliminating coarse alloy carbides present in steel. Properties of matrix may also have an important influence on fracture and fatigue proper behaviour. Most high-strength materials are fracture and fatigue limited. Fatigue strength is directly proportional to the difficulty of dislocation cross slip. Grain size has its greatest effect on fatigue life in the low-stress, high-cycle regime.
In this paper, fatigue crack initiation threshold of quenched and tempered steel is predicted. The method of computer simulation of mechanical properties was applied for a workpiece of complex form made of quenched and tempered steel. Distribution of as-quenched hardness within workpiece of complex form was predicted by computer simulation of steel quenching using the finite volume method. Microstructure composition and hardness of tempered steel were predicted based on as-quenched hardness. Fatigue crack initiation threshold of quenched and tempered steel were predicted based on microstructure composition and hardness.
It was found that the proposed method can be successfully applied in calculating fatigue crack initiation threshold of quenched and tempered steel.

Keywords - quenching, tempering, computer simulation, microstructure, mechanical properties

Paper's information
Strojniški vestnik - Journal of Mechanical Engineering 56(2010)2, 115-120
UDC 621.785.616

 Predictions of Mechanical Properties of Quenched and Tempered Steel(pdf)

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Effect of Antioxidants and Corrosion Inhibitor Additives on the Quenching Performance of Soybean Oil

Corresponding author - Daniel Komatsu

Authors - Cristina Souza - Ester Carvalho de Souza - Lauralice de Campos Franceschini Canale - George Edward Totten

Abstract

Cooling curve analysis was used to evaluate the effect of corrosion inhibitor additives and antioxidants on the quenching properties of soybean oil. The results showed that addition of corrosion inhibitors provided significant changes in the cooling curve behavior and of the yellow metal corrosion inhibitors evaluated tolyltriazole exhibits the greatest rate acceleration of heat transfer. However, the presence of antioxidants did not exhibit a significant effect on quenching properties of soybean oil.

Keywords - vegetable oil, corrosion inhibitors, antioxidants, cooling curves, soybean oil, quenchant

Paper's information
Strojniški vestnik - Journal of Mechanical Engineering 56(2010)2, 121-130 
UDC 621.785

 Effect of Antioxidants and Corrosion Inhibitor Additives on the Quenching Performance of Soybean Oil (pdf)

 

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Vegetable Oil Quenchants: Calculation and Comparison of The Cooling Properties of a Series of Vegetable Oils

Corresponding author - Nikolai Ivanovich Kobasko

Authors - - Ester Carvalho de Souza - Lauralice de Compos Franceschini Canale - George Edward Totten

Abstract
The compositions of canola, soybean, corn, cottonseed and sunflower oils suggest that they exhibit substantially different propensity for oxidation following the order of: Canola < corn < cottonseed < sunflower ≈ soybean.
These data suggest that any of the vegetable oils evaluated could be blended with minimal impact on viscosity although compositional differences would surely affect oxidative stability. Cooling curve analysis showed that similar cooling profiles were obtained for different vegetable oils. Interestingly, no film boiling or transition nucleate boiling was observed with any of the vegetable oils and heat transfer occurs only by pure nucleate boiling and convection. High-temperature cooling properties of vegetable oils are considerable faster than those observed for petroleum oil-based quenchants.

Keywords - quenchant, heat transfer, vegetable oil, cooling curve, oxidation, cooling curves

Paper's information
Strojniški vestnik - Journal of Mechanical Engineering 56(2010)2, 131-142
UDC 621.785

 Vegetable Oil Quenchants: Calculation and Comparison of The Cooling Properties of a Series of Vegetable Oils (pdf)

 

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The Effect of Heat Treatment on the Stability of Centerline Segregation

Corresponding author - Mihaly Reger

Authors - Balazs Vero - Imre Felde - Ibolya Kardos

Abstract
The paper deals with the stability of centerline inhomogenity of the continuously cast slabs. The pattern of the centerline segregation was modeled physically by preparing a sandwich structure of steel plates with different levels of carbon and alloying elements. The eligibility of sandwich structured samples for diffusional experiments, i.e. the permeability of the metal-metal boundaries in the samples from diffusional point of view was checked by the comparison of measured and theoretically calculated hardness value for plain carbon steels. Diffusional homogenization experiments were performed and the samples were examined metallographically. Great microstructural difference remains between the core and cover layers after a long time diffusional homogenization if there is a difference also in the manganese content in the thickness direction of the sandwich structured sample. Manganese has a double role in this process: it reduces the possibility of homogenization of carbon and exaggerates the effect of this slight difference in carbon content during austenite decomposition.

Keywords - centerline segregation, continuous casting, effect of manganese, diffusional homogenization

Paper's information
Strojniški vestnik - Journal of Mechanical Engineering 56(2010)2, 143-149 
UDC 621.78.08

 The Effect of Heat Treatment on the Stability of Centerline Segregation (pdf)

 

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Influence of the Graphite Absorber During Laser Surface Hardening

Corresponding author - Tomaž Kek

Authors - Janez Grum

Abstract
The paper presents the results of the research of a laser surface hardening process applied to the C45E steel with graphite absorber coating on specimen surfaces. The evaluation of the laser surface hardening process was performed by measuring the IR radiation from the interaction spot. The results confirmed a strong correlation between the IR radiation voltage signal and the dimensions of microstructural changes occuring in the laser surface hardening steel.
Changes of the absorbing coating thickness produced changes of the absorptivity of the laser beam, which was confirmed by measurements of the depth and width of hardened traces. For laser surface hardening the optimum coating thickness of a graphite absorber was determined. A factorial analysis and a method of orthogonal polynomials were used to determine response surfaces for the voltage signal of IR radiation the depth and width of the hardened trace achieved. Absorptivity difference between various graphite absorber coating thicknesses was evaluated based on the Ashby-Shercliff model.

Keywords - laser surface hardening, IR radiation, IR photodiode, steel C45E, absorption, interaction

Paper's information
Strojniški vestnik - Journal of Mechanical Engineering 56(2010)2, 150-157
UDC 620.1:621.787

 Influence of the Graphite Absorber During Laser Surface Hardening (pdf)

 

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