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Article

Jaroslav Mackerle

This paper gives a review of the finite element techniques (FE) applied in the area of material processing. The latest trends in metal forming, non‐metal forming, powder…

Abstract

This paper gives a review of the finite element techniques (FE) applied in the area of material processing. The latest trends in metal forming, non‐metal forming, powder metallurgy and composite material processing are briefly discussed. The range of applications of finite elements on these subjects is extremely wide and cannot be presented in a single paper; therefore the aim of the paper is to give FE researchers/users only an encyclopaedic view of the different possibilities that exist today in the various fields mentioned above. An appendix included at the end of the paper presents a bibliography on finite element applications in material processing for 1994‐1996, where 1,370 references are listed. This bibliography is an updating of the paper written by Brannberg and Mackerle which has been published in Engineering Computations, Vol. 11 No. 5, 1994, pp. 413‐55.

Details

Engineering Computations, vol. 15 no. 5
Type: Research Article
ISSN: 0264-4401

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Article

Kushalkumar Thakkar, Suhas Suresh Ambekar and Manoj Hudnurkar

Longitudinal facial cracks (LFC) are one of the major defects occurring in the continuous-casting stage of thin slab caster using funnel molds. Longitudinal cracks occur…

Abstract

Purpose

Longitudinal facial cracks (LFC) are one of the major defects occurring in the continuous-casting stage of thin slab caster using funnel molds. Longitudinal cracks occur mainly owing to non-uniform cooling, varying thermal conductivity along mold length and use of high superheat during casting, improper casting powder characteristics. These defects are difficult to capture and are visible only in the final stages of a process or even at the customer end. Besides, there is a seasonality associated with this defect where defect intensity increases during the winter season. To address the issue, a model-based on data analytics is developed.

Design/methodology/approach

Around six-month data of steel manufacturing process is taken and around 60 data collection point is analyzed. The model uses different classification machine learning algorithms such as logistic regression, decision tree, ensemble methods of a decision tree, support vector machine and Naïve Bays (for different cut off level) to investigate data.

Findings

Proposed research framework shows that most of models give good results between cut off level 0.6–0.8 and random forest, gradient boosting for decision trees and support vector machine model performs better compared to other model.

Practical implications

Based on predictions of model steel manufacturing companies can identify the optimal operating range where this defect can be reduced.

Originality/value

An analytical approach to identify LFC defects provides objective models for reduction of LFC defects. By reducing LFC defects, quality of steel can be improved.

Details

International Journal of Innovation Science, vol. 13 no. 1
Type: Research Article
ISSN: 1757-2223

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Article

Kirill Blinov, Alexander Nikanorov, Bernard Nacke and Markus Klöpzig

Because of their widespread use in industry, induction through‐heaters of various metal products must be of high effectiveness not only in “quasi” steady‐state operation…

Abstract

Purpose

Because of their widespread use in industry, induction through‐heaters of various metal products must be of high effectiveness not only in “quasi” steady‐state operation but in different transient modes as well. Nowadays, they are usually designed to provide the required characteristics in “quasi” steady‐state operation mode mainly. The purpose of this paper is to examine numerical simulation of transient processes in induction through‐heating lines generally and investigate dynamic temperature fields during the first start of the heaters particularly.

Design/methodology/approach

The research methodology is based on coupled numerical electromagnetic and thermal analyses using FEM approach. ANSYS simulations are supported with the developed tools for imitation of mass transfer effects in continuous induction heating lines.

Findings

The results show that transient temperature fields in the heated strip or slab significantly differ from their “quasi” steady‐state descriptions. Local temperature variations acquired in longitudinal as well as transverse flux induction heaters during the first start have been predicted.

Practical implications

The received results can be used for design of induction through‐heaters and improvement of their characteristics in dynamic operation modes.

Originality/value

Investigation of dynamic characteristics of the heaters in dynamic modes can be only done by numerical modelling based on special algorithms providing a time loop additional to coupling between electromagnetic and thermal analyses. Such algorithms have been developed and used for investigation of two types of induction installations: through‐heaters of cylindrical billets for forging and heating lines of strip or thin slab for rolling mills.

Details

COMPEL - The international journal for computation and mathematics in electrical and electronic engineering, vol. 30 no. 5
Type: Research Article
ISSN: 0332-1649

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Article

Spyros Papaefthymiou, Theofani Tzevelekou, Alexandros Antonopoulos and Antonios Gypakis

During steel plate and long-product production, numerous imperfections and defects appear that deteriorate product quality and consequently reduce revenue. The purpose of…

Abstract

Purpose

During steel plate and long-product production, numerous imperfections and defects appear that deteriorate product quality and consequently reduce revenue. The purpose of this paper is to provide a practical overview of typical defects (surface and internal) that occur and their root causes.

Design/methodology/approach

The data presented here derive from the quality department and from more than 50 technical reports of ELKEME S.A. on the last decade’s production of steel making companies STOMANA S.A. and SIDENOR S.A., with emphasis on the defects occurred in some of the products of the Bulgarian plant. Stereoscopic observations of surface defects, light optical metallography, and scanning electron microscopy with EDS represent the most used techniques to characterize defected macro-/micro-areas and microstructures.

Findings

In general, the most commonly encountered defects from semi-finished (billets, blooms, and slabs) and final (round bar and plate) steel products are as follows: network cracks, porosity, gas holes, shrinkage, shell, slivers, casting powder entrapment, ladle slag entrapment, other non-metallic inclusions, low hot ductility, centerline segregation cracking, macro- and micro-segregation, and mechanical defects (scratches, transverse cracks, and seams).

Practical implications

External and internal quality improvement can reduce the production cost (Euro/ton).

Social implications

Improvement of the quality of industrial plates and long products increases the safety of the further-produced constructions and systems such as bridges, cranes, heavy equipment, automobile parts, etc.

Originality/value

Root cause analysis and categorization of the most commonly encountered defects can pave the way to production process improvements that directly affect final product quality and the overall per ton production cost. The benefits of this work obviously affect all steel producers/processers, and also society through the safety increase achieved by the quality improvement in the steel products used in constructions and automobile parts.

Details

International Journal of Structural Integrity, vol. 7 no. 5
Type: Research Article
ISSN: 1757-9864

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Article

Jaroslav Mackerle

To provide a selective bibliography for researchers working with bulk material forming (specifically the forging, rolling, extrusion and drawing processes) with sources…

Abstract

Purpose

To provide a selective bibliography for researchers working with bulk material forming (specifically the forging, rolling, extrusion and drawing processes) with sources which can help them to be up‐to‐date.

Design/methodology/approach

A range of published (1996‐2005) works, which aims to provide theoretical as well as practical information on the material processing namely bulk material forming. Bulk deformation processes used in practice change the shape of the workpiece by plastic deformations under forces applied by tools and dies.

Findings

Provides information about each source, indicating what can be found there. Listed references contain journal papers, conference proceedings and theses/dissertations on the subject.

Research limitations/implications

It is an exhaustive list of papers (1,693 references are listed) but some papers may be omitted. The emphasis is to present papers written in English language. Sheet material forming processes are not included.

Practical implications

A very useful source of information for theoretical and practical researchers in computational material forming as well as in academia or for those who have recently obtained a position in this field.

Originality/value

There are not many bibliographies published in this field of engineering. This paper offers help to experts and individuals interested in computational analyses and simulations of material forming processes.

Details

Engineering Computations, vol. 23 no. 3
Type: Research Article
ISSN: 0264-4401

Keywords

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Article

Robert E. Cole and Tsuyoshi Matsumiya

The purpose of this paper is to examine the possible impediments to radical innovation created by the pursuit of quality improvement in the dynamic hi‐tech sector.

Abstract

Purpose

The purpose of this paper is to examine the possible impediments to radical innovation created by the pursuit of quality improvement in the dynamic hi‐tech sector.

Design/methodology/approach

First examines contributions and limitations of extant literature. Then analyzes three cases from the Japanese hi‐tech sector, dynamic random access memory chips , network equipment, and system integration, to understand the conditions under which the pursuit of quality creates impediments for radical innovation.

Findings

Identifies a number of mechanisms, beyond the existing literature, through which the quality culture of Japanese hi‐tech firms can inhibit innovation. Particular attention is paid to the risk averse culture that may be created, thereby damaging the potential to develop radical innovation. Some exploratory strategies are offered through which firms might minimize these problems.

Originality/value

The ways in which the quality culture of Japanese hi‐tech firms poses a challenge for innovation are explored and some exploratory views on how Japanese firms might meet this challenge are offered. Above all, the paper calls for firms to think more strategically and flexibly about the role of quality at the early stages of the product cycle for hi‐tech products.

Details

The TQM Journal, vol. 20 no. 2
Type: Research Article
ISSN: 1754-2731

Keywords

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Article

Stephen H. Goldstein

Change is the catalyst of growth—it has become an axiom of our age. But why do so many companies struggle so painfully to grow in the face of change? As industry after…

Abstract

Change is the catalyst of growth—it has become an axiom of our age. But why do so many companies struggle so painfully to grow in the face of change? As industry after industry is reshaped by change, some companies thrive while others restructure. New competitors emerge and failing companies are acquired. Indeed, an updated restatement of the axiom should probably be: “Change is inevitable, but growth is optional.”

Details

Strategy & Leadership, vol. 24 no. 5
Type: Research Article
ISSN: 1087-8572

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Article

Xiaoming Luo and Matthew C. Frank

The purpose of this paper is to present an algorithm for an additive/subtractive rapid pattern manufacturing (RPM) process where thick slabs of material are sequentially…

Abstract

Purpose

The purpose of this paper is to present an algorithm for an additive/subtractive rapid pattern manufacturing (RPM) process where thick slabs of material are sequentially stacked and then cut to 3D shapes. Unlike traditional rapid prototyping processes where layer thickness is typically uniform, this process is able to vary the layer thickness in order to most effectively generate feature shapes.

Design/methodology/approach

This paper discusses the factors affecting layer thickness decisions and then presents an algorithm to determine layer thicknesses for a given part model. The system is designed to import a computer‐aided design file and use the algorithm to automatically generate the set of layers based on the slab height, material and bonding properties and the process parameters used in the system.

Findings

The layer thickness algorithm is implemented and tested using an additive/subtractive manufacturing system developed in the laboratory. The algorithm has proved effective in determining appropriate layer heights for thick slab machining, taking into account a variety of geometries. Several sand casting patterns have been successfully created using the proposed system, which could significantly improve traditional sand casting pattern manufacturing.

Originality/value

The proposed RPM process is a new process presented by the authors, developed for rapid sand castings. The layer thickness algorithm is an original contribution that enables automatic process planning for this new process.

Details

Rapid Prototyping Journal, vol. 16 no. 2
Type: Research Article
ISSN: 1355-2546

Keywords

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Article

N. Brännberg and J. Mackerle

This paper gives a review of the finite element techniques (FE)applied in the area of material processing. The latest trends in metalforming, non‐metal forming and powder…

Abstract

This paper gives a review of the finite element techniques (FE) applied in the area of material processing. The latest trends in metal forming, non‐metal forming and powder metallurgy are briefly discussed. The range of applications of finite elements on the subjects is extremely wide and cannot be presented in a single paper; therefore the aim of the paper is to give FE users only an encyclopaedic view of the different possibilities that exist today in the various fields mentioned above. An appendix included at the end of the paper presents a bibliography on finite element applications in material processing for the last five years, and more than 1100 references are listed.

Details

Engineering Computations, vol. 11 no. 5
Type: Research Article
ISSN: 0264-4401

Keywords

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Abstract

A CRITICAL stage in the process of making aircraft occurs with alarming frequency in the history of aviation.

Details

Aircraft Engineering and Aerospace Technology, vol. 26 no. 9
Type: Research Article
ISSN: 0002-2667

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