The quality of a product is given by the extent, to which the product meets customer requirements. It is generally accepted that the extent, to which the product meets such customer requirements, ...and, consequently, the resulting quality of the product itself, substantially depend on the early stages of the product lifecycle, i.e. on the design and development stages. Appropriate means for effective product quality planning can be found among quality management methods and tools. These methods are typically employed in engineering production and automotive industry, This paper focuses on exploring the potential of Quality Function Deployment (QFD) and Failure Mode and Effect Analysis (FMEA) methods for use in metallurgical production, an industrial branch where they have not been commonly employed as yet.
Cilj članka je kritička ocjena mogućnosti matematičkog modeliranja rabljenjem softvera metode konačnih elemenata pri tekućem razrješavanju problema toplog valjanja plosnatih i šipkastih profila. U ...konkretnom primjeru fokusirano je na tvrtke u Moravsko-Sleskom rejonu (Češka). Istraživanja su uvijek kombinirana pilot mjerenjima ili laboratorijskim eksperimentima.
Thermal and mechanical parameters of forming and the process of microstructure development should be bro ught as close to real-world conditions as possible. The plane strain compression test and ...subsequent computer simulation provided an analysis of the recrystallization kinetics. A study of distribution of deformation charac teristics in the sample upon upsetting was performed together with an analysis of microstructure of AISI 304 steel during hot forming. The result of the investigation is information on grain size in the sample in relation to applied strain.
The aim of this paper is to critically assess the potential of mathematical modelling which uses finite element method software for solving operation problems in the hot rolling of flat and long ...products. We focused on concrete issues faced by rolling plants in the Moravian-Silesian region (Czech Republic). The investigation was always combined with field or pilot measurements or laboratory experiments.
The theory of kinetics of static recrystallization of steel during hot forming links the phenomenon to certain critical strain, grain size, strain rate, activation energy and temperature. The basic ...description is provided by the Avrami equation. An overview of equations used was compiled and comments on selected parameters prepared.
This paper presents a new model for calculation of critical strain for initialization of dynamic recrystallization. The new model reflects the history of forming in the deformation zone during ...rolling. In this region of restric ted deformation, the strain rate curve for the surface of the strip exhibits two peaks. These are the two reasons why the onset of dynamic recrystallization DRX near the surface of the rolled part occurs later than in theory during strip rolling. The present model had been used in a program for simulation of forming processes with the aid of FEM and a comparison between the physical experiment and a mathematical model had been drawn.
Teorija kinetike statičke rekristalizacije čelika tijekom vrućeg oblikovanja ovu pojavu povezuje s kritičnom deformacijom, veličinom zrna, brzinom deformacije, aktivacijskom energijom te s ...temperaturom. Osnovni opis pruža Avrami jednadžba. Rad pruža pregled korištenih jednadžbi i raspravu pojedinih parametara.
Termički i mehanički parametri oblikovanja i stvaranje mikrostrukture trebaju biti što bliži realnim uvjetima. Test ravninskom tlačnom deformacijom i daljnja računalna simulacija omogućili su analizu ...kinetike rekristalizacije. Istraživanje raspodjele deformacijskih karakteristika u uzorku po rasterećenju provedeno je zajedno s analizom mikrostrukture čelika AISI 304 tijekom vrućeg oblikovanja. Dobiveni su podaci o veličini zrna uzorka ovisno o narinutoj deformaciji.
Investigation of causes of cracking in the interior of thick rolled products. First part of the study concerns research into possible causes of cracking with respect to termal conditions of rolling ...and microstructural features of steel. Examination of microstructure revealed casting cracks on prior austenite grain boundaries, which might initiate formation of the critical cracks. Second part of paper contains FormFEM and Forge2005 program simulation-aided feasibility study of enhancing the amount of reduction in the bloom centre by means of bloom surface undercooling. Comparison of common rolling process and the newly-designed process is provided. Primary attention has been paid to the magnitude (and sign) of the longitudinal and tansversal stresses in the bloom cross-section and to penetration of strain into the bloom centre.
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