Livarski vestnik 56 / 2009 Nr. 1

Tomas Elbel, Jiri Hampl
EFFECT OF CHEMICAL COMPOSITION UPON PINHOLES FORMATION IN COMPACTED GRAPHITE CAST IRON

Mitja Petrič, Primož Mrvar, Jožef Medved, Maja Vončina, Boštjan Meglič
MECHANICAL PROPERTIES OF AL-ALLOYS THAT DEPEND ON DIE-CASTING PARAMETERS

Sebastjan Kastelic, Primož Mrvar, Jožef Medved, Marek Slovaček
SIMULATION OF THE WELDING AND HEAT TREATMENT PROCESS FOR S355 STEEL

Tomas Elbel, Jiri Hampl
VSB – Technical University of Ostrava, Faculty of Metallurgy and Materials Engineering (CZ)

EFFECT OF CHEMICAL COMPOSITION UPON PINHOLES FORMATION IN COMPACTED GRAPHITE CAST IRON

Abstract

The authors of this contribution have met the occurrence of pinholes in experimental iron castings during the study of reoxidation processes of metals cast in green sand moulds. Several contributions were published with this topic [1, 2, 3]. In technical literature the problem of pinholes formation in iron castings has been thoroughly discussed, and namely for lamellar graphite cast irons (EN GJL) and spheroidal graphite ones (EN GJS). Therefore it can be assumed that the mechanism of pinholes formation in cast irons is sufficiently well-known and this casting defect can be prevented as well as in the case of steel castings. In spite of this pinholes occur in foundries when pouring lamellar graphite as well as spheroidal graphite cast irons, ones, too, and similarly as in case of steel castings in the past the question appears as an emergency epidemic occurrence. This study is aimed at an almost unexplored field of the pinholes occurrence in castings from compacted graphite cast iron (EN GJV).

Mitja Petrič, Primož Mrvar, Jožef Medved, Maja Vončina, Boštjan Meglič
Department of Materials and Metallurgy, Faculty of Natural Sciences and Engineering, University of Ljubljana

MECHANICAL PROPERTIES OF AL-ALLOYS THAT DEPEND ON DIE-CASTING PARAMETERS

Abstract

This paper presents some mechanical properties of various Al-alloys determined with the high-pressure die-cast test bars. The tested alloys were: Al-230D (AlSi12(Fe)), Al-231D (AlSi12Cu(Fe)), Al-226D (AlSi9Cu3(Fe)), and Al-UF-94 (AlZn10Si8Mg), and they all were the high-pressure die casting alloys. The specimens were cast and prepared according to European standards and then tested with two different tensile-testing machines. The temperatures of the high-pressure die-casting tools were monitored, and casting parameters were changed during casting the test bars. Variations of mechanical properties were determined with changing casting parameters.

Sebastjan Kastelic 1, Primož Mrvar 1, Jožef Medved 1, Marek Slovaček 2
1) Faculty of Natural Sciences and Engineering, University of Ljubljana, Slovenia
2) Mecas Esi, Czech Republic

SIMULATION OF THE WELDING AND HEAT TREATMENT PROCESS FOR S355 STEEL

Abstract

Several parameters influence the welding process. Some of them can be very well forecast when having enough experience. But in welding big, unique structures the complicated geometry can lead to wrong forecasts. Deformations after welding can be foreseen also with a simulation program. The only program that takes into account all the parameters of the welding process is the Sysweld software package. The mentioned software enables the simulation of the welding and heat treatment process for steel since it also takes the CCT diagram into account in the calculations. Thus the microstructure after welding can be foreseen. Further, the foreseen change of microstructure enables accurate calculation of stresses and deformations after the welding procedure. The results of the first stage of simulation calculation in welding a test cover will be presented. Calculation will be performed with the local-global method. The first stage represents the calculation of stresses and deformations in local models. These results will be applied in the calculation of stresses and deformations for the complete – global – model in the second stage.
Key words: Simulation of welding, local-global method, Sysweld