1.
R. Dojka1, J. Jezierski1, J. Campbell2
1Silesian University of Technology, Gliwice, Poland;
2University of Birmingham, Birmingham, United Kingdom
THE PRODUCTION OF QUALITY CASTINGS

2.
D. Molnar, A. Kiss, C. Majoros, D. Halapi,
Institute of Foundry Engineering, University of Miskolc, Miskolc, Hungary
CALCULATION AND SIMULATION OF PRE-FILLING AT HIGH PRESSURE DIE CASTING

3.
P. Mrvar, S. Kastelic, A. Križman, M. Terčelj, M. Petrič, D. Mitrović
Faculty of Natural Sciences and Engineering, University of Ljubljana, Ljubljana, Slovenia
NEW CAST IRON ALLOY FOR A TRANSPORT OF MOLTEN Al-ALLOYS

4.
B. Horvat1, V. Ducman1, A. Sešek Pavlin2
1Slovenian National Building and Civil Engineering Institute, Ljubljana, Slovenia
2Termit d.d., Moravče, Slovenia
WASTE FOUNDRY SAND AS PRECURSOR IN ALKALI ACTIVATION PROCESS

1.
R. Dojka1, J. Jezierski1, J. Campbell2
1Silesian University of Technology, Gliwice, Poland;
2University of Birmingham, Birmingham, United Kingdom
THE PRODUCTION OF QUALITY CASTINGS

Abstract

Traditionally in the casting industry, the pouring of liquid metal has been turbulent, entraining the surface oxide film of the metal into the melt, and so generating large populations of crack-like defects (known as bifilms) and large populations of air bubbles. The bifilms reduce mechanical properties, particularly elongation and fatigue, but can also bridge wall-to-wall, producing through-wall leakage of fluids. The bifilms are the most serious defects but are sufficiently thin to be largely invisible by X-ray, but the generally less-damaging features, the bubbles, are clearly visible and can often scrap the casting.
Transfer of metals without bifilms or bubbles into moulds is therefore an essential requirement for high quality casting. The gravity pouring techniques including contact pouring, and the fundamental aspects of the Naturally Pressurised filling system design will be described. The new uses for ceramic foam filters as bubble diverting features, and the contribution of terminal spin traps at the end of runners for bubbles and cold metal are valuable new features.
The new techniques are already in production and being proven in Al alloys, Ni alloys and steels. In general, scrap levels are greatly reduced, sometimes to zero, and costs are reduced.

2.
D. Molnar, A. Kiss, C. Majoros, D. Halapi,
Institute of Foundry Engineering, University of Miskolc, Miskolc, Hungary
CALCULATION AND SIMULATION OF PRE-FILLING AT HIGH PRESSURE DIE CASTING

Abstract

Die casting is a manufacturing process for producing accurately dimensioned, sharply defined, smooth or textured surface metal parts. It is accomplished by injecting liquid metal at fast velocity and under high pressure into reusable steel dies. Compared to other casting processes, die casting is at the top end of both velocity and pressure. The high velocity translates into a very turbulent flow condition. The process is often described as the shortest distance between raw material and the finished product.
Pre-fill is a process technique that is the result of significantly delaying the start of fast shot beyond the “metal at the gate” position. It can be stated as a percentage of cavity fill or as a distance beyond metal at the gate.

Key words: HPDC, pre-filling, simulation

Abstract

In this study, we have developed, manufactured and tested new material, perusing preferred wear resistance, superior heat conductivity and notable decreasing the cost of the unit towards existing widely used materials (hot working tool steels) for shot sleeve at HPDC process.
Investigated cast iron alloy was tested and submitted to a real production conditions, subsequently wear evaluation was performed on the critical tribologically effected surfaces.
Total production cost of the sleeve manufactured with a new advanced material, together with a different production approach has been reduced to only one third of an existing, most widely used one.

Key words: High temperature resistant cast iron alloy, characterization, microstructure.

Abstract

Aim of the article is to present the usefulness of waste foundry sand in the process of alkali activation in the building industry. With this low-price process, waste would be upgraded in circular economy, its value increased, and the problem of disposal of waste foundry sand would be lowered for the industry and nature.
Precursor, that are promissing for manufacture of alkali activated materials, contain amorphous SiO2 and Al2O3. Therefore we determined chemical and mineralogical composition of foundry sand stored in Termit's landfills and determined amounts of Si and Al in crystal and amorphous phase. Shape, size and surface of unprocessed waste foundry sand were also analyzed.
After curing, demolding and drying of alkali activated prizms from waste foundry sand, compressive and bending strength were tested.

Key words: alkali activation, foundry sand, SEM, XRF, XRD, mechanical strength