The paper presents results of measuring heat diffusivity and thermal conductivity coefficients of used green foundry sand in temperature

range ambient – 600 o

C. During the experiments a technical purity Cu plate was cast into the green-sand moulds. Basing on measurements

of the mould temperature field during the solidification of the casting, the temperature relationships of the measured properties were

evaluated. It was confirmed that the obtained relationships are complex and that water vaporization strongly influences thermal

conductivity of the moulding sand in the first period of the mould heating by the poured and solidified casting

The paper presents issues related to the technology of layered castings manufactured in the system: working part made of high-chromium steel X46Cr13 - base part made of gray cast iron with flake graphite, using the mould cavity preparation technology. Considering the high hardenability of the above-mentioned steel grade, the aim of the research was to optimize the casting parameters of gray cast iron in such a way that it would be possible to perform heat treatment of X46Cr13 steel directly in the casting mould. As part of the research, the geometry of the working and base parts of layered castings was selected, and guidelines for mould technology from the point of view of the moulding sand were developed. In order to control the cooling rate, three matrix of the moulding sand were used - quartz sand, chromite sand and silicon carbide, with the same granularity. The thermal conductivity coefficient of sands made on selected matrix, bound with synthetic resin in the ratio of 30:1, was experimentally determined. Then, the bimetal casting process in a given mass was simulated in the MagmaSoft® (ver. 5.4.1). The purpose of the simulation was to determine the maximum virtual temperature Tm in the thermal center of the outer surface of the X46Cr13 steel insert. From the point of view of the research purpose, the insert was expected to heat up to the austenitization temperature, i.e. at least 950°C.

The paper presents results of measuring attenuation coefficient of the Al-20 wt.% Zn alloy (AlZn20) inoculated with different grain

refiners. During experiments the melted alloys were doped with Al-Ti3-C0.15 refining master alloy. Basing on measurements performed

by Krautkramer USLT2000 device with 1MHz ultrasound wave frequency it was stated that grain refinement reduces the attenuation

coefficient by about 20-25%. However, the examined alloys can be still classified as the high-damping ones of attenuation greater than 150

dB/m.

The paper is devoted to grain-refinement of the medium-aluminium zinc based alloys (MAl-Zn). The system examined was sand cast Zn10

wt. %. Al binary alloy (Zn-10Al) doped with commercial Al-3 wt. % Ti – 0.15 wt. % C grain refiner (Al-3Ti-0.15C GR). Basing on the

measured attenuation coefficient of ultrasonic wave it was stated that together with significantly increased structure fineness damping

decreases only by about 10 – 20%. The following examinations should establish the influence of the mentioned grain-refinement on

strength and ductility of MAl-Zn cast alloys.

The paper presents results of measuring thermal conductivity and heat capacity of bentonite foundry sand in temperature range ambient –

900 OC. During the experiments a technical purity Cu plate was cast into the green-sand moulds. Basing on measurements of the mould

temperature field during the solidification of the casting, the temperature relationships of the measured properties were evaluated. It was

confirmed that water vaporization strongly influences thermal conductivity of the moulding sand in the first period of the mould heating by

the poured casting.