The copper and copper alloys’ ingots have been subjected to structural observation in order to estimate the Peclet Number at which these ingots were solidifying. It was stated that the formation of columnar structure within the ingots occurred at a high Peclet Number, higher than the threshold value of this parameter, Pe = 500. The formulated relationships of the Growth Law correspond to a high Peclet Number due to application of the adequate development in series of the Ivantsov’s function. The Growth Law has been developed on the basis of the definition of the wavelength of perturbation which leads to the dispersion of the planar s/l interface. New definition of the index of stability connected with the behavior of solute concentration at the s/l interface has been delivered. The current definition is related to non-equilibrium solidification. The index can be easily calculated using some parameters delivered by a given Cu-X phase diagram. Physical meaning of the formulated Growth Law has also been presented.

Micro-defects detection in solidified castings of aluminum alloy has always been a hot topic, and the method employed is mainly depends upon the size and shape of the specimens. In present paper, the amount and distribution characters of micro-defects in a series of 2219 aluminum alloy ingot, with diameters of φ1380 mm, φ1250 mm, φ1000 mm, φ850 mm and φ630 mm, prepared by direct chill casting were investigated by means of metallographic, respectively. Samples were cut along the radius direction from slices in the steady casting stage. The result reveals that typical micro-defects are consist of inclusions, porosity and shrinkage under optical microscope, and the total amount of micro-defect per unit area in an ingot slightly decreased with the increase of its diameter. Meanwhile, defects were classified into 2 types according to its size, the results suggesting that defects greater than 40 μm account for the largest proportion among the counted two kinds of defects. Moreover, the distribution of defects greater than 40 μm along the radial direction was detected, its amount increases as its distance from the side, indicating that the micro-defects greater than 40 μm distributed the most in the center zone of ingots and the larger the ingot diameter, the more obvious the tendency was.

ABSTRACT:

The main goal of this publication is to familiarize western numismatists with the current trends and findings in the research on medieval payment ingots (grivnas) in Eastern Europe. The author presents up-to-date chronological classification of silver payment ingots, shortly describes their basic types and gives the basic list of classic and modern works in this field.

Assessing the level of metallurgical and foundry technology in prehistoric times requires the examination of raw material finds, including elongated ingots, which served as semi-finished products ready for further processing. It is rare to find such raw material directly at production settlements, but Wicina in western Poland is an exception. During the Hallstatt period (800-450 BC), this area, situated along the middle Oder River, benefited from its favorable location in the heart of the Central European Urnfield cultures and developed networks for raw material exchange and bronze foundry production. Numerous remnants of casting activities, such as clay casting molds, casting systems, and raw materials, have been discovered at the Wicina settlement. This article aims to provide an archaeometallurgical interpretation of raw material management and utilization by prehistoric communities during the Early Iron Age. To achieve this, a collection of 31 ingots from the defensive settlement in Wicina, along with two contemporary deposits from Bieszków and Kumiałtowice, both found within a 20 km radius of the stronghold, were studied. Investigations were conducted using a range of methods, including optical microscopy(OM), scanning electron microscopy (SE M), energy-dispersive X-ray spectroscopy (SE M-EDS), X-ray fluorescence spectroscopy (ED-XRF), powder X-ray diffraction (PXRD), AAS and ICP-OES spectrometer. The significance of ingots is examined in the context of increasing social complexity and the rising popularity of bronze products, which necessitated diversified production and a demand for raw materials with different properties and, consequently, different chemical compositions.

The aim of this publication is to present practical application of the R. Kolman’s quality rating method used in the evaluation of aluminium alloys. The results of studies of the mechanical and physical properties of the three selected test materials are discussed. To find the best material, the quality level of each of the tested materials was assessed using quality ratings proposed by R. Kolman. The results of the conducted analysis have proved that the best material was an AKII MM alloy, i.e. a casting AK11 aluminium alloy from the 4XXX series.

The article presents the results of research concerning AlCu4MgSi alloy ingots produced using horizontal continuous casting process under variable conditions of casting speed and cooling liquid flow through the crystallizer. The mechanical properties and structure of the obtained ingots were correlated with the process parameters. On the basis of the obtained results, it has been shown that depending on the cooling rate and the intensity of convection during solidification, significant differences in the mechanical properties and structure and of the ingots can occur. The research has shown that, as the casting speed and the flow rate of the cooling liquid increase, the hardness of the test samples decreases, while their elongation increases, which is related to the increase of the average grain size. Also, the morphology of the intermetallic phases precipitations lattice, as well as the centerline porosity and dendrite expansion, significantly affect the tensile strength and fracture mechanism of the tested ingots.

Currently there is a constant development in the field of aluminium alloys engineering. This results from, i.a., better understanding of the

mechanisms that direct strengthening of these alloys and the role of microalloying. Now it is microalloying in aluminum alloys that is

receiving a lot of attention. It affects substantially the macro- and microstructure and kinetics of phase transformation influencing the

properties during production and its exploitation. 7xxx series aluminum alloys, based on the Al-Zn-Mg-Cu system, are high-strength

alloys, moreover, the presence of Zr and Sr further increases their strength and improves resistance to cracking.

This study aims to present the changes of the properties, depending on the alloy chemical composition and the macro- and microstructure.

Therefore, the characteristics in the field of hardness, tensile strength, yield strength and elongation are shown on selected examples.

Observations were made on ingot samples obtained by semi-continuous casting, in the homogenized state.

Samples were prepared from aluminum alloys in accordance with PN-EN 573-3: 2013. The advantage of Al-Zn-Mg-Cu alloys are

undoubtedly good strength, Light-weight and resistance to corrosion. As widening of the already published studies it is sought to

demonstrate the repeatability of the physical parameters in the whole volume of the sample.

The paper consists the problem of developing a scientific toolkit allowing to predict the thermal state of the ingot during its formation in all elements of the casting and rolling complex, between the crystallizer of the continuous casting machine and exit from the furnace. As the toolkit for the decision making task the predictive mathematical model of the ingot temperature field is proposed. Displacement between the various elements of the CRC is accounted for by changing the boundary conditions. Mass-average enthalpy is proposed as a characteristic of ingot cross-section temperature state. The next methods of solving a number of important problems with the use of medium mass enthalpy are developed: determination of the necessary heat capacity of ingots after the continuous casting machine for direct rolling without heating; determination of the rational time of alignment of the temperature field of ingots having sufficient heat capacity for rolling after casting; determination of the total amount of heat (heat capacity) required to supply the metal for heating ingots that have insufficient amount of internal heat.

Experimental observations of the steel morphology as well as measurements of the solutes concentration in the macro-scale were made on the basis of the vertical cut at the mid-depth of the 15-tons steel forging ingot serially produced in one of the steel plant in Poland. Experimental observations of the morphology accompanied by the measurements of the Peclet Number were also made on the cross-section of the continuously cast brass ingots serially produced in the copper / brass industry in Poland. The performed measurements allowed to work out some maps of the alloying elements segregation for the longitudinal section of the steel static ingot and a Growth Law for the columnar grains formation in the brass ingots. The marginal stability criterion has been applied to the last mentioned development / description. Some suggestions for the micro-segregation measurement mode in the columnar structure are derived.