The paper presents Lusatian culture bronze artefacts recovered in the Orava region in northern Slovakia, which allows for tracing connections with the territory of present-day Poland in the Late Bronze Age and the Early Iron Age. The object is to discuss the provenance of the Lusatian bronze artefacts and analyse possible intercultural contacts with the north, across the Carpathians.
The mold temperature of the downward continuous unidirectional solidification (CUS) cannot be controlled higher than the liquidus of alloys to be cast. Therefore, the continuous casting speed becomes the main parameter for controlling the growth of columnar crystal structure of the alloy. In this paper, the tin bronze alloy was prepared by the downward CUS process. The microstructure evolution of the CUS tin bronze alloy at different continuous casting speeds was analysed. In order to further explain the columnar crystal evolution, a relation between the growth rate of columnar crystal and the continuous casting speed during the CUS process was built. The results show that the CUS tin bronze alloy mainly consists of columnar crystals and equiaxed crystals when the casting speed is low. As the continuous casting speed increases, the equiaxed crystals begin to disappear. The diameter of the columnar crystal increases with the continuous casting speed increasing and the number of columnar crystal decreases. The growth rate of columnar crystal increases with increasing of the continuous casting speed during CUS tin bronze alloy process.
The focus of the article is the Vatin culture settlement at the site of Vinča-Belo Brdo in Northern Serbia. The general idea is that this settlement, whose existence was relatively short in time, benefited from being established by the Danube — a great connective factor in the world of the Middle Bronze Age. It shares many characteristics with the contemporary settlements in the southernmost part of the Carpathian basin, starting from the position in the vicinity of the Danube, at the places which had already been settled in prehistory, prior to the Middle Bronze Age. Not only do they have pottery style in common, but the wider repertoire of finds illustrating the material culture. What’s more, comparison of the material remains from Vinča with the neighbouring sites from the left Danube bank enlightens how the Vatin culture was integrated into a wider space of the Bronze Age cultures of the Carpathian basin, influencing the Balkans hinterland, too.
Among the copper based alloys, Cu-Al-X bronzes are commonly used as mold materials due to their superior physical and chemical properties. Mold materials suffer from both wear and corrosion, thus, it is necessary to know which one of the competitive phenomenon is dominant during the service conditions. In this study, tribo-corrosion behavior of CuAl10Ni5Fe4 and CuAl14Fe4Mn2Co alloys were studied and electrochemical measurements were carried out using three electrode system in 3.5 % NaCl solution in order to evaluate their corrosion resistance. In tribo-corrosion tests, alloys were tested against zirconia ball in 3.5 % NaCl solution, under 10N load with 0.04 m/s sliding speed during 300 and 600 m. The results indicate that (i) CuAl10Ni5Fe4 alloy is more resistant to NaCl solution compared to CuAl14Fe4Mn2Co alloy that has major galvanic cells within its matrix, (ii) although CuAl10Ni5Fe4 alloy has lower coefficient of friction value, it suffers from wear under dry sliding conditions, (iii) as the sliding distance increases, corrosion products on CuAl14Fe4Mn2Co surface increase at a higher rate compared to CuAl10Ni5Fe4 leading to a decrease in volume loss due to the lubricant effect of copper oxides.
Metallographic investigations and a computer simulation of stresses in a gravity die-casting bushing were performed. Simulation of the casting process, solidification of the thick-walled bushing and calculations of the stress was performed using MAGMA5.3 software. The size variability of phases κIIaffecting the formation of phase stresses σf, depending on the location of the metallographic test area, was identified. The distribution of thermal σtand shrinkage stresses σs, depending on the location of the control point SC in the bushing's volume, was estimated. Probably the nature of these stresses will change slightly even after machining. This can cause variations in operating characteristics (friction coefficient, wear). Due to the strong inhomogeneity of the stress distribution in the bushing's casting, it is necessary to perform further tests of the possibility to conduct thermal treatment guaranteeing homogenization of the internal stresses in the casting, as well as to introduce changes in the bushing's construction and the casting technology. The paper presents the continuation of the results of research aimed at identifying the causes of defects in the thick-walled bushing, die-casting made of CuAl10Fe5Ni5Cr aluminium bronze.
The article presents research results performed on aluminum bronze CuAl10Fe5Ni5 (BA1055) castings used for marine propellers.
Metallographic studies were made on light microscope and a scanning electron microscope to assess quantitatively and qualitatively the
alloy microstructure. It has been shown that the shape, size and distribution of the iron-rich κ−phase precipitates in bronze microstructure
significantly affect its mechanical properties. With an increase in the number of small κ−phase precipitates increases the tensile strength of
castings, while the presence of large globular precipitates improves ductility. Fragmentation and shape of κ−phase precipitates depends on
many factors, particularly on the chemical composition of the alloy, Fe/Ni ratio, cooling rate and casting technology.
The exudation layer seriously affects the properties and the surface finish of the tin bronze alloy. The effective control of the exudation thickness is important measure for improving the properties of the alloy. In order to study the influence of process parameters on the thickness of exudate layer, the tin bronze alloy was prepared by continuous unidirectional solidification technology at different process parameters. The microstructure of the continuous unidirectional solidification tin bronze alloy was analyzed. The effect of process parameters on microstructure and chemical compositions was studied by orthogonal experiment. The results show that there exists an exudation layer on the surface of the continuous unidirectional solidification tin bronze alloy, and the exudation is mainly composed of a tin-rich precipitated phase. It indicates that the continuous casting speed is the main factor affecting the thickness of exudation layer, followed by mold temperature, melt temperature, cooling water temperature and cooling distance.
A significant part of the knowledge used in the production processes is represented with natural language. Yet, the use of that knowledge
in computer-assisted decision-making requires the application of appropriate formal and development tools. An interesting possibility is
created by the use of an ontology that is understandable both for humans and for the computer. This paper presents a proposal for
structuring the information about the foundry processes, based on the definition of ontology adapted to the physical structure of the
ongoing technological operations that make up the process of producing castings.
The publication presents a novel concept of the process of plastic forming of variable longitudinal-section cylindrical products, being the subject of Patent Application P.427426 [1]. Additionally, these products are provided with a connection stub pipe. The plastic forming method proposed in the article combines many advantages and utilitarian benefits associated with the manufacturing technology itself, as well as with its further implementation. Using stock in the form of normalized bar commonly available in the metal product market as a finished product obviously reduces the process costs involved with stock preparation, i.e. casting, rolling, machining, etc. It also results in obtaining a much smaller surface area of stock contact with the tool and, as a consequence, a smaller surface of stock friction against the tool, which contributes to a reduction of force needed for the plastic forming of the product. The smaller contact surface area and the shorter time of stock contact with the cooler tool cause, above all, less intensive heat exchange and stock chilling. This has a significant effect on the plasticity of the cast material and, as a consequence, the plastic forming force. The proposed method enables also manufacturing cylinders with either a closed or open stub pipe with a regulated length and a varying section. In addition, unlike the method known from Polish Patent Specification PL 212062 [2], the proposed method does not require using a multi-tool press. The upper punch is furnished with a flange, whose job is to start the stock extruding sleeve at the next process stage.
Cast axes are one of the most numerous categories of bronze products from earlier phases of the Bronze Age found in Poland. They had multiple applications since they were not only used objects such as tools or weapons but also played the prestigious and cult roles.
Investigations of the selected axes from the bronze products treasure of the Bronze Age, found in the territory of Poland, are presented
in the hereby paper. The holder of these findings is the State Archaeological Museum in Warsaw. Metallurgical investigations of axes with bushing were performed in respect of the casting technology and quality of obtained castings. Macroscopic observations allowed to document the remains of the gating system and to assess the range and kind of casting defects. Light microscopy revealed the microstructure character of these relicts. The chemical composition was determined by means of the X-ray fluorescence method with energy dispersion (ED-XRF) and by the scanning electron microscopy with X-ray energy dispersion analysis in micro-areas (SEM-EDS). The shape and dimensions of cores, reproducing inner parts of axes were identified on the basis of the X-ray tomography images. Studies reconstructed production technology of the mould with gating system, determined chemical composition of the applied alloys and casting structures as well as revealed the casting defects being the result of construction and usage of moulds and cores.
With the increase in wall thickness of the casting of iron-nickel-aluminium-bronze, by the reduction of the cooling rate the size of κII phase
precipitates increases. This process, in the case of complex aluminium bronzes with additions of Cr, Mo and W is increased. Crystallization
of big κII phase, during slow cooling of the casting, reduces the concentration of additives introduced to the bronze matrix and hardness.
Undertaken research to develop technology of thick-walled products (g> 6 mm) of complex aluminium bronzes. Particular attention
was paid to the metallurgy of granules. As a result, a large cooling speed of the alloy, and also high-speed solidification casting a light
weight of the granules allows: to avoid micro-and macrosegregation, decreasing the particle size, increase the dispersion of phases in
multiphase alloys. Depending on the size granules as possible is to provide finished products with a wall thickness greater than 6 mm by
infiltration of liquid alloy of granules (composites). Preliminary studies was conducted using drip method granulate of CuAl10Fe5Ni5
bronze melted in a INDUTHERM-VC 500 D Vacuum Pressure Casting Machine. This bronze is a starting alloy for the preparation of the
complex aluminium bronzes with additions of Cr, Mo, W and C or Si. Optimizations of granulation process was carried out. As the process
control parameters taken a casting temperature t (°C) and the path h (mm) of free-fall of the metal droplets in the surrounding atmosphere
before it is intensively cooled in a container of water. The granulate was subjected to a sieve analysis. For the objective function was
assume maximize of the product of Um*n, the percentage weight "Um" and the quantity of granules 'n' in the mesh fraction. The maximum
value of the ratio obtained for mesh fraction a sieve with a mesh aperture of 6.3 mm. In the intensively cooled granule of bronze was
identified microstructure composed of phases: β and fine bainite (α+β'+β'1) and a small quantity of small precipitates κII phase. Get high
microhardness bronze at the level of 323±27,9 HV0,1.
The present article deals with the possibility of using the reverse engineering method for the production of prototype molds by Patternless
process technology. Article describes method how to obtain virtual model by using a 3D scanner. Article also explains principle of the
Patternless process technology, which is based on the milling mold cavity using CNC machining equipment. The aim of the research is the
use of advanced technologies that speed up and facilitate the process of production prototype mold. The practical result of the presented
experiment is bronze casting, which serves as a foot rest bracket on historic bike.
The main scope of the article is the development of a computer system, which should give advices at problem of cooper alloys
manufacturing. This problem relates with choosing of an appropriate type of bronze (e.g. the BA 1044 bronze) with possible modification
(e.g. calcium carbide modifications: Ca + C or CaC2) and possible heat treatment operations (quenching, tempering) in order to obtain
desired mechanical properties of manufactured material described by tensile strength - Rm, yield strength - Rp0.2 and elongation - A5. By
construction of the computer system being the goal of presented here work Case-based Reasoning is proposed to be used. Case-based
Reasoning is the methodology within Artificial Intelligence techniques, which enables solving new problems basing on experiences that
are solutions obtained in the past. Case-based Reasoning also enables incremental learning, because every new experience is retained each
time in order to be available for future processes of problem solving. Proposed by the developed system solution can be used by
a technologist as a rough solution for cooper alloys manufacturing problem, which requires further tests in order to confirm it correctness.
This paper presents the influence of annealing time 30, 60 and 120 min at 1000°C for quenching CuAl7Fe5Ni5W2Si2 bronze in 10% water solution of NaCl, on the microstructure and mechanical properties. The presented results concern the species newly developed aluminum-iron-nickel bronze, with additions W and Si. In order to determine changes in the microstructure of the hardened bronze metallographic studies were performed on cylindrical samples of diameter 10 mm, on the metallographic microscope with digital image analysis, X-ray phase analysis, EDX point with the digital recording on the computer. Specified percentage of the microstructure of martensite and bainite, participation of proeutectoid α phase in the microstructure, grain size of former β phase, the amount of dissolved κ phase. It was found that in the microstructure of bronze in the cast state, there are a number of intermetallic phases of κ type. At interphase boundaries of primary intermetallic faceted precipitates, especially rich in tungsten (IM_W), nucleate and grow dendritic primary intermetallic κI phases, with chemical composition similar to the type of Fe3Si iron silicide. Dissolved, during the heating, in the β phase are all the intermediate phase included in the microstructure, with the exception of primary intermetallic phases of tungsten and κI. Prolongation of the isothermal annealing causes coagulation and coalescence of primary phases. In microstructure of the bronze after quenching obtained the α phase precipitation on the grain boundary of secondary β phase, coarse bainite and martensite, for all annealing times. With the change of annealing time are changed the relative proportions of individual phases or their systems, in the microstructure. In the microstructure of bronze, hold at temperature of 1000°C for 60 min, after quenching martensitic microstructure was obtained with the primary phases, and the least amount of bainite