In this study, the mechanical tests were carried out on ductile iron of EN-GJS-600-3 grade and on grey cast iron of EN-GJL-250 grade. The fatigue life was evaluated in a modified low-cycle fatigue test (MLCF), which enables the determination of parameters resulting from the Manson-Coffin-Morrow relationship. The qualitative and quantitative metallographic studies conducted by light microscopy on selected samples of ductile iron with spheroidal graphite and grey cast iron with lamellar graphite (showing only small variations in mechanical properties,) confirmed also small variations in the geometrical parameters of graphite related with its content and morphological features.
The paper presents the results of comparative tests of the fatigue properties conducted on two non-ferrous alloys designated as Al 6082 and
Al 7075 which, due to the satisfactory functional characteristics, are widely used as engineering materials. The fatigue tests were carried
out using a proprietary, modified low cycle test (MLCF). Particular attention was paid to the fatigue strength exponent b and fatigue
ductility exponent c. Based on the tests carried out, the results comprised within the range defined by the literature were obtained. These
results prove a satisfactory sensitivity of the method applied, its efficiency, the possibility of conducting tests in a fully economical way
and above all the reliability of the obtained results of the measurements. Thus, the thesis has been justified that the modified low cycle
fatigue test (MLCF) can be recommended as a tool used in the development of alloy characteristics within the range of low-cycle variable
loads
This study discloses the characteristic features of the modified low-cycle fatigue test used for the determination of the mechanical
properties of two types of cast iron, i.e. EN-GJL-250 and EN-GJS-600-3. For selected materials, metallographic studies were also
conducted in the range of light microscopy and scanning microscopy.
Theory and practice of environmental protection in the case of foundries in Europe and Asia
• Experience resulting from the cooperation with the foundries in a few European countries, China and India
• Phenomena and factors affecting the pollution of the natural environment and the implementation of measures aiming at the
environmental protection
Every specialist dealing with foundry processes and their impact on environmental pollution must have encountered in their professional
careers numerous situations in which the theory of environmental protection confronts the stark reality. The discrepancy between theory
and practice can particularly be noticed in foundry engineering in developing countries where the contrasts between different countries and
casting plants are extremely striking. The comparison of working conditions in European and Asian foundries provides a vast scope for
further observations and analyses. Environmental protection seems not only a concern of manufacturers of castings, but also of their
customers whose opinion exerts a significant influence on both the acceptability of working conditions and on the approach to
environmental pollution adopted in metal casting industry.
The article presents a number of examples of various outlooks on environmental issues in foundries manufacturing a wide range of cast
steel and cast iron castings, where different technologies and production processes are applied.
Of great importance in the selection of materials for cast structures is keeping a proper balance between the mechanical and plastic properties,
while preserving the relevant casting properties. This study has been devoted to an analysis of the choice and application of highstrength
aluminium-based alloys maintaining sufficient level of casting properties. The high level of tensile strength (Rm > 500 MPa)
matched with satisfactory elongation (A > 3%) is important because materials of this type are used for cast parts operating in the aerospace,
automotive, and military industries. These beneficial relationships between the high tensile strength and toughness are relatively easy to
obtain in the Al-Zn-Mg-Cu alloys subjected to plastic forming and proper heat treatment. In gravity cast products, on the other hand,
whether poured into sand moulds or metal moulds (dies), obtaining this favourable combination of properties poses a number of research
problems (mostly resulting from the alloy chemical composition) as well as technical and technological difficulties.
The results of studies presented in this article are an example of the research activity of the authors related to lead-free alloys. The studies covered binary SnZn90 and SnZn95 lead-free alloys, including their microstructure and complex mechanical characteristics. The microstructure was examined by both light microscopy (LM) and scanning electron microscopy (SEM). The identification of alloy chemical composition in micro-areas was performed by SEM/EDS method. As regards light microscopy, the assessment was of both qualitative and quantitative character. The determination of the geometrical parameters of microstructure was based on an original combinatorial method using phase quantum theory. Comprehensive characterization of mechanical behavior with a focus on fatigue life of alloys was performed by means of the original modified low cycle fatigue method (MLCF) adapted to the actually available test machine. The article discusses the fatigue life of binary SnZn90 and SnZn95 alloys in terms of their microstructure. Additionally, the benefits resulting from the use of the combinatorial method in microstructure examinations and MLCF test in the quick estimation of several mechanical parameters have been underlined.
Fatigue investigations of two 4XXX0-series aluminum alloys (acc. PN-EN 1706) within a range of fewer than 104 cycles at a coefficient of cycle asymmetry of R = –1 were performed in the current paper. The so-called modified low-cycle test, which provided additional information concerning the fatigue life and strength of the tested alloys, was also performed. The obtained results were presented in the form of diagrams: stress amplitude σa – number of cycles before damage N. On the basis of the microscopic images of sample fractures, the influence of the observed casting defects on the decrease of cycle numbers at a given level of stress amplitude were analyzed. Based on the images and dimensions of the observed defects, stress intensity factor KI was analytically determined for each. Their numerical models were also made, and stress intensity factor KI was calculated by the finite element method (FEM).
The study includes the results of research conducted on selected lead-free binary solder alloys designed for operation at high temperatures.
The results of qualitative and quantitative metallographic examinations of SnZn alloys with various Zn content are presented. The
quantitative microstructure analysis was carried out using a combinatorial method based on phase quanta theory, per which any
microstructure can be treated as an array of elements disposed in the matrix material. Fatigue tests were also performed using the
capabilities of a modified version of the LCF method hereinafter referred to in short as MLCF, which is particularly useful in the
estimation of mechanical parameters when there are difficulties in obtaining many samples normally required for the LCF test. The fatigue
life of alloys was analyzed in the context of their microstructure. It has been shown that the mechanical properties are improved with the
Zn content increasing in the alloy. However, the best properties were obtained in the alloy with a chemical composition close to the
eutectic system, when the Zn-rich precipitates showed the most preferred morphological characteristics. At higher content of Zn, a strong
structural notch was formed in the alloy because of the formation in the microstructure of a large amount of the needle-like Zn-rich
precipitates deteriorating the mechanical characteristics. Thus, the results obtained during previous own studies, which in the field of
mechanical testing were based on static tensile test only, have been confirmed. It is interesting to note that during fatigue testing, both
significant strengthening and weakening of the examined material can be expected. The results of fatigue tests performed on SnZn alloys
have proved that in this case the material was softened.
The ecological meanings clearly indicates the need of reducing of the concentration of the CO2in the atmosphere, which can be accomplished through the lowering of the fuel consumption. This fact implies the research for the new construction solutions regarding the reduction of the weight of vehicles. The reduced weight of the vehicle is also important in the case of application of the alternative propulsion, to extend the lifetime of the batteries with the reduction of recharge cycles. The use of cast alloy AlZnMgCu compliant of plastic forming class 7xxx alloy, are intended to significantly reduce the weight of the structures, while ensuring high strength properties. The wide range of the solidification temperature, which is more than 150°C, characterizes this alloy with a high tendency to create the micro and macro porosity. The study presents the relationship between the cooling rate and the area of occurrence and percentage of microporosity. Then the results were linked to the local tensile strength predicted in the simulation analysis. The evaluation of the microporosity was performed on the basis of the CT (computed tomography) and the analysis of the alloy microstructure. The microstructure analysis was carried out on test specimen obtained from the varying wall thickness of the experimental casting. The evaluation of the mechanical properties was prepared on the basis of the static tensile test and the modified low cycle fatigue test (MLCF).
The article discusses the weldment to casting conversion process of rocker arm designed for operation in a special purpose vehicle to
obtain a consistency of objective functions, which assume the reduced weight of component, the reduced maximum effort of material
under the impact of service loads achieved through topology modification for optimum strength distribution in the sensitive areas, and the
development of rocker arm manufacturing technology. As a result of conducted studies, the unit weight of the item was reduced by 25%,
and the stress limit values were reduced to a level guaranteeing safe application.
The article presents the analysis of properties of the high-strength AlZnMgCu (abbr AlZn) aluminium alloy and estimates possibilities of
its application for responsible structures with reduced weight as an alternative to iron alloy castings. The aim of the conducted studies was
to develop and select the best heat treatment regime for a 7xx casting alloy based on high-strength materials for plastic working from the
7xxx series. For analysis, wrought AlZnMgCu alloy (7075) was selected. Its potential of the estimated as-cast mechanical properties
indicates a broad spectrum of possible applications for automotive parts and in the armaments industry. The resulting tensile and fatigue
properties support the thesis adopted, while the design works further confirm these assumptions.
Lead-free alloys containing various amounts of zinc (4.5%, 9%, 13%) and constant copper addition (1%) were discussed. The results of
microstructure examinations carried out by light microscopy (qualitative and quantitative) and by SEM were presented. In the light
microscopy, a combinatorial method was used for the quantitative evaluation of microstructure. In general, this method is based on the
phase quanta theory according to which every microstructure can be treated as an arrangement of phases/structural components in the
matrix material. Based on this method, selected geometrical parameters of the alloy microstructure were determined. SEM examinations
were based on chemical analyses carried out in microregions by EDS technique. The aim of the analyses was to identify the intermetallic
phases/compounds occurring in the examined alloys. In fatigue testing, a modified low cycle fatigue test method (MLCF) was used. Its
undeniable advantage is the fact that each time, using one sample only, several mechanical parameters can be estimated. As a result of
structure examinations, the effect of alloying elements on the formation of intermetallic phases and compounds identified in the examined
lead-free alloys was determined. In turn, the results of mechanical tests showed the effect of intermetallic phases identified in the
examined alloys on their fatigue life. Some concepts and advantages of the use of the combinatorial and MLCF methods in materials
research were also presented.
The article presents the study results of Sn-Zn lead-free solders with the various Zn content. The results concern the hypoeutectic, eutectic and hypereutectic alloys containing respectively 4.5% Zn, 9% Zn and 13.5% Zn. Moreover, these alloys contain the constant Ag (1%) addition. The aim of the study was to determine the microstructural conditionings of their fatigue life. In particular it was focused on answer the question what meaning can be assigned to the Ag addition in the chemical composition of binary Sn-Zn alloys. The research includes a qualitative and quantitative assessments of the alloy microstructures, that have been carried out in the field of light microscopy (LM). In order to determine some geometrical parameters of the microstructure of alloys the combinatorial method based on the phase quanta theory was applied. Moreover, for the identification necessities the chemical analyses in the micro-areas by SEM/EDS technics were also performed. Based on the SEM/EDS results the phases and intermetallic compounds existing in the examined lead-free solders were identified. The mechanical characteristics were determined by means of the modified low cycle test (MLCF). Based on this method and on the results obtained every time from only one sample the dozen of essential mechanical parameters were evaluated. The research results were the basis of analyzes concerning the effects of microstructural geometrical parameters of lead-free alloys studied on their fatigue life at ambient temperature.
The development of a novel design for the toothed segment of drive transmission in longwall shearer is expected to significantly reduce
the cost of individual components of the feed system and the related work of repair and renovations, increasing at the same time the safety
of mine repair teams.
The conducted experimental and numerical analysis of the state of stress and strain in the innovative design of the toothed segment has
enabled estimating the maximum effort of the developed structure. Based on the results of fundamental mechanical studies of the cast
L20HGSNM steel and fatigue tests combined with the numerical stress/strain analysis, the fatigue life curve was plotted for the examined
casting of the rack.