Results of investigations of wear resistant of two species of cast steel were introduced in the article (low-alloyed and chromium cast steel) on the background of the standard material which was low alloy wear resistant steel about the trade name CREUSABRO ®8000. The investigations were executed with two methods: abrasive wears in the stream of loose particles (the stream of quartz sand) and abrasive wears particles fixed (abrasive paper with the silicon carbide). Comparing the results of investigations in the experiments was based about the counted wear index which characterizes the wears of the studied material in the relation to the standard material.
The paper presents the results of simulation of alloy layer formation process on the model casting. The first aim of this study was to
determine the influence of the location of the heat center on alloy layer’s thickness with the use of computer simulation. The second aim of
this study was to predict the thickness of the layer. For changes of technological parameters, the distribution of temperature in the model
casting and temperature changes in the characteristic points of the casting were found for established changes of technological
parameters. Numerical calculations were performed using programs NovaFlow&Solid. The process of obtaining the alloy layer with good
quality and proper thickness depends on: pouring temperature, time of premould hold at the temperature above 1300o
C. The obtained
results of simulation were loaded to authorial program Preforma 1.1 in order to determine the predicted thickness of the alloy casting
The paper presents the results of investigation into the technological possibility of making light-section castings of GX2CrNiMoN25-6-3
cast steel. For making castings with a wall thickness in the thinnest place as small as below 1 mm, the centrifugal casting technology was
employed. The technology under consideration enables items with high surface quality to be obtained, while providing a reduced
consumption of the charge materials and, as a result, a reduction in the costs of unit casting production.
Structure, and thus the mechanical properties of steel are primarily a function of chemical composition and the solidification process which can be influenced by the application of the inoculation treatment. This effect depends on the modifier used. The article presents the results of studies designed to assess the effects of structural low alloy steel inoculation by selected modifying additives. The study was performed on nine casts modeled with different inoculants, assessment of the procedure impact was based on the macrostructure of made castings. The ratio of surface area equivalent to the axial zone of the crystals and columnar crystals zone was adopted as a measure of the inoculation effect.
The investigations were inspired with the problem of cracking of steel castings during the production process. A single mechanism
of decohesion – the intergranular one – occurs in the case of hot cracking, while a variety of structural factors is decisive for hot cracking
initiation, depending on chemical composition of the cast steel. The low-carbon and low-alloyed steel castings crack due to the presence
of the type II sulphides, the cause of cracking of the high-carbon tool cast steels is the net of secondary cementite and/or ledeburite
precipitated along the boundaries of solidified grains. Also the brittle phosphor and carbide eutectics precipitated in the final stage
solidification are responsible for cracking of castings made of Hadfield steel. The examination of mechanical properties at 1050°C
revealed low or very low strength of high-carbon cast steels.
In the paper the results and analysis of abrasive wear studies were shown for two grades of cast steels: low-alloyed cast steel applied for
heavy machinery parts such as housing, covers etc. and chromium cast steels applied for kinetic nodes of pin-sleeve type. Studies were
performed using the modified in Department of Foundry pin-on-disc method.
In this study, Taguchi method is used to find out the effect of micro alloying elements like vanadium, niobium and titanium on the
hardness and tensile strength of the normalized cast steel. Based on this method, plan of experiments were made by using orthogonal
arrays to acquire the data on hardness and tensile strength. The signal to noise ratio and analysis of variance (ANOVA) are used to
investigate the effect of these micro alloying elements on these two mechanical properties of the micro alloyed normalized cast steel. The
results indicated that in the micro alloyed normalized cast steel both these properties increases when compared to non-micro-alloyed
normalized cast steel. The effect of niobium addition was found to be significantly higher to obtain higher hardness and tensile strength
when compared to other micro alloying elements. The maximum hardness of 200HV and the maximum tensile strength of 780 N/mm2
were obtained in 0.05%Nb addition micro alloyed normalized cast steel. Micro-alloyed with niobium normalized cast steel have the finest
and uniform microstructure and fine pearlite colonies distributed uniformly in the ferrite. The optimum condition to obtain higher hardness
and tensile strength were determined. The results were verified with experiments.
The paper presents the results of research on the microstructure of GX2CrNiMoCuN25-6-3-3 and GX2CrNiMoCuN25-6-3 cast steels with
a varying carbon content. The cause for undertaking the research were technological problems with hot cracking in bulk castings of duplex
cast steel with a carbon content of approx. 0.06% and with 23% Cr, 8.5% Ni, 3% Mo and 2.4% Cu. The research has shown
a significant effect of increased carbon content on the ferrite and austenite microstructure morphology, while exceeding the carbon content
of 0.06% results in a change of the shape of primary grains from equiaxial to columnar.
The paper attempts to analyze distortions of cast iron and cast steel rings, after heat treatment cycles. The factors influencing distortion are: chemical composition of material, sample geometry, manufacturing process, hardenability, temperature and heat treatment method. Standard distortion tests are performed on C-ring samples. We selected a ring-model, which approximate the actual part, so that findings apply to gear rings. Because distortion depends on so many variables, this study followed strictly defined procedures. The research was started by specifying the appropriate geometry of the samples. Then, the heat treatment was conducted and samples were measured again. The obtained results allow to determine the value of the resulting distortion and their admissibility. The research will be used to evaluate the possibility of using the material to produce parts of equipment operated under extreme load conditions.
The article shows results of studies of primary crystallization and wear resistance of Cr-Ni-Mo cast steel intended for work in corrosive
and abrasive conditions. The studies of primary crystallization were conducted with use of TDA method and modified tester allowing
measurement casting cooling time influence on the cooling and crystallization curves of studied alloys. After heat treatment of examined
cast steel wear tests of the samples were conducted on pin-on-disc type device.
In paper is presented technology of bimetallic layered castings based on founding method of layer coating directly in cast proces so-called method of mould cavity preparation. Prepared castings consist two fundamental parts i.e. bearing part and working part (layer). The bearing part of bimetallic layered casting is typical foundry material i.e. ferritic-pearlitic unalloyed cast steel, whereas working part (layer) is plate of austenitic alloy steel sort X2CrNi 18-9. The ratio of thickness between bearing and working part is 8:1. The aim of paper was assessed the quality of the joint between bearing and working part in dependence of pouring temperature and carbon concentration in cast steel. The quality of the joint in bimetallic layered castings was evaluated on the basis of ultrasonic non-destructive testing, structure and microhardness researches.
The paper is concerned with comparing the methods for determining the ferrite content in castings from duplex stainless steels. It uses Schaeffler diagram, empirical formula based calculation, image analysis of metallographic sample, X-ray diffraction and measurement with a feritscope. The influence of wall thickness of the casting on the ferrite content was tested too. The results of the experiments show that the casting thickness of 25 or 60 mm does not have a significant effect on the measured amount of ferrite. The image analysis of metallographic sample and the measurement with the feritscope appear to be the most suitable methods. On the contrary, predictive methods, such as Schaeffler diagram or empirical formula based calculation are only indicative and cannot replace the real measurements. X-ray diffraction seems to be the least suitable measuring method. Values of ferrite content measured in such a way often deviated from the values measured by image analysis and with feritscope.
The work presents the analysis results of the structure of the coat obtained by dipping in silumin AlSi5 of two grades of alloy cast steel: GX6CrNiTi18-10 (LH18N9T) and GX39Cr13 (LH14). The temperature of the silumin bath was 750±5°C, and the hold-up time of the cast steel element τ = 180 s. The absolute thickness of the coat obtained in the given conditions was g = 104 μm on cast steel GX6CrNiTi18-10 and g = 132 μm on GX39Cr13. The obtained coat consisted of three layers of different phase structure. The first layer from the base “g1`” was constructed of the phase AlFe including Si and alloy additives of the tested cast steel grades: Cr and Ni (GX6CrNiTi18-10) and Cr (GX39Cr13). The second layer “g1``” of intermetallic phases AlFe which also contains Si and Cr crystallizes on it. The last, external layer “g2” of the coat consists of the silumin containing the intermetallic phases AlFeSi which additionally can contain alloy additives of the cast steel. It was shown that there were no carbides on the coat of the tested cast steels which are the component of their microstructure, as it took place in the case of the coat on the high speed steels.
In paper is presented technology of bimetallic layered castings based on founding method of layer coating directly in cast process so-called method of mould cavity preparation. Prepared castings consist two fundamental parts i.e. bearing part and working part (layer). The bearing part of bimetallic layered casting is typical foundry material i.e. unalloyed cast steel, whereas working part is plate of austenitic alloy steel sort X2CrNi 18-9. The ratio of thickness between bearing and working part is 8:1. The aim of paper was assessed the quality of the joint between bearing and working part in dependence of pouring temperature and carbon concentration in cast steel. The quality of the joint in bimetallic layered castings was evaluated on the basis of ultrasonic non-destructive testing, structure and microhardness researches.
In this paper crystallization studies of low-alloyed construction cast steel were presented for different additions of chromium, nickel and
molybdenum modified with vanadium and titanium. Studies were conducted using developed TDA stand, which additionally enabled
evaluation of cooling rate influence on crystallization process of investigated alloys.
In the high-alloy, ferritic - austenitic (duplex) stainless steels high tendency to cracking, mainly hot-is induced by micro segregation
processes and change of crystallization mechanism in its final stage. The article is a continuation of the problems presented in earlier
papers [1 - 4]. In the range of high temperature cracking appear one mechanism a decohesion - intergranular however, depending on the
chemical composition of the steel, various structural factors decide of the occurrence of hot cracking. The low-carbon and low-alloy cast
steel casting hot cracking cause are type II sulphide, in high carbon tool cast steel secondary cementite mesh and / or ledeburite segregated
at the grain solidified grains boundaries, in the case of Hadfield steel phosphorus - carbide eutectic, which carrier is iron-manganese and
low solubility of phosphorus in high manganese matrix. In duplex cast steel the additional factor increasing the risk of cracking it is very
"rich" chemical composition and related with it processes of precipitation of many secondary phases.
The paper presents the results of research on low cycle properties of high-chromium martensitic GX12CrMoVNbN9-l (GP91) cast steel. The tests of fatigue strength were carried out at two temperatures: room temperature and at 600 degrees centigrade. At both temperatures the occurrence of cyclic softening of the cast steel was observed, revealing no clear stabilization period. Moreover, it has been proved that the fatigue life is influenced by the temperature which depends on the level of strain. The greatest influence was observed for the smallest strain levels applied in the research.