The repair of foundry defects in steel castings using welding technology

Use of welding technology for the repair of steel castings is particularly common in two areas. These include weld surfacing of protrusions that remained incomplete after casting, or filling the surface defects (cavities). These defects are more common for steel casting than for graphite cast iron, due to the lower fluidity of steel. This article describes a suitable technological process of repairing the defects on the casting using the welding technology. A specimen produced for this purpose was prepared by carving a groove into a cast steel plate 20 GL, which was then filled with a weld metal using MAG (135) technology. The following evaluation of the basic characteristics of the repaired site point to the suitability of the selected technological parameters of the repair procedure. Metallographic evaluation was carried out, further evaluation of mechanical properties by tensile test, bend test and Vickers hardness test. The proposed methodology for the evaluation repair of foundry defects in steel castings also meets the requirements for the approval of welding procedures in accordance with the relevant valid legislation.Web of Science18218017

How do we value our income from which we save?

In this paper we analyze the relationship between the perception of income as satisfying household needs and saving rate of this household. Using the multinomial logit regression function we measure the probability of a household to fall into one of the groups categorized by the subjective perception of income in relation to the current household disposable income. The variable specified for the valuation of income is income perception, defined as a class of observed disposable income located on the scale of the subjectively satisfying income. Factors determining the perception of income are: gender and education of the household head, family characteristics, source of income and place of residence. The analysis of relations between the income perception and the household saving rates shows that the perception of income affects both the household observed and predicted saving rates. The research is based on the Household Budget Surveys data for Poland in 2008.household, income, needs, valuation, saving, probability

How do we value our income from which we save?

In this paper we analyze the relationship between the perception of income as satisfying household needs and saving rate of this household. Using the multinomial logit regression function we measure the probability of a household to fall into one of the groups categorized by the subjective perception of income in relation to the current household disposable income. The variable specified for the valuation of income is income perception, defined as a class of observed disposable income located on the scale of the subjectively satisfying income. Factors determining the perception of income are: gender and education of the household head, family characteristics, source of income and place of residence. The analysis of relations between the income perception and the household saving rates shows that the perception of income affects both the household observed and predicted saving rates. The research is based on the Household Budget Surveys data for Poland in 2008

Mild hypothermia provides Treg stability

Regulatory T cells (Tregs) play crucial role in maintenance of peripheral tolerance. Recent clinical trials confirmed safety and efficacy of Treg treatment of deleterious immune responses. However, Tregs lose their characteristic phenotype and suppressive potential during expansion ex vivo. Therefore, multiple research teams have been studding Treg biology in aim to improve their stability in vitro. In the current paper, we demonstrate that mild hypothermia of 33 °C induces robust proliferation of Tregs, preserves expression of FoxP3, CD25 and Helios, and prevents TSDR methylation during culture in vitro. Tregs expanded at 33 °C have stronger immunosuppressive potential and remarkably anti-inflammatory phenotype demonstrated by the whole transcriptome sequencing. These observations shed new light on impact of temperature on regulation of immune response. We show that just a simple change in temperature can preserve Treg stability, function and accelerate their proliferation, responding to unanswered question- how to preserve Treg stability in vitro

Determining the causes of failure of the distillation column for the esterification of n-butanol with acetic acid

The aim of the work is to determine the causes of corrosion of the distillation column from material 1.4571 (316Ti) in which acetic acid was produced. The column underwent a rapid and significant wear in a very short time during exploitation. To determine the causes of the failure, samples for testing were cut out of the components of the used distillation column. In the first test chemical analysis of the individual elements was carried out in order to specify the type of steel out of which they were made. The next step was to examine the structure of these elements and to perform microanalysis of the chemical composition of ferrite and austenite. After the completion and analysis of all necessary tests, conclusions were formulated to explain the causes of material consumption

Analysis of thermal cycles and phase transformations during multi-pass arc weld surfacing of steel casts taking into account heat of the weld

In this work, a model of phase transformations during multipass weld surfaced steel casts is presented. In the temperature field calculation algorithm, the influence of the heat of overlaying beads and a self-cooling of previously overlayed beads have been taken into account. The fusion area, full and part transformation zones, by solidus, A1 and A3 and A A1 temperatures has been determined, respectively. The temperatures of the beginning and the end of the phase changes during cooling were determined on the basis of the time-temperature-transformation welding diagram. In the phase change kinetic description, the JMAK law and KM formula were used. Theoretical considerations are illustrated by example of volume share calculations of particular structural components during the weld surfaced 230-450 W steel cast. The results of computation in the graphical forms are presented: welding thermal cycle diagrams and structural share change histories at selected points, as well as temperature and the phase share distributions in cross section

Analysis of deformation and microstructure evolution during the cogging process of Waspaloy alloy

The hot deformation behavior of Waspaloy alloy has been investigated by two-pass hot cogging process. The paper presents theoretical end experimental analysis of deformations and microstructural evolutions. The results of a thermo-mechanical simulation for the spatial hot cogging process on the shaped anvils with the application of the three–dimensional finite element method, are presented. The numerical calculation gave an assessment of the effective strain, mean stress and temperature distributions in the work-piece. Models for predicting the evolution of microstructure were developed for dynamic recrystallization and grain growth phenomena. The influence of shape of the anvils on the grain size after dynamic recrystallization was analyzed. The numerical analysis was performed using a commercial program "DEFORM 3D" with thermo-mechanical and microstructural evolution coupled. The results are compared with the experimental data, a good agreement between the predicted and experimental results was obtained

Szacowanie energii cieplnej w regeneracji części maszyn rolniczych metodami spawalniczymi

In the paper, the method of calculating the welding energy needed to regenerate parts of agricultural machines by welding (joining) or surfacing (rebuilding, hardfacing) is presented. Problems with the lack of adequacy of the commonly used formula for linear welding energy to the actual amount of heat introduced into the welded joint are discussed. A volumetric approach based on the effective amount of heat generated by the electric arc introduced per unit volume of the weld was proposed. The simplified formulas for volumetric energy are presented. The considerations are illustrated with examples of calculations. The analyzed examples include the use of a computerized stand for geometric measurements of metallographic specimens. The proposed volumetric method of calculating the amount of heat introduced into the welded joint is a more realistic indicator of heat demand than linear energy. On the other hand, based on the volume of the weld (padding weld), it allows to determine the amount of energy needed to regenerate machine parts, including agricultural ones.W pracy przedstawiono sposób obliczania energii spawania potrzebnej do regeneracji części maszyn rolniczych poprzez spawanie (łączenie) lub napawanie (uzupełnianie ubytków, utwardzanie powierzchni). Omówiono problemy braku adekwatności powszechnie stosowanego wzoru na energię liniową spawania do rzeczywistej ilości ciepła wprowadzanego do złącza spawanego. Zaproponowano objętościowe ujęcie oparte na efektywnej ilości ciepła wytworzonej przez łuk elektryczny wprowadzanej na jednostkę objętości spoiny. Przedstawiono uproszczone wzory na energię objętościową. W rozważaniach uwzględniono zastosowanie skomputeryzowanego stanowiska do pomiarów geometrycznych zgładów metalograficznych. Rozważania zilustrowano przykładami obliczeń. Zaproponowana objętościowa metoda obliczania ilości ciepła wprowadzanego do złącza spawanego jest bardziej realnym wskaźnikiem zapotrzebowania ciepła niż energia liniowa. Z kolei na podstawie objętości spoiny (napoiny) pozwala na wyznaczenie ilości energii potrzebnej do regeneracji części maszyn, w tym rolniczych

Analysis of deformation and microstructure evolution during the cogging process of Waspaloy alloy

The hot deformation behavior of Waspaloy alloy has been investigated by two-pass hot cogging process. The paper presents theoretical end experimental analysis of deformations and microstructural evolutions. The results of a thermo-mechanical simulation for the spatial hot cogging process on the shaped anvils with the application of the three–dimensional finite element method, are presented. The numerical calculation gave an assessment of the effective strain, mean stress and temperature distributions in the work-piece. Models for predicting the evolution of microstructure were developed for dynamic recrystallization and grain growth phenomena. The influence of shape of the anvils on the grain size after dynamic recrystallization was analyzed. The numerical analysis was performed using a commercial program "DEFORM 3D" with thermo-mechanical and microstructural evolution coupled. The results are compared with the experimental data, a good agreement between the predicted and experimental results was obtained