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METALLURGY AND FOUNDRY ENGINEERING

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Metallurgy and Foundry Engineering will disseminate knowledge relating to the metallurgical and foundry engineering in general.

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Now showing 1 - 10 of 275
  • thumbnail.journal.alt
    Item type:Article, Access status: Open Access ,
    Diminishment of internal polygonization of tubes in hot stretch-reducing mill
    (Wydawnictwa AGH, 2010) Stefański, Krzysztof; Kubiński, Wiktor
    One of the most important issues in hot stretch-reducing process is the maintaining precision of wall thickness. Exactly the same wall thickness at all cross-sections of tubes after stretch-reducing mill increases suitability of tubes in the next treatment processes. Internal polygonization of tubes and its removal during hot reducing is constantly the most important problem. The study is a presentation of test results for decrease of internal polygonization. Internal polygonization, as a result of deformation of tube wall thickness in all stands during hot reducing, can be minimized first of all by optimization of inter-stand tension. The tubes and pipes with minimal internal polygonization could be obtained during experiments of rolling after applying maximal average tension using a developed system for equations of axial forces equilibrium in the rolling mill.
  • thumbnail.journal.alt
    Item type:Article, Access status: Open Access ,
    Microstructure evaluation of laser-welded 600 nickel alloy
    (Wydawnictwa AGH, 2016) Tuz, Lechosław
    This paper presents the results of a microstructure analysis of a laser butt-welded 600 nickel alloy. A microstructure evaluation of the joint is carried out with the use of light microscopy and scan- ning electron microscopy. The results indicate a phase γ with some particles in the grain boundaries in the base metal. In the weld, a cellular-dendritic structure was observed.
  • thumbnail.journal.alt
    Item type:Article, Access status: Open Access ,
    Detection of nitrates(V) and sulfates(VI) by UV-Vis spectrophotometry method in used green sand bonded by bentonite with modified starch addition
    (Wydawnictwa AGH, 2016) Grabowska, Beata; Kurleto-Kozioł, Żaneta; Szymański, Łukasz; Kaczmarska, Karolina; Bobrowski, Artur
    The research results (SEM, UV-Vis) that contain a part of the work connected with determining the influence of a modified starch addition on the physical and chemical property changes of green sands (including the emission levels of harmful substances from the used molding sands formed as a result of the liquid metal pouring of molds) are presented in this paper. A surface analysis (SEM) was performed for the fresh molding sands and used molding sands with and without modified starch samples. On the bases of the received microscopic images, the impact of the temperature factor on the morphology of the molding sand samples after the liquid metal pour- ing process are assessed. In the second part of the performed work on the UV-Vis research, eluates from two used molding sands (green sand [sand number 1] and green sand with the addition of a modified starch [sand number 2]) were tested for nitrate and sulfate content. In order to deter- mine whether the level of nitrate and sulfate elusion from the used molding sands is permissible, the received results were compared with the Minister of Environment’s regulations concerning the requirements of surface waters used for supplying the population with potable water.
  • thumbnail.journal.alt
    Item type:Article, Access status: Open Access ,
    Microstructure and texture welds of 15-7Mo steel after heat treatment
    (Wydawnictwa AGH, 2016) Ziewiec, Aneta; Zielińska-Lipiec, Anna; Witkowska, Małgorzata
    This paper presents the results of determining the effect of heat treatment after welding X8CrNiMoAl15-7-2 steel (commercial name: PH 15-7Mo steel) on the microstructure and texture of the welds. XRD studies showed the presence of the two phases in the welds of 15-7Mo steel, i.e., δ ferrite and austenite. Annealing at a temperature of 400°C/1 h and 550°C/1 h results in changes of the intensities for individual peaks derived from austenite and ferrite. Microstructure investigations carried out by LM and TEM indicated that the austenite and δ ferrite coexist in the microstructure of 15-7Mo steel in as-welded condition. Annealing at a temperature range of be- tween 400–620°C after welding causes small changes in the microstructure. The hardness of the welds after annealing in that temperature range increases.
  • thumbnail.journal.alt
    Item type:Article, Access status: Open Access ,
    Application of water equivalents method to calculations of cross-finned aluminium heat exchangers
    (Wydawnictwa AGH, 2010) Karczewski, Krzysztof
    On an experimental post were carried out hydraulic and heat research of exchanger elements made of aluminium alloy. The research and calculations make possible to identify the reduction over-all heat-transfer coefficient from oil to heating air. The results of research enable to determine by water equivalents method design and using parameters of heat exchanger.
  • thumbnail.journal.alt
    Item type:Article, Access status: Open Access ,
    Characterization of microstructure and mechanical properties of laser-welded stainless steels
    (Wydawnictwa AGH, 2016) Koclęga, Damian; Radziszewska, Agnieszka; Kąc, Sławomir; Zowczak, Włodzimierz; Dębowska, Aleksandra; Jędrusik, Mateusz; Petrzak, Paweł
    This work presents the laser welding of dissimilar X12CrCoWVNbN12-2-2 and X10CrNi18-10 steels. This system is of interest, as laser welding offers new flexibility in the joining of metals and laser welds (LWs) and are usually of high quality, they are obtained only after the optimization of process parameters. The aim of the work was to investigate the microstructure, chemical composition, and hardness changes of laser-welded steels. After laser welding, two zones were generated in the processed materials: a fusion zone and a heat-affected zone. Due to solidification, a refinement of the microstructure occurred in the fusion zone. Examinations of the chemical composition of particular melted areas showed the occurrence of Nb-rich precipitations. The laser welding of steels led to increased hardness in the fusion zone (about 240–530 HV0.3).
  • thumbnail.journal.alt
    Item type:Article, Access status: Open Access ,
    The influence of temperature and the ratio of air excess on combustion efficiency of polyolefin materials
    (Wydawnictwa AGH, 2010) Kuźnia, Monika
    Combustion of plastics is a very complex process and phenomena, which occur during this process, have not been sufficiently investigated. Polyolefins constitute almost half of all the generated plastics. In this study, the influence of temperature and the ratio of air excess on the concentration of pollutants in flue gases have been presented. The studies carried out on the designed test bench were preceded by a series of thermal analyses (TG, DSC, TG-MS).
  • thumbnail.journal.alt
    Item type:Article, Access status: Open Access ,
    Effect of grain size of the reclaimed matrix ceramic moulds used in the lost wax technology on the strength at high temperature
    (Wydawnictwa AGH, 2010) Kamińska, Jadwiga; Kolczyk, Joanna; Żymankowska-Kumon, Sylwia
    Production technology of investment casting involves transmitting the elements of shape, dimensions and properties by filling in the appropriate liquid metal ceramic forms reproduced by a model made of wax removed by melting it. The manufacturing process of investment casting in the 8 lost wax technology consists of a number of technological operations: preparing of wax models and their assembling in the model units, the preparation of ceramic mixture, successive layers of debris, wax melting in an autoclave, drying the samples at 100 °C, heating the samples at temperatures ranging from 400 to 700 °C. So far, the technology was based on the use of ceramic mixture, which the bond was hydrolysed ethyl silicate. Currently, due to environmental protection and improvement of working conditions, more and more binders with alcohol is replaced with an aqueous solution of colloidal silica. In the study, as the basic of individual layers a ceramic form, used regenerated ceramic mixture derived from foundry and green ingredients. Used ceramic moulds after mechanical reclamation was given to sieve analysis to determine the grain size $(d_{L})$. Grain sizes 0.2, 0.4 and 0.63 mm were used for the coating of ceramic moulds. The paper presents results of research aimed at the determination of the relationship between tensile wet strength and grain size of ceramic mould: $R_{m} = f(d_{L})$. Tests were conducted on cylindrical samples, which deposited a layer of reclaimed ceramic material.
  • thumbnail.journal.alt
    Item type:Article, Access status: Open Access ,
    The reduction of the emission of NOx in the heat-treating furnaces
    (Wydawnictwa AGH, 2010) Wilk, Małgorzata; Magdziarz, Aneta; Kuźnia, Monika; Jerzak, Wojciech
    Despite the fossil fuel are still dominant source of primary energy in the word, the natural gas is generally used in many branches in industry. The interest in natural gas is caused by new production technologies (shale gas). This situation leads to take an interest in natural gas combustion technologies, especially low-emission combustion. In spite of many advantages of natural gas, it is also a source of nitrogen oxides generated during combustion in high temperature processes. The knowledge of the mechanisms of the formation of $NO_{x}$ allows to modify the combustion process. There are two ways of low emission combustion processes leading to reduce pollutants: “primary and secondary methods”. This paper presents the primary low-emission combustion method using the recirculation of flue gas and air excess ratio.
  • thumbnail.journal.alt
    Item type:Article, Access status: Open Access ,
    Strain distribution in ECAP process with various friction conditions - numerical modelling
    (Wydawnictwa AGH, 2010) Chyła , Paweł; Bednarek, Sylwia; Łukaszek-Sołek, Aneta; Sińczak, Jan
    In this paper are introduced analytical calculations of strain distribution in ECAP process in plane strain state. Analysed was friction influence on distribution and value of effective strain in channel die band. Numerical calculations were done by using of QForm 3D commercial programme.