Wyniki wyszukiwania - BazTech

1

Quality Assessment Method for Chromite Sand to Reduce the Number of Cast Steel Surface Defects

Wróbel Tomasz, Jezierski J., Bartocha D., Feliks E., Paleń A.

Archives of Foundry Engineering

|

2024

|

Vol. 24, iss. 4

31--38

EN

This paper discusses the ability to apply the test method using a scanning electron microscope (SEM) together with EDS (Energy Dispersive Spectroscopy) analysis to assess the quality of fresh chromite sand delivered by various suppliers to Huta Małapanew Sp. z o.o. The research was initiated due to the non-cyclical occurrence of surface casting defects, i.e. pitted skin and burn-on of chromite moulding sand for cast steel casting. The scope of studies comprised the quality assessment of sixteen chromite sand batches delivered for six months by two suppliers. The analysis of the results obtained was used to describe components of the tested chromite sand batches and develop criteria for their quality assessment, considering the chemical composition of chromite grains and the amount of impurities in the form of silica sand and the binder particles. Moreover, clear suggestions were developed concerning the ability to use the given chromite sand batch as the base of moulding sand made in Alphaset technology in Huta Małapanew Sp. z o.o.

2

Casting Production in Poland Versus European Trends in 21st Century

Soiński M.S., Jakubus A.

Archives of Foundry Engineering

|

2024

|

Vol. 24, iss. 3

57--62

EN

This article presents changes of the total casting production volumes and of the production of castings made from basic casting alloys in Poland, in Europe and worldwide in years 2001–2021. Analogous casting production parameters were compared for Poland, Europe and countries being the leading European and global manufacturers in years 2001, 2011 and 2021. The leading casting manufacturers in Europe (with the manufacturing volume exceeding 1 million tons in the mentioned years) include Germany, Italy, the Ukraine, France and Spain. For years, the largest casting manufacturer worldwide has been China. In 2001–2021, global casting production increased from ca. 68 million tons to ca. 97 million tons (i.e. by ca. 42%), whereas the European one decreased from ca. 17 million tons to ca. 12 million tons (i.e. by close to 30%). In the analyzed period, the Polish production volume grew from ca. 0.75 million tons to ca. 0.88 million tons (i.e. by ca. 17%). The presented data reveal the decreasing importance of gray cast iron and cast steel and the increasing one of ductile cast iron and aluminum alloys. However, the Polish average annual growth rate for aluminum alloy casting production was 10.3%, whereas the global one was 3% and the European one 0.7%.

3

Analysis of Fragmentation Phenomenon of Composite Layers of Fe-TiC Type Obtained “in situ” in Steel Casting

Marosz J., Sobula S.

Archives of Foundry Engineering

|

2024

|

Vol. 24, iss. 2

131--136

EN

A method for fabrication of a composite layer on the surface of a steel casting using coating containing TiC substrates was presented. The reaction of the synthesis of the ceramic phase was based on the SHS method (Self-propagating High-temperature Synthesis) and was triggered by the heat of molten steel. High hardness titanium carbide ceramic phases were obtained, which strengthened the base material improving its performance properties presented in this article. Microstructural examinations carried out by light microscopy (LM) on the in-situ produced composite layers showed that the layers were the products of reaction of the TiC synthesis – the phenomenon called “fragmentation” by the authors of study. The examinations carried out by scanning electron microscopy (SEM) have revealed the presence of spheroidal precipitated and free of impurities. The presence of titanium carbide was twofold increase in hardness in the area of the composite layer as compared to the base alloy which was carbon cast steel.

4

Staliwo stopowe wysokomanganowe w zastosowaniach na odlewane elementy infrastruktury kolejowej

Wróbel Tomasz, Bartocha Dariusz, Jezierski Jan, Sobula Sebastian, Kostrzewa Krzysztof, Feliks Edward

Stal, Metale & Nowe Technologie

|

2023

|

nr 1-2

30--34

PL

W publikacji przedstawiono charakterystykę staliwa stopowego wysokomanganowego, potocznie określanego mianem staliwa Hadfielda. Staliwa z tej grupy w warunkach wzrostu ciśnienia lub obciążenia, np. w wyniku uderzenia, wykazują dużą skłonność do tzw. umocnienia zgniotem, objawiającego się zwiększeniem powierzchniowej twardości i odporności na zużycie przy zachowaniu ciągliwości rdzenia.

EN

The paper presents the characteristics of a high-manganese alloy cast steel, commonly referred to as Hadfield cast steel. Cast steels of this group demonstrate a high tendency to the so-called strain hardening under the conditions of pressure or load increase, e.g. as a result of an impact, which is manifested by an increase in surface hardness and wear resistance while maintaining the ductility of the core. This is decisive for the applicability of a high-manganese cast steel for the castings of hammers and liners for coal mills and other mills, crusher cones, working elements of construction machines as well as cast elements of turnouts. In particular, the paper presents the chemical composition and usable properties of a high- -manganese cast steel intended for use in railway infrastructure as well as the characteristics of its microstructure finally shaped by heat treatment.

5

Effect of Heat Treatment on Microstructure and Mechanical Properties of High-Carbon and High-Manganese Cast Steel Subjected to Bainitic Reaction

Garbień P., Kokosza A., Maj W., Rogal Łukasz, Chulist Robert, Janus K., Wójcik Anna, Żółkiewicz Z., Maziarz Wojciech

Archives of Metallurgy and Materials

|

2023

|

Vol. 68, iss. 4

1667--1676

EN

The new cast steel with a chemical composition of Fe-(0.85-0.95)C-(1.50-1.60)Si-(2.40-2.60)Mn-(1.0-1.2)Al-(0.30-0.40)Mo-(0.10-0.15)V-(1.0-1.1)Ni (all in wt.%) was investigated in aspect of formation of the multiphase microstructure leading to high strength and ductility. Two types of heat treatment technologies were developed. The first one involves softening annealing at a temperature of 650°C for 4 hours, heating up to 950°C and holding for 2 hours, and then fast cooling down to 200°C and isothermally treated for 2 hours. The second one involves homogenizing annealing at 1100°C for 6 hours, then cooling with furnace down to 950°C and holding for 2 hours, then fast cooling down to 200°C and isothermally treated for 2 hours. A unique microstructure of cast steel consisting of martensite and retained austenite plates of various thicknesses and volume fractions was obtained. Additionally, nanometric transition carbides were noticed after the above-mentioned heat treatments. This microstructure ensures high hardness, strength and plasticity (Rm = 1426 MPa and A = 9.5%), respectively, due to the fact that TWIP/TRIP processes occur during deformation related to the high volume fraction of retained austenite, which the stacking fault energy is above 15 mJ/m-2 resulting from the chemical composition of the investigated cast steel.

6

Effect of Corrosion on Wear Resistance of the Composite Based on GX120Mn13 Cast Steel Zonally Reinforced with Particles (Al2O3+ZrO2)

Medyński Daniel

Archives of Foundry Engineering

|

2023

|

Vol. 23, iss. 3

133--139

EN

The subject of the work are modern composite materials with increased wear resistance intended for elements of machines operating in difficult conditions in the construction and mining industries. The study determined the effect of zone reinforcement of GX120Mn13 cast steel with macroparticles (Al2O3+ZrO2) on the corrosion resistance and abrasion wear of the composite thus obtained. SEM studies have shown that at interface between two phases, and more precisely on the surface of particles (Al2O3+ZrO2) a durable diffusion layers are formed. During the corrosion tests, no significant differences were found between the obtained parameters defining the corrosion processes of GX120Mn13 cast steel and GX120Mn13 with particles (Al2O3+ZrO2) composite. No intergranular corrosion was observed in the matrix of the composite material, nor traces of pitting corrosion at both phases interface. This is very important in terms of tested material’s service life. Reinforcement of cast steel with particles (Al2O3+ZrO2) resulted in a very significant improvement in the abrasion resistance of the composite – by about 70%. After corrosion tests, both materials were subjected to further operational investigations. These examinations consisted in determining the impact of corrosion processes on the durability of the composite in terms of abrasion. The obtained results indicate that corrosion processes did not significantly deteriorate the wear resistance of both the cast steel and the composite.

7

Eksploatacja belek podsuwnicowych wykonanych ze stali zlewnej

Gierczak Jan, Ignatowicz Rajmund, Marcinczak Krzysztof

Builder

|

2022

|

R.26, nr 4

40--45

PL

Przedstawiono problematykę eksploatowania belek podsuwnicowych wykonanych ze stali zlewnej używanych od końca I wojny światowej tj. ponad 100 lat. Na przestrzeni lat belki podsuwnicowe były modernizowane i wzmacniane w celu zainstalowania suwnic o większym udźwigu. W okresie eksploatacji obiektu dokonywano modernizacji technologii produkcji, co wymuszało instalowanie większej liczby suwnic na istniejących belkach. W ostatnim czasie, w celu dalszej modernizacji zakładu produkcyjnego, belki podsuwnicowe wymieniono na nowe o lepszych parametrach wytrzymałościowych. Belki zdemontowane poddano badaniom cyklicznym w akredytowanym laboratorium Politechniki Wrocławskiej. Przedstawiono problematykę, z jaką musi się zmierzyć inżynier budownictwa przy ocenie i dopuszczeniu do dalszej eksploatacji konstrukcji wykonanej ze stali zlewnej.

EN

The problem of operating crane girders made of cast steel in use since the end of the First World War, i.e. for over 100 years, is presented. Over the years, crane girders have been modernised and reinforced in order to install overhead travelling cranes with higher lifting loads. During the lifetime of the facility, production technology was modified, which made it necessary to install more cranes on the existing beams. Recently, in order to further modernise the production plant, the crane beams were replaced with new ones with better strength parameters. The dismantled beams have been subjected to cyclic tests in an accredited laboratory of the Wrocław University of Technology. The problems that a structural engineer has to face when assessing and admitting to further operation a structure made of stainless steel are presented.

8

Flaw Detection of Cast-Steel Safety Parts in Automotive Application

Dizdar K. C., Sahin H., Ardicli M., Dispinar D.

Archives of Foundry Engineering

|

2022

|

Vol. 22, iss. 1

13--17

EN

Casting is the most economical way of producing parts for many industries ranging from automotive, aerospace to construction towards small appliances in many shares. One of the challenges is the achievement of defect-free cast parts. There are many ways to do this which starts with calculation and design of proper runner system with correct size and number of feeders. The first rule suggests starting with clean melt. Yet, rejected parts can still be found. Although depending on the requirement from the parts, some defects can be tolerated, but in critical applications, it is crucial that no defect should exist that would deteriorate the performance of the part. Several methods exist on the foundry floor to detect these defects. Functional safety criteria, for example, are a must for today's automotive industry. These are not compromised under any circumstances. In this study, based on the D-FMEA (Design Failure Mode and Effect Analysis) study of a functional safety criterion against fuel leakage, one 1.4308 cast steel function block, which brazed-on fuel rail port in fuel injection unit, was investigated. Porosity, buckling, inclusion and detection for leak were carried out by non-destructive test (NDT) methods. It was found that the best practice was the CT-Scan (Computed Tomography) for such applications.

9

Postępy w zalewaniu odlewów staliwnych z osłoniętym strumieniem metalu

Hrabinia David, Filip Petr

Przegląd Odlewnictwa

|

2021

|

Vol. 71, nr 7-8

404--413

PL

Natychmiast po kontakcie ciekłego metalu z atmosferą powstaje cienki film tlenkowy. Chroni on przed dalszym utlenianiem powierzchni stopu oraz jego nasyceniem gazem. Film ten jest jednakże kruchy i łatwo się rozdziera, powodując wtrącenia. Jego temperatura topnienia jest znacznie wyższa, niż temperatura ciekłego stopu, w związku z tym raz powstały film tlenkowy jest trwały. Jest on wypierany przez ciekły metal, jednak czas tego procesu jest długi ze względu na niewielkie rozmiary tlenków (kilka nanometrów przy prawie zerowej objętości). Podwójne filmy tlenkowe (tzw. bi-filmy) powstające podczas konwencjonalnego zalewania formy nie mają czasu na wypłynięcie. Rozwijają się i tworzą aglomeraty podczas procesu odlewniczego. Bi-filmy posiadają dużą aktywność powierzchniową i tworzą niemetaliczne skupiska podczas procesu krzepnięcia. Odlewnie często zwiększają temperaturę zalewania, by usunąć pęcherze powietrzne i nieczystości, jednak jest to niekorzystne dla jakości odlewu, w szczególności jego powierzchni.

EN

Thin oxide films rapidly form on a liquid metal surface when exposed to the atmosphere. These protect the melt from further oxidation or gas enrichment. However, these surface films become brittle, tear and are then entrained in the molten metal. The melting temperatures of most oxide films are far greater than the temperature of the melt, so once formed they remain solid. These films float through buoyancy forces, as they have a lower density than molten metal, but this process is slow due to their extremely small size (just several nanometers having almost no volume). Oxide bi-films generated within conventional molten metal casting process have no time to float. They unfurl and agglomerate during the casting process. These bi-films have high surface activity and grow into bigger non-metallic agglomerations as solidification advances. Foundries increase pouring temperature hoping gas bubbles and related impurities float, but an increased pouring temperature is not beneficial to castings quality and cast surface appearance.

10

Materials used in the structure of rail vehicle wheels

Słowiński Marcin Stanisław

Pojazdy Szynowe

|

2021

|

Nr 4

14--24

EN

The subject of this text is the description of structural materials used in the structure of railway vehicle wheels. The characteristic of this structural element as well as its functional and material requirements are presented. The description of commonly used carbon steels and alternative construction materials, such as cast steel, ADI cast iron or aluminum alloys, are presented in the further part, which are supposed to limit the wear of the wheel-rail friction pair and reduce the level of noise.

PL

Przedmiotem niniejszego tekstu jest opis materiałów konstrukcyjnych stosowanych w budowie kół pojazdów szynowych. Przedstawiono charakterystykę tego elementu konstrukcyjnego, a także jego wymagania funkcjonalne oraz materiałowe. W dalszej części zaprezentowano opis powszechnie używanych stali węglowych oraz alternatywnych materiałów konstrukcyjnych, takich jak staliwa, żeliwa ADI czy stopy aluminium, które w założeniu miałyby ograniczać zużywanie pary ciernej koło-szyna oraz zmniejszać poziom emitowanego hałasu.

11

Set-up of a Generalized Dataset for Crack-Closure-Mechanisms of Cast Steel

Horvath Michael, Oberreiter Matthias, Stoschka Michael, Leitner Martin

Journal of Casting & Materials Engineering

|

2021

|

Vol. 5, no. 4

84--88

EN

In components, crack propagation is subjected to crack-closure-mechanisms which affect the build-up of the relevant threshold stress intensity factor range during cyclic loading. As structural parts are exposed to service loads incorporating a variety of load ratios, a significant change of the long-crack threshold value occurs, leading to a severe stress ratio dependency of crack-closure-mechanisms. Thus, an extensive number of crack propagation experiments is required to gain statistically proven fracture mechanical parameters describing the build-up of closure effects as crack growth resistance curves. The article presents a generalized dataset to assess the formation of crack-closure-mechanisms of cast steel G21Mn5+N. Numerous crack propagation experiments utilizing single edge notched bending (SENB) sample geometries are conducted, incorporating alternate to tumescent stress ratios. The statistically derived, generalized crack growth resistance curve features the impact of closure effects on the crack propagation rate in a uniform manner. To extend the dataset to arbitrary load ratios, the long-crack threshold approach according to Newman is invoked. The generalized dataset for the cast steel G21Mn5+N is validated by analytical fracture mechanical calculations for the utilized SENB-sample geometries. Incorporating a modified NASGRO equation, a sound correlation of analytical and experimental crack propagation rates is observed. Moreover, the derived master crack propagation resistance curve is implemented as a user-defined script into a numerical crack growth calculation tool and supports a local, node--based numerical crack propagation study as demonstrated for a representative SENB-sample. Concluding, the derived dataset facilitates the calculation of fatigue life of crack-affected cast steel components subjected to arbitrary stress ratios.

12

Assessment of Microstructure and Mechanical Properties of the Slag Ladle after Exploitation

Kalandyk Barbara, Zapała Renata, Sobula Sebastian, Tęcza Grzegorz, Piotrowski K.

Archives of Metallurgy and Materials

|

2021

|

Vol. 66, iss. 2

351--358

EN

The results of tests and examinations of the microstructure and mechanical properties of cast steel used for large-size slag ladles are presented. Castings of this type (especially large-size ladles with a capacity of up to 16 m3) operate under very demanding conditions resulting from the repeated cycles of filling and emptying the ladle with liquid slag at a temperature exceeding even 1600°C. The changes in operating temperature cause faster degradation and wear of slag ladle castings, mainly due to thermal fatigue.The tests carried out on samples taken from different parts/areas of the ladle (flange, bottom and half-height) showed significant differences in the microstructure of the flange and bottom part as compared to the microstructure obtained at half-height of the ladle wall. The flange and bottom were characterized by a ferritic-pearlitic microstructure, while the microstructure at the ladle half-height consisted of a ferritic matrix, cementite and graphite precipitates. Changes in microstructure affected the mechanical properties. Based on the test results it was found that both the flange and the bottom of the ladle had higher mechanical properties, i.e. UTS, YS, hardness, and impact energy than the centre of the ladle wall. Fractography showed the mixed character of fractures with the predominance of brittle fracture. Microporosity and clusters of non-metallic inclusions were also found in the fractures of samples characterized by low properties.

13

Microsegregation of Elements in Steel Composite Reinforced with Ceramic

Medyński D., Janus A. J.

Archives of Foundry Engineering

|

2021

|

Vol. 21, iss. 1

63--66

EN

The paper presents results of research on steel castings GX120Mn13 (L120G13 by PN-89/H-83160), zone-reinforced by elektrocorundum particles (Al2O3), with a grain size from 2 to 3.5 mm. Studies revealed continuity at interface between composite components and formation of a diffusion zone in the surface layer of electrocorundum grains. In the area of this zone, simple manganese segregation and reverse iron and chromium segregation were found. The transfer of these elements from cast steel to electrocorundum grains resulted superficial depletion in aluminum and oxygen in this area. No porosity was observed at the interface between two components of the composite. We found it very beneficial from an exploitation point of view, as confirmed by the study of resistance to abrasive wear.

14

Comparison of Microstructure and Mechanical Properties of Cast Steel Carried out on Cast-on Samples and Samples Cast Separately

Kalandyk B. E., Zapała R. E.

Archives of Foundry Engineering

|

2021

|

Vol. 21, iss. 2

81--88

EN

The results of microstructure examinations and UTS, YS, El, RA carried out on low-carbon cast steel containing 0.15% C. The tests were carried out on specimens cut out from samples cast on a large-size casting and from samples cast in separate foundry moulds. It has been shown that significant differences in grain size observed in the material of the separately cast samples and cast-on samples occur only in the as-cast. In the as-cast state, in materials from different tests, both pearlite percent content in the structure and mean true interlamellar spacing remain unchanged. On the other hand, these parameters undergo significant changes in the materials after heat treatment. The mechanical properties (after normalization) of the cast-on sample of the tested cast steel were slightly inferior to the values obtained for the sample cast in a separate foundry mould. The microscopic examinations of the fracture micro-relief carried out by SEM showed the presence of numerous, small non-metallic inclusions, composed mainly of oxide-sulphides containing Mn, S, Al, Ca and O, occurring individually and in clusters.

15

Analysis of Fracture Mechanism of Cast Steel for Different States of Stress

Lachowski J., Borowiecka-Jamrozek J.

Archives of Foundry Engineering

|

2021

|

Vol. 21, iss. 2

29--34

EN

In this paper a plastic deformation and a damage evolution in low-carbon cast steel containing non-metallic inclusions are analysed experimentally and numerically. Two microstructures of the cast steel have been obtained after appropriate heat treatment. Tensile tests of smooth specimens and axisymmetric notched specimens have been performed. The notched specimens have the notch radii: 1 mm, 3 mm and 7 mm. Fractography of the specimens was carried out to observe fracture mechanisms. The mechanism depended on the stress state in the notched specimens. The fractography showed the existence of two fracture mechanisms: ductile failure and by shear. The process of the voids growth formed on the non-metallic inclusions was the process which included in the explanation of the damage mechanism. Modelling of deformation of the specimens has been used with the model suggested by Gurson, Tvergaard and Needleman. The model is implemented in the Abaqus finite element program. The computer simulation was performed using ABAQUS system. The computed output was compared with the experimental results obtained for specimens of the same shape.

16

Wear-Fatigue Study of Carbon Steels

Hejwowski Tadeusz, Szala Mirosław

Advances in Science and Technology. Research Journal

|

2021

|

Vol. 15, no. 3

179--190

EN

The process of conjoined stress cycling and abrasive or erosive wear is encountered in industry. However, very scant attention has been paid till now to this issue. The paper presents two test rigs designed and built to cope with this experimental problem. Tests were carried out on the range of pure iron (Armco), carbon steels namely S235JR, C45, C70U, C80U, C110U and unalloyed cast steels (L40III, L45III and L50III). Tested iron-based alloys differ in chemical composition, microstructure and Brinell hardness ranging from 80HB to 350HB. Stress cycling caused strain hardening of ferrite in hypoeutectoid steels and thus reduced their abrasive wear loss. In the hypereutectoid steel stress cycling impaired integrity of the microstructure thus increasing abrasive wear loss. Alternating stresses enhanced ploughing and cutting micromechanisms of erosion. Tensile stress in the tested cast steel had a stronger effect on wear loss than the prior stress history.

17

The Morphology of Impact Fracture Surfaces in Manganese Cast Steel Modified by Rare Earth Elements

Kasińska J.

Archives of Foundry Engineering

|

2020

|

Vol. 20, iss. 2

89--94

EN

The morphology of G20Mn5 specimens made of non-modified and rare earth metals (REM) modified cast steel was investigated. Molten metal was treated with a cerium-rich mischmetal contain 49.8% Ce, 21.8% La, 17.1% Nd, 5.5% Pr and 5.35% other rare earth metals making up the balance. The melting, quenching (920°C/water) and tempering (720°C/air) were performed under industrial conditions. Analysis included G20Mn5 cast steel fracture specimens subjected to Charpy V-notch impact testing at 20°C, -30°C and -40°C. The purpose of the analysis was to determine the influence of REM on the microstructure and mechanical properties of G20Mn5 cast steel and the REM effect on the morphology, impact strength and character of the fracture surfaces. In addition, a description of the mechanism by which fracture occurred in the two materials was proposed. The author demonstrated the beneficial effects of adding REM to molten steel, manifested by a 20 - 40% increase in impact toughness, depending on test temperature, as compared to the non-modified cast steel. Important findings included more than 100% increase in impact strength in comparison with the required impact toughness of 27J at -40C for heat treated steels (EN 10213).

18

Innovation technology for the production of massive slag ladles at the Krakodlew S.A. Foundry. Presentation of design works on research and development

Paszkiewicz M., Guzik E., Kopyciński D., Kalandyk B., Burbelko A., Gurgul D., Sobula S., Ziółko A., Piotrowski K., Bednarczyk P.

Archives of Foundry Engineering

|

2020

|

Vol. 20, iss. 4

67--71

EN

This article is a description of the progress of research and development in the area of massive large-scale castings - slag ladles implemented in cooperation with the Faculty of Foundry Engineering of UST in Krakow. Slag ladles are the one of the major castings that has been developed by the Krakodlew (massive castings foundry) for many years. Quality requirements are constantly increasing in relation to the slag ladles. Slag ladles are an integral tool in the logistics of enterprises in the metallurgical industry in the process of well-organized slag management and other by-products and input materials. The need to increase the volume of slag ladles is still growing. Metallurgical production is expected to be achieved in Poland by 2022 at the level of 9.4 million Mg/year for the baseline scenario - 2016 - 9 million Mg/year. This article describes the research work carried out to date in the field of technology for the production of massive slag ladles of ductile cast iron and cast steel.

19

The possibility of extending the life of cast steel hulls of the steam turbine

Charchalis Adam, Dyl Tomasz, Wieczorska Agata

Journal of KONBiN

|

2019

|

Vol. 49, iss. 3

17--32

EN

The paper presents the analyze the lifetime of the HP steam turbine hull for the EC Gdynia TG1 combined heat and power plant as part of the renovation. The impact of exploitation on changes in mechanical properties of the steam turbine hulls was determined. At the preliminary material tests were carried out, qualifying the hull of the steam turbine to undertake the revitalization process. Then, after non-destructive testing, trepanation samples were taken from the cold zone and the hot hull, which were subjected to mechanical properties tests. The next stage of work was the revitalization process including hardening and tempering. The mechanical properties and metallographic were carried out testing. In the next stage of work, non-destructive testing was performed to detect cracks and a decision was made to repair these areas by welding. The last stage of the work includes an analysis of the vitality of the steam turbine hull after revitalization.

PL

W pracy przedstawiono analizę żywotności kadłuba turbiny parowej WP w elektrociepłowni EC Gdynia TG1 w ramach remontu. Określono wpływ eksploatacji na zmiany własności mechaniczne metalu kadłubów turbiny parowej. Przeprowadzono wstępne testy materiałowe, kwalifikujące kadłub turbiny parowej do podjęcia procesu rewitalizacji. Następnie po badaniach nieniszczących pobrano próbki trepanacyjne ze strefy zimnej i gorącej kadłuba, które poddano badaniom mechanicznym. Kolejnym etapem pracy był proces rewitalizacji, w tym hartowanie i odpuszczanie. Następnie przeprowadzono badania metalograficzne i wytrzymałościowe, a w dalszej kolejności badania nieniszczące w celu wykrycia pęknięć i podjęto decyzję o naprawie tych obszarów przez spawanie. Ostatni etap prac obejmuje analizę żywotności kadłuba turbiny parowej po rewitalizacji.

20

Pomiar zawartości gazów w kąpieli metalowej drogą do optymalizacji zabiegów odtleniania i modyfikacji staliwa na odlewy

Kuder Mieczysław, Żyrek Adam, Bitka Adam, Uhl Waldemar

Journal of Applied Materials Engineering

|

2019

|

Vol. 59, no. 4

183--197

PL

W artykule przedstawiono wyniki prac nad optymalizacją procesu wytopu staliwa na odlewy armaturowe w piecu indukcyjnym o wyłożeniu kwaśnym. Do realizacji zabiegów odtleniania i modyfikacji używano materiały zawierające pierwiastki o wysokiej aktywności, jak: Al, Ca, Ti, Zr, Ce, V i Nb. Parametry tych zabiegów zostały ustalone na podstawie wyników prowadzonych pomiarów i oznaczeń zawartości tlenu, azotu i wodoru na różnych etapach prowadzonego procesu. Jakość staliwa oceniano w oparciu o wyniki badań metalograficznych, wytrzymałości i udarności w niskich temperaturach. Stwierdzono, że pomiary zawartości wodoru i aktywności tlenu w ciekłym stopie umożliwiają identyfikację zagrożeń procesu metalurgicznego, opracowanie optymalnych parametrów zabiegów odtleniania i modyfikacji, stabilizację właściwości mechanicznych i uniknięcia powstania wad wewnętrznych typu gazowego w odlewach.

EN

The paper presents the results of works concerning the optimisation of the process of steel melting for castings of industrial fittings in an induction furnace with an acid lining. Materials containing high activity elements such as Al, Ca, Ti, Zr, Ce, V and Nb were used for deoxidation and modification. The parameters of these procedures were determined on the basis of the results of measurements and determinations of oxygen, nitrogen and hydrogen content at various stages of the process. The quality of cast steel was evaluated on the basis of metallographic, tensile and low temperature impact strength test results. It was found that the measurements of hydrogen content and oxygen activity in the liquid alloy allow for the identification of hazards of the metallurgical process, the development of optimal parameters of deoxidation and modification procedures, the stabilisation of mechanical properties and the avoidance of internal gas type defects in castings.