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Wilgotność mas klasycznych – czynnik determinujący skłonność do tworzenia przypaleń i wżarć na odlewach żeliwnych

Zych Jerzy S., Mocek Jan

Przegląd Odlewnictwa

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2023

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Vol. 73, nr 11-12

378--384

PL

Wady powierzchni surowej odlewów, wśród których dominują przypalenia i wżarcia, żeliwnych wykonywanych w formach piaskowych są powszechne i nie do wyeliminowania. Należą do grupy najłatwiej wykrywalnych w ocenia wizualnej, decydują o estetyce wyrobów, a to ważny marketingowo i nie tylko wskaźnik ogólnej jakości odlewów. Można jedynie dążyć do ich znaczącego ograniczania. Jakkolwiek są to wady naprawialne, jednak uciążliwość prac w ich usuwaniu. W pracy prezentowane są wyniki badań laboratoryjnych i analizy procesów przemysłowych na wpływem wilgotności mas bentonitowych na tworzenie się przypaleń i wżarć na odlewach żeliwnych. Analizowane jest oddziaływanie wilgotności mas na rodzaj atmosfery chemicznej panującej we wnęce form w powiązaniu z jej wpływem ze skłonnością do przypaleń i wżarć. Proponuje się zastosowanie nowego wskaźnika, którym można by charakteryzować podatność masy do tworzenia przypaleń chemicznych. Został on nazwany: uproszczonym wskaźnikiem potencjału tlenowego masy wilgotnej (WPT). Wskaźnik WPT jest określany jako stosunek wilgotności masy (W) do zawartości nośników węgla błyszczącego, określanej w próbie strat prażenia (S). Jego wartość oscyluje wokół liczby 1,0 i poniżej. Ogólnie im wyższa wartość tego wskaźnika, tym większa skłonność masy do tworzenia przypaleń i wżarć o charakterze chemicznym. W artykule przywoływane są dane i przykłady wad powierzchni z praktyki przemysłowej w powiązaniu z analizą wilgotności mas i wartości wskaźnika WPT.

EN

Defects of crude surfaces of iron castings produced in sand moulds, among which dominate burns-on and pitting, are universal and not to be eliminated. They belong to the group of the easiest detectable defects in visual assessments, which decide about the aesthetics of products, a very important general indicator of the casting quality. Although these defects are repairable but since their removal is very tiresome, it is only possible to limit them. The results of laboratory investigations and analysis of industrial processes concerning the influence of a moisture content of bentonite moulding sands on forming burn-on and pits on iron castings, are presented in the paper. The influence of a moisture content of sands on the chemical atmosphere inside the mould cavity in connection with its influence on the tendency for burn-on and pits, is analysed. The application of new indicator, which could characterise the sand susceptibility to form chemical burns-on, is proposed. It was called: simplified indicator of oxygen potential of sand moistness (WPT). This indicator is determined as the ratio of sand moistness (W) to the content of lustrous carbon carrier, determined in the ignition loss test (S). Its value oscillates around 1.0 and below. Generally, the higher value of this indicator the higher inclination for burns and pits of a chemical character. The data and examples of surface defects known from industrial practice in relation with the sand moistness analysis and the WPT indicator value, are also presented in the hereby publication.

2

Numerical Modelling for the Effect of Metal-mould Air Gaps on Shell Thickness in Horizontal Continuous Casting of Cast Iron

Chawla Ashish, Tiedje N. S., Spangenbe Jon

Archives of Foundry Engineering

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2023

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Vol. 23, iss. 1

53--60

EN

This paper presents a numerical model for the horizontal continuous casting of cast iron (HCCCI). A computational three-dimensional (3D) steady-state, coupled with fluid flow and heat transfer simulation model was developed and validated against experimental results to study the shell thickness and solidification of ductile cast iron. The study introduces the influence of an air gap at the melt-mould interface, which has long been known to have a detrimental effect on the efficiency of the process. The effect of the length and thickness of the melt-mould air gaps (also referred to as top air gaps) on solidification and remelting of the solid strand is studied. Parametric studies on top air gaps suggested a substantial effect on the solid and eutectic area at the top-outlet end of the die when the length of air gas was varied. This study serves to create a foundational and working model with the overall objective of process optimisation and analyzing the effect of operating process input parameters on the shell thickness of the strand.

3

Studies of mechanical and technological parameters and evaluation of the role of lustrous carbon carriers in green moulding sands with hybrid bentonite

Kamińska Jadwiga, Stachowicz Mateusz, Puzio Sabina, Angrecki Michał

Archives of Civil and Mechanical Engineering

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2023

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Vol. 23, no. 1

art. no. e11, 2023

EN

Green moulding sands containing special carbonaceous additives, which are the source of lustrous carbon (LC), are discussed in this paper. Five potential lustrous carbon carriers, i.e., two types of hard coal dust (No.1 and No.2), amorphous graphite (No.3) and two hydrocarbon resins (No.4 and No.5), were selected for tests as carbonaceous additives to conventional moulding sands. To better emphasize the differences in the additives used, reference green moulding sand (GMS1) was prepared and subjected to a wide range of basic tests focussed on technological parameters, such as permeability (Pw), friability (Fw), Dietert mouldability test (PD) and compactability (Z) and mechanical parameters, such as compressive strength (Rcw), tensile strength (Rmw), strength in the transformation zone (Rkw). The proposed comprehensive spectrum of tests was repeated on sands with five carbonaceous additives. The most important for the use of additives as carbon carriers was to interrelate the content of lustrous carbon (LC), loss on ignition (LOI) and the obtained results of mechanical and technological tests carried out on conventional moulding sands with the surface quality of iron castings. For this purpose, a series of iron castings was made in the prepared moulding sands and used for the assessment of surface quality based on a number of roughness parameters (Ra, Rz, Rp, Rq, Rv, Rlr, RSm). As a result of the studies it was found that the carbonaceous additives proposed for use help to obtain high-quality surfaces in iron castings.

4

Composite Material with Cast Iron Matrix Designed for Brake Systems of Technical Means of Transport

Posmyk Andrzej, Myalski Jerzy

Tribologia

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2022

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nr 3

79--86

EN

The paper presents the basics of manufacturing and the tribological properties of the developed cast iron-ceramic composite designed for brake discs or drums. The matrix of the composite consists of GJL-150 grey cast iron used for the production of brake discs. The reinforcing phase is a SiC foam with an activated surface. The use of ceramic foam simplifies the production process because it does not require expensive mixing of the matrix and the reinforcing phase to ensure the homogeneity of the composite. An addition of 10% SiC (λSiC= 100–350 Wm-1K-1) improves the thermal conductivity of cast iron (λCI = 50–60 Wm-1K-1). The presence of foam elements homogenously distributed throughout the whole matrix volume reduces the wear of both the composite and the counter-sample. The results of comparative studies of contacts between the cast iron and the composite brake disc showed almost a threefold lower wear of the pad and disc and about a 10°C lower temperature in the pad near the friction zone under the pressure of 1 MPa and at a sliding velocity of 0.5 m/s. The significantly lower wear of the friction elements of the brake system will contribute to a reduction in environmental pollution by wear debris, which is required by European Union directives.

PL

W artykule opisano podstawy wytwarzania i właściwości tribologiczne opracowanego kompozytu żeliwno-ceramicznego przeznaczonego na tarcze lub bębny hamulcowe. Osnowę kompozytu stanowi stosowane do wytwarzania tarcz hamulcowych żeliwo szare GJL-150, a umocnieniem jest pianka z SiC z aktywowaną powierzchnią. Użycie pianki ceramicznej upraszcza proces wytwarzania, ponieważ nie wymaga kosztownego mieszania osnowy i fazy zbrojącej dla zapewnienia homogeniczności kompozytu. Dodanie 10% pianki SiC (λSiC= 100–350 Wm-1K-1) poprawia przewodność cieplną żeliwa (λCI = 50–60 Wm-1K-1). Obecność równomiernie rozłożonych w całej objętości osnowy elementów pianki zmniejsza zużycie zarówno kompozytu, jak i współpracującego z nim materiału ciernego. Wyniki badań porównawczych skojarzeń z tarczą żeliwną i kompozytową wykazały mniejsze prawie trzykrotnie zużycie klocka i tarczy oraz niższą o 10°C temperaturę w klocku w pobliżu strefy tarcia przy nacisku 1 MPa i prędkości 0,5 m/s. Znacząco zmniejszone zużycie elementów ciernych układu hamulcowego przyczyni się do zmniejszenia zapylenia środowiska produktami zużycia, co jest wymagane w dyrektywach Unii Europejskiej.

5

Advantages of colour etching in quality control of graphitic cast irons

Vaško Alan

Production Engineering Archives

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2022

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Vol. 28, Iss. 4

319--324

EN

Graphitic cast irons are the most important and most widely used materials for the production of castings. Increasing requirements for the quality of these castings lead to increased demands on the control of foundry production from raw materials through technological operations to the finished product. An integral part of this control process is structural analysis, because the properties of graphitic cast irons depend mainly on their structure (on the shape, size and number of graphitic particles and on the character of a metal matrix in which graphite occurs). The paper deals with the structural analysis of graphitic cast irons using the classical black and white contrast, as well as the use of colour metallography, which enables to obtain additional information about the structure of cast iron. The article contains photographs of microstructures of graphitic cast irons, obtained using black and white etching, as well as colour etching. It deals with the advantages of colour etching compared to the use of classical black and white methods.

6

Various Aspects of Application of Silicon Carbide in the Process of Cast Iron Melting

Janerka Krzysztof, Kostrzewski Łukasz, Stawarz Marcin, Jezierski Jan, Szajnar Jan

Archives of Metallurgy and Materials

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2022

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Vol. 67, iss. 3

1093--1098

EN

The article discusses benefits associated with the use of silicon carbide in the process of melting gray cast iron and ductile cast iron in induction electric furnaces. It presents the analysis of the impact of various charge materials and the addition of a variable amount of SiC and FeSi to the fixed charge when melting cast iron of grades GJS 400-15 and GJS 500-7 on mechanical properties and microstructure. Moreover, the article includes an analysis of the efficiency of carburization and the increase in the content of silicon during the application of SiC. The article also presents the results of the study of primary modification using silicon carbide at the minimum temperature of Temin eutectic and Tsol solidus. Based on analysis of the literature, conducted research, and calculations, it was found that the addition of silicon carbide has a beneficial impact on the properties of melted cast iron. The addition of SiC in the charge increases the content of C and Si without increasing the amount of contaminations. The addition of SiC at reduced pig iron presence in the charge decreases production costs, while the use of SiC as an inoculant increases both Temin and Tsol, which is beneficial from the point of view of cast iron nucleation.

7

Wettability of the System of Cast Iron and Magnesia Ceramics with Graphite

Hosadyna-Kondracka Małgorzata, Nowak Rafał, Turalska Patrycja, Bruzda Grzegorz, Boroń Łukasz, Wawrylak Marek

Archives of Foundry Engineering

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2022

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Vol. 22, iss. 3

25--33

EN

In this paper examinations of high-temperature wetting tests of 3 systems of liquid alloy – cast iron in contact with ceramic materials: magnesia ceramics in combination with natural graphite were presented. After wettability testing, the microscopic observations of the morphology of the sample surface and the cross-section microstructure with the chemical composition in micro-areas were examined. One of the objective of this work was also to verify whether the graphite content would affect the wettability of the magnesia ceramics. The study of high-temperature wetting kinetics of the liquid alloy in contact with the ceramic material, by the "sessile drop" method with capillary purification (CP) procedure was conducted. Under the test conditions, at a temperature of 1450°C and time 15 minutes, all 3 experimental systems showed a non-wetting behaviour. The average contact angle for the system with cast iron drop on magnesia ceramics was 140°, on magnesia ceramics with 10 parts per weight of graphite was 137° and on magnesia ceramics with 30 parts per weight of graphite - 139°. Microscopic observations revealed that in the case of the sample consisting of the cast iron drop on the substrate with magnesia ceramics, the formation of fine separations was not observed, unlike the systems with the substrate with magnesia ceramics and the addition of natural graphite. Numerous, fine droplets accumulate on the graphite flakes and consist mainly of Si as well as Fe and O. On the other hand, the rough MgO grains have a gray, matt surface, without fine separations. The conducted observations indicate the mechanical nature of the bonding - liquid metal penetrates into the pores of the rough ceramics of the substrate. However, in the case of systems of cast iron drop with magnesia ceramics and addition of graphite, probably the adhesive connection and the physical attraction of elements derived from cast iron drop with the flake graphite appeared as well.

8

Żeliwna klatka schodowa w XIX-wiecznym budynku więzienia przy ulicy Piekary w Toruniu

Lewandowski Łukasz, Kucharzewska Joanna, Pabich Marek

Wiadomości Konserwatorskie

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2021

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Nr 67

115--128

PL

W 1859 w Toruniu powstał projekt zespołu budynków sądu i więzienia, dla którego przewidziano narożną działkę u zbiegu ulic Piekary i Fosa Staromiejska. W pierwszej kolejności zrealizowano sąd, później budynek więzienia na planie koła, przypominający istniejącą w tym miejscu basteję zwaną Kocim Ogonem. Projekt funkcjonalno-przestrzenny więzienia zakładał rozmieszczenie cel po obwodzie budynku oraz umieszczenie wewnętrznej klatki schodowej. Architekt planował połączenie tradycyjnej konstrukcji murowanej z nowoczesną technologią, polegającą na użyciu żeliwnej klatki schodowej i żeliwnych wsporników w celu podtrzymania wewnętrznych podestów. Artykuł przedstawia tę nowatorską konstrukcję, stanowiącą pierwszy w Toruniu przykład zastosowania na taką skalę żelaza lanego w budynku municypalnym. Schody wykonano z prefabrykatów, których sposoby montażu i oprawy dekoracyjnej były wówczas novum. Temat stanowi ważny problem badawczy, zwłaszcza w kontekście stanu zachowania żeliwnych klatek schodowych i ginącego dziedzictwa techniki, a także wyzwań konserwatorskich.

EN

In 1859, a design of a complex that consisted of a court and prison building was drafted in Toruń, for which a corner plot at the intersection of Piekary and Fosa Staromiejska streets was assigned. The court building was built first, and the prison building, with a circular plan, that resembled a bastei called the Cat’s Tail that had previously stood at the site, was built later. The functio-spatial design of the prison assumed placing the cells along the perimeter of the building and included an internal stairwell. The architect planned to combine a traditional masonry structure with modern technology that entailed the use of a cast-iron stairwell and cast-iron cantilevers to support internal platforms. This paper presents this innovative structure, which is the first-ever case of the use of cast iron in a municipal building on this scale in Toruń. The stairs were built from prefabricated elements, whose assembly methods and ornamentation had been a novelty at the time. This subject is a key research problem, especially in the context of the state of preservation of cast-iron stairwells and the disappearing heritage of engineering, as well as conservation challenges.

9

Właściwości sorbentów kompozytowych stosowanych do obniżania zawartości siarki w żeliwach

Gara Paweł, Wisła-Walsh Ewa

Przemysł Chemiczny

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2021

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T. 100, nr 9

835--838

PL

Otrzymanie żeliwa uszlachetnionego, takiego jak sferoidalne lub wermikularne, wymaga przeprowadzenia grafitu obecnego w żeliwie wyjściowym z formy płatkowej w formę wermikularną lub sferoidalną. Tak sferoidyzacja, jak wermikulizacja grafitu możliwa jest w żeliwie, w którym zawartość siarki wynosi 0,02%. Przedstawiono wyniki odsiarczania żeliwa szarego o zawartości siarki 0,184% za pomocą węglanu, dolomitu oraz ich form scalonych otrzymanych w procesie aglomeracji ciśnieniowej.

EN

Calcium carbonate, dolomite and magnesite mineral samples were briquetted in a press with H₂O (5-10% by mass) and Na₂CO₃ (50% by mass) or CaF₂ (50% by mass) using water glass as a binder and seasoned for 24 h and then studied for humidity, chem. compn., phase compn., S removal capacity and analyzed thermogravimetrically. The addition of Na₂CO₃ resulted in the formation of new phases that were not obsd. in the case of merging the minerals with CaF₂. CaCO₃-based sorbents, both the combination with Na₂CO₃ and CaF₂ increased the S removal from the starting cast iron to contain 0.02%.

10

Dynamic properties of hybrid machine tool body - theoretical and experimental investigation

Kępczak Norbert, Pawłowski Witold

Mechanics and Mechanical Engineering

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2021

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Vol. 25, nr 1

6--14

EN

The article presents theoretical and experimental investigation in order to obtain dynamic properties of hybrid machine tool body in comparison with cast iron body. For this purpose, the theoretical and experimental modal analyses were carried out. The influence of the mineral cast material for filling voids on the dynamic properties of the machine tool body was discussed. During the analysis, the modes and frequencies of free vibrations, the amplitude values and the damping ratios were compared. Despite lowering the free vibration frequency of the hybrid construction, compared to the cast iron body, in some cases, the dynamic propertieswere affected. This could be determined on the basis of decreasing the amplitude value of the transfer function (from 12.16% to 58.66%) and the increasing the vibration damping coefficient ratio (from 12.22% to 75.24%) in the case of a hybrid body as compared to a cast iron body. The final conclusions were drawn about the application of mineral casts in the construction of machine tools and its impact on the dynamic properties of the structure.

11

Ocena nośności zabytkowego słupa żeliwnego wiaty peronowej

Domagała Rafał

Inżynieria i Budownictwo

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2021

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R. 77, nr 9-10

438--441

PL

Dokonano oceny nośności zabytkowego słupa wiaty peronowej wykonanego z żeliwa szarego perlitycznego z grafitem płatkowym w osnowie perlitycznej EN-GJL-100. Obliczenia wykonano według zbioru norm PN-EN 1993 Eurokod 3.

EN

The load-bearing capacity of a historic platform shed made of gray pearlitic cast iron with EN-GJL-100 pearlitic matrix flake graphite was assessed. The calculations were made according to the set of PN-EN 1993 Eurocode 3 standards.

12

Analysis of the Mechanical Properties of the Titanium Layer Obtained by the Mold Cavity Preparation Method

Dulska A., Szajnar J., Król M.

Archives of Metallurgy and Materials

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2021

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Vol. 66, iss. 1

51--56

EN

The article presents the technology of layered casting with the use of 3D printing to make a frame insert. The insert was made of powdered titanium and then filled with liquid cast iron. The paper presents the results of research, including structure observation and hardness measurements, as well as abrasion resistance tests. The results indicate the possibility of creating a local reinforcement using a frame insert. The resulting casting is characterized by a local increase in hardness and, in addition, an increase in abrasion resistance of the entire surface layer. The quality of the obtained connection depends strongly on the casting parameters.

13

Influence of Tungsten on the Structure and Properties of Ductile Iron Containing 0.8% Cu

Myszka Dawid, Kasińska J., Penkul A.

Archives of Foundry Engineering

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2021

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Vol. 21, iss. 4

121--126

EN

The possibilities of producing ductile cast iron with the addition of 1÷3% of tungsten are presented. Tungsten from waste chips from mechanical processing was introduced into the liquid cast iron in the form of specially prepared cartridges. Correct dissolution of tungsten in the metal bath was found, and there were no casting defects in the alloy. The form of carbide precipitates in the microstructure of cast iron was determined and the influence of increasing tungsten content on the reduction of the number of graphite precipitates in the structure was determined. Impact tests show that this property degrades with increasing tungsten content as opposed to hardness which increases. It was found that the addition of tungsten from machining waste is a potential source of enrichment of cast iron with this element.

14

Factors Influencing Cavitation Erosion of NiCrSiB Hardfacings Deposited by Oxy-Acetylene Powder Welding on Grey Cast Iron

Szala Mirosław, Walczak Mariusz, Hejwowski Tadeusz

Advances in Science and Technology. Research Journal

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2021

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Vol. 15, no 4

376--386

EN

The work presents the results of a study on cavitation erosion (CE) resistance of two NiCrSiB self-fluxing powders deposited by oxy-acetylene powder welding on cast iron substrate grade EN-GJL-200. The mean hardness of deposits A-NiCrSiB, C-NiCrSiB is equal to 908 HV, 399 HV and exceeds those of EN-GJL-200 and X5CrNi18-10 reference specimens 197 HV and 209 HV, respectively. To study CE, the vibratory apparatus has been used and tests were conducted according to the ASTM G32 standard. Cavitation eroded surfaces were examined using a profilometer, optical and scanning electron microscopy. The research indicated that the CE resistance, expressed by the cumulative mass loss decreased in the following order C-NiCrSiB > A-NiCrSiB > X5CrNi18-10 > EN-GJL-200. Therefore, hardfacings were characterised by lower cumulative mass loss, in turn, higher CE resistance than the reference sample and therefore they may be applied as layers to increase resistance to cavitation of cast iron machine components. Results indicate that in the case of multiphase materials, hardness cannot be the main indicator for CE damage prediction while it strongly depends on the initial material microstructure. To qualitatively estimate the cavitation erosion damage (CEd) of NiCrSiB self-fluxing alloys at a specific test time, the following factors should be considered: material microstructure, physical and mechanical properties as well as surface morphology and material loss both estimated at specific exposure time. A general formula for the CEd prediction of NiCrSiB deposits was proposed.

15

Open Atlas of Defects as a Supporting Knowledge Base for Cast Iron Defects Analysis

Sika R., Rogalewicz M., Kroma A., Ignaszak Z.

Archives of Foundry Engineering

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2020

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Vol. 20, iss. 1

55--60

EN

A significant development of the foundry industry contributes to the creation of high reliability and operational strength castings so that they meet specific standards in accordance with customers’ needs. This technology, however, is inseparably connected with casting defects in finished products. Cast products are subject to various defects which are considered acceptable or not, which is conditioned by the alloy chemical composition and strength characteristics, that is, generally – qualities to be agreed between the foundry and the customer. It is the latter that led the authors to research on designing a tool enabling the most reliable possible assessment of the emerging casting defects, which after proper consultations can be repaired and the casting – sold. The paper presents an original tool named the Open Atlas of Defects (OAD), developed for the last few years to support the evaluation of cast iron defects using Non-Destructive Testing (NDT) casting defects analysis tools (DCC card – Demerit Control Chart, Pareto-Lorenz analysis and ABC analysis). The OAD tool structure was presented as an integral part of the original system module for acquisition and data mining (A&DM) in conjunction with the possibilities of using selected tools for defect analysis support on the example of cast iron casting.

16

Cause-effect Analysis Using A&DM System for Casting Quality Prediction

Sika R., Ignaszak Z.

Archives of Foundry Engineering

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2020

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Vol. 20, iss. 2

5--12

EN

The paper indicates the significance of the problem of foundry processes parameters stability supervision and assessment. The parameters, which can be effectively tracked and analysed using dedicated computer systems for data acquisition and exploration (Acquisition and Data Mining systems, A&D systems) were pointed out. The state of research and methods of solving production problems with the help of computational intelligence systems (Computational Intelligence, CI) were characterised. The research part shows capabilities of an original A&DM system in the aspect of selected analyses of recorded data for cast defects (effect) forecast on the example of a chosen iron foundry. Implementation tests and analyses were performed based on selected assortments for grey and nodular cast iron grades (castings with 50 kg maximum weight, casting on automatic moulding lines for disposable green sand moulds). Validation tests results, applied methods and algorithms (the original system’s operation in real production conditions) confirmed the effectiveness of the assumptions and application of the methods described. Usability, as well as benefits of using A&DM systems in foundries are measurable and lead to stabilisation of production conditions in particular sections included in the area of use of these systems, and as a result to improvement of casting quality and reduction of defect number.

17

A New Laser-Registered View of the Shrinkage Kinetics of Foundry Alloys

Zych J., Snopkiewicz T.

Archives of Foundry Engineering

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2020

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Vol. 20, iss. 3

41--46

EN

This paper presents a new stand for studying the linear shrinkage kinetics of foundry alloys. The stand is equipped with a laser displacement sensor. Thanks to this arrangement, the measurement is of a contactless nature. This solution allows for the elimination of errors which occur in measurements made using intermediary elements (steel rods). The supposition of the expansion (shrinkage) of the sample and the expansion of the heated rod lead to the distortion of the image of the actual dimensional changes of the studied sample. A series of studies of foundry alloys conducted using the new stand allowed a new image of shrinkage kinetics to be obtained, in particular regarding cast iron. The authors introduce in the study methodology a real-time measurement of two linked quantities; shrinkage (the displacement of the free end of the sample) and temperature in the surface layer of the sample casting. This generates not only a classic image of shrinkage (S) understood as S = f (t), but also the view S = f (T). The latter correlation, developed based on results obtained using the contactless method, provide a new, so far poorly known image of the course of shrinkage in foundry alloys, especially cast iron with graphite in the structure. The study made use of hypo- and hypereutectic cast iron in order to generate an image of the differences which occur in the kinetics of shrinkage (as well as in pre-shrinkage expansion - expansion occurs during solidification).

18

Żeliwne płyty brukowe w Warszawie w II poł. XIX w.

Skowron Marek

Przegląd Odlewnictwa

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2019

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Vol. 69, nr 5-6

132--136

PL

Powszechne zastosowanie żelaza, w tym także żelaza lanego, było jedną z charakterystycznych cech XIX w. Potwierdzeniem tego może być fakt, że dzisiaj okres ten nazywany jest wiekiem żelaza i pary. Żelazo lane, jak dawniej nazywano żeliwo, wykorzystywane było jednak nie tylko w budowie maszyn. Na niespotykaną skalę używane było w budownictwie, a także do wytwarzania przedmiotów gospodarstwa domowego i wyrobów artystycznych. W drugiej połowie XIX w. znalazło jeszcze jedno i to bardzo nietypowe zastosowanie. Były to bowiem elementy... bruku ulicznego, które na masową skalę przez kilkadziesiąt lat były stosowane w Warszawie.

EN

A general application of iron, including cast iron, was one of the characteristic features of the 19th century. This can be confirmed by: the fact, that this period is currently called: The iron and steam age. Cast iron was applied not only in machine building. It was used, on unprecedented scale, in construction engineering and also for producing household items and artistic elements. In the second half of the 19th century it found one more, quite unusual application. These . were elements... of pavements, which on a massive scale were for j several dozen of years, applied in Warsaw.

19

Peculiarities of Alloying Effect on the Eutectic Cementite Behavior Under Hot Rolling

Mironova Tatiana, Proidak Svetlana

New Trends in Production Engineering

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2019

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Vol. 2, Iss. 2

289-300

EN

Currently, cast iron remains one of the major modern casting materials in metallurgy and machine-building industry and is sure to take the lead in the future. Chilled cast iron has high hardness and wear resistance due to a large number of carbide phases in its structure. However, low ductility and impact hardness essentially limit its applicability in terms of processing. Hot plastic working, under which the eutectic net crushing is observed, appears to be one of the most effective means of the eutectic alloy products shape and microstructure transformation. Chilled cast iron properties fundamentally improve after hot plastic working: ductility, strength and impact hardness increase by 2-3 times on retention of the high hardness factor. Chilled cast iron ductility increase can be attained when using phase transformations in eutectic cementite under lean alloying with carbide forming elements. The purpose of the paper is to study alloying effect on the chilled cast iron ductility as well as eutectic cementite behavior under hot rolling. In the paper hardening and softening of the structural components in chilled cast iron under hot working have been studied. The deformation texture forming in eutectic cementite under hot rolling has been revealed, which is connected with the dynamic softening and depends on the degree and the nature of its alloying. The mechanism and regularities of the phase transformation effect in cementite on its behavior under plastic deformation and on the alloys ductility in general have been studied. In cementite chromium alloying initiates processes, that can be characterized as the pre-precipitation stage of the new phases, and this way it contributes to the cast iron ductility reduction and embrittles cementite. Carbide transformation, that occurs in eutectic cementite under alloying with vanadium, stimulates softening of the alloy and increases its ductility level. Moreover, the multiple glide planes {130},{011},{112} in cementite have been determined. It has been found out, that in supersaturated cementite vanadium carbides precipitation stimulates the extra glide plane {111} occurrence under hot rolling. The essence of the carbide transformation phenomenon is that under hot working there occurs the lubricating effect at the transition of the metastable iron carbide condition, which is strengthened with vanadium supersaturation and mechanical hardening, to a more stable condition due to precipitation of the proeutectoid constituents on the one hand, and because of the dynamic softening processes on the other hand. At that, the autocatalyticity effect is observed: there is precipitation of carbides with hardening and softening, similar to the processes that arise as a result of the superplastic effect induced by phase transformations.

20

Szkodliwość eksploatacyjna skażenia powierzchni ścierniwem po procesie docierania technologicznego

Barylski Adam

Autobusy : technika, eksploatacja, systemy transportowe

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2019

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R. 20, nr 6

150--154

PL

Przedstawiono metodykę i wyniki jakościowych i ilościowych badań skażenia powierzchni mikroziarnami ściernymi oraz wpływ warunków docierania na intensywność zjawiska. W badaniach wykorzystano mikroskopię skaningową i mikroanalizę rentgenowską.

EN

The methodology and results of qualitative and quantitative tests of surface contamination with abrasive micrograins and the influence of lapping conditions on the intensity of the phenomenon are presented. In the research, scanning microscopy and X-ray microanalysis were used.