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1
Content available Effect of Cr, Mo and Al on Structure and Selected Mechanical Properties of Austenitic Cast Iron
Medyński D., Janus A.
Archives of Foundry Engineering
|
2019
|
iss. 4
39--44
EN
Results of a research on influence of chromium, molybdenum and aluminium on structure and selected mechanical properties of Ni-Mn- Cu cast iron in the as-cast and heat-treated conditions are presented. All raw castings showed austenitic matrix with relatively low hardness, making the material machinable. Additions of chromium and molybdenum resulted in higher inclination to hard spots. However, a small addition of aluminium slightly limited this tendency. Heat treatment consisting in soaking the castings at 500 °C for 4 h resulted in partial transformation of austenite to acicular, carbon-supersaturated ferrite, similar to the bainitic ferrite. A degree of this transformation depended not only on the nickel equivalent value (its lower value resulted in higher transformation degree), but also on concentrations of Cr and Mo (transformation degree increased with increasing total concentration of both elements). The castings with the highest hard spots degree showed the highest hardness, while hardness increase, caused by heat treatment, was the largest in the castings with the highest austenite transformation degree. Addition of Cr and Mo resulted in lower thermodynamic stability of austenite, so it appeared a favourable solution. For this reason, the castings containing the highest total amount of Cr and Mo with an addition of 0.4% Al (to reduce hard spots tendency) showed the highest tensile strength.
2
Content available Dilatometric Research of High-quality Nodular Cast Iron
Medyński D., Janus A.
Archives of Foundry Engineering
|
2018
|
Vol. 18, iss. 2
163--168
EN
In the research, relationships between matrix structure and hardness of high-quality Ni-Mn-Cu cast iron containing nodular graphite and nickel equivalent value were determined. Nickel equivalent values were dependent on chemical composition and differences between them resulted mostly from nickel concentration in individual alloys. Chemical compositions of the alloys were selected to obtain, in raw condition, austenitic and austenitic-martensitic cast iron. Next, stability of matrix of raw castings was determined by dilatometric tests. The results made it possible to determine influence of nickel equivalent on martensite transformation start and finish temperatures.
3
Content available Abrasive-wear Resistance of Austenitic Cast Iron
Medyński D., Janus A.
Archives of Foundry Engineering
|
2018
|
Vol. 18, iss. 3
43--48
EN
A research of wear resistance of an austenitic cast iron with higher resistance to abrasive-wear and maintained corrosion resistance characteristic for Ni-Resist cast iron is presented. For the examination, structure of raw castings was first formed by proper selection of chemical composition (to make machining possible). Next, a heat treatment was applied (annealing at 550 °C for 4 hours followed by air cooling) in order to increase abrasive-wear resistance. One of the factors deciding intensity of wear appeared to be the chilling degree of castings. However, with respect to unfavourable influence of chilling on machining properties, an important factor increasing abrasive-wear resistance is transformation of austenite to acicular ferrite as a result of annealing non-chilled castings. Heat treatment of non-chilled austenitic cast iron (EquNi > 16%) resulted in much higher abrasive-wear resistance in comparison to the alloy having pearlitic matrix at ambient temperature (EquNi 5.4÷6.8%).
4
Content available Effect of Heat-treatment Parameters of Cast Iron GJS-X350NiMnCu7-3-2 on its Structure and Mechanical Properties
Medyński D., Janus A., Zaborski S.
Archives of Foundry Engineering
|
2017
|
Vol. 17, iss. 1
121--126
EN
The paper presents influence of soaking parameters (temperature and time) on structure and mechanical properties of spheroidal graphite nickel-manganese-copper cast iron, containing: 7.2% Ni, 2.6% Mn and 2.4% Cu. Raw castings showed austenitic structure and relatively low hardness (150 HBW) guaranteeing their good machinability. Heat treatment consisted in soaking the castings within 400 to 600°C for 2 to 10 hours followed by air-cooling. In most cases, soaking caused changes in structure and, in consequence, an increase of hardness in comparison to raw castings. The highest hardness and tensile strength was obtained after soaking at 550°C for 6 hours. At the same time, decrease of the parameters related to plasticity of cast iron (elongation and impact strength) was observed. This resulted from the fact that, in these conditions, the largest fraction of fine-acicular ferrite with relatively high hardness (490 HV0.1) was created in the matrix. At lower temperatures and after shorter soaking times, hardness and tensile strength were lower because of smaller degree of austenite transformation. At higher temperatures and after longer soaking times, fine-dispersive ferrite was produced. That resulted in slightly lower material hardness.
5
Content available Effect of Annealing on Nature of Corrosion Damages of Medium-nickel Austenitic Cast Iron
Medyński D., Janus A., Chęcmanowski J.
Archives of Foundry Engineering
|
2017
|
Vol. 17, iss. 3
85--90
EN
Within the presented research, effect of annealing on nature of corrosion damages of medium-nickel austenitic nodular cast iron castings, containing 5.5% to 10.3% Ni, was determined. Concentration of nickel, lower than in the Ni-Resist cast iron, was compensated with additions of other austenite-stabilising elements (manganese and copper). In consequence, raw castings with austenitic matrix structure and gravimetrically measured corrosion resistance increasing along with nickel equivalent value EquNi were obtained. Annealing of raw castings, aimed at obtaining nearly equilibrium structures, led to partial austenite-to-martensite transformation in the alloys with EquNi value of ca. 16%. However, corrosion resistance of the annealed alloys did not decrease in comparison to raw castings. Annealing of castings with EquNi value above 18% did not cause any structural changes, but resulted in higher corrosion resistance demonstrated by smaller depth of corrosion pits.
6
Content available Effect of Chemical Composition on Structure and Corrosion Resistance of Ni-Mn-Cu Cast Iron
Medyński D., Janus A.
Archives of Foundry Engineering
|
2016
|
Vol. 16, iss. 3
59--62
EN
In the paper, a relationship between chemical composition of Ni-Mn-Cu cast iron and its structure, hardness and corrosion resistance is determined. The examinations showed a decrease of thermodynamic stability of austenite together with decreasing nickel equivalent value, in cast iron solidifying according to both the stable and the metastable systems. As a result of increasing degree of austenite transformation, the created martensite caused a significant hardness increase, accompanied by small decline of corrosion resistance. It was found at the same time that solidification way of the alloy and its matrix structure affect corrosion resistance to a much smaller extent than the nickel equivalent value, in particular concentration of elements with high electrochemical potential.
7
Content available Effect of Austenite Transformation on Abrasive Wear and Corrosion Resistance of Spheroidal Ni-Mn-Cu Cast Iron
Medyński D., Janus A.
Archives of Foundry Engineering
|
2016
|
Vol. 16, iss. 3
63--66
EN
Within the presented work, the effect of austenite transformation on abrasive wear as well as on rate and nature of corrosive destruction of spheroidal Ni-Mn-Cu cast iron was determined. Cast iron contained: 3.1÷3.4 %C, 2.1÷2.3 %Si, 2.3÷3.3 %Mn, 2.3÷2.5 %Cu and 4.8÷9.3 %Ni. At a higher degree of austenite transformation in the alloys with nickel equivalent below 16.0%, abrasive wear resistance was significantly higher. Examinations of the corrosion resistance were carried out with the use of gravimetric and potentiodynamic method. It was shown that higher degree of austenite transformation results in significantly higher abrasive wear resistance and slightly higher corrosion rate, as determined by the gravimetric method. However, results of potentiodynamic examinations showed creation of a smaller number of deep pinholes, which is a favourable phenomenon from the viewpoint of corrosion resistance.
8
Content available Effect of nickel equivalent on austenite transition ratio in Ni-Mn-Cu cast iron
Janus A., Kurzawa A.
Archives of Foundry Engineering
|
2013
|
Vol. 13, iss. 2
53--58
EN
Determined was quantitative effect of nickel equivalent value on austenite decomposition degree during cooling-down castings of Ni-Mn- Cu cast iron. Chemical composition of the alloy was 1.8 to 5.0 % C, 1.3 to 3.0 % Si, 3.1 to 7.7 % Ni, 0.4 to 6.3 % Mn, 0.1 to 4.9 % Cu, 0.14 to 0.16 % P and 0.03 to 0.04 % S. Analysed were castings with representative wall thickness 10, 15 and 20 mm. Scope of the examination comprised chemical analysis (including WDS), microscopic observations (optical and scanning microscopy, image ana-lyser), as well as Brinell hardness and HV microhardness measurements of structural components.
9
Content available Effect of chemical composition on number of eutectic colonies in Ni-Mn-Cu cast iron
Janus A.
Archives of Foundry Engineering
|
2013
|
Vol. 13, iss. 1
51--56
EN
Determined were direction and intensity of influence of alloying additions on the number of eutectic graphite colonies in austenitic cast iron Ni-Mn-Cu. Chemical composition of the cast iron was 1.7 to 3.3% C, 1.4 to 3.1% Si, 2.8 to 9.9% Ni, 0.4 to 7.7% Mn, 0 to 4.6% Cu, 0.14 to 0.16% P and 0.03 to 0.04% S. Analysed were structures of mottled (20 castings) and grey (20 castings) cast iron. Obtained were regression equations determining influence intensity of individual components on the number of graphite colonies per 1 cm2 (LK). It was found that, in spite of high total content of alloying elements in the examined cast iron, the element that mainly decides the LK value is carbon, like in a plain cast iron.
10
Content available Effect of alloying elements on solidification of primary austenite in Ni-Mn-Cu cast iron
Janus A., Kurzawa A.
Archives of Foundry Engineering
|
2011
|
Vol. 11, iss. 2 spec.
93--96
EN
Within the research, determined were direction and intensity of alloying elements influence on solidification way (directional or volumetric) of primary austenite dendrites in hypoeutectic austenitic cast iron Ni-Mn-Cu. 50 cast shafts dia. 20 mm were analysed. Chemical composition of the alloy was as follows: 1.7 to 3.3 % C, 1.4 to 3.1 % Si, 2.8 to 9.9 % Ni, 0.4 to 7.7 % Mn, 0 to 4.6 % Cu, 0.14 to 0.16 % P and 0.03 to 0.04 % S. The discriminant analysis revealed that carbon influences solidification of primary austenite dendrites most intensively. It clearly increases the tendency to volumetric solidification. Influence of the other elements is much weaker. This means that the solidification way of primary austenite dendrites in hypoeutectic austenitic cast iron Ni-Mn-Cu does not differ from that in an unalloyed cast iron.
11
Content available remote Effect of alloying elements on branching of primary austenite dendrites in Ni-Mn-Cu cast iron
Janus A.
Archives of Foundry Engineering
|
2011
|
Vol. 11, iss. 2
51-54
EN
Within the research, determined were direction and intensity of influence of individual alloying elements on branching degree of primary austenite dendrites in austenitic cast iron Ni-Mn-Cu. 30 cast shafts dia. 20 mm were analysed. Chemical composition of the alloy was as follows: 2.0 to 3.3 % C, 1.4 to 3.1 % Si, 2.8 to 9.5 % Ni, 0.4 to 7.7 % Mn, 0 to 4.6 % Cu, 0.14 to 0.16 % P and 0.03 to 0.04 % S. Analysis was performed separately for the dendrites solidifying in directional and volumetric way. The average distance "x" between the 2nd order arms was accepted as the criterion of branching degree. It was found that influence of C, Si, Ni, Mn and Cu on the parameter "x" is statistically significant. Intensity of carbon influence is decidedly higher than that of other elements, and the influence is more intensive in the directionally solidifying dendrites. However, in the case of the alloyed cast iron Ni-Mn-Cu, combined influence of the alloying elements on solidification course of primary austenite can be significant.
12
Content available remote Characteristics of flake graphite in Ni-Mn-Cu cast iron. Part 2.
Janus A.
Archives of Foundry Engineering
|
2010
|
Vol. 10, iss. 1
75-78
EN
The paper continues the article published by Archives of Foundry Engineering, vol. 9, issue 1/2009, pp. 185-190, that presented influence of chemical composition of hypo- and hypereutectic nickel-manganese-copper alloyed cast iron on properties of the contained flake graphite. In this second part of the research, effect of chemical composition of hypereutectic cast iron containing 3.5 to 5.1% C, 1.7 to 2.8% Si, 3.5 to 10.5 % Ni, 2.0 to 8.0% Mn, 0.1 to 3.5% Cu, 0.14 to 0.17% P and 0.02 to 0.04% S on properties of flake graphite is determined. Evolution of graphite properties with changing eutecticity degree of the examined cast iron is presented. For selected castings, histograms of primary and eutectic graphite are presented, showing quantities of graphite precipitates in individual size ranges and their shape determined by the coefficient [zeta] defined as ratio of a precipitate area to square of its circumference. Moreover, presented are equations obtained by discriminant analysis to determine chemical composition of Ni-Mn-Cu cast iron which guarantee the most favourable distribution of A-type graphite from the point of view of castings properties.
13
Content available remote Characteristics of flake graphite in Ni-Mn-Cu cast iron. Part 1
Janus A.
Archives of Foundry Engineering
|
2009
|
Vol. 9, iss. 1
185-190
EN
Relationship between chemical composition of cast iron and properties of flake graphite occurring in hypoeutectic and eutectic nickelmanganese-copper cast iron was determined. The research covered over 60 alloys of cast iron containing 1.6 to 4.1 % C, 1.3 to 2.8 % Si, 2.4 to 10.5 % Ni, 0.2 to 8.2 % Mn, 0.1 to 3.5 % Cu, 0.14 to 0.17 % P and 0.02 to 0.04 % S. Evolution of graphite properties with changing eutecticity degree of the examined cast iron is presented. For selected castings, histograms of eutectic graphite colonies are presented, showing numbers of graphite precipitates in individual size ranges and their shape described by the coefficient [...], defined as the ratio of a graphite precipitate area to square of its circumference. Statistical evaluation of individual elements influence on graphite properties will be presented in part 2 of the work.
14
Content available remote Effect of chemical composition of cast iron Ni-Mn-Cu on susceptibility to hard-spotting
Janus A.
Archives of Foundry Engineering
|
2008
|
Vol. 8, iss. 1 spec.
151--154
EN
Influence of carbon, Silicon, nickel, manganese and copper content on susceptibility to hard-spotting in nickel-manganese-copper cast iron was determined. Over a hundred alloys were analysed, containing: 1.6÷4.7% C, 1.3÷3.3% Si, 2.4÷10.5% Ni, 0.2÷8.2% Mn, 0.1÷5.2% Cu, 0.14÷0.17% P and 0.02÷0.04% S. Tendency to hard-spotting was determined on the ground of a test consisting in measuring the height of hard-spotting in a casting chilled from its face (ASTM A 367-55T). The measurement results permitted developing a regression equation describing direction and intensity of individual element influence on tendency of the examined cast iron to solidifying in a metastable system. This equation, together with the nickel equivalent equation, permits proper selection of chemical composition of austenitic cast iron with flake graphite.
15
Content available remote Wpływ wartości ekwiwalentu niklowego na strukturę żeliwa Ni-Mn-Cu
Janus A.
Archiwum Odlewnictwa
|
2006
|
R. 6, nr 18/2
159--164
PL
Na podstawie analizy struktur opracowano równanie ekwiwalentu niklowego dla odlewów wykonanych z żeliwa Ni-Mn-Cu zawierającego: 2,5-4,5% C; 1,5-3,0% Si; 2,0-8,0% Ni; 2,0-8,0% Mn i 0,1-5,0% Cu. Określono minimalną wartość ekwiwalentu, konieczną do uzyskania trwałej w temperaturze otoczenia austenitycznej struktury osnowy metalowej żeliwa w stanie po odlaniu.
EN
On the base of structures analysis the equation of nickel equivalent for castings made of Ni-Mn-Cr cast iron containing 2.5-4.5% C, 1.5-3.0% Si, 2.0-8.0% Ni, 2.0-8.0% Mn and 0.1-5.0% Cu was elaborated. The minimum value of this equivalent necessary for the obtainment of the stable austenitic structure of the rough castings at the ambient temperature was determined.
16
Content available remote Warstwy na żeliwie niklowo-miedziowo-chromowym wytwarzane w kąpieli AL-SI
Rzadkosz S., Lepka E.
Archiwum Odlewnictwa
|
2006
|
R. 6, nr 18/1
363--368
PL
W referacie omówiono wyniki badań połączenia dyfuzyjnego między żeliwem austenitycznym typu Niresist a siluminem. Połączenie wytwarzano w kąpieli Al-Si. Przeprowadzono badania mikrostruktury połączenia, składu chemicznego i fazowego poszczególnych warstw oraz kinetykę ich wzrostu w różnych temperaturach.
EN
In the paper results of diffusion bonding between cast iron Ni-Resist and silumin have been introduced. Junction was made in the Al-Si bath. Investigations of microstructure of diffusion bonding, chemical analysis and phase composition of individual layers and kinetic growth in different temperatures were conducted.
17
Content available remote Graniczna rozpuszczalność węgla w ciekłym żeliwie Ni-Mn-Cu
Janus A., Granat K., Naplocha K.
Archiwum Odlewnictwa
|
2006
|
R. 6, nr 22
240-245
PL
Na podstawie analizy krzywych ATD opracowano równanie określające maksymalną rozpuszczalność węgla w ciekłym żeliwie Ni-Mn-Cu. Badania obejmowały, pochodzące z ponad 50 wytopów, nadeutektyczne żeliwo zawierające: 2,8+4,0% C; 1,5+3,2% Si; 4,3+11,0% Ni; 2,1+8,2% Mn i 0,1+5,8% Cu. Stwierdzono, że w przypadku żeliwa austenitycznego rozpuszczalność węgla w ciekłym żeliwie jest większa od wartości obliczonych w oparciu o dane literaturowe [2]. Różnica ta zwiększa się wraz ze wzrostem temperatury kąpieli metalowej.
EN
On the base of DTA curves, equation that describes maximum solubility of carbon in Ni-Mn-Cu liquid cast iron was elaborated. Investigations over materials from 50 heats include hypereutectic cast iron containing: 2,8+4,0% C; 1,5+3,2% Si; 4,3+11,0% Ni; 2,1+8,2% Mn i 0,1+5,8% Cu. It was ascertained that solubility of carbon in liquid austenitic cast iron exceeds values calculated using literature data. This difference increases with temperature increase of metal bath.
18
Europejska norma na żeliwo austenityczne
Pawłowska H.
Odlewnictwo - Nauka i Praktyka
|
2004
|
R. 6, nr 3
42-43
19
Content available remote Struktura oraz udarność żeliwa austenitycznego przeznaczonego do pracy w niskich temperaturach
Guzik E., Kopyciński D.
Archiwum Odlewnictwa
|
2004
|
R. 4, nr 12
115--120
PL
W pracy przedstawiono wyniki badań strukturalnych oraz badań udarności żeliwa sferoidalnego austenitycznego z różnymi dodatkami niklu (15% do 30%) oraz manganu ok. 1.6%. W miarę zwiększania zawartości Ni pojawiają się obok grafitu kulkowego, zdegenerowane wydzielenia grafitu (grafit „chunky”). Wprowadzenie manganu do żeliwa wysokoniklowego powoduje zanik wydzieleń martenzytu w osnowie oraz wyraźne zwiększenie udarności w niskich temperaturach. W pracy przedstawiono omówienie wyników i wnioski.
EN
The study shows the results of impact strength tests carried out on austenitic ductile iron with various additions of nickel (15%÷30%Ni) and 1.6% manganese. By increasing the Ni content it was obtain ductile iron with degeneration of graphite nodules and so called “chunky” graphite. Introducing into liquid cast iron the amount of Mn approximate adequately 1,6% cause the austenitic matrix is observed in nodular cast iron and increasing impact strength. The final part of the study includes discussion of results and conclusions.
20
Zmodyfikowane równanie ekwiwalentu niklowego żeliwa austenitycznego
Janus A.
Prace Naukowe Instytutu Technologii Maszyn i Automatyzacji Politechniki Wrocławskiej. Konferencje
|
2003
|
Vol. 83, nr 40
21-26
PL
Opracowano równanie ekwiwalentu niklowego, które określa minimalną zawartość pierwiastków stabilizujących austenit, konieczną do uzyskania żeliwa austenitycznego. Badano żeliwo z 60 wytopów o następującym zakresie składu chemicznego: 2,5-3,7% C; 1,5-3,0% Si; 4,0-10,0% Ni; 2,0-8,0% Mn i 0,1-6,0% Cu. Po przeprowadzonych obliczeniach uzyskano równanie w postaci: -0,3 Si + Ni + 4 Mn + 0,5 Cu > 22 [% wag.]. Równanie to wyraźnie różni się od stosowanego w praktyce odlewniczej równania ekwiwalentu niklowego opracowanego przez Girsovica, i jak wykazała przeprowadzona analiza, skuteczniej klasyfikuje strukturę stopów.
EN
An equation of nickel equivalent that determines the minimum content of the austenite stabilising elements, necessary to obtain austenitic cast iron, was developed. Cast iron from 60 melts was examined, with the following chemical composition: C 2.5-3.7%, Si 1.5-3.0%, Ni 4.0-10.0%, Mn 2.0-8.0%, Cu 0.1-6.0%. The calculations resulted in the following relationship: -0.3 Si + Ni + 4 Mn + 0.5 Cu > 22 [% wag]. The relationship obtained is clearly different from the nickel equivalent equation developed by Girsovic, used in foundry practice, and it classifies the alloy structure more effectively, as evidenced by the analysis performed.
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