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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.
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.
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.
EN
Within the research determined was the effect of nickel equivalent on structure, hardness and corrosion resistance of nodular cast iron Ni- Mn-Cu. The examinations revealed a drop of thermodynamic stability of austenite along with decreasing nickel content. Along with in-creasing degree of austenite transformation, the created martensite resulted in significant increase of hardness (and of abrasion resistance as well) of the examined of cast iron, accompanied by insignificant decrease of corrosion resistance.
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.
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.
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.
8
Content available remote Characteristics of flake graphite in Ni-Mn-Cu cast iron. Part 2.
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.
9
Content available remote Characteristics of flake graphite in Ni-Mn-Cu cast iron. Part 1
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.
10
Content available remote Skłonność do zabieleń żeliwa Ni-Mn-Cu przeznaczonego na odlewy kokilowe
PL
Określono wpływ zawartości manganu (od 1,5 do 6,2%) i miedzi (od 0,1% do 6,0%) na skłonność do zabieleń oraz wrażliwość na zmianę grubości ścianki odlewu dla niklowego żeliwa zawierającego średnio 3,1% C, 2,3% Si i 6, i % Ni. Stwierdzono możliwość wytwarzania niezabielonych odlewów kokilowych o średnicy 10 - 40 mm wykonanych z żeliwa zawierającego ok. 3% miedzi i do 43% manganu.
EN
Effect of manganese (1.5-6.2%) and copper (0.1-6.0%) content on hard spots susceptibility and sectional susceptibility of medium - nickel cast iron containing 3.1% C, 2.3% Si and 6.1 % Ni was determined. It was ascertained the possibility of manufacturing of not spot hardened chill casts of dimeters 10-40 mm made of cast iron containing of 3% of copper and up to 4.5%
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