Influence of Stress Mode on Failure Micromechanisms of Nodular Cast Iron

2014 ◽  
Vol 693 ◽  
pp. 382-387 ◽  
Author(s):  
Alan Vaško ◽  
Milan Vaško
Keyword(s):  
Cast Iron ◽  
Nodular Cast Iron ◽  
Mechanical Tests ◽  
Fatigue Tests ◽  
Bending Test ◽  
Metallographic Analysis ◽  
Cast Irons ◽  
Fracture Surfaces ◽  
Static Tensile ◽  
Different Content

The paper deals with comparison of the failure micromechanisms of nodular cast iron at static, impact and fatigue stress. Several specimens of ferrite-pearlitic nodular cast irons with different content of ferrite in a matrix were used for metallographic analysis, mechanical tests and microfractographic analysis. Mechanical properties were found out by static tensile test, impact bending test and fatigue tests. The microfractographic analysis was made with use of scanning electron microscope on fracture surfaces of the specimens fractured by these mechanical tests. Fracture surfaces of analysed specimens are characteristic of mixed mode of fracture. Failure micromechanism of nodular cast irons is dependent on mode of stress.

scholarly journals Fatigue Properties Of Nodular Cast Irons Alloyed By Si, Mo And Cu

2019 ◽  
Vol 1 (1) ◽  
pp. 738-744
Author(s):  
Alan Vaško ◽  
Marek Krynke
Keyword(s):  
Cast Iron ◽  
Low Frequency ◽  
Hardness Test ◽  
Nodular Cast Iron ◽  
Fatigue Behaviour ◽  
Fatigue Tests ◽  
Bending Test ◽  
Fatigue Properties ◽  
Cast Irons ◽  
Number Of Cycles

AbstractIn recent years, the research of nodular cast iron has been focused on increasing fatigue resistence. In the paper, two types of alloyed nodular cast irons have been investigated – SiMo-nodular cast iron alloyed by 4% of silicon and 1% of molybdenum and SiCu-nodular cast iron alloyed by 4% of silicon and 1.5% of copper. SiMo-nodular cast iron is suitable for high-temperature applications, for example the exhaust manifolds of the combustion engines. SiCu-nodular cast iron is used in various components of tribotechnical units. These components are often loaded by fatigue. The mechanical and fatigue behaviour of both nodular cast iron types has been studied by means of tensile test, impact bending test, hardness test and fatigue tests. Fatigue tests were realised at low frequency cyclic push-pull loading up to 10 million cycles. The relationship between the amplitude of stress and number of cycles to failure was investigated and the fatigue strength was determined. Mechanical and fatigue properties of both nodular cast iron types are correlated with the microstructure of specimens.

scholarly journals Fatigue Properties of Nodular Cast Iron at Low Frequency Cyclic Loading

2017 ◽  
Vol 62 (4) ◽  
pp. 2205-2210 ◽  
Author(s):  
A. Vaško
Keyword(s):  
Cast Iron ◽  
Cyclic Loading ◽  
High Frequency ◽  
Stress Ratio ◽  
Low Frequency ◽  
Nodular Cast Iron ◽  
Fatigue Tests ◽  
Fatigue Properties ◽  
Charge Composition ◽  
Cast Irons

Abstract Three melts of ferrite-pearlitic nodular cast iron with different charge composition were used for fatigue tests. Wöhler fatigue curves and fatigue strength were obtained, and microstructure and fracture surfaces were investigated. The aim of the paper is to determine the influence of charge composition on microstructure, mechanical and fatigue properties of synthetic nodular cast irons and their micromechanisms of failure. Fatigue tests were realised at low frequency sinusoidal cyclic push-pull loading (stress ratio R = −1) at ambient temperature (T = 20 ±5°C). They were carried out with using the fatigue experimental machine Zwick/Roell Amsler 150HFP 5100 at frequency f ≈ 120 Hz. The results of fatigue tests at low frequency cyclic loading are compared with fatigue properties at high frequency cyclic loading.

scholarly journals Corrosion Resistance of SiMo- and SiCu-Types of Nodular Cast Iron in NaCl Solution

2020 ◽  
Vol 2 (1) ◽  
pp. 191-198
Author(s):  
Alan Vaško ◽  
Viera Zatkalíková ◽  
Václav Kaňa
Keyword(s):  
Corrosion Resistance ◽  
Cast Iron ◽  
Sea Water ◽  
Nodular Cast Iron ◽  
Industrial Applications ◽  
Bending Test ◽  
Fatigue Properties ◽  
Nacl Solution ◽  
Cast Irons ◽  
Wide Range

AbstractNodular cast irons are used in a wide range of industrial applications, especially in the automotive industry. SiMo-type of nodular cast iron is suitable for high-temperature applications, for example the exhaust manifolds of the combustion engines; SiCu-type of nodular cast iron is used in various components of tribotechnical units. These automotive components often work in a corrosive environment. Therefore, the aim of this paper is to compare the corrosion resistance of two types of the nodular cast irons (SiMo-type and SiCu-type). Corrosion resistance was determined by the exposure immersion test at ambient temperature. Specimens of both types of nodular cast iron were immersed in 3.5 % NaCl solution (to simulate sea water) and gradually removed from the solution after 1, 2, 4 and 8 weeks. Subsequently, the weight loss (g) and the average corrosion rate (g m−2 day−1) were calculated. Experimental results show that nodular cast iron alloyed by Si and Mo has higher corrosion resistance than the nodular cast iron alloyed with Si and Cu. Moreover, the mechanical properties (evaluated by tensile test, impact bending test and hardness test) and fatigue properties of both types of nodular cast iron has been compared in the paper.

scholarly journals PRELIMINARY STUDY ON EFFECT OF ROD GEOMETRY IN FHPP BETWEEN FE55006 NODULAR CAST IRON AND SAE 8620 STELL

2019 ◽  
Vol 16 (31) ◽  
pp. 642-650
Author(s):  
Douglas MARTINAZZI ◽  
Guilherme V. B LEMOS ◽  
Renan M LANDELL ◽  
Diogo T BUZZATTI ◽  
André BRUSIUS ◽  
...  
Keyword(s):  
Cast Iron ◽  
Base Material ◽  
Nodular Cast Iron ◽  
Lower Surface ◽  
Fusion Welding ◽  
Plastic State ◽  
Cast Irons ◽  
Preliminary Study ◽  
Sae 8620 Steel ◽  
Made In

Nodular cast irons are an excellent alternative in manufacturing process of axels due to their characteristics and good mechanical properties. However, the necessity of joining the axels to the gears and other components, made in carbon steel, is a great challenge. Traditional fusion welding methods applied to dissimilar ferrous materials are not deeply studied. In this context, it is well known that different materials have distinct melting points which can cause difficulty in welding, besides of defects formation from solidification. Therefore, modern joining processes such as Friction Hydro Pillar Processing (FHPP) are a great alternative. In this technology, a consumable rod is rotated against to a base material, generating the heat due to the friction, promoting materials in the plastic state and then producing the weld. Hence, this work presents a preliminary study of FHPP between the FE55006 nodular cast iron and SAE 8620 steel and evaluates the rod geometry influence on microstructure and surface stresses of the welded joints. Two rod geometries were used and two welds were further produced. The results indicated that an increase in the rod contact area promoted a lower surface stress as well as a better welded joint.

scholarly journals Determination of Braking Speed of Developed Hybrid Particle Reinforced Aluminium Alloy

2021 ◽  
Vol 6 (3) ◽  
Author(s):  
Justine O Bucham ◽  
Baba A Aliyu ◽  
Abubakar Muhammad
Keyword(s):  
Silicon Carbide ◽  
Cast Iron ◽  
Aluminium Alloy ◽  
Nodular Cast Iron ◽  
Mechanical Tests ◽  
Coconut Shell ◽  
Brake Disc ◽  
Alloy Sample ◽  
Alloy Matrix ◽  
Coconut Shell Ash

Abstract- This paper is aimed at comparing the braking speed of the developed Composite Brake Disc (CBD) with that of a nodular cast iron Honda Accord (2000) Model Brake Disc (HABD). The test samples were produced from Aluminium alloy (Al6061), Coconut Shell Ash (CSA) and Silicon Carbide (SiC) by Stir casting and machined into standard specimens for microstructure analysis, density test, mechanical tests (hardness, tensile and impact), wear test and thermal test. The characterization of coconut shell ash particle was carried out using X-ray Flourescent equipment. Six samples were produced, four composite samples; C1 (70% Al, 5% SiC, 20% CSA), C2 (70% Al, 10% SiC, 15% CSA), C3 (70% Al, 15% SiC, 10% CSA) and C4 (70% Al, 20% SiC, 5% CSA), aluminium alloy sample (A1) and as-cast nodular cast iron sample (N1) obtained from HABD. Sample ‘C4’ had the best physical, mechanical, wear and thermal properties (Densty: 3.15 g/cm3, Hardness: 68 kg/mm2, Tensile Strength:  196.12 N/mm2, Impact Energy: 8.05 J, Wear rate: 0.0002328 g/m, Thermal Conductivity: 72.57 W/m-K) and was used to produce the CBD. From the values of coefficient of frictions obtained for CBD and HABD, the braking speeds were calculated and HABD was seen to have a lower braking speed (56.65 m/s) than the CBD (94.42 m/s) because of its higher coefficient of friction. The higher braking speed of the composite brake disc (CBD) as compared to the Honda Accord Brake Disc (HABD) could be as a result of inadequate reinforcements in the aluminium alloy matrix. Hence,  the produced CBD cannot be used as an alternative for the nodular cast iron Honda accord brake disc (HABD) even as problems of heavy weight and breakage that may occur due to heavy impact associated with cast iron brake disc have been addressed using the developed composite.Keywords,- Aluminium Alloy, Braking Speed, Coconut Shell, Composite, Silicon Carbide

scholarly journals MICROSTRUCTURE AND PROPERTIES OF HIGH CHROMIUM WHITE CAST IRONS ALLOYED WITH BORON

2021 ◽  
Vol 3 ◽  
pp. 137-141
Author(s):  
Julieta Kaleicheva ◽  
Krasimir Kirov ◽  
Valentin Plamenov Mishev ◽  
Zdravka Karaguiozova
Keyword(s):  
Mechanical Properties ◽  
Cast Iron ◽  
Impact Toughness ◽  
Boron Content ◽  
Bending Strength ◽  
White Cast Iron ◽  
Metallographic Analysis ◽  
Cast Irons ◽  
High Chromium ◽  
The Impact

The microstructure and mechanical properties of high chromium white cast iron with composition: 2,6÷3,4% C; 0,9÷1,1% Si; 0,8÷1,1% Mn; 1,0÷1,3% Mo; 12,3÷13,4% Cr, additionally doped with boron in an amount of 0,18% to 1,25% is investigated. The microstructure of six compositions of white cast irons is studied by means of an optical metallographic analysis - one without boron, and the others contain 0,18%; 0,23%; 0,59%; 0,96% and 1,25% boron. A test is performed to determine: hardness by the Rockwell method; microhardness; bending strength and impact toughness. It was found that at a boron content of 0,18%; 0,23% and 0,59%, the structure of white cast irons is subeutectic, with impact toughness in the range of 1,80÷1,52 J/cm2; with a boron content of 0,96%, the structure of white cast iron is close to the eutectic, with impact toughness 0,98 J/cm2 ; at a boron content of 1,25% the structure of white cast iron is supereutectic and the impact toughness decreases to 0,68 J/cm2. With a change in the boron content from 0,8% to 1,25%, the amount of carbide phase in the structure of white cast iron increases, which leads to an increase in hardness from 53 to 59 HRC. The highest bending strength (Rmi=660,85 MPa) was obtained in white cast irons with a boron content of 0,23%. 

scholarly journals Influence of graphite morphology on static and cyclic strength of ferritic nodular cast iron

2018 ◽  
Vol 165 ◽  
pp. 14014 ◽  
Author(s):  
Christian Gebhardt ◽  
Geng Chen ◽  
Alexander Bezold ◽  
Christoph Broeckmann
Keyword(s):  
Cast Iron ◽  
Nodular Cast Iron ◽  
Tensile Tests ◽  
Cyclic Strength ◽  
Fatigue Tests ◽  
Point Of View ◽  
Experimental Point ◽  
Suitable Material ◽  
Material Parameters ◽  
Perfectly Plastic

High silicon alloyed nodular cast iron consists of a purely ferritic matrix and graphite nodules, mainly. Varying wall thicknesses and manufacturing conditions result in different graphite morphologies throughout a structural component. From an experimental point of view, axial fatigue and tensile tests were carried out on specimens with differently degraded graphite. From a numerical point of view, the microstructure has been modelled using a finite element (FE) approach with representative volume elements (RVE). The RVE models were built according to micrographs of fatigue specimens. The generated RVEs determine effective material properties through elasto-plastic homogenization and were subsequently analysed using a shakedown approach. In shakedown theory, the material re-enters the elastic regime after a few cycles of initial plastic deformation. This work uses the shakedown theorem to derive a lower bound estimation of the endurance limit from a non-incremental simulation. Here, the material has to be modelled elastic-perfectly plastic. The major challenge in modelling nodular cast iron is to determine suitable material parameters for the graphite and ferrite phase, revealed by parameter studies on the static and cyclic model. By using reasonable material parameters, fundamental effects, observed in the fatigue tests, were reproduced on the model level.

Fatigue Properties of Synthetic Nodular Cast Irons

2014 ◽  
Vol 635 ◽  
pp. 5-8 ◽  
Author(s):  
Alan Vaško
Keyword(s):  
Mechanical Properties ◽  
Silicon Carbide ◽  
Cast Iron ◽  
Nodular Cast Iron ◽  
Positive Influence ◽  
Fatigue Properties ◽  
Steel Scrap ◽  
Cast Irons ◽  
Metallurgical Silicon ◽  
A Charge

The contribution deals with comparison of microstructure, mechanical properties and fatigue properties of synthetic nodular cast irons with a different ratio of steel scrap in a charge. Chemical composition of individual melts was regulated alternatively by ferrosilicon (FeSi) and carburizer or metallurgical silicon carbide (SiC). The paper shows positive influence of SiC additive on the microstructure, mechanical properties as well as fatigue properties of nodular cast iron. The additive of metallurgical silicon carbide in analysed specimens increases the content of ferrite in the matrix, decreases the size of graphite and increases the average count of graphitic nodules per unit of area. Consequently, the mechanical and fatigue properties of nodular cast iron are improved.

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