scholarly journals The Reliability of the Results of the Modified Low-cycle Fatigue Test for Cast Iron Evaluated by Metallographic Studies

2015 ◽  
Vol 15 (1) ◽  
pp. 41-46
Author(s):  
M. Maj ◽  
K. Pietrzak
Keyword(s):  
Mechanical Properties ◽  
Cast Iron ◽  
Light Microscopy ◽  
Fatigue Test ◽  
Low Cycle Fatigue ◽  
Scanning Microscopy ◽  
Cycle Fatigue ◽  
Characteristic Features

Abstract This study discloses the characteristic features of the modified low-cycle fatigue test used for the determination of the mechanical properties of two types of cast iron, i.e. EN-GJL-250 and EN-GJS-600-3. For selected materials, metallographic studies were also conducted in the range of light microscopy and scanning microscopy.

scholarly journals Fatigue Life Assessment of Selected Engineering Materials Based on Modified Low-Cycle Fatigue Test

2013 ◽  
Vol 13 (1) ◽  
pp. 89-94
Author(s):  
M. Maj
Keyword(s):  
Cast Iron ◽  
Fatigue Life ◽  
Fatigue Test ◽  
Ductile Iron ◽  
Low Cycle Fatigue ◽  
Grey Cast Iron ◽  
Life Assessment ◽  
Geometrical Parameters ◽  
Cycle Fatigue ◽  
Grey Cast

Abstract In this study, the mechanical tests were carried out on ductile iron of EN-GJS-600-3 grade and on grey cast iron of EN-GJL-250 grade. The fatigue life was evaluated in a modified low-cycle fatigue test (MLCF), which enables the determination of parameters resulting from the Manson-Coffin-Morrow relationship. The qualitative and quantitative metallographic studies conducted by light microscopy on selected samples of ductile iron with spheroidal graphite and grey cast iron with lamellar graphite (showing only small variations in mechanical properties,) confirmed also small variations in the geometrical parameters of graphite related with its content and morphological features.

scholarly journals STUDY OF MECHANICAL PROPERTIES AND STRUCTURE OF LARGE-SIZED SEMI-FINISHED PRODUCTS MADE OF VT6ch TITANIUM ALLOY

2020 ◽  
pp. 12-18
Author(s):  
A.L. Yakovlev ◽  
◽  
A.A. Arislanov ◽  
S.V. Putyrskiy ◽  
N.A. Nochovnaya ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Titanium Alloy ◽  
Comparative Analysis ◽  
Impact Strength ◽  
Low Cycle Fatigue ◽  
Cycle Fatigue ◽  
Structural Components ◽  
Final Deformation

The article presents the results of a complex of studies (analysis of microstructure, as well as determination of mechanical properties under tension, impact strength (KCU), low-cycle fatigue (LCF), fracture toughness (K1с)) of large-sized forgings made of titanium alloy Vt6сh, providing for the final deformation in the (α+β)-region, as well as large-sized profiles and stamping made of titanium alloy Vt6сh, providing for the final deformation in the β-region. A comparative analysis of the data obtained during the research shows the dependence of the mechanical properties of semi-finished products with plate-like structure on the size of the structural components – of primary β-grains and colonies of α-plates. This is especially noticeable for the characteristics of plasticity.

Evaluation of the Heat Treatment Role for Light Aluminum Alloys Subjected to Creep and Low Cycle Fatigue

2010 ◽  
Vol 638-642 ◽  
pp. 455-460 ◽  
Author(s):  
A. Rutecka ◽  
L. Dietrich ◽  
Zbigniew L. Kowalewski
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Low Cycle Fatigue ◽  
Numerical Models ◽  
Cyclic Hardening ◽  
Fatigue Tests ◽  
Cycle Fatigue ◽  
Lower Stress ◽  
Creep Tests ◽  
Different Temperatures

The AlSi8Cu3 and AlSi7MgCu0.5 cast aluminium alloys of different composition and heat treatment were investigated to verify their applicability as cylinder heads in the car engines [1]. Creep tests under the step-increased stresses at different temperatures, and low cycle fatigue (LCF) tests for a range of strain amplitudes and temperatures were carried out. The results exhibit a significant influence of the heat treatment on the mechanical properties of the AlSi8Cu3 and AlSi7MgCu0.5. An interesting fact is that the properties strongly depend on the type of quenching. Lower creep resistance (higher strain rates) and lower stress response during fatigue tests were observed for the air quenched materials in comparison to those in the water quenched. Cyclic hardening/softening were also observed during the LCF tests due to the heat treatment applied. The mechanical properties determined during the tests can be used to identify new constitutive equations and to verify existing numerical models.

Proposal of a new low-cycle fatigue life model for cast iron with room temperature calibration involving mean stress and high-temperature effects

2019 ◽  
Vol 233 (14) ◽  
pp. 5056-5073 ◽  
Author(s):  
Cristiana Delprete ◽  
Raffaella Sesana
Keyword(s):  
Finite Element ◽  
Cast Iron ◽  
High Temperature ◽  
Finite Element Model ◽  
Life Prediction ◽  
Low Cycle Fatigue ◽  
Element Model ◽  
Mean Stress ◽  
Exhaust Manifold ◽  
Cycle Fatigue

The paper presents and discusses a low-cycle fatigue life prediction energy-based model. The model was applied to a commercial cast iron automotive exhaust manifold. The total expended energy until fracture proposed by the Skelton model was modified by means of two coefficients which take into account of the effects of mean stress and/or mean strain, and the presence of high temperature. The model was calibrated by means of experimental tests developed on Fe–2.4C–4.6Si–0.7Mo–1.2Cr high-temperature-resistant ductile cast iron. The thermostructural transient analysis was developed on a finite element model built to overtake confidentiality industrial restrictions. In addition to the commercial exhaust manifold, the finite element model considers the bolts, the gasket, and a cylinder head simulacrum to consider the corresponding thermal and mechanical boundary conditions. The life assessment performance of the energy-based model with respect the cast iron specimens was compared with the corresponding Basquin–Manson–Coffin and Skelton models. The model prediction fits the experimental data with a good agreement, which is comparable with both the literature models and it shows a better fitting at high temperature. The life estimations computed with respect the exhaust manifold finite element model were compared with different multiaxial literature life models and literature data to evaluate the life prediction capability of the proposed energy-based model.

scholarly journals Mechanical Properties and Low Cycle Fatigue Strength at 4 and 300 K of Welded Alloy A286

1987 ◽  
Vol 73 (14) ◽  
pp. 1770-1777 ◽  
Author(s):  
Keijiro HIRAGA ◽  
Toshio OGATA ◽  
Kotobu NAGAI ◽  
Tetsumi URI ◽  
Keisuke ISHIKAWA ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Fatigue Strength ◽  
Low Cycle Fatigue ◽  
Cycle Fatigue

Low-cycle fatigue test and life assessment of carbon structural steel GB Q235B butt joints and cruciform joints

2018 ◽  
Vol 22 (3) ◽  
pp. 581-596
Author(s):  
Zhao Fang ◽  
Aiqun Li ◽  
Sheng Shen ◽  
Wanrun Li
Keyword(s):  
Fatigue Test ◽  
Failure Mode ◽  
Stress Amplitude ◽  
Low Cycle Fatigue ◽  
Butt Joint ◽  
Life Assessment ◽  
Cycle Fatigue ◽  
Carbon Structural Steel ◽  
Cruciform Joint ◽  
Linear Slip Model

Axial low-cycle fatigue tests are conducted on transverse butt joint specimens and cruciform joint specimens made of carbon structural steel GB Q235B. The effect of slip between the specimens and the grips of the test machine is considered by the proposal of a linear slip model. The cyclic softening properties are studied by observing the variation of stress amplitude with cycles. The cyclic stress–strain curve and the strain–life curve for both kinds of specimens are obtained based on the fatigue test data, and the corresponding coefficients are fitted. In order to verify the fatigue test results, finite element models of specimens are established and the corresponding fatigue life assessment is conducted using the local stress–strain approach and the equivalent structural stress approach, respectively. The results show that the effect of slip is unneglectable and the established linear slip model is reasonable. The two kinds of specimens both show a strain softening property, but cruciform joint specimens experience sudden falls of stress amplitude during the test due to the damage of welded lines; cruciform joint specimens show an either one-side failure mode or two-side failure mode while butt joint specimens only show a one-side failure mode; the two-side failure mode tends to lead to shorter fatigue life, so in the design of cruciform joint, such failure mode should be avoided.

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