Installation for high-temperature cyclic creep and low-cycle fatigue tests

1982 ◽  
Vol 14 (1) ◽  
pp. 130-133
Author(s):  
V. V. Osasyuk ◽  
Yu. A. Kuzema ◽  
V. D. Man'ko
Keyword(s):  
High Temperature ◽  
Low Cycle Fatigue ◽  
Cyclic Creep ◽  
Fatigue Tests ◽  
Cycle Fatigue

Comparative Study of Microstructure and High Temperature Low Cycle Fatigue Behaviour of Nickel Base Superalloys Inconel 713LC and MAR-M247

2016 ◽  
Vol 713 ◽  
pp. 86-89 ◽  
Author(s):  
Ivo Šulák ◽  
Karel Obrtlík ◽  
Ladislav Čelko
Keyword(s):  
High Temperature ◽  
Fatigue Life ◽  
Low Cycle Fatigue ◽  
Strain Curve ◽  
Cyclic Stress ◽  
Fatigue Tests ◽  
Casting Defects ◽  
Cycle Fatigue ◽  
Stress Strain Curve ◽  
Nickel Base

The present work is focused on the study of microstructure and low cycle fatigue behavior of the first generation nickel-base superalloy IN 713LC (low carbon) and its promising second generation successor MAR-M247 HIP (hot isostatic pressing) at 900 °C. Microstructure of both alloys was studied by means of scanning electron microscopy (SEM). The microstructure of both materials is characterized by dendritic grains, carbides and casting defects. Size and morphology of precipitates and casting defects were evaluated. Fractographic observations have been made with the aim to reveal the fatigue crack initiation place and relation to the casting defects and material microstructure. Low cycle fatigue tests were conducted on cylindrical specimens in symmetrical push-pull cycle under strain control with constant total strain amplitude and strain rate at 900 °C in air. Hardening/softening curves, cyclic stress-strain curve and fatigue life data of both materials were obtained. Cyclic stress-strain curve of MAR M247 is shifted approximately to 120 MPa higher stress amplitudes in comparison with IN 713LC. Significantly higher fatigue life of MAR-M247 has been observed in Basquin representation. On the other hand IN 713LC shows prolonged lifetime compared with MAR-M247 in the Coffin-Manson representation. Results obtained from high temperature low cycle fatigue tests are discussed.

Low Cycle Fatigue Behaviors of TI-6AL-4V Alloy Controlled by Strain and Stress

2012 ◽  
Vol 525-526 ◽  
pp. 441-444
Author(s):  
Rui Feng Wang ◽  
You Tang Li ◽  
Hu Ping An
Keyword(s):  
Stress Ratio ◽  
Low Cycle Fatigue ◽  
Cyclic Strain ◽  
Cyclic Creep ◽  
Cyclic Stress ◽  
Fatigue Tests ◽  
Cycle Fatigue ◽  
Compressive Stresses ◽  
Initial Stage ◽  
Main Factor

The low cycle fatigue behaviors of TI-6AL-4V alloy controlled by strain were investigated by experiment. The fatigue tests were performed at room temperature, and cyclic strain and stress ratio are 0.1 with triangle load wave. The results show that TI-6AL-4V alloy is soften rapidly under the cyclic tensile stresses and it is harden rapidly under the cyclic compressive stresses during the initial-stage of strain controlled fatigue, and the rates of cyclic soften and cyclic harden are decreased with the fatigue progress. The soften rate is related to the cyclic strain but little to the cyclic stress during the overall fatigue progress. The change of cyclic stress is related to the macro friction stresses. The results of experiment show that obvious cyclic creep occurs under the stress controlled low cycle fatigue conditions, and the magnitude of cyclic creep strain is related to the maximum cyclic stress. The softening of tensile friction stresses is the main factor of cyclic creep.

Creep and Low Cycle Fatigue Characterisation of IN718 TIG Butt-Welds at 620°C

2010 ◽  
Vol 636-637 ◽  
pp. 1504-1510
Author(s):  
D.W.J. Tanner ◽  
A.A. Becker ◽  
Thomas H. Hyde
Keyword(s):  
Tensile Strength ◽  
High Temperature ◽  
Failure Time ◽  
Low Cycle Fatigue ◽  
Constant Load ◽  
Fatigue Tests ◽  
Inert Gas ◽  
Fatigue Properties ◽  
Cycle Fatigue ◽  
High Temperature Fatigue

The testing setups, results and analysis of constant load creep and low-cycle high temperature fatigue tests of tungsten inert gas (TIG) butt-welded, thin-section INCONEL 718 (IN718) specimens are presented. The main objectives were to determine the effect the welds have on failure time and analyse any differences in their failure behaviour. It was found that although welded IN718 may exhibit comparatively little loss of tensile strength, its ductility and creep and high temperature fatigue properties are severely compromised due to its changed microstructure.

Evaluation of Continuous Low-Cycle Fatigue Behaviour of High Temperature P122 Boiler Material

2002 ◽  
Author(s):  
John Pumwa ◽  
Soo Woo Nam
Keyword(s):  
High Temperature ◽  
Fracture Mode ◽  
Low Cycle Fatigue ◽  
Testing Machine ◽  
Fatigue Behaviour ◽  
Fatigue Tests ◽  
Transgranular Fracture ◽  
Cycle Fatigue ◽  
Boiler Material ◽  
As Stress

The complex thermal-mechanical loading of power-generating plant components usually comprises of creep, high-cycle and low-cycle fatigue which are thermally induced by start-ups, load changes and shut-downs, producing instationary temperature gradients and hence creating strain as well as stress fields. In order to select the correct materials for these hostile environmental conditions, it is vitally important to understand the behaviour of mechanical properties of these materials. This paper reports the results of Low-cycle fatigue tests of P122 (HCM12A or 12Cr-1.8W-1.5Cu) high temperature boiler material, which is one of the latest developed materials for high temperature environments. The tests were conducted at temperatures ranging from 550°C to 700 °C at 50°C intervals with strain ranges of ±1.5 to ±3.0% at 0.5% intervals using a closed-loop hydraulic Instron material testing machine with a servo hydraulic controller. The results confirm that P122 is comparable to conventional high temperature steels. Moreover, the fracture mode assessments strongly revealed a ductile transgranular fracture mode.

A machine for cyclic creep and low-cycle fatigue tests in the complex stressed state in a broad temperature range

1987 ◽  
Vol 19 (2) ◽  
pp. 274-277 ◽  
Author(s):  
O. K. Shkodzinskii ◽  
F. F. Giginyak ◽  
V. V. Bashta ◽  
M. V. Storchak ◽  
N. V. Stepanenko
Keyword(s):  
Stressed State ◽  
Low Cycle Fatigue ◽  
Cyclic Creep ◽  
Fatigue Tests ◽  
Broad Temperature Range ◽  
Complex Stressed State ◽  
Cycle Fatigue ◽  
Temperature Range

High Temperature Multiaxial Low Cycle Fatigue of Cruciform Specimen

1994 ◽  
Vol 116 (1) ◽  
pp. 90-98 ◽  
Author(s):  
Takamoto Itoh ◽  
Masao Sakane ◽  
Masateru Ohnami
Keyword(s):  
High Temperature ◽  
Low Cycle Fatigue ◽  
Crack Opening ◽  
Strain Ratio ◽  
Equivalent Strain ◽  
Fatigue Tests ◽  
Principal Strain ◽  
Cycle Fatigue ◽  
Opening Displacement ◽  
Crack Morphology

This paper describes high temperature multiaxial low cycle fatigue lives of type SUS304 stainless steel and 1Cr-1Mo-1/4V steel cruciform specimens at 923K and 823K in air. Strain controlled multiaxial low cycle fatigue tests were carried out using cruciform specimens at the principal strain ratios between −1 and 1. The principal strain ratio had a significant effect on low cycle fatigue lives. Fatigue lives drastically decreased as the principal strain ratio increased. Multiaxial low cycle faitgue strain parameters were applied to the experimental data and the applicability of the parameters was discussed. The equivalent strain based on crack opening displacement (COD strain) developed in the paper and Γ* —plane parameter successfully predicted multiaxial low cycle fatigue lives. The crack morphology was also extensively discussed from not only the surface crack direction but also the crack inclination into the specimen.

scholarly journals High-Temperature Low Cycle Fatigue Life Prediction and Experimental Research of Pre-Tightened Bolts

Metals ◽  
2018 ◽  
Vol 8 (10) ◽  
pp. 828 ◽  
Author(s):  
Qingmin Yu ◽  
Honglei Zhou ◽  
Xudong Yu ◽  
Xiangjin Yang
Keyword(s):  
High Temperature ◽  
Fatigue Life ◽  
Life Prediction ◽  
Low Cycle Fatigue ◽  
Equivalent Stress ◽  
Fatigue Tests ◽  
Fatigue Life Prediction ◽  
Cycle Fatigue ◽  
Stress Strain ◽  
Fatigue Model

Bolted connections are widely used in various mechanical structures due to their superior fastening properties. However, vibration and fatigue loads in the structure are likely to cause fatigue failure of the bolted joints, especially those under high temperature, such as in aero-engines. This paper mainly studies the low-cycle fatigue life of the pre-tightened bolts working at a high temperature. A novel test fixture is designed for fatigue tests, and low cycle fatigue tests of pre-tightened bolts are conducted at the temperatures of 550 °C and 650 °C, respectively. Furthermore, a new low cycle fatigue model that is based on the Von Mises equivalent stress/strain criterion is proposed. Meanwhile, the proposed model is used to predict the high-temperature low cycle fatigue life of pre-tightened bolts according to the stress/strain results obtained by finite element analysis. There is good agreement between the experimental results and those obtained by theoretical prediction, which validates the accuracy of the proposed fatigue model. Research results will provide a theoretical basis for the low cycle fatigue life prediction of pre-tightened bolts.

Interactive Mechanisms of Sulfide Inclusions and Environmental Factors in Low Cycle Fatigue Process of Pressure Vessel Steels in High Temperature Water

2005 ◽  
Vol 475-479 ◽  
pp. 253-256
Author(s):  
Xin Qiang Wu
Keyword(s):  
High Temperature ◽  
Pressure Vessel ◽  
Low Cycle Fatigue ◽  
Fatigue Cracking ◽  
Cyclic Stress ◽  
Fatigue Tests ◽  
Cycle Fatigue ◽  
High Temperature Water ◽  
Pressure Vessel Steels ◽  
Temperature Water

Low cycle fatigue tests were conducted in high temperature water for A533B pressure vessel steels with sulfur contents of 0.013, 0.025 and 0.038 wt.% respectively. Cyclic stress amplitude response and fatigue resistance as well as influence of strain rate, temperature and dissolved oxygen concentration in water were investigated. Fatigue cracking/fractograhpic features were examined. Sulfide-related environmentally assisted cracking mechanism is discussed.

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