scholarly journals Determination of the Creep-Fatigue Interaction Diagram for Alloy 617

Author(s):  
J. K. Wright ◽  
L. J. Carroll ◽  
T.-L. Sham ◽  
N. J. Lybeck ◽  
R. N. Wright

Alloy 617 is the leading candidate material for an intermediate heat exchanger for the very high temperature reactor (VHTR). As part of evaluating the behavior of this material in the expected service conditions, creep–fatigue testing was performed. The cycles to failure decreased compared to fatigue values when a hold time was added at peak tensile strain. At 850°C, increasing the tensile hold duration continued to degrade the creep–fatigue resistance, at least to the investigated strain–controlled hold time of up to 60 minutes at the 0.3% strain range and 240 minutes at the 1.0% strain range. At 950°C, the creep–fatigue cycles to failure are not further reduced with increasing hold duration, indicating saturation occurs at relatively short hold times. The creep and fatigue damage fractions have been calculated and plotted on a creep–fatigue interaction D–diagram. Test data from creep–fatigue tests at 800 and 1000°C on an additional heat of Alloy 617 are also plotted on the D–diagram.

Author(s):  
Keiji Kubushiro ◽  
Hiroki Yoshizawa ◽  
Takuya Itou ◽  
Hirokatsu Nakagawa

Creep-fatigue properties of candidate materials of 700°C-USC boiler are investigated. The candidate materials are Alloy 230, Alloy 263, Alloy 617 and HR6W. Creep-fatigue tests were conducted at 700°C and the effect of both strain range and hold time were studied. Experimental results showed that at 1.0% strain range, cycles to failure with 60 min strain holding is about 10% of that without strain holding, but at 0.7% strain range, cycles to failure with 60 min strain holding decreases down to about 1% of without strain holding. It appears that cycles to failure is decreased by increasing strain holding time at all tested strain ranges, and the effect of holding time is emphasized at small strain range. These phenomena depend on the kind of alloys.


2013 ◽  
Vol 135 (6) ◽  
Author(s):  
Celine Cabet ◽  
Laura Carroll ◽  
Richard Wright

Alloy 617 is the leading candidate material for an intermediate heat exchanger (IHX) application of the very high temperature nuclear reactor (VHTR), expected to have an outlet temperature as high as 950 °C. Acceptance of Alloy 617 in Section III of the ASME Code for nuclear construction requires a detailed understanding of the creep-fatigue behavior. Initial creep-fatigue work on Alloy 617 suggests a more dominant role of environment with increasing temperature and/or hold times evidenced through changes in creep-fatigue crack growth mechanisms and failure life. Continuous cycle fatigue and creep-fatigue testing of Alloy 617 was conducted at 950 °C and 0.3% and 0.6% total strain in air to simulate damage modes expected in a VHTR application. Continuous cycle fatigue specimens exhibited transgranular cracking. Intergranular cracking was observed in the creep-fatigue specimens and the addition of a hold time at peak tensile strain degraded the cycle life. This suggests that creep-fatigue interaction occurs and that the environment may be partially responsible for accelerating failure.


Author(s):  
Shengde Zhang ◽  
Yukio Takahashi

This paper presents creep and creep-fatigue deformations and lives of both Ni-based alloys, Alloy 740H and Alloy 617. Creep tests were performed using solid bar specimens at 650°C-800°C, and effect of cyclic loading on creep deformation and rupture was discussed. Strain controlled creep-fatigue tests were also performed under triangular and trapezoidal waveforms at 700°C. Alloy 740H showed stronger creep-fatigue resistance compared to Alloy 617. Creep-fatigue lives in trapezoidal waveform were smaller than those in the pure fatigue test and the creep-fatigue lives decreased as the hold time increased. Applicability of four representative creep-fatigue life prediction methods was discussed.


Author(s):  
Terry C. Totemeier

Creep-fatigue testing of nickel alloy 617 base metal and fusion weldments was performed at temperatures of 800 and 1000°C in air in support of ASME BPV Sec III code qualification of alloy 617 for the Next-Generation Nuclear Plant. Cyclic loading was performed in strain control with a trapezoidal waveform and was fully reversed. Creep was introduced into the fatigue cycle by a hold period at maximum tensile strain which varied from 18 to 9000 seconds. Base metal specimens were machined from 20 mm thick rolled plate; weldment specimens were machined from GTAW butt-welded plate such that the loading direction was oriented transverse to the welding direction. Weld metal, heat-affected zone, and base metal were present in the reduced section of weldment specimens. Creep-fatigue lives decreased with increasing hold time for both base metal and weldments; lives of weldments were reduced relative to those of base metal. Creep-fatigue cracking in weldment specimens initiated in the weld metal.


Author(s):  
Laura Carroll ◽  
Celine Cabet ◽  
Richard Wright

Alloy 617 is the leading candidate material for an intermediate heat exchanger (IHX) application of the Very High Temperature Nuclear Reactor (VHTR), expected to have an outlet temperature as high as 950°C. Acceptance of Alloy 617 in Section III of the ASME Code for nuclear construction requires a detailed understanding of the creep-fatigue behavior. Initial creep-fatigue work on Alloy 617 suggests a more dominant role of environment with increasing temperature and/or hold times evidenced through changes in creep-fatigue crack growth mechanism/s and failure life. Furthermore, previous work on corrosion of nickel base alloys in impure helium has suggested that this environment is far from inert with respect to Alloy 617. Continuous cycle fatigue and creep-fatigue testing of Alloy 617 was conducted at 950°C and 0.3% and 0.6% total strain in air to simulate damage modes expected in a VHTR application. Continuous cycle and creep-fatigue specimens exhibited intergranular cracking, but did not show evidence of grain boundary cavitation. Despite the absence of grain boundary cavitation to accelerate crack propagation, the addition of a hold time at peak tensile strain was detrimental to cycle life. This suggests that creep-fatigue interaction may occur by a different mechanism or that the environment may be partially responsible for accelerating failure.


2017 ◽  
Vol 734 ◽  
pp. 194-201 ◽  
Author(s):  
Yutaka Konishi ◽  
Takamoto Itoh ◽  
Masao Sakane ◽  
Fumio Ogawa ◽  
Hideyuki Kanayama

This paper investigates the fatigue results in low cycle fatigue region obtained from a miniaturized specimen having a 6mm gage length, 3mm diameter and 55mm total length. Fatigue tests were performed for two type lead-free solders using horizontal-type electrical servo hydraulic push-pull fatigue testing machine. Materials employed were Sn-3.0Ag-0.5Cu and Sn-5Sb. The results from Sn-3.0Ag-0.5Cu were compared with those obtained using a bulk specimen in a previous study. Relationship between strain range and number of cycles to failure of the small-sized specimen agreed with those of the bulk specimens. The testing techniques are applicable to Sn-5Sb following the Manson-Coffin law. These results confirm that the testing technique proposed here, using small-sized specimen, is suitable to get fruitful fatigue data for lead-free solder compounds.


2016 ◽  
Vol 250 ◽  
pp. 232-237
Author(s):  
Tomasz Tomaszewski ◽  
Janusz Sempruch ◽  
Przemysław Strzelecki

This paper presents results of fatigue tests performed on standard specimens and minispecimens taken from two EN 1.4301 acid-resistant steel plates of different thickness. The tests were required for determination of the state of vibrating machines made from the same material. The results confirmed that the proposed testing method can be used for experimental tests.


2007 ◽  
Vol 345-346 ◽  
pp. 323-326 ◽  
Author(s):  
Katsuyuki Tokimasa

The present paper summarizes the fully reversed strain-controlled creep-fatigue tests conducted on thin-walled tubular specimens of SUS304 austenitic stainless steel at 973K in air under push-pull, cyclic torsion, in-phase straining and 90deg out-of-phase straining of push-pull and cyclic torsion. It is shown that, as the results of analysis of the experimental data by the strain-range partitioning methodand the critical plane model parameter, a new inelastic-strain based parameter was proposed for life estimation of SUS304 subject to nonproportionally combined push-pull and cyclic torsion by the strain-range partitioning method.


2007 ◽  
Vol 353-358 ◽  
pp. 190-194
Author(s):  
Nian Jin Chen ◽  
Zeng Liang Gao ◽  
Wei Zhang ◽  
Yue Bao Le

The law of low-cycle fatigue with hold time at elevated temperature is investigated in this paper. A new life prediction model for the situation of fatigue and creep interaction is developed, based on the damage due to fatigue and creep. In order to verify the prediction model, strain-controlled low-cycle fatigue tests at temperature 693K, 823K and 873K and fatigue tests with various hold time at temperature 823K and 873K for 316L austenitic stainless steel were carried out. Good agreement is found between the predictions and experimental results.


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