Thermal Ratcheting Test Results for Alloy 617

2014 ◽  
Author(s):  
Yanli Wang ◽  
T.-L. (Sam) Sham ◽  
R. I. Jetter
Keyword(s):  
High Temperatures ◽  
Hold Time ◽  
Test Procedure ◽  
Material Modeling ◽  
Mean Stress ◽  
Alloy 617 ◽  
Thermal Transients ◽  
Inelastic Analysis ◽  
Thermal Ratcheting ◽  
Very High

Alloy 617 has been selected as a reference material supporting the Very High Temperature Gas Cooled Reactor (VHTR). However, current simplified design methods in Subsection NH have been deemed inapplicable at very high temperatures because, at these conditions, it is not possible to decouple plasticity and creep which is the basis for the current methods. Also, the alternative use of inelastic analysis requires development and verification of material modeling at these very high temperatures. A test procedure has been developed and implemented to support verification of new simplified methods and material modeling of Alloy 617 at very high temperatures. The procedure is based on two bars tested in series using two coupled servo-controlled testing machines to achieve equal displacement and constant applied load, mimicking the behavior of a pressurized cylinder subjected to through wall thermal transients. The tests were conducted with a hold time at 950°C. The bars were heated and cooled out of phase to generated thermal induced loading superimposed on a constant mean stress. The results are presented for different mean stress levels, heating and cooling rates, and thermal histories.

scholarly journals Two-Bar Thermal Ratcheting for Alloy 617—Part II: Ratcheting Results

2015 ◽  
Vol 137 (3) ◽  
Author(s):  
Yanli Wang ◽  
T.-L. Sham ◽  
R. I. Jetter
Keyword(s):  
High Temperatures ◽  
Time Delays ◽  
Alloy 617 ◽  
Design Rules ◽  
Testing Conditions ◽  
Heating And Cooling ◽  
Thermal Ratcheting ◽  
Thermal Histories ◽  
Very High ◽  
Mean Stresses

This is Part II of a study on two-bar thermal ratcheting for Alloy 617. The ratcheting strains were evaluated for conditions with the same temperature range but with different mean stresses, heating and cooling rates, time delays, and thermal histories. These testing conditions were designed to be closely aligned to the development of design rules for strain limits at very high temperatures for Alloy 617. These new design rules have been formulated to address the fact that the effects of plastic deformation and creep deformation on the ratcheting strains are not separable at very high temperatures for this alloy.

scholarly journals Evaluation of Creep-Fatigue Damage Based on Simplified Model Test Approach

2013 ◽  
Author(s):  
Yanli Wang ◽  
Tianlei Li ◽  
T.-L. (Sam) Sham ◽  
Robert I. Jetter
Keyword(s):  
Fatigue Damage ◽  
High Temperatures ◽  
Test Data ◽  
Model Test ◽  
Hold Time ◽  
Simplified Model ◽  
Creep Fatigue ◽  
Asme Code ◽  
Cyclic Damage ◽  
Very High

Current methods used in the ASME Code, Subsection NH for the evaluation of creep-fatigue damage are based on the separation of elevated temperature cyclic damage into two parts, creep damage and fatigue damage. This presents difficulties in both evaluation of test data and determination of cyclic damage in design. To avoid these difficulties, an alternative approach was identified, called the Simplified Model Test or SMT approach based on the use of creep-fatigue hold time test data from test specimens with elastic follow-up conservatively designed to bound the response of general structural components of interest. A key feature of the methodology is the use of the results of elastic analysis directly in design evaluation similar to current methods in the ASME Code, Subsection NB. Although originally developed for current material included in Subsection NH, recent interest in the application of Alloy 617 for components operating at very high temperatures has caused renewed interest in the SMT approach because it provides an alternative to the proposed restriction on the use of current Subsection NH simplified methods at very high temperatures. A comprehensive review and assessment of five representative simplified methods for creep-fatigue damage evaluation is presented in Asayama [1]. In this review the SMT methodology was identified as the best long term approach but the need for test data precluded its near term implementation. Asayama and Jetter [2] is a summary of the more comprehensive report by Asayama [1] with a summary of the SMT approach presented by Jetter [3]. In this paper, the previously documented development of the SMT approach and applicable restrictions are discussed and reviewed; the design of the SMT specimen, measurement issues and constraints are presented; the test apparatus and measurement system is described; initial test results and their application to a prototypic design curve are presented; and further testing and analysis for ASME Code incorporation are discussed.

scholarly journals Two-Bar Thermal Ratcheting for Alloy 617—Part I: Scoping Tests

2015 ◽  
Vol 137 (3) ◽  
Author(s):  
Yanli Wang ◽  
T.-L. Sham ◽  
R. I. Jetter
Keyword(s):  
Slow Heating ◽  
Test Results ◽  
Alloy 617 ◽  
Thermally Induced ◽  
Thermal Transients ◽  
Heating And Cooling ◽  
Hydraulic Machines ◽  
Thermal Ratcheting ◽  
Thermal Histories ◽  
Pressurized Cylinder

A two-bar thermal ratcheting procedure has been implemented to Alloy 617 at very high temperatures. The procedure is based on two bars tested on two coupled servo hydraulic machines to achieve equal displacement and constant total applied load, mimicking the behavior of a pressurized cylinder subjected to through wall thermal transients. The bars were heated and cooled out of phase to generate thermally induced loading superimposed on a constant mean stress. Scoping test results at slow heating and cooling rates are presented for different mean stresses and thermal histories.

Beyond Ni-based superalloys: Development of CoRe-based alloys for gas turbine applications at very high temperatures

2011 ◽  
Vol 102 (9) ◽  
pp. 1125-1132 ◽  
Author(s):  
Debashis Mukherji ◽  
Joachim Rösler ◽  
Pavel Strunz ◽  
Ralph Gilles ◽  
Gerhard Schumacher ◽  
...  
Keyword(s):  
Gas Turbine ◽  
High Temperatures ◽  
Very High

Interferometric testing at very high temperatures by TV holography (ESPI)

1988 ◽  
Vol 28 (3) ◽  
pp. 315-321 ◽  
Author(s):  
J. T. Malmo ◽  
O. J. Jøkberg ◽  
G. A. Slettemoen
Keyword(s):  
High Temperatures ◽  
Very High

scholarly journals Gaseous combustion at high pressures. —Part X. The co-volume corrections, maximum temperatures and dissociation of steam and carbon dioxide in explosions

1928 ◽  
Vol 119 (782) ◽  
pp. 464-480
Keyword(s):  
Carbon Dioxide ◽  
High Pressure ◽  
Internal Energy ◽  
High Temperatures ◽  
High Pressures ◽  
Internal Combustion ◽  
Systematic Survey ◽  
Explosion Method ◽  
Maximum Temperatures ◽  
Very High

During the researches upon high-pressure explosions of carbonic oxide-air, hydrogen-air, etc., mixtures, which have been described in the previous papers of this series, a mass of data has been accumulated relating to the influence of density and temperature upon the internal energy of gases and the dissociation of steam and carbon dioxide. Some time ago, at Prof. Bone’s request, the author undertook a systematic survey of the data in question, and the present paper summarises some of the principal results thereof, which it is hoped will throw light upon problems interesting alike to chemists, physicists and internal-combustion engineers. The explosion method affords the only means known at present of determining the internal energies of gases at very high temperatures, and it has been used for this purpose for upwards of 50 years. Although by no means without difficulties, arising from uncertainties of some of the assumptions upon which it is based, yet, for want of a better, its results have been generally accepted as being at least provisionally valuable. Amongst the more recent investigations which have attracted attention in this connection should be mentioned those of Pier, Bjerrum, Siegel and Fenning, all of whom worked at low or medium pressures.

MAS-NMR at very high temperatures

2004 ◽  
Vol 26 (2) ◽  
pp. 84-86 ◽  
Author(s):  
Leo van Wüllen ◽  
Georg Schwering ◽  
Ernst Naumann ◽  
Martin Jansen
Keyword(s):  
High Temperatures ◽  
Mas Nmr ◽  
Very High

Reactor Core Materials Interactions at Very High Temperatures

1989 ◽  
Vol 87 (1) ◽  
pp. 327-333 ◽  
Author(s):  
Peter Hofmann ◽  
Siegfried J. L. Hagen ◽  
Gerhard Schanz ◽  
Alfred Skokan
Keyword(s):  
High Temperatures ◽  
Reactor Core ◽  
Very High ◽  
Core Materials
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