Development of a design methodology for high temperature cyclic applications of materials which experience cyclic softening

Technical Report · Thu Dec 01 04:00:00 EST 1988

DOI:https://doi.org/10.2172/5004743· OSTI ID:5004743

Marriott, D. L.; Stubbins, J. F. ^[1]

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1. Illinois Univ., Urbana, IL (USA). Dept. of Mechanical and Industrial Engineering

The project has as its original focus the high temperature behavior of 2.25 Cr-1 Mo steel, heat treated to produce a predominantly bainitic microstructure and the load carrying response of components made of this material. Experiments were carried out on uniform and notched specimens under both steady and cyclic loading using specially acquired electromechanical test machines. It emerged that a very important feature of mechanical behavior under the conditions of interest was the strong tendency of this material to cyclically soften, particularly at high temperature in the creep range, giving the illusion of a severe creep-fatigue interaction under certain conditions. This finding led to a significant component of the project being devoted to investigation of the effects of local, as opposed to generalized, cyclic softening, and the implications this phenomenon might have on the setting of allowable design stress limits. The format of this report is as follows: The second chapter is a review of the work carried out in approximately chronological order under the headings of work was carried out under the following: (1) 2.25 Cr 1 Mo Steel -- Elevated Temperature Fatigue and Environmental Effects; (2) Preliminary Studies of Advanced Austenitics; (3) A Uniaxial Constitutive Model for Cyclic Softening; (4) The Iso-Cyclic Stress-Strain Approach to Evaluation of Components in Cyclic Softening Materials; (5) Testing of High Temperature Austenitic Alloys; and (6) Design Methodology for Aging Materials -- Application to Cyclic Softening. 65 refs., 39 figs., 7 tabs.

• Research Organization: Oak Ridge National Lab., TN (USA); Illinois Univ., Urbana, IL (USA). Dept. of Mechanical and Industrial Engineering
• Sponsoring Organization: DOE/FE
• DOE Contract Number: AC05-84OR21400
• OSTI ID: 5004743
• Report Number(s): ORNL/Sub-85-55904/02; UILU-ENG--88-4020; ON: DE90006722; CNN: 19X-559904C
• Country of Publication: United States
• Language: English

Related Subjects

01 COAL, LIGNITE, AND PEAT
010400* -- Coal
Lignite
& Peat-- Processing
36 MATERIALS SCIENCE
360103 -- Metals & Alloys-- Mechanical Properties
CHROMIUM-MOLYBDENUM STEELS
CONTAINERS
CREEP
DOCUMENT TYPES
FATIGUE
HEAT TREATMENTS
MATERIALS TESTING
MECHANICAL PROPERTIES
PRESSURE VESSELS
PROGRESS REPORT
STRESSES
TEMPERATURE EFFECTS
TESTING