The influence of long term thermal aging on the microstructure and mechanical properties of modified 9Cr-1Mo steel

Conference · Wed Jan 01 04:00:00 EST 1992

OSTI ID:7183207

Brinkman, C R; Gieseke, B; Alexander, D J; Maziasz, P J

Results of room- and elevated-temperature tensile and creep tests are reported from tests conducted on three heats of Modified 9Cr-1Mo steel. The heats were thermally aged at various temperatures from 482 to 704[degrees]C and at aging times to 75,000 h (8.6 years). Tensile strain rates were also varied in order to determine strain rate sensitivity of tensile properties. Changes in the yield and tensile strengths occurred following exposure to these temperatures with decreases noted at the higher temperatures. The material showed a strain-rate sensitivity particularly at temperatures in excess of about 538[degrees]C due to the presence of what was believed to be strain aging. The tensile-strength data were parameterized in order to permit estimates of changes in both room- and elevated-temperature properties to be made following exposure for prolonged periods in service time. Estimates are given of the changes in yield and tensile strengths following isothermal exposure at several temperatures for 60 years of service. Observations are presented concerning microstructural and microcompositional changes as observed by conventional and transmission, analytical electron microscopy, and quantitative precipitate extraction.

• Research Organization: Oak Ridge National Lab., TN (United States)
• Sponsoring Organization: DOE; USDOE, Washington, DC (United States)
• DOE Contract Number: AC05-84OR21400
• OSTI ID: 7183207
• Report Number(s): CONF-9211110-1; ON: DE93001373
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360102 -- Metals & Alloys-- Structure & Phase Studies
360103* -- Metals & Alloys-- Mechanical Properties
AGING
CHROMIUM-MOLYBDENUM STEELS
CRYSTAL STRUCTURE
MECHANICAL PROPERTIES
MICROSTRUCTURE
TEMPERATURE RANGE
TEMPERATURE RANGE 0400-1000 K
TENSILE PROPERTIES