Relationship of bainitic microstructure to impact toughness in Cr-Mo and Cr-W steels

Technical Report · Thu Dec 31 04:00:00 EST 1992

OSTI ID:139216

Klueh, R L; Alexander, D J ^[1]

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1. Oak Ridge National Lab., TN (United States)

Non-classical bainite microstructures can develop during continuous cooling of low-carbon alloy steels. These differ from classical upper and lower bainite developed by isothermal transformation. Two non-classical bainite microstructures were produced in a 3Cr-1.5Mo-0.25V-0.1C steel using different cooling rates after austenitizing--water quenching and air cooling. The carbide-free acicular bainite formed in the quenched steel had a lower ductile-brittle transition temperature (DBTT) than the granular bainite formed in the air-cooled steel. With increasing tempering parameter, the DBTT of both decreased and approached a common value, although the final value occurred at a much lower tempering parameter for the quenched steel than for the air-cooled steel. The upper-shelf energy was similarly affected by microstructure. These observations along with similar observations in two Cr-W steels indicate that control of the bainite microstructure can be used to optimize strength and toughness.

• Research Organization: Oak Ridge National Lab., TN (United States)
• OSTI ID: 139216
• Report Number(s): DOE/ER--0313/13; ORNL/M--2722; ON: DE93013462
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
70 PLASMA PHYSICS AND FUSION TECHNOLOGY
BAINITE
CARBON ADDITIONS
CHARPY TEST
CHROMIUM ALLOYS
DUCTILE-BRITTLE TRANSITIONS
IMPACT STRENGTH
IRON BASE ALLOYS
LOW ALLOY STEELS
MECHANICAL PROPERTIES
MICROSTRUCTURE
MOLYBDENUM ALLOYS
PROGRESS REPORT
TEMPERING
THERMONUCLEAR REACTOR MATERIALS
VANADIUM ADDITIONS