Low temperature mechanical properties, fractographic and metallographic evaluation of several alloy steels

Technical Report · Thu Nov 01 04:00:00 EST 1973

OSTI ID:6527764

Montano, J W

The mechanical properties are presented of alloy steels, 4130, 4140, 4340, 6150, and 8740. Test specimens were manufactured from approx 1.00 in. (2.54 cm) diam bar stock which had been heat treated to two different hardness levels. The following mechanical tests were performed at temperatures of 80/sup 0/F (+26.7 C), 0/sup 0/F (-17.8/sup 0/ C), -100/sup 0/F (-73/sup 0/C), and -200/sup 0/F (129/sup 0/C): (1) tensile test (ultimate, yield, modulus, elongation, and reduction of area), (2) notched tensile test, (3) charpy V-notched impact test (impact energy) and (4) double shear strength test (ultimate and yield). The test data indicate excellent tensile strength, notched/unnotched tensile ratios, ductility, impact, and shear properties at all test temperatures, except at -200/sup 0/F (-129/sup 0/C) where the impact strength of the higher strength group of alloy steels, 4130 (Rc-37) and 4140 (Rc-44) decreased to approx. 9 ft.-lb. (12 joules) and 6 ft-lb. (8 joules), respectively. Chemical, metallographic, and fractographic analyses also were performed to evaluate microstructure, microhardness and the effect of decrease in temperature on the ductile to brittle failure transition.

• Research Organization: National Aeronautics and Space Administration, Washington, DC (USA)
• OSTI ID: 6527764
• Report Number(s): NASA-TM-X-64791; N-74-10530/5GA
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360103* -- Metals & Alloys-- Mechanical Properties
ALLOYS
BRITTLE-DUCTILE TRANSITIONS
CHARPY TEST
COMPARATIVE EVALUATIONS
CRYSTAL STRUCTURE
DESTRUCTIVE TESTING
ELONGATION
FRACTOGRAPHY
HARDENING
HARDNESS
HEAT TREATMENTS
IMPACT TESTS
IRON ALLOYS
IRON BASE ALLOYS
LOW TEMPERATURE
MATERIALS TESTING
MECHANICAL PROPERTIES
MECHANICAL TESTS
MEDIUM TEMPERATURE
METALLOGRAPHY
MICROHARDNESS
MICROSTRUCTURE
NOTCHES
STEELS
TEMPERATURE DEPENDENCE
TESTING