Accession Number:

ADA210571

Title:

Mechanisms of Strength and Toughness in a Microalloyed, Precipitation Hardened Steel

Descriptive Note:

Research and development rept.

Corporate Author:

DAVID TAYLOR RESEARCH CENTER BETHESDA MD SHIP MATERIALS ENGINEERING DEPT

Personal Author(s):

• Natishan, M. E.

Report Date:

1989-04-01

Pagination or Media Count:

226.0

Abstract:

The microstructural parameters contributing to the strength and toughness of low carbon, microalloyed, precipitation hardenable steels were identified in two ASTM A710, grade A, 50 mm thick plates in the reaustenitized, quenched and aged condition. Tensile, impact toughness and fracture toughness properties were determined over a full range of test temperatures to characterize the mechanical behavior and the fracture processes in the fracture mode transition temperature region, especially as related to cleavage failure and cracking parallel to the loading direction longitudinal cracking. Microstructural and fractographic characterization, carbide precipitates in the longitudinal direction and a non-homogeneous grain size distribution as the primary contributing factors to lower toughness, while copper precipitation played a large role in strengthening. Keywords HSLA steel, Structureproperty relationship, Fracture characteristics, Physical metallurgy.

Descriptors:

• *MICROSTRUCTURE
• *STEEL
• *HARDENING
• TEST AND EVALUATION
• TEMPERATURE
• MECHANICAL PROPERTIES
• TENSILE STRENGTH
• DISTRIBUTION
• PARAMETERS
• PHYSICAL PROPERTIES
• CRACKS
• FAILURE
• CARBIDES
• TOUGHNESS
• GRAIN SIZE
• CARBON
• FRACTURE(MECHANICS)
• IMPACT STRENGTH
• PRECIPITATION
• HIGH STRENGTH
• COPPER
• STRENGTH(GENERAL)
• HETEROGENEITY
• CLEAVAGE
• PRECIPITATES
• PHYSICAL METALLURGY
• CARBON STEELS

Subject Categories:

• Properties of Metals and Alloys

Distribution Statement:

APPROVED FOR PUBLIC RELEASE