Mixed mode fracture of an HSLA-100 steel

Journal Article · Fri Sep 04 04:00:00 EDT 1998 · Scripta Materialia

DOI:https://doi.org/10.1016/S1359-6462(98)00266-8· OSTI ID:665227

Densley, J M; Hirth, J P ^[1]

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1. Washington State Univ., Pullman, WA (United States). School of Mechanical and Materials Engineering

Traditionally, mode I instability criteria have marked the conservative fracture toughness limit. However, some high-toughness, particle strengthened materials have been shown to have a lower resistance to the onset of stable crack growth under mixed-mode loading. By testing both standard compact tension specimens and modified mixed-mode compact tension specimens, the authors have determined the pure mode I plain strain fracture toughness and mixed-mode I/III fracture toughness for an HSLA 100 steel. Limited mixed-mode I/II tests of the type described by Kamat were also performed. The steel was provided by E. Czyryca of the Naval Research Laboratory and tested in the as received condition. Czyryca found {sigma}{sub ys} = 780 MPa, {sigma}{sub uts} = 800 MPa, and a two specimen average J{sub Ic} = 490 kJ/m{sup 2} for specimens tested in the T-L orientation. The steel was austenitized at 900 C for 40 minutes, water quenched then aged at 665 C for one hour than air cooled. The hardenability provided by manganese, molybdenum and nickel resulted in a mixed ferrite-bainite microstructure with fine carbonitride and copper precipitates. Such a microstructure gives high strength and toughness, improved weldability, lower DBTT as well as lower cost.

• OSTI ID: 665227
• Journal Information: Scripta Materialia, Journal Name: Scripta Materialia Journal Issue: 7 Vol. 39; ISSN 1359-6462; ISSN SCMAF7
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
CHEMICAL COMPOSITION
CRACK PROPAGATION
CRACKS
FRACTURE MECHANICS
FRACTURE PROPERTIES
LOW ALLOY STEELS