The mechanical properties of drawn dual phase steel wire

Technical Report · Tue Dec 01 04:00:00 EST 1987

DOI:https://doi.org/10.2172/6902128· OSTI ID:6902128

Miyasato, S M

Dual-phase steels are a class of composite high strength, low alloy steels. The outstanding properties of ferrite/martensite dual-phase steels include its very high work-hardening rates and resistance to fatigue failure. The high work-hardening rates make dual-phase steels ideal for large strain cold forming applications, since high strengths may be achieved with less deformation. Dual-phase steels have been shown to be especially suited to wire drawing. In this study, Fe/xC/2Si alloys were heat treated to obtain different ferrite/martensite morphologies and relative volume fractions, then the work-hardening rates at true plastic strain {var epsilon} = 0.006 were determined. Wires were then drawn from 4.2 to 1.4 mm in diameter, which corresponded to a strain of {var epsilon} = 2.2, and tested in tension and fatigue. The early work-hardening rate increased with increased volume fraction of martensite, increased strength of martensite, and decreased ferrite/martensite interface coherency. The wire drawing limit was raised by discouraging void formation at ferrite/martensite interfaces and shear cracking through martensite particles. The lowest void density was obtained in a structure of fibrous martensite with coherent ferrite/martensite interfaces (i.e. produced by intermediate quenching). The fatigue limit of drawn dual-phase wires was {approximately}600 MPa, or 25--30% of the ultimate tensile strength, which appears to be higher than that of similar pearlitic steel wire. There was no superior microstructure for fatigue resistance in wires, as any morphology differences which exist in the initial structure are indistinguishable after heavy deformation.

• Research Organization: Lawrence Berkeley Lab., CA (USA)
• Sponsoring Organization: DOE/ER
• DOE Contract Number: AC03-76SF00098
• OSTI ID: 6902128
• Report Number(s): LBL-29060; ON: DE90013870
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360101 -- Metals & Alloys-- Preparation & Fabrication
360102 -- Metals & Alloys-- Structure & Phase Studies
360103* -- Metals & Alloys-- Mechanical Properties
ALLOYS
CARBON ADDITIONS
CRYSTAL STRUCTURE
DRAWING
FABRICATION
FATIGUE
FERRITE
FRACTURE PROPERTIES
HEAT TREATMENTS
IRON ALLOYS
IRON BASE ALLOYS
MARTENSITE
MATERIALS WORKING
MECHANICAL PROPERTIES
MICROSCOPY
MICROSTRUCTURE
STEELS
TENSILE PROPERTIES
WIRES