Work Hardening of Hypereutectoid and Eutectoid Steels during Drawing
Work hardening of pearlite and bainite during drawing of high-carbon steel wires was studied by using stress-strain curves of drawn wires and making a detailed observation of their microstructure. The study revealed the following relationship between flow stress and strain in high-carbon steel wires. Flow stress σ is represented by a weighted average of the strengths of ferrite and cementite. The amount of work hardening Δσ is represented by an equation corresponding to exp(<I>B</I>ε) where <I>B</I> is a constant that depends on the initial microstructure of the steel wire and ε is the strain. When the initial microstructure of steel wire is made up entirely of a pearlite lamellar structure, the value of <I>B</I> is 0.5. When the initial microstructure contains some bainite, the value of <I>B</I> is lower than 0.5. Finally the flow stress was formulated as a function of carbon content, supercooling degree, and ε. The calculated maximum flow stress showed good correlation with the measured flow stress of 0.8 % C and 0.2%Cr-0.92%C steel wires during drawing.
- ISIJ international
ISIJ international 38(2), 177-186, 1998-02-15
The Iron and Steel Institute of Japan