| Tenslle test and microstructural analysis were performed to investigate the effects of dual phase heat treatment and cold drawing so as to promote the mechanical properties of 0.07%C steel wire. The strength of the dual phase steel wires varied with volume fraction, shape, and size of martensite and grain size of ferrite. The strength of the dual phase steel wire was appromiately proportional to a reciprocal of square root of mean free path. The elongation of dual phase steel wires varied with volume fraction, distribution, and size of martensite. The carbon content in martensite changed the strength of martensite, which affected the elongation of the specimens. Low carbon steel wire of 1257 MPa in tensile strength and 4 percent in elongation was obtained, when low carbon steel rod with 475 MPa and 38% in tensile strength and elongation, respectively, was heat treated and cold drawn. |
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