The present invention provides a high strength, high toughness steel wire
rod useful for a PC steel wire, galvanized steel strands, spring use
steel wire, cables for suspension bridges, etc. By hot rolling, then
directly patenting or reaustenitizing, then patenting a high carbon steel
wire rod of a specific chemical composition of the steel and chemical
composition, size, and numerical density of inclusions, piano wire rod or
high carbon steel wire rod having a structure of mainly pearlite, having
an average value of the proeutectoid cementite area ratio of 5% or less
in a center region of less than 20% of the wire rod diameter from the
center of the wire rod, having a micromartensite size of the C section of
100 .mu.m or less, having a tensile strength of the 170 kgf/mm.sup.2
class or more, and having a drawing ratio at break of 30% or more is
obtained.