Wire rod for 600MPa special welding rod which can omit heat treatment and its manufacturing method

摘要

PURPOSE: A 600MPa grade wire rod for welding rod and a manufacturing method thereof excluding heat treatment are provided to maintain proper tensile strength without separate facility or device and to prevent brittle part by keeping the content of S less than 0.03 weight%. CONSTITUTION: A 600MPa grade wire rod for welding rod comprises C 0.03~013 weight%, Mn 1.5~2.5 weight%, Si 0.5~1.2 weight%, Mo 0.2~0.4 weight%, Ti 0.1~0.3 weight%, N 70ppm or less, S 0.03 weight% or less and the rest Fe and an inevitable impurity. The wire rod has a tensile strength of 600~700MPa and an average grain size of 10~30m and includes a TiN precipitate an average size of which is 30~100nm.