PURPOSE: To provide an alloy steel wire rod which is decreased in the deviation of tensile strength and the total amt. of scale and is improved in uniformity in a steel rod to be subjected to a slow cooling treatment right after rolling by adjusting adequately the coiling temp. in the stage of rolling and the crystallization rate in the stage of coiling.
CONSTITUTION: The coiling temp. in rolling is adjusted to Ar1+30°C so that the crystal grain size in the stage of coiling attains ≥7.0 fine grains when measured by a carburization method conforming to JIS. An alloy steel wire rod having ≤1.0kg/mm2 standard deviation in tensile strength, ≤0.05mm JIS DmT in decarburization and ≤0.03% total amt. of scale is obtd. by the above-mentioned adjustment. Since the wire rod manufactured under such conditions is suppressed of decarburization during slow cooling and is reduced in the variance in tensile strength, the wire rod has excellent uniformity. The alloy steel wire rod is suited as a blank material for automotive members.
ARAKI KENJIROU
KUMAGAI AKIYOSHI
OKANIWA KENICHI
