PURPOSE: To manufacture the steel for welding structures having high vibration damping capacity and constituted of a composite structure of network transformation-formed phases by repeatedly subjecting a steel for welding structures after hot rolling to a stage of bonding under heating to the temp. range from the AC3 to the AC1 transformation point and thereafter executing cooling.
CONSTITUTION: A steel for welding structures as hot-rolled or subjected to heat treatment after hot rolling is repeatedly subjected to a stage of holding under heating to the temp. range from the AC3 transformation point or below to the AC1 transformation point or above and thereafter executing cooling. By this treatment, network transformation-formed phases are formed on the above steel. By this transformation-forming, a composite structure of ferrite+ martensite, ferrite+austenite, ferrite+bainite, ferrite+pearlite or austenite+ martensite is formed, and one of the formed phase in the composite structure is formed by distributing into a network shape. In this way, the steel for welding structures having high vibration damping capacity as well as excellent in strength, toughness and weldability can be obtd.
AMANO KENICHI
NAKANO SHOZABURO
UEDA SHUZO
