Welded Steel Tubes for High Strength Hollow Stabilizers, Manufacturing Method of Welded Steel Tubes for High Strength Hollow Stabilizers, High Strength Hollow Stabilizer, and Manufacturing Method of High Strength Hollow Stabilizer

摘要

The present invention provides a method of manufacturing a steel pipe for a high strength hollow stabilizer excellent in internal fatigue characteristics, a method of manufacturing a steel pipe for a high strength hollow stabilizer, and a method of manufacturing a high strength hollow stabilizer and a high strength hollow stabilizer. A steel pipe obtained by further subjecting a steel pipe to a hot-rolled steelmaking process by subjecting the steel pipe obtained by hot rolling to a hot-rolled steel pipe, wherein the steel pipe comprises 0.20 to 0.40% by mass of C, 0.1 to 1.0% of Si, 0.1 to 2.0% of Mn, , The balance Fe and inevitable impurities, and a composition including at least one of Cr, 0.01 to 0.5%, Ti to 0.01 to 0.05%, B to 0.0005 to 0.005%, Ca to 0.0001 to 0.0050% and N to 0.0050% : TiS particles of 10 탆 or more and MnS particles of 10 탆 or more in particle size are each reduced to 0.1% or less in cleanliness. As a result, it is possible to obtain a high strength (hardness) in which the hardness becomes harder than 400HV and less than 550HV at Vickers hardness after cold forming, quenching and tempering treatment, and the average grain diameter of the old austenite grains is 50μm or less, As the stabilizer, it becomes a seamless steel pipe with excellent endothelial property (internal fatigue) even under corrosive environment.