Steel Pipe, Component For Vehicles, Method For Producing Steel Pipe And Method For Producing Component For Vehicles

Abstract: The present invention provides: a component for vehicles having excellent fatigue strength; a steel pipe which enables the production of a component for vehicles having excellent fatigue strength; a method for producing this steel pipe; and a method for producing this component for vehicles. A steel pipe according to the present disclosure comprises a base material and an oxide coating film on the base material. The base material has a chemical structure that contains, in mass%, 0.23% to 0.50% of C, 0.01% to 0.50% of Si, 0.50% to 2.50% of Mn, 0.050% or less of P, 0.0100% or less of S, 0.0100% or less of N and 0.0100% or less of O, with the balance being made up of Fe and impurities; and the base material has a microstructure that is composed, in area ratios, of 20% to 60% of ferrite and 40% to 80% of pearlite. The oxide coating film is composed, in terms of the X-ray diffraction peak intensity ratios, of 70% or more of Fe3O4, 20% or more of Fe2O3 and 10% or less of FeO, with the balance being made up of impurities, if the sum of the X-ray diffraction peak intensities of Fe3O4, Fe2O3 and FeO is taken as 100%; the oxide coating film has a thickness of 0.80 µm to 2.50 µm; and the standard deviation of the thickness is 0.90 µm or less.

Patent Information

Applicants

Inventors

Specification

Documents

Application Documents