| 摘要 |
PROBLEM TO BE SOLVED: To provide a steel material that does not generate a treatment waste fluid for surface treatment and has excellent workability.SOLUTION: The steel material has a plate-like iron oxide that is formed by being heated at 690-820°C in an atmosphere with an oxygen partial pressure of 20-8,000 Pa, at the surface thereof. The plate-like iron oxide has a height of 1-15 μm, a width of 0.2-2 μm, and a thickness smaller than the width and 0.5 μm or less, and is present at a presence density of 20 pieces or more per 1 mm in length in a surface direction of the steel material. |
