Hot rolled steel and steel component
AssigneeNippon Steel & Sumitomo Metal Corporation
InventorsSuguru YOSHIDA, Shinya TERAMOTO, Akira SHIGA, Manabu KUBOTA, Hajime HASEGAWA, Hideo MIZUKAMI
Life of this patent
Estimating the term…
Abstract
There is provided a hot rolled steel according to one aspect of the invention including, as a predetermined chemical composition: Bi: 0.0001 mass % to 0.0050 mass %, in which 90 area % or more of a metallographic structure is configured with a ferrite and a pearlite, and an average number density of Mn sulfides measured on a cross section parallel to a rolling direction having an aspect ratio of more than 10 and 30 or less which is extended along the rolling direction, is 50 pieces/mm2 to 200 pieces/mm2.
Claims6
A hot rolled steel comprising, as a chemical composition:
- C:
- 0.35 mass % to 0.45 mass %;
- Si:
- 1.0 mass % to 1.9 mass %;
- Mn:
- 0.10 mass % to 0.20 mass %;
- P:
- 0.010 mass % to 0.035 mass %;
- S:
- 0.06 mass % to 0.10 mass %;
- Cr:
- 0.25 mass % or less;
- V:
- 0.20 mass % to 0.40 mass %;
- N:
- 0.0060 mass % to 0.0150 mass %;
- B:
- 0.0050 mass % or less;
- Bi:
- 0.0001 mass % to 0.0050 mass %;
- Ti:
- 0 mass % to 0.050 mass %;
- Nb:
- 0 mass % to 0.030 mass %;
- and
- a remainder including Fe and impurities,
- wherein 90 area % or more of a metallographic structure is configured with a ferrite and a pearlite, and
- an average number density of Mn sulfides measured on a cross section parallel to a rolling direction having an equivalent circle diameter of 1 μm to 5 μm and an aspect ratio of more than 10 and 30 or less which is extended along the rolling direction, is 50 pieces/mm2 to 200 pieces/mm2.
A steel component comprising, as a chemical composition:
- C:
- 0.35 mass % to 0.45 mass %;
- Si:
- 1.0 mass % to 1.9 mass %;
- Mn:
- 0.10 mass % to 0.20 mass %;
- P:
- 0.010 mass % to 0.035 mass %;
- S:
- 0.06 mass % to 0.10 mass %;
- Cr:
- 0.25 mass % or less;
- V:
- 0.20 mass % to 0.40 mass %;
- N:
- 0.0060 mass % to 0.0150 mass %;
- B:
- 0.0050 mass % or less;
- Bi:
- 0.0001 mass % to 0.0050 mass %;
- Ti:
- 0 mass % to 0.050 mass %;
- Nb:
- 0 mass % to 0.030 mass %;
- and
- a remainder including Fe and impurities,
- wherein 90 area % or more of a metallographic structure is configured with a ferrite and a pearlite, and
- an average number density of Mn sulfides measured on a cross section parallel to a rolling direction having an equivalent circle diameter of 1 μm to 5 μm and an aspect ratio of more than 10 and 30 or less which is extended along the rolling direction, is 50 pieces/mm2 to 200 pieces/mm2.
Dependencies are inferred from the claim text.