Nb microalloyed high strength high hole expansion steel and production method therefor
AssigneeBaoshan Iron & Steel Co., Ltd.
InventorJianchun Wu
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Abstract
Disclosed are a Nb microalloyed high strength high hole expansion steel comprising in percentages by weight: 0.01-0.05% of C, 0.2-0.6% of Si, 0.8-1.5% of Mn, ≤0.02% of P, ≤0.005% of S, ≤0.008% of N, <0.001% of Als, ≤0.0050% of Ca, 0.01-0.08% of Nb, and optionally one or both of 0.1-0.6% of Cu and 0.005-0.04% of Sn, wherein Mn/S>250, total oxygen [O]T is 0.007-0.020%, and the balance is Fe and inevitable impurities, and a method for manufacturing the same. The present disclosure makes full use of steel scraps as raw materials to reduce cost of molten steel and further reduce production process costs and improve product performance through the short process advantages of thin strip continuous casting.
Claims14
A Nb microalloyed high strength high hole expansion steel comprising the following chemical elements in weight percentages:
- C:
- 0.01-0.05%, Si:
- 0.2-0.6%, Mn:
- 0.8-1.5%, P≤0.02%, S≤0.005%, N≤0.008%, Als:
- <0.001%, Ca≤0.0050%, Nb:
- 0.01-0.08%, optionally one or both of Cu:
- 0.1-0.6% and Sn:
- 0.005-0.04%, wherein, Mn/S>250, total oxygen [O]T:
- 0.007-0.020%, and a balance of Fe and unavoidable impurities, wherein a microstructure of the high hole expansion steel consists of ferrite and bainite, wherein the bainite phase has a ratio of ≥15%;
- and
- wherein the high hole expansion steel has a yield strength of ≥440 MPa, a tensile strength of ≥590 MPa, an elongation of ≥19%, and a hole expansion rate of ≥100%.
Dependencies are inferred from the claim text.