Steel sheet having high young'S modulus, hot-dip galvanized steel sheet using the same, alloyed hot-dip galvanized steel sheet, steel pipe having high young'S modulus and methods for manufacturing the same
View Patent ↗One aspect of the steel sheet having high Young's modulus includes in terms of mass %, C: 0.0005 to 0.30%, Si: 2.5% or less, Mn: 2.7 to 5.0%, P: 0.15% or less, S: 0.015% or less, Mo: 0.15 to 1.5%, B: 0.0006 to 0.01%, and Al: 0.15% or less, with the remainder being Fe and unavoidable impurities, wherein one or both of {110}<223> pole density and {110}<111> pole density in the ⅛ sheet thickness layer is 10 or more, and a Young's modulus in a rolling direction is more than 230 GPa. Another aspect of the steel sheet having high Young's modulus includes, in terms of mass %, C: 0.0005 to 0.30%, Si: 2.5% or less, Mn: 0.1 to 5.0%, P: 0.15% or less, S: 0.015% or less, Al: 0.15% or less, N: 0.01% or less, and further comprises one or two or more of Mo: 0.005 to 1.5%, Nb: 0.005 to 0.20%, Ti: at least 48/14×N (mass %) and 0.2% or less, and B: 0.0001 to 0.01%, at a total content of 0.015 to 1.91 mass %, with the remainder being Fe and unavoidable impurities, wherein the {110}<223> pole density and/or the {110}<111> pole density in the ⅛ sheet thickness layer is 10 or more, and a Young's modulus in a rolling direction is more than 230 GPa.
1. A steel sheet having high Young's modulus, comprising, in terms of mass %, C: 0.0005 to 0.30%, Si: 2.5% or less, Mn: 3.01 to 4.34%, P: 0.15% or less, S: 0.015% or less, Mo: 0.15 to 1.5%, B: 0.0006 to 0.01%, and Al: 0.15% or less, with the remainder being Fe and unavoidable impurities, wherein one or both of {110}<223> pole density and {110}<111> pole density in the ⅛ sheet thickness layer is 10 or more, and a Young's modulus in a rolling direction is more than 230 GPa.
2. The steel sheet having high Young's modulus according to claim 1 , wherein the {112}<110> pole density in the ½ sheet thickness layer is 6 or more.
3. The steel sheet having high Young's modulus according to claim 1 , which further comprises one or two of Ti: 0.001 to 0.20 mass % and Nb: 0.001 to 0.20 mass %.
4. The steel sheet having high Young's modulus according to claim 1 , wherein a BH amount (MPa), which is evaluated by the value obtained by subtracting a flow stress when stretched 2% from an upper yield point when, after stretched 2%, the steel sheet is heat treated at 170° C. for 20 minutes and then a tensile test is performed again, is in a range from 5 MPa or more to 200 MPa or less.
5. The steel sheet having high Young's modulus according to claim 1 , which further comprises Ca: 0.0005 to 0.01 mass %.
6. The steel sheet having high Young's modulus according to claim 1 , which further comprises one or two or more of Sn, Co, Zn, W, Zr, V, Mg, and REM at a total content of 0.001 to 1.0 mass %.
7. The steel sheet having high Young's modulus according to claim 1 , which further comprises one or two or more of Ni, Cu, and Cr at a total content of 0.001 to 4.0 mass %.
8. A hot-dip galvanized steel sheet comprising: the steel sheet having high Young's modulus according to claim 1 ; and hot-dip zinc plating that is applied to the steel sheet having high Young's modulus.
9. An alloyed hot-dip galvanized steel sheet comprising: the steel sheet having high Young's modulus according to claim 1 ; and alloyed hot-dip zinc plating that is applied to the steel sheet having high Young's modulus.
10. A steel pipe having high Young's modulus comprising the steel sheet having high Young's modulus according to claim 1 , wherein the steel sheet having high Young's modulus is curled in any direction.