Weather-resistant hot-rolled steel sheet superior high-strength, and manufacturing method

Abstract

There are provided a high-strength hot-rolled steel sheet having excellent weather resistance used for containers and a method of manufacturing the same. A high-strength hot-rolled steel sheet having excellent weather resistance includes, by weight: C: 0.05 to 0.07%, Mn: 2.5% or less, Nb: 0.04 to 0.06%, Ti: 0.08 to 0.10%, Cu: 0.30 to 0.60%, Cr: 0.5 to 1.0%, and Ni: 0.15 to 0.30%, and the balance of Fe and other inevitable impurities. A method of manufacturing the hot-rolled steel sheet is also provided. A hot-rolled steel sheet provided has weather resistance by addition of Cu, Cr, and Ni and material characteristics of a tensile strength within the range of 800 to 900 MPa and a yield strength within the range of 700 to 800 MPa.

1 - 7 . (canceled) 
   
   
       8 . A high-strength hot-rolled steel sheet having excellent weather resistance, comprising, by weight: C: 0.05 to 0.07%, Mn: 2.5% or less, Nb: 0.04 to 0.06%, Ti: 0.08 to 0.10%, Cu: 0.30 to 0.60%, Cr: 0.5 to 1.0%, and Ni: 0.15 to 0.30%, and the balance of Fe and other inevitable impurities. 
   
   
       9 . The high-strength hot-rolled steel sheet having excellent weather resistance according to  claim 8 , the Mn content is within the range of 2.0 to 2.5%. 
   
   
       10 . The high-strength hot-rolled steel sheet having excellent weather resistance according to  claim 8 , wherein a fine structure of the steel comprises acicular ferrite. 
   
   
       11 . The high-strength hot-rolled steel sheet having excellent weather resistance according to  claim 8 , wherein the steel has material characteristics of a tensile strength within the range of 800 to 900 MPa and an yield strength within the range of 700 to 800 MPa. 
   
   
       12 . The high-strength hot-rolled steel sheet having excellent weather resistance of  claim 11 , wherein the steel has an yield ratio (yield strength/tensile strength) of 80% or more. 
   
   
       13 . A method of manufacturing a high-strength hot-rolled steel sheet having excellent weather resistance, method comprising:
 hot rolling steel including, by weight: C: 0.05 to 0.07%, Mn: 2.5% or less, Nb: 0.04 to 0.06%, Ti: 0.08 to 0.10%, Cu: 0.30 to 0.60%, Cr: 0.5 to 1.0%, and Ni: 0.15 to 0.30%, and the balance of Fe and other inevitable, and coiling the hot-rolled steel at the temperature within the range of 580 to 600° C.   
   
   
       14 . The method of  claim 13 , wherein the Mn content is within the range of 2.0 to 2.5%. 
   
   
       15 . The high-strength hot-rolled steel sheet having excellent weather resistance according to  claim 9 , wherein the steel has material characteristics of a tensile strength within the range of 800 to 900 MPa and an yield strength within the range of 700 to 800 MPa. 
   
   
       16 . The high-strength hot-rolled steel sheet having excellent weather resistance according to  claim 10 , wherein the steel has material characteristics of a tensile strength within the range of 800 to 900 MPa and an yield strength within the range of 700 to 800 MPa. 
   
   
       17 . The high-strength hot-rolled steel sheet having excellent weather resistance of  claim 15 , wherein the steel has an yield ratio (yield strength/tensile strength) of 80% or more. 
   
   
       18 . The high-strength hot-rolled steel sheet having excellent weather resistance of  claim 16 , wherein the steel has an yield ratio (yield strength/tensile strength) of 80% or more.