High Manganese Steel Strips with Excellent Coatability and Superior Surface Property, Coated Steel Strips Using Steel Strips and Method for Manufacturing the Steel Strips

Abstract

A high-ductility, high-strength and high Mn steel strip used for steel strips of automobiles requiring superior formability and high strength, a plated steel strip produced by using the same, and a manufacturing method thereof are disclosed. The high Mn steel strip comprises, by weight %, 0.2˜1.5% of C, 10˜25% of Mn, 0.01˜3.0% of Al, 0.005˜2.0% of Si, 0.03% or less of P, 0.03% or less of S, 0.040% or less of N, and the balance of Fe and other unavoidable impurities. The high-ductility, high-strength and high Mn steel strip, and the plated steel strip produced by using the same have superior surface properties and plating characteristics.

1 . A high Mn steel strip having superior surface properties and plating characteristics, comprising, by weight %:
 0.2˜1.5% of C; 10˜25% of Mn; 0.01˜3.0% of Al; 0.005˜2.0% of Si; 0.03% or less of P; 0.03% or less of S; 0.040% or less of N; and the balance of Fe and other unavoidable impurities.   
     
     
         2 . The steel strip according to  claim 1 , wherein the steel strip comprises a cold-rolled steel strip and a hot-rolled steel strip. 
     
     
         3 . The steel strip according to  claim 2 , further comprising:
 at least one component selected from the group consisting of 0.1˜2.0% of Cr; 0.0005˜0.010% of Ca; 0.01˜0.10% of Ti; and 0.001˜0.020% of B.   
     
     
         4 . A high Mn plated steel strip having superior plating properties, wherein the plated steel strip has a plated layer formed on a surface of a steel strip according to  claim 2 . 
     
     
         5 . The steel strip according to  claim 4 , wherein the plated layer is one of an electroplated layer, a hot-dip galvanized layer and a galvannealed layer. 
     
     
         6 . The steel strip according to  claim 4 , wherein the plated layer comprises Zn. 
     
     
         7 . A method for manufacturing a high Mn hot-rolled steel strip having superior surface properties and plating characteristics, comprising:
 homogenizing either a steel ingot or a continuous cast steel slab at 1,050˜1,300° C., the steel ingot or the steel slab comprising, by weight %: 0.2˜1.5% of C, 10˜25% of Mn, 0.01˜3.0% of Al, 0.005˜2.0% of Si, 0.03% or less of P, 0.03% or less of S, 0.040% or less of N, and the balance of Fe and other unavoidable impurities; and   hot rolling the homogenized steel ingot or steel slab with finish rolling at a finish rolling temperature of 850˜950° C. to form a hot-rolled steel strip, followed by coiling the hot-rolled steel strip at a temperature of 700° C. or less.   
     
     
         8 . The method according to  claim 7 , wherein the steel ingot or slab further comprises at least one component selected from the group consisting of 0.1˜2.0% of Cr, 0.0005˜0.010% of Ca, 0.01˜0.10% of Ti, and 0.001˜0.020% of B. 
     
     
         9 - 13 . (canceled) 
     
     
         14 . A high Mn plated steel strip having superior plating properties, wherein the plated steel strip has a plated layer formed on a surface of a steel strip according to  claim 3 .