Plated steel sheet having excellent fusion resistance, and manufacturing method therefor

Abstract

A plated steel sheet having excellent fusion resistance, and a manufacturing method. therefor are provided. Provided is a hot forming plated steel sheet having a plated layer formed on one surface or the both surfaces of a base steel sheet and having excellent fusion resistance, wherein a surface layer portion of the plated layer is comprised of an hard alloy layer with a surface area ratio of 1% or more including hard alloy phases, the hard alloy layer having a thickness of 0.1-100 μm, and a balance of a soft plating layer, wherein the hard alloy phases comprise Al, Zn, Mg, Si, Fe and a balance of unavoidable impurities, a sum of Al, Zn and Fe being 70 wt % or more on the basis of weight % thereof.

1 . A plated steel sheet for hot forming having excellent fusion resistance, comprising:
 a plated layer disposed on one surface or both surfaces of a base steel sheet,   wherein a surface layer portion of the plated layer is comprised of a hard alloy layer with a surface area ratio of 1% or more including hard alloy phases, the hard alloy layer having a thickness of 0.1-100 μm, and a balance of a soft plating layer,   wherein the hard alloy phases comprise Al, Zn, Mg, Si, Fe and a balance of unavoidable impurities, a sum of Al, Zn and Fe being 70 wt % or more on the basis of weight % thereof.   
     
     
         2 . The plated steel sheet for hot forming having excellent fusion resistance of  claim 1 , wherein the hard alloy layer has an area ratio in a range of 15 to 100%. 
     
     
         3 . The plated steel sheet for hot forming having excellent fusion resistance of  claim 1 , wherein the soft plating layer includes Al, Zn, Mg, Si and a balance of unavoidable impurities, a sum of Al and Zn being 60% or more on the basis of weight % thereof. 
     
     
         4 . A method of manufacturing a plated steel sheet for hot forming having excellent fusion resistance, comprising:
 immersing a base steel sheet in a plating bath and plating a surface thereof; and   tempering rolling the plated steel sheet discharged from the plating bath and having a plating layer formed on the surface thereof,   wherein in the tempering rolling, hot tempering rolling is performed at a pressure of 10 to 50,000 MPa while heating the plated steel sheet at a temperature ranging from 300 to 700° C.   
     
     
         5 . The method of manufacturing a plated steel sheet for hot forming having excellent fusion resistance of  claim 4 , wherein the plating layer includes Al, Zn, Mg, Si and a balance of unavoidable impurities, a sum of Al and Zn being 60% or more on the basis of weight % thereof. 
     
     
         6 . The method of manufacturing a plated steel sheet for hot forming having excellent fusion resistance of  claim 4 , wherein a surface layer portion of a plated layer of the temper-rolled plated steel sheet is comprised of a hard alloy layer with an area ratio of 1% or more having a thickness of 0.1 to 100 μm and including hard alloy phases, and a soft plating layer as a remainder thereof,
 wherein the hard alloy phases include Al, Zn, Mg, Si, Fe, and a balance of unavoidable impurities, a sum of Al, Zn and Fe being 70% or more on the basis of weight % thereof. 
 
     
     
         7 . The method of manufacturing a plated steel sheet for hot forming having excellent fusion resistance of  claim 6 , wherein the hard alloy layer has an area ratio in a range of 15 to 100%. 
     
     
         8 . The method of manufacturing a plated steel sheet for hot forming having excellent fusion resistance of  claim 4 , wherein the plating is performed by immersing the base steel sheet in a hot-dip plating bath and forming a hot-dip plated layer on a surface of the base steel plate.