Material for hot stamping

Abstract

A material for hot stamping according to an embodiment of the present disclosure includes: a steel sheet including carbon (C) in an amount of 0.28 to 0.50 wt %, silicon (Si) in an amount of 0.15 to 0.70 wt %, manganese (Mn) in an amount of 0.5 to 2.0 wt %, phosphorus (P) in an amount of 0.05 wt % or less, sulfur(S) in an amount of 0.01 wt % or less, chromium (Cr) in an amount of 0.1 to 0.5 wt %, boron (B) in an amount of 0.001 to 0.005 wt %, an additive in an amount of 0.1 wt % or less, a remainder of iron (Fe), and other inevitable impurities; fine precipitates distributed inside the steel sheet, wherein the additive includes at least one of titanium (Ti), niobium (Nb), and vanadium (V), the fine precipitates include nitride or carbide of at least one of titanium (Ti), niobium (Nb), and vanadium (V), and traps hydrogen, and a mean diameter variation coefficient, which is a value obtained by dividing a standard deviation of a mean diameter of the fine precipitates by the mean diameter of the fine precipitates, is 0.7 or less.

1 . A material for hot stamping, the material comprising:
 a steel sheet comprising carbon (C) in an amount of 0.28 to 0.50 wt %, silicon (Si) in an amount of 0.15 to 0.70 wt %, manganese (Mn) in an amount of 0.5 to 2.0 wt %, phosphorus (P) in an amount of 0.05 wt % or less, sulfur(S) in an amount of 0.01 wt % or less, chromium (Cr) in an amount of 0.1 to 0.5 wt %, boron (B) in an amount of 0.001 to 0.005 wt %, an additive in an amount of 0.1 wt % or less, a remainder of iron (Fe), and other inevitable impurities; and   fine precipitates distributed inside the steel sheet,   wherein the additive comprises at least one of titanium (Ti), niobium (Nb), and vanadium (V),   the fine precipitates comprise nitride or carbide of at least one of titanium (Ti), niobium (Nb), and vanadium (V), and traps hydrogen, and a mean diameter variation coefficient, which is a value obtained by dividing a standard deviation of a mean diameter of the fine precipitates by the mean diameter of the fine precipitates, is 0.7 or less.   
     
     
         2 . The material of  claim 1 , wherein the material after hot stamping exhibits a tensile strength of 1,680 MPa or greater, a bending angle of 40 degrees or greater, and an amount of activated hydrogen of 0.5 wppm or less. 
     
     
         3 . The material of  claim 1 , wherein the mean diameter of the fine precipitates is 0.006 μm or less. 
     
     
         4 . The material of  claim 3 , wherein 90% or greater of the fine precipitates have a diameter of 0.01 μm or less. 
     
     
         5 . The material of  claim 4 , wherein 60% or greater of the fine precipitates have a diameter of 0.005 μm or less. 
     
     
         6 . The material of  claim 1 , wherein the number of the fine precipitates per unit area (100 μm 2 ) is 25,000 to 30,000. 
     
     
         7 . The material of  claim 6 , wherein the number of the fine precipitates per unit area (100 μm 2 ) having a diameter of 0.01 μm or less is 23,000 to 29,000. 
     
     
         8 . The material of  claim 7 , wherein the number of the fine precipitates per unit area (100 μm 2 ) having a diameter of 0.005 μm or less is 15,200 to 29,000. 
     
     
         9 . The material of  claim 1 , wherein a number variation coefficient, which is a value obtained by dividing a standard deviation of a mean number of the fine precipitates by the mean number of the fine precipitates, is 0.8 or less. 
     
     
         10 . A material for hot stamping, the material comprising:
 a steel sheet comprising carbon (C) in an amount of 0.28 to 0.50 wt %, silicon (Si) in an amount of 0.15 to 0.70 wt %, manganese (Mn) in an amount of 0.5 to 2.0 wt %, phosphorus (P) in an amount of 0.05 wt % or less, sulfur(S) in an amount of 0.01 wt % or less, chromium (Cr) in an amount of 0.1 to 0.5 wt %, boron (B) in an amount of 0.001 to 0.005 wt %, an additive in an amount of 0.1 wt % or less, a remainder of iron (Fe), and other inevitable impurities; and   fine precipitates distributed inside the steel sheet,   wherein the additive comprises at least one of titanium (Ti), niobium (Nb), and vanadium (V),   the fine precipitates comprise nitride or carbide of at least one of titanium (Ti), niobium (Nb), and vanadium (V), and traps hydrogen, and   a number variation coefficient, which is a value obtained by dividing a standard deviation of a mean number of the fine precipitates by the mean number of the fine precipitates, is 0.8 or less.   
     
     
         11 . The material of  claim 10 , wherein the material after hot stamping exhibits a tensile strength of 1,680 MPa or greater, a bending angle of 40 degrees or greater, and an amount of activated hydrogen of 0.5 wppm or less. 
     
     
         12 . The material of  claim 10 , wherein a first number variation coefficient, which is a value obtained by dividing a standard deviation of a mean number of the fine precipitates having a diameter of 0.01 μm or less from among the fine precipitates, by the mean number of the fine precipitates having a diameter of 0.01 μm or less, is 0.8 or less. 
     
     
         13 . The material of  claim 12 , wherein a second number variation coefficient, which is a value obtained by dividing a standard deviation of a mean number of the fine precipitates having a diameter of 0.005 μm or less from among the fine precipitates, by the mean number of the fine precipitates having a diameter of 0.005 μm or less, is 0.8 or less. 
     
     
         14 . The material of  claim 10 , wherein the number of the fine precipitates per unit area (100 μm 2 ) is 25,000 to 30,000. 
     
     
         15 . The material of  claim 14 , wherein the number of the fine precipitates per unit area (100 μm 2 ) having a diameter of 0.01 μm or less is 23,000 to 29,000. 
     
     
         16 . The material of  claim 15 , wherein the number of the fine precipitates per unit area (100 μm 2 ) having a diameter of 0.005 μm or less is 15,200 to 29,000. 
     
     
         17 . The material of  claim 10 , wherein the mean diameter of the fine precipitates is 0.006 μm or less. 
     
     
         18 . The material of  claim 17 , wherein 90% or greater of the fine precipitates have a diameter of 0.01 μm or less. 
     
     
         19 . The material of  claim 18 , wherein 60% or greater of the fine precipitates have a diameter of 0.005 μm or less.