Hot stamping part

Abstract

According to an aspect of the present disclosure, provided is a hot stamping part including a steel plate that includes carbon (C) in an amount of 0.26 to 0.40 wt %, silicon (Si) in an amount of 0.02 to 2.0 wt %, manganese (Mn) in an amount of 0.3 to 1.60 wt %, phosphorus (P) in an amount of 0.03 wt % or less, sulfur(S) in an amount of 0.008 wt % or less, chromium (Cr) in an amount of 0.05 to 0.90 wt %, boron (B) in an amount of 0.0005 to 0.01 wt %, molybdenum (Mo) in an amount of 0.05 to 0.2 wt %, titanium (Ti) in an amount of 0.001 to 0.095 wt %, niobium (Nb) in an amount of 0.001 to 0.095 wt %, vanadium (V) in an amount of 0.001 to 0.095 wt %, the balance of iron (Fe), and other inevitable impurities, the hot stamping part having tensile strength of 1,700 MPa or more and yield strength of 1,150 MPa or more, wherein the hot stamping part includes microstructure including austenite grains and carbon-based precipitates including at least one of niobium (Nb), titanium (Ti), molybdenum (Mo), and vanadium (V), and an average size of the austenite grains is 15 μm or less.

1 . A hot stamping part comprising: a steel plate that comprises carbon (C) in an amount of 0.26 to 0.40 wt %, silicon (Si) in an amount of 0.02 to 2.0 wt %, manganese (Mn) in an amount of 0.3 to 1.60 wt %, phosphorus (P) in an amount of 0.03 wt % or less, sulfur(S) in an amount of 0.008 wt % or less, chromium (Cr) in an amount of 0.05 to 0.90 wt %, boron (B) in an amount of 0.0005 to 0.01 wt %, molybdenum (Mo) in an amount of 0.05 to 0.2 wt %, titanium (Ti) in an amount of 0.001 to 0.095 wt %, niobium (Nb) in an amount of 0.001 to 0.095 wt %, vanadium (V) in an amount of 0.001 to 0.095 wt %, the balance of iron (Fe), and other inevitable impurities,
 the hot stamping part having tensile strength of 1,700 MPa or more and yield strength of 1,150 MPa or more,   wherein the hot stamping part comprises microstructure including austenite grains and carbon-based precipitates including at least one of niobium (Nb), titanium (Ti), molybdenum (Mo), and vanadium (V), and an average size of the austenite grains is 15 μm or less.   
     
     
         2 . The hot stamping part of  claim 1 , wherein
 a fraction of the austenite grains having a size of 10 μm or more is 67% or less.   
     
     
         3 . The hot stamping part of  claim 1 , wherein
 a fraction of the austenite grains having a size of 20 μm or more is 10% or less.   
     
     
         4 . The hot stamping part of  claim 1 , wherein,
 when contents of titanium (Ti), niobium (Nb), vanadium (V), and molybdenum (Mo) included in the steel plate are represented by [Ti], [Nb], [V], and [Mo] in wt %, respectively, [Inequality 1] below is satisfied,
   0.015≤0.25([Ti]+[Nb]+[V]+0.25[Mo])≤0.060(unit: wt %).  [Inequality 1]
 
   
     
     
         5 . The hot stamping part of  claim 1 , wherein
 an amount of activated hydrogen of the hot stamping part is 0.6 wppm or less.   
     
     
         6 . The hot stamping part of  claim 1 , wherein
 an average particle size of the precipitates is 10 nm or less.   
     
     
         7 . The hot stamping part of  claim 1 , wherein
 the precipitates include 50 wt % or less of titanium (Ti) and 30 wt % or more of molybdenum (Mo).   
     
     
         8 . The hot stamping part of  claim 1 , wherein
 an average number of the precipitates per unit area is 10,000/100 μm 2  to 35,000/100 μm 2 .   
     
     
         9 . The hot stamping part of  claim 1 , wherein
 an average gap between the precipitates is 0.1 nm to 100 nm.   
     
     
         10 . The hot stamping part of  claim 1 ,
 satisfying a bending angle of 50° or more.