Steel used for hot stamping, hot stamping process and formed component

Abstract

A kind of steel is able to achieve a high elongation with the steel used for hot stamping by means of simple hot stamping process. The formed component has excellent yield strength, tensile strength and elongation. The steel used for hot stamping comprises by weight percent 0.1-0.19% of C, 5.09-9.5% of Mn, 0.11-0.4% of V, and 0-2% Si+Al, wherein the combination of C and V meets one of the following two requirements: 1) 0.1-0.17% of C and 0.11-0.4% of V; and 2) 0.171-0.19% of C and 0.209-0.4% of V.

1 . A steel used for hot stamping, characterized in that the steel used for hot stamping comprises, by weight percent, the following components: 0.1˜0.19% of C, 5.09˜9.5% of Mn, 0.11˜0.4% of V, and 0˜2% Si+Al, wherein the combination of C and V also meets one of the following two requirements: 1) 0.1˜0.17% of C and 0.11˜0.4% of V; and 2) 0.171˜0.19% of C and 0.209˜0.4% of V. 
     
     
         2 . The steel used for hot stamping according to  claim 1 , characterized in that the steel used for hot stamping also comprises at least one of the following components: 0˜5% of Cr, 0˜0.2% of Ti, 0˜0.2% of Nb, 0˜0.2% of Zr, 0˜0.005% of B, 0˜4% of Ni, 0˜2% of Cu, 0˜2% of Mo and 0˜2% of W. 
     
     
         3 . The steel used for hot stamping of  claim 1 , wherein the C content ranges from 0.12 to 0.17%, and the Mn content ranges from 5.09 to 8%. 
     
     
         4 . The steel used for hot stamping of  claim 1 , wherein the steel used for hot stamping is provided on its surface with a coating selecting from the group comprising an Al—Si coating, a galvanized coating and a high-temperature oxidization coating. 
     
     
         5 . The steel used for hot stamping of  claim 1 , wherein the component ratio of the steel used for hot stamping meets the following requirement: the actual measured value of the martensitic transformation start temperature of the steel used for hot stamping after hot stamping is from 150 to 280° C. 
     
     
         6 . A hot stamping process, wherein the hot stamping process comprises:
 Step A: heating the steel used for hot stamping of  claim 1 , or a preformed component obtained by preforming the steel used for hot stamping to a temperature ranging from 700 to 890° C. and maintaining the temperature for 0.1 to 10000 seconds;   Step B: transferring the steel used for hot stamping or the preformed component processed in the Step A into a die for stamping so as to obtain a formed component; and   Step C: cooling the formed component at an average cooling speed of 0.1 to 1000° C./s.   
     
     
         7 . The hot stamping process according to  claim 6 , characterized in that in the Step A, the heating temperature ranges from 740 to 850° C. 
     
     
         8 . The hot stamping process according to  claim 7 , characterized in that in the Step A, the heating temperature ranges from 740 to 780° C. 
     
     
         9 . The hot stamping process according to  claim 7 , characterized in that in Step C, the average cooling speed is between 1 and 100° C./s. 
     
     
         10 . A formed component, wherein the formed component is obtained by hot stamping the steel used for hot stamping of  claim 1  or a preformed component made by preforming the steel used for hot stamping. 
     
     
         11 . The formed component according to  claim 10 , characterized in that the formed component comprises, by volume, the following structures: 0.1 to 5% of vanadium carbide or composite carbonitride, 2 to 15% of retained austenite, 0 to 10% of ferrite, with the balance being martensite. 
     
     
         12 . The formed component according to  claim 10 , characterized in that the formed component has an elongation of ≥6%. 
     
     
         13 . The formed component of  claim 10 , wherein the formed component is heated and maintains the temperature within the temperature range from 140 to 220° C., and the time for the temperature maintaining lasts for 1 to 100000 seconds. 
     
     
         14 . The formed component according to  claim 13 , characterized in that the formed component is used as a vehicle component, and the temperature maintaining is conducted for 5 to 30 minutes during the paint baking of the vehicle production procedure. 
     
     
         15 . The formed component according to  claim 13 , characterized in that the formed component comprises, by volume, the following structures: 0.1 to 2% of vanadium carbide or composite carbonitride, 5 to 25% of retained austenite, 0 to 10% of ferrite, with the balance being martensite. 
     
     
         16 . The formed component according to  claim 13 , characterized in that the formed component has a yield strength of ≥1100 MPa, a tensile strength of ≥1400 MPa and an elongation of ≥10%.