Manufacturing method for hot stamping component having aluminium-silicon alloy coating, and hot stamping component

Abstract

A manufacturing method for a hot stamping component having an aluminium-silicon alloy coating, and a hot stamping component, said method comprising the following steps: a steel plate coated with an aluminium-silicon alloy coating is machined into a blank having a shape required for a part, and the blank is subjected to heat treatment and hot stamping. The blank heat treatment is two-stage or three-stage heating, and the temperature of the heating increases in steps. The steel plate coated with the aluminium-silicon alloy coating comprises a substrate, and the aluminium-silicon alloy coating on at least one surface of the substrate. The present method fully takes into account the characteristics of the aluminium-silicon coating, effectively solves the problem of aluminium-silicon coating roller adhesion, reduces the probability of heat treatment furnace roller nodulation, increases roller service life, and also ensures the integrity of the hot stamping component coating, and the mechanical properties, welding performance, coating performance and corrosion resistance of the component.

1 . A method of manufacturing a hot stamping component having an aluminum-silicon alloy coating, comprising the following steps:
 (a) machining a steel plate coated with an aluminum-silicon alloy coating into a blank having a shape required for a part; and   (b) conducting heat treatment and hot stamping of the blank;   wherein, in the heat treatment of the blank, the blank is put into a heat treatment furnace for austenitizing heat treatment, and the heat treatment process of the blank comprises a first heating and holding stage, a second heating and holding stage, and a third heating and holding stage; and   wherein
 when the thickness of the steel plate coated with an aluminum-silicon alloy coating is less than 1.5 mm;
 in the first heating and holding stage, the temperature and time of heating and holding lie within a graph ABCD, and the graph ABCD represents the ranges of temperature and time defined by coordinates of A (750° C., 30 s), B (750° C., 90 s), C (870° C., 90 s) and D (870° C., 30 s); 
 in the second heating and holding stage, the temperature and time of heating and holding lie within a graph EFGH, and the graph EFGH represents the ranges of temperature and time defined by coordinates of E (875° C., 60 s), F (875° C., 240 s), G (930° C., 150 s) and H (930° C., 30 s); and 
 in the third heating and holding stage, the temperature and time of heating and holding lie within a graph IJKL, and the graph IJKL represents the ranges of temperature and time defined by coordinates of I (935° C., 60 s), J (935° C., 240 s), K (955° C., 180 s) and L (955° C., 30 s); and 
 
 when the thickness of the steel plate coated with an aluminum-silicon alloy coating is 1.5 mm or more;
 in the first heating and holding stage, the temperature and time of heating and holding lie within a graph A′B′C′D′, and the graph A′B′C′D′ represents the ranges of temperature and time defined by coordinates of A′ (750° C., 30 s), B′ (750° C., 90 s), C′ (890° C., 90 s) and D′ (890° C., 30 s); 
 in the second heating and holding stage, the temperature and time of heating and holding lie within a graph E′F′G′H′, and the graph E′F′G′H′ represents the ranges of temperature and time defined by coordinates of E′ (895° C., 90 s), F′ (895° C., 270 s), G′ (940° C., 210 s) and H′ (940° C., 60 s); and 
 in the third heating and holding stage, the temperature and time of heating and holding lie within a graph I′J′K′L′, and the graph I′J′K′L′ represents the ranges of temperature and time defined by coordinates of I′ (945° C., 60 s), J′ (945° C., 240 s), K′ (955° C., 180 s) and L′ (955° C., 30 s). 
 
   
     
     
         2 . The method of  claim 1 , wherein the heating and holding time of the second heating and holding stage is zero so that the heat treatment process of the blank comprises two-stages of heating and temperature-holding, consisting of the first heating and holding stage and the third heating and holding stage, and
 wherein
 when the thickness of the steel plate coated with an aluminum-silicon alloy coating is less than 1.5 mm;
 in the first heating and holding stage, the temperature and time of heating and holding lie within a graph abcd, and the graph abcd represents the ranges of temperature and time defined by coordinates of a (750° C., 30 s), b (750° C., 90 s), c (870° C., 90 s) and d (870° C., 30 s); and 
 in the third heating and holding stage, the temperature and time of heating and holding lie within a graph ijkl, and the graph ijkl represents the ranges of temperature and time defined by coordinates of i (935° C., 180 s), j (935° C., 300 s), k (955° C., 270 s) and l (955° C., 150 s); and 
 
 when the thickness of the steel plate coated with an aluminum-silicon alloy coating is 1.5 mm or more;
 in the first heating and holding stage, the temperature and time of heating and holding lie within a graph a′b′c′d′, and the graph a′b′c′d′ represents the ranges of temperature and time defined by coordinates of a′ (750° C., 30 s), b′ (750° C., 90 s), c′ (890° C., 90 s) and d′ (890° C., 30 s); and 
 in the third heating and holding stage, the temperature and time of heating and holding lie within a graph i′j′k′l′, and the graph i′j′k′l′ represents the ranges of temperature and time defined by coordinates of i′ (945° C., 180 s), j′ (945° C., 300 s), k′ (955° C., 270 s) and  1 ′ (955° C., 150 s). 
 
   
     
     
         3 . The method of  claim 1 , wherein, in the heat treatment process of the blank, the temperature increases stepwise in the order of the first, second, and third heating and holding stages or the temperatures in the first, second, and third heating and holding stages are set to be certain temperatures. 
     
     
         4 . The method of  claim 1 , wherein the time of the heat treatment process of the blank is not less than 150 s and not more than 600 s. 
     
     
         5 . The method of  claim 1 , wherein a heat treatment furnace is used in the heat treatment process of the blank, and the oxygen content in the furnace's atmosphere is not less than 15%, and the dew point in the furnace is not higher than −5° C. 
     
     
         6 . The method of  claim 1 , wherein
 in the hot stamping process, the heat-treated blank is transferred to a mold for stamping, the transfer time is 4-12 seconds, and the blank is at a temperature of not lower than 600° C. before being fed into the mold; and   the mold is cooled before stamping to ensure that the surface temperature of the mold before stamping is lower than 100° C., and the cooling rate of the blank is greater than 30° C./s.   
     
     
         7 . The method of  claim 1 , wherein the steel plate coated with an aluminum-silicon alloy coating comprises a substrate and an aluminum-silicon alloy coating on at least one surface of the substrate, and the substrate comprises the following composition in percentage by weight: C: 0.04-0.8%, Si<1.2%, Mn: 0.1-5%, P<0.3%, S<0.1%, Al<0.3%, Ti<0.5%, B<0.1%, Cr<3%, and the balance being Fe and impurities. 
     
     
         8 . The method of  claim 7 , wherein the aluminum-silicon alloy coating comprises the following composition in percentage by weight: Si: 4-14%, Fe: 0-4%, and the balance being Al and impurities. 
     
     
         9 . The method of  claim 7 , wherein the average weight of the aluminum-silicon alloy coating is 58-105 g/m 2  on one side. 
     
     
         10 . The method of  claim 7 , wherein the average weight of the aluminum-silicon alloy coating is 72-88 g/m 2  on one side. 
     
     
         11 . A hot stamping component obtained by the method of  claim 1 , wherein the aluminum-silicon alloy coating of the hot stamping component comprises a surface alloy layer and a diffusion layer, and the ratio of the thickness of the diffusion layer to the thickness of the aluminum-silicon alloy coating is 0.08-0.5. 
     
     
         12 . The hot stamping component obtained by the method of  claim 11 , wherein the hot stamping component has a yield strength of 400-1300 MPa, a tensile strength of 500-2000 MPa, and an elongation of 4% or more. 
     
     
         13 . The method of  claim 8 , wherein the average weight of the aluminum-silicon alloy coating is 58-105 g/m 2  on one side. 
     
     
         14 . The method of  claim 8 , wherein the average weight of the aluminum-silicon alloy coating is 72-88 g/m 2  on one side.