Hot stamping alloy, method of making hot stamped parts with such alloy, and parts made from such alloy

Abstract

A metal alloy suitable for hot stamping comprises between about 0.05 and about 0.45 wt % carbon; between about 0.5 and about 4.5 wt % manganese; between about 0.5 and about 6 wt % chromium; between about 0.5 and about 2.5 wt % Si, between about 0.1 and about 0.5 wt % cerium, the balance being iron and impurities. A method of making a structural automobile part comprises heating a blank of the metal alloy and hot stamping the blank into the desired structural automotive part. A structural part is made by hot stamping a blank of the metal alloy.

What is claimed is: 
     
         1 . A metal alloy suitable for hot stamping, the alloy comprising between about 0.05 and about 0.45 wt % carbon; between about 0.5 and about 4.5 wt % manganese; between about 0.5 and about 6 wt % chromium; between about 0.5 and about 2.5 wt % Si, between about 0.1 and about 0.5 wt % cerium, the balance being iron and impurities. 
     
     
         2 . The metal alloy according to  claim 1  wherein the total of Cr and Si content is less than or equal to about 5 wt %. 
     
     
         3 . The metal alloy according to  claim 2  wherein the ratio of Cr:Si is between about 1.25 and about 3. 
     
     
         4 . The metal alloy according to  claim 1  wherein the ratio of Cr:Si is between about 1.25 and about 3. 
     
     
         5 . A method of making a structural automobile part comprising: heating a blank of a metal alloy comprising between about 0.05 and about 0.45 wt % carbon; between about 0.5 and about 4.5 wt % manganese; between about 0.5 and about 6 wt % chromium; between about 0.5 and about 2.5 wt % Si, between about 0.1 and about 0.5 wt % cerium, the balance being iron and impurities; and hot stamping the blank into the desired structural automotive part. 
     
     
         6 . The method of  claim 5  wherein the heating occurs in the space bounded by the time, temperature points (300 s, 870° C.), (200 s, 980° C.), (800 s, 870° C.), and (1000 s, 980° C.). 
     
     
         7 . The method of  claim 5  wherein the heating occurs in the space bounded by the time, temperature points (300 s, 870° C.), (200 s, 980° C.), (1000 s, 870° C.), and (800 s, 980° C.). 
     
     
         8 . The method of  claim 5  wherein the heating occurs in an inert atmosphere. 
     
     
         9 . The method according to  claim 5  wherein the composition of the blank has a total of Cr and Si content is less than or equal to about 5 wt %. 
     
     
         10 . The method according to  claim 9  wherein the composition of the blank has a ratio of Cr:Si is between about 1.25 and about 3. 
     
     
         11 . The method according to  claim 5  wherein the ratio of Cr:Si is between about 1.25 and about 3. 
     
     
         12 . An automotive structural part made of between about 0.05 and about 0.45 wt % carbon; between about 0.5 and about 4.5 wt % manganese; between about 0.5 and about 6 wt % chromium; between about 0.5 and about 2.5 wt % Si, between about 0.1 and about 0.5 wt % cerium, the balance being iron and impurities, shaped by hot stamping with a uniform oxidation thickness after hot stamping of 0.5 μm. 
     
     
         13 . The automotive structural part according to  claim 12  wherein the total of Cr and Si content is less than or equal to about 5 wt %. 
     
     
         14 . The automotive structural part according to  claim 13  wherein the ratio of Cr:Si is between about 1.25 and about 3. 
     
     
         15 . The automotive structural part according to  claim 12  wherein the ratio of Cr:Si is between about 1.25 and about 3. 
     
     
         16 . The automotive structural part according to  claim 11 , wherein the part is an automotive pillar, a door beam, or a bumper beam.