Steel Sheet Coated with a Metallic Coating based on Aluminum

Abstract

A steel sheet coated with a metallic coating is provided. The steel sheet includes from 2.0 to 24.0% by weight of zinc, from 7.1 to 12.0% by weight of silicon, optionally from 1.1 to 8.0% by weight of magnesium, and optionally additional elements chosen from Pb, Ni, Zr, or Hf, the content by weight of each additional element being less than 0.3% by weight, the balance being aluminum and optionally unavoidable impurities and residual elements. The ratio Al/Zn is above 2.9.

What is claimed is: 
     
         1 - 25 . (canceled) 
     
     
         26 . A steel sheet coated with a metallic coating, the metallic coating comprising:
 2.0 to 24.0% by weight of zinc;   7.1 to 12.0% by weight of silicon; and   a balance being aluminum, unavoidable impurities and residual elements; and   a ratio of Al/Zn being greater than 2.9   
     
     
         27 . The steel sheet according to  claim 26 , further comprising from 1.1 to 8.0% by weight of magnesium 
     
     
         28 . The steel sheet according to  claim 26 , further comprising additional elements chosen from Pb, Ni, Zr, or Hf, the content by weight of each additional element being less than 0.3% by weight. 
     
     
         29 . The steel sheet according to  claim 26 , wherein the ratio Al/Zn is less than or equal to 8.5. 
     
     
         30 . The steel sheet according to  claim 29 , wherein the ratio Al/Zn is between 3.0 and 7.5. 
     
     
         31 . The steel sheet according to  claim 30 , wherein the ratio Al/Zn is between 4.0 and 6.0. 
     
     
         32 . The steel sheet according to  claim 26 , wherein a microstructure of the metallic coating comprises an Al—Zn phase. 
     
     
         33 . The steel sheet according to  claim 26 , wherein the coating comprises from 10.0 to 20.0% by weight of zinc. 
     
     
         34 . The steel sheet according to  claim 26 , wherein the coating comprises from 10.0 to 15.0% by weight of zinc. 
     
     
         35 . The steel sheet according to  claim 26 , wherein the coating comprises from 8.1 to 10.0% by weight of silicon. 
     
     
         36 . The steel sheet according to  claim 26 , wherein the coating comprises from 3.0 to 8.0% by weight of magnesium. 
     
     
         37 . The steel sheet according to  claim 36 , wherein the coating comprises from 3.0 to 5.0% by weight of magnesium. 
     
     
         38 . The steel sheet according to  claims 26 , wherein a microstructure of the metallic coating comprises a Mg 2 Si phase. 
     
     
         39 . The steel sheet according to  claim 26 , wherein a microstructure of the metallic coating comprises a MgZn 2  phase. 
     
     
         40 . The steel sheet according to  claim 26 , wherein an amount of aluminum is greater than 71% by weight. 
     
     
         41 . The steel sheet according  claim 26 , wherein an amount of aluminum is greater than 76% by weight. 
     
     
         42 . The steel sheet according to  claim 26 , wherein a thickness of the metallic coating is between 5 and 50 μm. 
     
     
         43 . The steel sheet according to  claim 42 , wherein the thickness is between 10 and 35 μm. 
     
     
         44 . The steel sheet according to  claim 42 , wherein the thickness is between 12 and 18 μm. 
     
     
         45 . The steel sheet according to  claim 42 , wherein the thickness is between 26 and 31 μm. 
     
     
         46 . The steel sheet according to  claim 26 , wherein the coating does not comprise elements selected among Cr, Mn, Ti, Ce, La, Nd, Pr, Ca, Bi, In, Sn and Sb or combinations thereof. 
     
     
         47 . A part comprising:
 the coated steel sheet according to  claim 26  formed into a part by hot-forming or cold-stamping.   
     
     
         48 . The part according to  claim 47 , wherein the part is formed by hot-forming and cold-stamping. 
     
     
         49 . The part according to  claim 47 , wherein the part is a press hardened steel part having a variable thickness. 
     
     
         50 . The part according to  claim 49 , wherein the variable thickness is produced by a continuous flexible rolling process. 
     
     
         51 . The part according to  claim 47 , wherein the part is a tailored rolled blank. 
     
     
         52 . The part according to  claim 47 , wherein the part is a front rail, a seat cross member, a side sill member, a dash panel cross member, a front floor reinforcement, a rear floor cross member, a rear rail, a B-pillar, a door ring or a shotgun. 
     
     
         53 . An automotive vehicle comprising:
 the part according to  claim 47 .