Aluminium alloy and aluminium alloy strip for pedestrian impact protection

Abstract

Embodiments of an aluminium alloy for vehicle applications, an aluminium alloy strip, and a sheet metal body part of a motor vehicle manufactured from the aluminium alloy strip are disclosed herein. The object to provide an aluminium alloy for vehicle applications, which can be processed into a strip using conventional method steps such that the manufactured strip, with a moderate level of strength, exhibits only a low tendency to hardening from the T4 condition and a use in the area of pedestrian impact protection is possible, is achieved in that the aluminium alloy has the following alloy constituents in percent by weight 0.40-0.55 wt % Si, 0.15-0.25 wt % Fe, 0-0.06 wt % Cu, 0.15-0.4 wt % Mn, 0.33-0.4 wt % Mg, 0-0.03 wt % Cr, 0.01-0.10 wt % Ti, and the remainder being Al and unavoidable impurities, individually at most 0.05 wt %, in total at most 0.15 wt %.

1 . An aluminium alloy strip comprising an aluminium alloy for vehicle applications with the following alloy constituents in percent by weight:
   0.40 wt %≤Si≤0.55 wt %,
     0.15 wt %≤Fe≤0.25 wt %,
     Cu≤0.06 wt %,
     0.15 wt %≤Mn≤0.40 wt %,
     0.33 wt %≤Mg≤0.40 wt %,
     Cr≤0.03 wt %,
     0.005 wt %≤Ti≤0.10 wt %,
   the remainder being Al and unavoidable impurities, individually at most 0.05 wt %, in total at most 0.15 wt %.   
     
     
         2 . The aluminium alloy strip according to  claim 1 , wherein the aluminium alloy has a Mn content in percent by weight of 0.25 wt %≤Mn≤0.35 wt %. 
     
     
         3 . The aluminium alloy strip according to  claim 1 , wherein the aluminium alloy has a Cu content in percent by weight of Cu<0.05 wt %. 
     
     
         4 . The aluminium alloy strip according to  claims 1  to  3 , wherein the aluminium alloy has an Si content in percent by weight of 0.40 wt %≤Si≤0.48 wt %. 
     
     
         5 . The aluminium alloy strip according to  claim 1 , wherein the aluminium alloy has an Mg content in percent by weight of 0.35 wt %≤Mg<0.40 wt %. 
     
     
         6 . The aluminium alloy strip according to  claim 1 , wherein the aluminium alloy strip has, in the T4 condition, a yield strength of 55 MPa to 70 MPa and a tensile strength of 130 MPa to 160 MPa measured transverse to the rolling direction. 
     
     
         7 . The aluminium alloy strip according to  claim 1 , wherein the aluminium alloy strip has, in the T6× condition, a yield strength of less than 100 MPa measured transverse to the rolling direction after solution annealing at 530° C. for 5 minutes, subsequent quenching to room temperature, natural aging for 7 days at room temperature, heating to 205° C. for 30 minutes and heating to 80° C. for 500 hours. 
     
     
         8 . A method for manufacturing an aluminium alloy strip according to  claim 1 , wherein the method comprises the method steps of:
 casting a rolling ingot or a cast strip;   homogenising the rolling ingot;   hot rolling the rolling ingot or the cast strip; and   optionally cold rolling with or without intermediate annealing to end thickness.   
     
     
         9 . A sheet metal body part of a motor vehicle manufactured from an aluminium alloy strip according to  claim 7 . 
     
     
         10 . The sheet metal body part according to  claim 9 , wherein the sheet metal body part is configured as sheet metal of a motor vehicle provided for pedestrian impact protection. 
     
     
         11 . The sheet metal body part according to  claim 9 , wherein the sheet metal body part is configured as a part of a wing, a part of an engine bonnet, a roof frame or a vehicle roof or a tailgate. 
     
     
         12 . An aluminium alloy for vehicle applications with the following alloy constituents in percent by weight:
   0.40 wt %≤Si≤0.55 wt %,
     0.15 wt %≤Fe≤0.25 wt %,
     Cu≤0.06 wt %,
     0.20 wt %≤Mn≤0.40 wt %,
     0.33 wt %≤Mg≤0.40 wt %,
     Cr≤0.03 wt %,
     0.005 wt %≤Ti≤0.10 wt %.
   
     
     
         13 . The aluminium alloy according to  claim 12 , wherein the aluminium alloy has an Mn content in percent by weight of 0.25 wt %≤Mn≤0.35 wt %. 
     
     
         14 . The aluminium alloy according to  claim 12 , wherein the aluminium alloy has a Cu content in percent by weight of Cu<0.05 wt %. 
     
     
         15 . The aluminium alloy according to  claim 12 , wherein the aluminium alloy has an Si content in percent by weight of 0.40 wt %≤Si≤0.48 wt % and/or an Mg content in percent by weight of 0.35 wt %≤Mg<0.40 wt %.