Wrought aluminium aa7000-series alloy product and method of producing said product

Abstract

A wrought aluminium AA7000-series alloy product, including (in wt %): Zn 7.5 to 14.0, Mg 1.0 to 5.0, Cu<0.28, Fe<0.6, Si<0.5, and one or more members selected from the group of: Zr<0.30, Ti<0.30, Hf<0.30, Mn<0.80, Cr<0.40, V<0.40, and Sc<0.70, remainder: incidental elements and impurities, each <0.05, total <0.15, and balance aluminium. The product has reduced hot crack sensitivity, and improved strength and toughness properties, and has a hardness of more than 180 HB in artificially aged condition.

1 . A wrought aluminium AA7000-series alloy product, consisting essentially of (in wt. %): 
 Zn 7.5-14.0    Mg 1.0-5.0    Cu≦0.28    Fe<0.60    Si<0.50    and one or more of: 
 Zr<0.30,  
 Ti<0.30,  
 Hf<0.30  
 Mn<0.80,  
 Cr<0.40  
 V<0.40,  
 Sc<0.70,  
   remainder: incidental elements and impurities, each <0.05, total <0.15, the balance aluminium,    the product having reduced hot crack sensitivity, and improved strength and toughness properties relative to at least one alloy selected from the group consisting of AA7050 or AA7075, and when in artificially aged condition having a hardness of more than 180 HB.    
   
   
       2 . A product according to  claim 1 , wherein Cu is ≦0.25%.  
   
   
       3 . A product according to  claim 1 , wherein Cu is ≦0.20%.  
   
   
       4 . A product according to  claim 1 , wherein the Cu content has a lower limit of 0.03%.  
   
   
       5 . A product according to  claim 1 , wherein the Cu content has a lower limit of 0.08%.  
   
   
       6 . A product according to any  claim 1 , wherein the Zr content is in a range of 0.04 to 0.15%.  
   
   
       7 . A product according to any  claim 1 , wherein the Zr content is in a range of 0.04 to 0.13%.  
   
   
       8 . A product according to  claim 1 , wherein the Zn content has a lower limit of 8.5%.  
   
   
       9 . A product according to  claim 1 , wherein the Zn content has a lower limit of 9.0%.  
   
   
       10 . A product according to  claim 1 , wherein the Zn content has a lower limit of 9.5%.  
   
   
       11 . A product according to  claim 1 , wherein Zn content has an upper limit of 12.0%.  
   
   
       12 . A product according to  claim 1 , wherein Zn content has an upper limit of 11.0%.  
   
   
       13 . A product according to  claim 1 , wherein Zn content has an upper limit of 10.0%.  
   
   
       14 . A product according to  claim 1 , wherein the Mg content has a lower limit of 2.5%.  
   
   
       15 . A product according to  claim 1 , wherein the Mg content has an upper limit of 4.5%.  
   
   
       16 . A product according to  claim 1 , wherein the Mg content has an upper limit of 4.0%.  
   
   
       17 . A product according to  claim 1 , wherein the Fe content is at most 0.14%.  
   
   
       18 . A product according to  claim 1 , wherein the Fe content is at most 0.08%.  
   
   
       19 . A product according to  claim 1 , wherein the Si content is at most 0.12%.  
   
   
       20 . A product according to  claim 1 , wherein the Si content is at most 0.07%.  
   
   
       21 . A product according to  claim 1 , wherein the Mn content is in a range of 0.05 to 0.40%.  
   
   
       22 . A product according to  claim 1 , wherein the Mn content is <0.02%.  
   
   
       23 . A product according to  claim 1 , wherein Mg≧6.6−(0.45×Zn).  
   
   
       24 . A product according to  claim 1 , wherein Mg≧10−(0.79×Zn).  
   
   
       25 . A product according to  claim 1 , wherein the product is in the form of a sheet, plate, or extrusion.  
   
   
       26 . A product according to  claim 1 , wherein the product is in the form of a plate.  
   
   
       27 . A product according to  claim 1 , wherein the product is in a T6-type or T7-type condition.  
   
   
       28 . A product according to  claim 1 , wherein the product has reduced hot crack sensitivity, and improved strength and toughness properties relative to at least one alloy selected from the group consisting of AA7050 or AA7075 in T6 or T7-type temper.  
   
   
       29 . A product according to  claim 1 , wherein the product has reduced hot crack sensitivity, and improved strength and toughness properties relative to at least one alloy selected from the group consisting of AA7050 or AA7075 in the T651 temper.  
   
   
       30 . A welded component comprising: 
 at least a first component part being a product according to  claim 1 , and    at least a second component part,    the component parts being welded together to form the welded component,    the at least one first and the at least one second component part being products according to  claim 1 , and    wherein the welded component is a welded structural aircraft component.    
   
   
       31 . A wrought product according to  claim 1 , wherein the wrought product is a weldable aerospace sheet or plate product in a T6-type or T7-type condition, and wherein said product consists essentially of, in wt. %: 
 Zn 7.5 to 11.0    Mg 1.0 to 5.0, and wherein the Mg-content depends on the Zn-content according to Mg≧6.6−(0.45×Zn),    Cu 0.03 to 0.25    Zr 0.04 to 0.15    Ti<0.10    Fe<0.08    Si<0.07,    remainder incidental elements and impurities, each <0.05, total <0.15, the balance aluminium.    
   
   
       32 . A wrought product according to  claim 1 , wherein the wrought product is a weldable aerospace sheet or plate product in a T6-type or T7-type condition, and wherein said product consists essentially of, in wt. %: 
 Zn 7.5 to 11.0    Mg 2.0 to 4.5, and wherein the Mg-content depends on the Zn-content according to Mg≧10−(0.79×Zn),    Cu 0.03 to 0.25    Zr 0.04 to 0.15    Ti<0.10    Fe<0.08    Si<0.07,    remainder incidental elements and impurities, each <0.05, total <0.15, the balance aluminium.    
   
   
       33 . A wrought product according to  claim 1 , wherein the wrought product is a weldable aerospace sheet or plate product in a T6-type or T7-type condition, and wherein said product consists essentially of, in wt. %: 
 Zn 8.5 to 10.0    Mg 2.0 to 4.5, and wherein the Mg-content depends on the Zn-content according to Mg≧10−(0.79×Zn),    Cu 0.03 to 0.25    Zr 0.04 to 0.15    Ti<0.10    Fe<0.08    Si<0.07,    remainder incidental elements and impurities, each <0.05, total <0.15, the balance aluminium.    
   
   
       34 . A wrought product according to  claim 1 , wherein the wrought product is a weldable aerospace sheet or plate product in a T6-type or T7-type condition, and wherein said product consists essentially of, in wt. %: 
 Zn 8.5 to 10.0    Mg 2.5 to 4.5, and wherein the Mg-content depends on the Zn-content according to Mg≧10−(0.79×Zn),    Cu 0.03 to 0.25    Zr 0.04 to 0.15    Ti<0.10    Fe<0.08    Si<0.07,    remainder incidental elements and impurities, each <0.05, total <0.15, the balance aluminium.    
   
   
       35 . A wrought product according to  claim 1 , wherein the wrought product is a weldable aerospace extrusion in a T6-type or T7-type condition, and wherein said product consists essentially of, in wt. %: 
 Zn 7.5 to 11.0    Mg 1.0 to 5.0, and wherein the Mg-content depends on the Zn-content according to Mg≧6.6−(0.45×Zn),    Cu 0.03 to 0.25    Zr 0.04 to 0.15    Ti<0.10    Fe<0.14    Si<0.12,    remainder incidental elements and impurities, each <0.05, total <0.15, the balance aluminium.    
   
   
       36 . A wrought product according to  claim 1 , wherein the wrought product is a weldable aerospace sheet or plate product in a T6-type or T7-type condition, and wherein said product consists essentially of, in wt. %: 
 Zn 8.5 to 10.0    Mg 2.5 to 4.5, and wherein the Mg-content depends on the Zn-content according to Mg≧10−(0.79×Zn),    Cu 0.03 to 0.25    Cr 0.04 to 0.20    Zr up to 0.15    Ti<0.10    Fe<0.08    Si<0.07,    remainder incidental elements and impurities, each <0.05, total <0.15, the balance aluminium.    
   
   
       37 . A wrought product according to  claim 1 , wherein the wrought product is a weldable tooling plate product in a T6-type or T7-type condition, and wherein said plate product consists essentially of, in wt. %: 
 Zn 7.5 to 14.0    Mg 1.0 to 5.0, and wherein the Mg-content depends on the Zn-content according to Mg≧6.6−(0.45×Zn),    Cu 0.03-0.25    Zr 0.04-0.15    Ti<0.10    Fe<0.60    Si<0.50,    remainder incidental elements and impurities, each <0.05, total <0.15, and balance aluminium.    
   
   
       38 . A wrought product according to  claim 1 , wherein the wrought product is a weldable tooling plate product in a T6-type or T7-type condition, and wherein said plate product consists essentially of, in wt. %: 
 Zn 7.5 to 14.0    Mg 2.0 to 4.0, and wherein the Mg-content depends on the Zn-content according to Mg≧10−(0.79×Zn),    Cu 0.03-0.25    Zr 0.04-0.15    Ti<0.10    Fe<0.60    Si<0.50,    remainder incidental elements and impurities, each <0.05, total <0.15, and balance aluminium.    
   
   
       39 . A wrought product according to  claim 1 , wherein the wrought product is a weldable tooling plate product in a T6-type or T7-type condition, and wherein said plate product consists essentially of, in wt. %: 
 Zn 7.5 to 12.0    Mg 2.0 to 4.0, and wherein the Mg-content depends on the Zn-content according to Mg≧10−(0.79×Zn),    Cu 0.03-0.25    Zr 0.04-0.15    Ti<0.10    Fe<0.60    Si<0.50,    remainder incidental elements and impurities, each <0.05, total <0.15, and balance aluminium.    
   
   
       40 . A wrought product according to  claim 1 , wherein the wrought product is a weldable tooling plate product in a T6-type or T7-type condition, and wherein said plate product consists essentially of, in wt. %: 
 Zn 9.5 to 12.0    Mg 2.5 to 4.5, and wherein the Mg-content depends on the Zn-content according to Mg≧10−(0.79×Zn),    Cu 0.03-0.25    Zr 0.04-0.15    Ti<0.10    Fe<0.60    Si<0.50,    remainder incidental elements and impurities, each <0.05, total <0.15, and balance aluminium.    
   
   
       41 . A wrought product according to  claim 1 , wherein the wrought product is a weldable tooling plate product in a T6-type or T7-type condition, and wherein said plate product consists essentially of, in wt. %: 
 Zn 8.5 to 11.0    Mg 2.5 to 4.5, and wherein the Mg-content depends on the Zn-content according to Mg≧10−(0.79×Zn),    Cu 0.03-0.25    Zr 0.04-0.15    Ti<0.10    Fe<0.60    Si<0.50,    remainder incidental elements and impurities, each <0.05, total <0.15, and balance aluminium.    
   
   
       42 . A wrought product according to  claim 1 , wherein the wrought product is a weldable tooling plate product in a T6-type or T7-type condition, and wherein said plate product consists essentially of, in wt. %: 
 Zn 9.5 to 12.0    Mg 2.5 to 3.5    Cu 0.03-0.25    Zr 0.04-0.15    Ti<0.10    Fe<0.60    Si<0.50,    remainder incidental elements and impurities, each <0.05, total <0.15, and balance aluminium, and having a hardness of more than 190 HB.    
   
   
       43 . (canceled)  
   
   
       44 . (canceled)  
   
   
       45 . A product according to  claim 1 , wherein Si is <0.25.  
   
   
       46 . (canceled)  
   
   
       47 . (canceled)  
   
   
       48 . (canceled)  
   
   
       49 . (canceled)  
   
   
       50 . (canceled)  
   
   
       51 . (canceled)  
   
   
       52 . Method of producing a wrought aluminium AA7000-series alloy product according to  claim 1  comprising the steps of: 
 a) casting an ingot having an elemental composition of said product    b) homogenising and/or pre-heating the ingot after casting    c) hot working the ingot into a pre-worked product by one or more methods selected from the group consisting of: rolling, extruding and forging    d) optionally reheating the pre-worked product and either    e) hot working and/or cold working the pre-worked product to a desired workpiece shape    f) solution heat treating (SHT) the formed workpiece at a temperature and time sufficient to place into solid solution essentially all soluble constituents in the alloy    g) quenching the solution heat treated workpiece, preferably by one of spray quenching or immersion quenching in water or other quenching media    h) optionally stretching or compressing of the quenched work piece or otherwise cold worked to relieve stresses, for example levelling of sheet products    i) artificially ageing the quenched and optionally stretched or compressed workpiece to achieve a desired temper, and    wherein the homogenising treatment comprises a first homogenisation stage and optionally a second homogenisation stage wherein the duration and the temperature during said first homogenisation stage for an ingot or a slab is chosen such that a cold spot, said cold spot being defined as the coldest spot in the ingot or slab, in the ingot or slab is at a dissolving temperature for at least a dissolving time necessary to dissolve the m-phase precipitates.    
   
   
       53 . Process according to  claim 52 , wherein during process step i) the product is artificially aged to a T6-type or T7-type temper.