Method for producing an attachment element

Abstract

The invention relates to a method for producing an attachment element (R) comprising a shaft ( 100 ) having a first end provided with a head ( 200 ) and a second end that is intended to be deformed in order to form a button ( 300 ) providing a bearing surface opposite the surface formed by the head ( 200 ), said shaft ( 100 ) having a nominal diameter (D). The method is characterised in that the element is sized such that the minimum length (L) of the shaft ( 100 ) to be deformed to form the button ( 300 ) is no less than 1.25 times the nominal diameter (D) of the shaft ( 100 ). The invention is suitable for use in the production of attachment elements, such as rivets.

1 . Method for manufacturing, using a metal wire, a fastening element such as that having a shank wherein a first end is equipped with a head, the second end being intended to be deformed to act as a knob forming a bearing surface to be positioned facing that formed by the head, said shank having a nominal diameter,
 said element being designed such that the minimum length of the shank intended to be deformed to act as the knob is not less than 1.25 times the nominal diameter of the shank,   characterized in that it comprises   obtaining, for the metal wire, a material grain adopting a size of 6 or finer according to the criteria defined by the ASTM E 112 standard,   performing, on said wire, a work-hardening step wherein the rate is greater than 30%, and   designing said element such that the minimum diameter of the knob obtained after deforming the shank is greater than 1.75 times the nominal diameter of the shank.   
     
     
         2 . Method according to  claim 1 , characterized in that it comprises designing said element such that the knob obtained after deforming the shank has a maximum thickness (e) equal to 0.45 times the nominal diameter of the shank. 
     
     
         3 . Method according to  claim 1 , characterized in that said element comprises a rivet. 
     
     
         4 . Method according to  claim 1 , characterized in that it comprises selecting, for the metal wire from which the element is formed, an aluminum alloy wherein the additional elements to aluminum adopt as a percentage the following proportions: 
       
         
           
                 
                 
                 
                 
               
                     
                     
                 
                     
                     
                   min 
                   max 
                 
                     
                     
                 
                     
                 
                 
                 
                 
                 
               
                     
                   CR 
                   0 
                   0.04 
                 
                     
                   CU 
                   2 
                   2.5 
                 
                     
                   FE 
                   0.011 
                   0.14 
                 
                     
                   MG 
                   2.04 
                   2.3 
                 
                     
                   MN 
                   0 
                   0.05 
                 
                     
                   SI 
                   0.02 
                   0.12 
                 
                     
                   TI 
                   0.02  
                   0.06 
                 
                     
                   ZN 
                   6.1 
                   6.7 
                 
                     
                   ZR 
                   0.08  
                   0.15. 
                 
                     
                     
                 
             
                
                
                
               
               
                
               
            
             
                
                
                
                
                
                
                
                
                
                
               
            
           
         
       
     
     
         5 . Method according to  claim 1 , characterized in that it comprises selecting, for the metal wire from which the fastening element is formed, an aluminum alloy wherein the additional elements to aluminum adopt as a percentage the following proportions: 
       
         
           
                 
                 
                 
                 
               
                     
                     
                 
                     
                     
                   min 
                   max 
                 
                     
                     
                 
                     
                 
                 
                 
                 
                 
               
                     
                   CR 
                   0.05  
                   0.1 
                 
                     
                   CU 
                   2.6 
                   3 
                 
                     
                   FE 
                   0.34 
                   0.5 
                 
                     
                   MG 
                   0.33 
                   0.5 
                 
                     
                   MN 
                   0.1 
                   0.2 
                 
                     
                   SI 
                   0.32  
                   0.8 
                 
                     
                   TI 
                   0 
                   0.01 
                 
                     
                   ZN 
                   0.1 
                   0.17 
                 
                     
                   FE—MN 
                   0.47 
                   0.68 
                 
                     
                   TI—ZR 
                   0.05 
                   0.15. 
                 
                     
                     
                 
             
                
                
                
               
               
                
               
            
             
                
                
                
                
                
                
                
                
                
                
                
               
            
           
         
       
     
     
         6 . Method according to  claim 1 , characterized in that it comprises selecting, for the metal wire from which the fastening element is formed, an aluminum alloy wherein the additional elements to aluminum adopt as a percentage the following proportions: 
       
         
           
                 
                 
                 
                 
               
                     
                     
                 
                     
                     
                   min 
                   max 
                 
                     
                     
                 
                     
                 
                 
                 
                 
                 
               
                     
                   CR 
                   0 
                   0.03 
                 
                     
                   CU 
                   3.5 
                   4.3 
                 
                     
                   FE 
                   0.016 
                   0.3 
                 
                     
                   MG 
                   0.43 
                   0.65 
                 
                     
                   MN 
                   0.41 
                   0.63 
                 
                     
                   SI 
                   0.21 
                   0.4 
                 
                     
                   TI 
                   0.005 
                   0.08 
                 
                     
                   ZN 
                   0.002 
                   0.04. 
                 
                     
                     
                 
             
                
                
                
               
               
                
               
            
             
                
                
                
                
                
                
                
                
                
               
            
           
         
       
     
     
         7 . Method according to  claim 1 , characterized in that it comprises of selecting a wire which does not have inclusions (isolated nicks, abrasions, pitting, isolated minor inclusions, cold shuts, non-continuous scratches, tool marks, burrs, etc.) greater than 0.15 millimeters in depth. 
     
     
         8 . Method according to  claim 1 , characterized in that it comprises selecting a wire wherein the depth of longitudinal continuous defects does not exceed 40 microns. 
     
     
         9 . Method according to  claim 1 , characterized in that it comprises subjecting said element to a cooling step wherein the time for transferring the fastening elements from one medium wherein the temperature is equivalent to that of the solution treatment to a medium wherein the temperature is 20 degrees Celsius is less than 5 seconds. 
     
     
         10 . Method according to  claim 1 , characterized in that it comprises subjecting said element to a quenching step wherein the temperature variation during the quenching of the same batch of elements does not exceed 5 degrees Celsius. 
     
     
         11 . Method according to  claim 1 , characterized in that the fastening element is designed such that the shank end radius is proportional to the diameter of the shank itself according to a proportion wherein said radius is equal to the nominal diameter of the shank divided by a value ranging between 3 and 3.5.