Method of manufacturing a semi-finished product using an aluminium alloy, in particular for an automobile structure

The process for making a semi-product constituting a head or a profile made of aluminum alloy to form a structural component of an automobile vehicle, comprises rolling, hardening or extruding the aluminum alloy to make the semi-product, and thermally treating the yield of semi-product. A sample is removed from a batch comprising a set of semi-products having common fabrication parameters in order to undergo a test. Conditions (T, delta t) for obtaining the semi-product yield is determined in function of the measured value (Cm, Fm, Rm m, Rp m, Am) during the test. The process for making a semi-product constituting a head or a profile made of aluminum alloy to form a structural component of an automobile vehicle, comprises rolling, hardening or extruding the aluminum alloy to make the semi-product, and thermally treating the yield of semi-product. A sample is removed from a batch comprising a set of semi-products having common fabrication parameters in order to undergo a test. Conditions (T, delta t) for obtaining the semi-product yield is determined in function of the measured value (Cm, Fm, Rm m, Rp m, Am) during the test and target values (Cc, Fc, Rm c, Rp c, Ac) of the functional characteristics. The thermal treatment is applied with the determined conditions such as treatment temperature (T) and treatment time (delta t). The set of semi-products are obtained from same alloy or same stream of the alloy, and produced respectively through same cylinders of a rolling-mill under same extrusion pressure. The respective interruption such as rolling and/or hardening between the two portions of the quantity of metal is not limited by a determined duration. A maturation period with ambient temperature is observed before the test of functional characteristics of the sample. The functional characteristics test is a sample crushing test, sample pulling test and sample folding test, and takes place for recording the displacement of the head and force applied for displacing the head, when the sample is crushed. The measured functional characteristic is a value of maximum force to be exerted on the semi-product and a value of energy absorbed for obtaining a deformation of the semi-product corresponding to a predetermined displacement, a mechanical characteristic representing the pulling behavior with limited elasticity, breakage and/or lengthening, and a mechanical characteristic representing the flexion behavior with limited folding angle. The measured functional cha