A manufacturing process for obtaining a solid extrusion with a thickness higher than 10 mm, wherein said manufacturing process comprises following steps a) casting a billet of aluminum an alloy comprising Si: 0.3-1.7 wt. %; Mg: 0.1-1.4 wt. %, Cu: 0.4-0.8 wt. %, Zn 0.005-0.7 wt %, one or more dispersoid element, from the group consisting of Mn 0.15-1 wt.%, Cr 0.05-0.4 wt.% and Zr 0.05-0.25 wt.%, Fe at most 0.5 wt.%, other elements at most 0.05 wt.% each, the rest being aluminium and wherein 0.2 wt.% ≤ Si - (Mg/1.73) - (Fe+Mn)/3 ≤ 0.7 wt.% and the quantity of Mg2Si is in the range of 1.2 wt. % to 1.6 wt. %. b) homogenizing said billet; c) heating the said homogenised cast billet; d) extruding the said billet through a die to form a solid extrusion with a thickness higher than 10 mm; e) quenching said solid extrusion down to room temperature; f) optionally stretching the solid extrusion to obtain a plastic deformation typically between 0,5% and 5%; g) ageing the quenched and optionally stretched solid extrusion without applying any separate post-extrusion solution heat treatment; wherein said ageing treatment is a one- or multiple-step heat treatment at a temperature between 150°C and 200°C for a prescribed period of time, defined to obtain the maximum ultimate strength characterised in that: i) the heating step c) is a solution heat treatment wherein: c1) the cast and homogenized billet is heated to a temperature between Ts-15°C and Ts, wherein Ts is the solidus temperature of the said aluminium alloy; c2) the billet is cooled until billet mean temperature reaches a value between 370°C and 480 °C while ensuring billet surface never goes below 370 °C ii) the cooled billet is immediately extruded (step d), preferably less than 40 s after the end of step c2). iii) said aged solid extrusion presents an ultimate tensile strength higher than 400 MPa, preferably higher than 430 MPa and more preferably 450 MPa a) casting a billet of aluminum an alloy comprising Si: 0.3-1.7 wt. %; Mg: 0.1-1.4 wt. %, Cu: 0.4-0.8 wt. %, Zn 0.005-0.7 wt %, one or more dispersoid element, from the group consisting of Mn 0.15-1 wt.%, Cr 0.05-0.4 wt.% and Zr 0.05-0.25 wt.%, Fe at most 0.5 wt.%, other elements at most 0.05 wt.% each, the rest being aluminium and wherein 0.2 wt.% ≤ Si - (Mg/1.73) - (Fe+Mn)/3 ≤ 0.7 wt.% and the quantity of Mg2Si is in the range of 1.2 wt. % to 1.6 wt. %. b) homogenizing said billet; c) heating the said homogenised cast billet; d) extruding the said billet through a die to form a solid extrusion with a thickness higher than 10 mm; e) quenching said solid extrusion down to room temperature; f) optionally stretching the solid extrusion to obtain a plastic deformation typically between 0,5% and 5%; g) ageing the quenched and optionally stretched solid extrusion without applying any separate post-extrusion solution heat treatment; wherein said ageing treatment is a one- or multiple-step heat treatment at a temperature between 150°C and 200°C for a prescribed period of time, defined to obtain the maximum ultimate strength i) the heating step c) is a solution heat treatment wherein: c1) the cast and homogenized billet is heated to a temperature between Ts-15°C and Ts, wherein Ts is the solidus temperature of the said aluminium alloy; c2) the billet is cooled until billet mean temperature reaches a value between 370°C and 480 °C while ensuring billet surface never goes below 370 °C c1) the cast and homogenized billet is heated to a temperature between Ts-15°C and Ts, wherein Ts is the solidus temperature of the said aluminium alloy; c2) the billet is cooled until billet mean temperature reaches a value between 370°C and 480 °C while ensuring billet surface never goes below 370 °C ii) the cooled billet is immediately extruded (step d), preferably less than 40 s after the end of step c2). iii) said aged solid extrusion presents an ultimate tensile strength higher than 400 MPa, preferably higher than 430 MPa and more preferably 450 MPa