A process for manufacturing a non-stamped prealloyed steel coil, sheet or blank, comprising the following successive steps: - providing a non-stamped precoated steel coil, sheet or blank composed of a heat treatable steel substrate comprising in weight % 0.20% ≤ C ≤ 0.25%, 1.1% ≤ Mn ≤ 1.4%, 0.15% ≤ Si ≤ 0.35%, Cr ≤ 0.30%, 0.020% ≤ Ti ≤ 0.060%, 0.020% ≤ Al ≤ 0.060%, S ≤ 0.005%, P ≤ 0.025%, 0.002% ≤ B ≤ 0.004%, the remainder being iron and unavoidable impurities resulting from the elaboration, covered by a precoating obtained by hot-dipping the sheet in a bath comprising, by weight, from 5% to 11% of Si, from 2% to 4% of Fe, the remainder being Al and impurities resulting from the smelting, the precoating resulting directly from a hot-dip aluminizing process without additional heat treatment, wherein the precoating thickness is comprised between 10 and 35 micrometers on each side of the steel coil, sheet or blank, then - heating the non-stamped steel coil, sheet or blank in a furnace under an atmosphere containing at least 5% oxygen, up to a temperature θ 1 comprised between 750 and 1000°C, for a duration t 1 comprised between timin and t 1max, wherein: t 1min = 23500 / θ 1 − 729.5 and t 1max = 4.946 × 10 41 × θ 1 − 13.08, t 1 designating the total duration in the furnace, θ 1 being expressed in °C and timin and t 1max being expressed in seconds, then - cooling the non-stamped steel coil, sheet or blank at a cooling rate V r1 down to a temperature θ i, wherein said cooling rate V r1 is selected so that the sum of the area fractions of bainite and martensite is less than 30% in the steel substrate and so as to obtain a ferrite-pearlite structure in the steel substrate, after said cooling V r1 and before subsequent heating, then - maintaining the non-stamped steel coil, sheet or blank at a temperature θ 2 comprised between 100 and 500°C, for a duration t 2 comprised between 3 and 45 minutes, so as to obtain a diffusible hydrogen content less than 0.35ppm measured by thermal desorption analysis as disclosed in the description. - providing a non-stamped precoated steel coil, sheet or blank composed of a heat treatable steel substrate comprising in weight % 0.20% ≤ C ≤ 0.25%, 1.1% ≤ Mn ≤ 1.4%, 0.15% ≤ Si ≤ 0.35%, Cr ≤ 0.30%, 0.020% ≤ Ti ≤ 0.060%, 0.020% ≤ Al ≤ 0.060%, S ≤ 0.005%, P ≤ 0.025%, 0.002% ≤ B ≤ 0.004%, the remainder being iron and unavoidable impurities resulting from the elaboration, covered by a precoating obtained by hot-dipping the sheet in a bath comprising, by weight, from 5% to 11% of Si, from 2% to 4% of Fe, the remainder being Al and impurities resulting from the smelting, the precoating resulting directly from a hot-dip aluminizing process without additional heat treatment, wherein the precoating thickness is comprised between 10 and 35 micrometers on each side of the steel coil, sheet or blank, then - heating the non-stamped steel coil, sheet or blank in a furnace under an atmosphere containing at least 5% oxygen, up to a temperature θ 1 comprised between 750 and 1000°C, for a duration t 1 comprised between timin and t 1max, wherein: t 1min = 23500 / θ 1 − 729.5 and t 1max = 4.946 × 10 41 × θ 1 − 13.08, t 1 designating the total duration in the furnace, θ 1 being expressed in °C and timin and t 1max being expressed in seconds, then t 1 designating the total duration in the furnace, θ 1 being expressed in °C and timin and t 1max being expressed in seconds, then - cooling the non-stamped steel coil, sheet or blank at a cooling rate V r1 down to a temperature θ i, wherein said cooling rate V r1 is selected so that the sum of the area fractions of bainite and martensite is less than 30% in the steel substrate and so as to obtain a ferrite-pearlite structure in the steel substrate, after said cooling V r1 and before subsequent heating, then - maintaining the non-stamped steel coil, sheet or blank at a temperature θ 2 comprised between 100 and 500°C, for a duration t 2 comprised between 3 and 45 minutes, so as to obtain a diffusible hydrogen content less than 0.35ppm measured by thermal desorption analysis as disclosed in the description.