welding application_number US 51563105 A description the process for manufacturing 6xxx alloy sheets for example comprises casting of a sheet followed by scalping of this sheet if required and homogenisation at a temperature of between 550 and 580 u00b0 c hot rolling preferably takes place at an input temperature of more than 540 u00b0 c the hot rolled strip is then cold rolled down to the final thickness the last cold rolling pass may be made with a textured cylinder for example by electron beam treatment ebt electrical discharge treatment edt or by laser beam which improves the formability and surface appearance of the part formed after painting the solution heat treatment takes place at a temperature as close as possible to the alloy melting initiating temperature while avoiding burning the strip enters into a passage homogenisation furnace in which the temperature is more than 500 u00b0 c the solution heat treated metal is immediately quenched by passing it into a tank containing cold water or it is sprayed with this cold water the characteristic of the invention is particularly to do this quenching with a liquid that reacts with the surface to form an oxide layer with bonding and stability properties comparable to what can normally be obtained with long chemical conversion surface treatment operations thus chemical pre treatment and post treatment operations normally used in chemical.