Dcomposition arborescente et cohrence locale souple dans les CSP pondrs

A method for producing a strip of material having a non-uniform cross section is carried out by passing a strip of material in the longitudinal direction through a first set of working rolls, at least one of which is provided with an annular slot intermediate the ends thereof so that a reducing force is applied only to those portions of the strip engaging said roll on opposite sides of the slot whereby the excess material flows toward that portion of the strip opposed to the slot to cause the strip to buckle outwardly into the slot. The strip is subsequently passed through a set of smooth rolls to flatten the buckled portion. This procedure is repeated any desired number of times with the width of the slot becoming progressively smaller. The strip may then be passed through one or more sets of finishing rolls and a heating and annealing operation can take place before each passage through a set of finishing rolls.