Abstract: A process for manufacturing a metal part (10), is described said part extending in a first direction (Y) and having a section comprising a central member (14) and at least a first side member (16) extending in a second direction. The process comprises the following steps: supply of a metal blank (30); removing material from the blank so as to form an intermediate part (32) comprising the central member (14), a junction zone (12) and at least first (116) and second (118) intermediate side members, with a space (34) between the first and second intermediate side members; and hot forming (104) the intermediate part, including spreading the first and second intermediate side members apart by inserting a first punch (212) between said members.