Front side member for an automobile body

摘要

A front side member (41A-D) has a body formed from a tubular body (40d) which has a closed cross section and which is constituted by a single member in the axial direction. The body has, from one end towards the other end in the axial direction, a front portion which extends in the fore and aft direction of a vehicle body, a sloping portion which is continuous with the front portion (55) and which slopes downwards along a dash panel, and a rear portion (57) which is continuous with the sloping portion and which extends along the bottom surface of a floor panel which is joined to the dash panel. A portion of the front portion is an unquenched portion which has not undergone quenching treatment and the remainder other than that portion is a high frequency quenched portion (57b) which has undergone high frequency quenching. All of the sloping portion (56) is a high frequency quenched portion (55b) which has undergone high frequency quenching. A portion of the rear portion is an unquenched portion (57a) which has not undergone quenching, and the remainder other than that portion is a high frequency quenched portion which has undergone high frequency quenching.