Axle beam for industrial vehicle, method of manufacturing the same and rear steering apparatus

An axle beam (110) for an industrial vehicle has a beam (1) and a boss (9). The beam (1) is supported on a vehicle body. The boss (9) is provided at opposite ends of the beam (1) for supporting a kingpin (6). The beam (1) includes at a longitudinally middle thereof a portion having a closed cross-section perpendicular to a longitudinal direction of the beam and is shaped at the portion to form a space (R) which is surrounded by a front and rear and a top and bottom of the beam (1). The portion is formed by welding two members or by one tube member (21).