Method of manufacturing hollow structural elements

A method of manufacturing a hollow, elongated structural element constituting a front vehicle axle, said method comprising the following steps:

• a) a first blank is led through an oven for heating to a working temperature,
• b) the first blank is led through a pair of rollers with profiled surfaces, the first blank being preformed in one or more steps to an intermediate shape with a predetermined profile along its length,
• c) the first blank is placed in a forging press with a number of cooperating dies, the first blank being worked therein in a plurality of die-forging steps to form a first, front half of the front vehicle axle, the first, front half so-produced including king pin bore-forming portions at ends thereof and having a cross-section substantially in the shape of a U-profile with a predetermined varying height, width, and thickness of material along its length,
• d) a second blank is led through an oven for heating to a working temperature,
• e) the second blank is led between said pair of rollers with profiled surfaces, the second blank being preformed in one or more steps to an intermediate shape with a predetermined profile along its length that is the same as the predetermined profile of said first blank formed in said step b),
• f) the second blank is placed in said forging press with cooperating dies, the second blank being worked therein in a plurality of die-forging steps to form a second, rear half of said front vehicle axle, the second, rear axle half so-produced including king pin bore-forming portions at ends thereof and being essentially identical to the first, front axle half, the front and rear axle halves each being symmetric about a vertical plane that passes through the lengthwise center point of the axle half such that right and left halves of each axle half, relative to the as-installed orientation of the axle halves, are symmetric, and
• g) the first, front axle half and the second, rear axle half are joined together, at least along their respective edges, to form said front vehicle axle with king pin bores at both ends thereof.