The hollow tubular axle is constructed with thick-walled seamless steel tube as its main beam and features a hollow interior, with the tube wall carrying all bending loads. Both ends are machined into axle journals and welded to brake flanges and hub seats. This is the dominant structure for semi-trailer support dead axles, and every axle receives full quenching and tempering heat treatment.
Complete quenching and tempering delivers consistent metallographic structure across the tube wall. The axle resists cracking under alternating loads during long-distance travel over rough terrain, making it ideal for air-suspended refrigerated semi-trailers and hazardous chemical transport semi-trailers.
When the vehicle runs fully loaded on bumpy roads, bending stress on the axle accumulates merely on the outer tube wall, and the central core bears almost no load.
Removing the core material hardly weakens load-bearing performance. At the same rated load capacity, it weighs 20%–40% less than solid forged axles. A tri-axle semi-trailer can cut nearly 100 kg of dead weight, allowing legal extra cargo payload and reduced fuel consumption.
This design perfectly combines lightweight build and high strength, adopting the same principle as hollow foundation pipe piles: a hollow layout with no loss of load capacity.
