Hollow bars in micro-alloyed steel have higher strength than the equivalent structural-steel product. This renders it possible to reduce the weight of a part or structure by reducing wall thickness. If at the same time, the design allows the possibility to increase the outer diameter, the potential for weight saving is further increased. Of course, the reduction of weight will be greatest if a solid bar of structural steel can be replaced by a tube with higher strength.
Despite having higher strength, hollow bars in micro-alloyed steel retain good weldability and their machinability is often better than the equivalent product in structural steel.