Comsteel embarked on a development program in conjunction with two partners (BHP Billiton and Monash University) in the mid 1980’s, looking at how heavy haul wheel performance could be improved.
Wheels in heavy haul service are subjected to a combination of mechanical and thermal loads, which together can severely curtail wheel life compared to a typical freight and passenger wheel wear.
The initial focus of the development program was on an improved (low stress) plate design, and the development of a micro-alloyed wheel grade with rim hardness levels approaching 400HB, offering excellent through-hardness characteristics in a 970mm diameter, multi-wear wheel.
Wheel performance improvements were achieved through a combination of improved wheel design, specifically using plate designs which offer enhanced resistance to the effects of severe thermal loads during drag braking. Material grades with high resistance to wear, rolling contact fatigue and thermo-mechanical fatigue, as well as improved steel quality helped reduce the probability of shattered rims and similar catastrophic failure modes.
Further refinement of manufacturing procedures for these wheels has included the implementation of ‘state-of-the-art’ non-destructive equipment for ultrasonic testing and measurement of residual stresses within the wheel rim. These aspects, expected in wheel s supplied to other industry sectors (for example high speed passenger rail transport), are less common in the heavy haul sector.
In summary, Comsteel has developed high hardness micro-alloy wheels which significantly increase wheel performance and dramatically decrease critical wheel failures.
Comsteel Technical Partner