Methods and apparatus for treating a shaped tire rasp blade for mounting on a rasp hub, said tire rasp blade comprising a blade body and blade teeth, wherein the method comprises an austenitising process for austenitising the main part of the tire rasp blade by heating it to an austenitisation temperature, a subsequent quenching process and finally a tempering process for tempering the tire rasp blade. The austenitising process is performed by using induction heating for heating of said tire rasp blade, increasing the durability of a rasp blade by 30-50%. Induction heating is fast (austenitisation temperature can be reached within 15 seconds), wherein energy is focused into the rasp blade, enabling austenitisation temperature to be reached quite fast throughout the entire rasp blade.