Manufacture of centrifugal cast high speed steel rolls for wire rod mills

Abstract

By means of a centrifugal casting method, high speed steel (HSS) rolls with excellent wear resistance have been manufactured. The hardness of the HSS rolls was 65–67 HRC, the range of hardness variation was smaller than 2 HRC and the impact toughness exceeded 15 J. The wear rate of the rolls was 2.5 × 10⁻⁴ mm t⁻¹ of steel passing through the prefinishing stands of the high speed hot wire rod rolling mill. Casting cracking of the HSS rolls was definitely decreased and the rejection rate owing to the presence of cracks was less than 3%, as a result of the use of a two layer paint and varying the rotation rate. In addition, the segregation of alloying elements could be decreased by adding a suitable amount of niobium (0.6–2.0%).

Keywords:

• HIGH SPEED STEELS
• CENTRIFUGAL CASTING
• ROLLS
• SEGREGATION
• CRACKLE