The choice of material determines the leveling roll's innate toughness and resistance to deformation. Common materials include high-alloy tool steels like GCr15, 9Cr2Mo, or specialized shock-resistant alloys.

High Carbon Chrome Steel: Offers excellent wear resistance.

Alloy Tool Steel: Provides the necessary core strength to prevent the rollers from snapping or bending under the heavy loads required to flatten high-tensile steel plates.

Heat Treatment: The Secret to Surface Integrity
While the material provides the "bones," heat treatment provides the "armor." The goal is to achieve a high surface hardness while maintaining a flexible, ductile core.

Induction Hardening: This is the industry standard. It creates a hardened layer (typically reaching HRC 58-63) that protects against abrasion.

Deep Hardening: The depth of this layer is critical. If it’s too shallow, the roll will wear out quickly or "peel" under pressure; if it's too deep, the roll becomes brittle and prone to cracking.

Tempering: This process relieves internal stresses caused by hardening, ensuring the rolls don't shatter during sudden high-impact operations.