... process of quenching and tempering,multiple to stress,hardening,hard chrome plating accuracy of Heef-25 high-efficieny micro-cracks: the ... , coaxial degree≤0.005mm. Surface hardness of HRC55-58, polished chrome hardness HV1000(HRC62). Suitable for calendering, rolling fields on the ... of plastic plates, sheets, film, leather, paper and other products. Mirror roller