Roughly speaking, the hard drive is more than HRC45 hardness of the part to a turning point alone, in most cases, the hardness of the material in the area between 68th ~ HRC58 to machine materials include steel, high hardness , tool steel, hardened steel, heat resistant alloys, nitriding and heat-treated powder metallurgy. Hard drive is often necessary in the semi-finishing or finishing, with a robust car, used to achieve greater dimensional accuracy, the precision of shape and surface roughness.
Finish milling hardened pieces of traditional solutions. However, the use of tools for the machining of the hardened can have many obvious advantages, these advantages have proven in many applications, their use is increasing, especially for the most difficult part of turning and milling . However, the set of hardened parts (hard disk, HPT) will not be able to all loops of a processing procedure, in fact, many applications also need to be replaced in both treatment and complement each other.
First in the automotive industry, uses the hard drive and was recognized in the industry, its main purpose is to improve the manufacture of transmission parts. The early use of cubic boron nitride (CBN) grinding the blade to replace the hard drive of the most typical example is the speed with the dental bearing surface of the transformation. Currently, many different industries with a large number of parts hardened turn.

Surface hardened parts is a typical example, the depth of the hardened layer is usually greater than 1 mm, so a hard surface with a tenacity and high anti-wear department base. Shows the typical characteristics of these materials will include pieces for transport and energy, gears, shafts, axles, camshafts, transmission shafts, gear and fittings, etc., while in general there are many applications engineering.