ABSTRACT
Machining hard alloy materials and coated workpieces is how easily the material can be cut to the desired shape (surface nish and tolerance) with respect to the tooling and the type of machining processes involved. In the machining operation, tool life, metal removal rate, component forces and power consumption, surface nish generated and surface roughness, hardness, stress of the machined component, and the shape of the chips can all be used to measure the performance and productivity of machining. The machining index can be signicantly affected by the properties of the hard alloy coating material, coated workpiece properties and geometry and material of the cutting tool, cutting conditions employed, and other additional factors such as rigidity of the machine tool and cutting environment. Machining productivity and performance can be signicantly improved by applying the right combination of cutting tools, cutting conditions, and machine tool that will promote high-speed machining without compromising the surface quality and tolerance of the machined workpiece. This is particularly essential for the economic machining of nickel-based hard alloy coatings on friction pairs in water, NaOH, and CH3COOH of 10%–50% concentration, whose peculiar characteristics generally impair high machining ability. The driving force for the continual development of many coating materials over the years is the need for harder, stronger, tougher, stiffer, more corrosion-, wear-, and hightemperature-resistant material that can also exhibit high strength to weight ratio, in the case of aeroengine alloy parts, precision parts, and other critical parts in rotating equipment. The use of nickel-based hard alloy-coated parts, precision parts, and critical parts for rotating equipment has increased the
demand for materials that have excellent high-temperature, wear-resistant, mechanical, and chemical properties relative to steels and stainless steel alloys originally employed in machine tools and rotating equipment applications.
