Cutting tool materials have different combinations of hardness, toughness and wear
resistance, and are divided into numerous grades with specific properties.
Generally, a cutting tool material that is successful in its application should be:
Hard, to resist flank wear and deformation
Tough, to resist bulk breakage
Non-reactive with the workpiece material
Chemically stable, to resist oxidation and diffusion
Resistant to sudden thermal changes
Advatages
Good mechanical and cutting performance: The coated metal cutting tools combines
the excellent performance of the base material and the coating material, which
not only maintains the good toughness and high strength of the base, but also
has the high hardness, high wear resistance and low resistance of the coating,
coefficient of friction. Therefore, the cutting speed of the coated tool can be
increased by more than 2 times than that of the uncoated tool, and a higher feed
rate is allowed, and its life has also been improved.
Strong versatility: The coated tools has wide versatility and the processing
range is significantly expanded. One type of coated tool can replace several
types of uncoated tools.
Thickness of coating: The tool life will increase with the increase of coating
thickness, but when the coating thickness reaches saturation, the tool life will
no longer increase significantly. When the coating is too thick, it is easy to
cause peeling; when the coating is too thin, the wear resistance is poor.
Regrind ability: poor regrind ability of coated blades, complex coating
equipment, high process requirements, and long coating time.
Coating materials: cutting tools with different coating materials have
different cutting performance. For example, when cutting at low speed, TiC
coating has an advantage; when cutting at high speed, TiN is more suitable.