Cutting Tool Materials – Factors for good Tool Design
Cutting Tool Materials
Cutting tools must simultaneously withstand big mechanical loads and high temperatures.
Temperature in the chip/tool interface reaches more than 700 °C in some cases.
In addition the friction between tool and removed chip, on one hand, and tool against the new machined surface, on the other, is very severe.
The main factors for a good tool design and post-manufacturing are:
Cutting-tool material must be very stable chemically and physically at high temperatures.
Material hardness must be kept to the high temperatures suffered at the chip/tool interface.
Tool material has to present a low wear ratio, both for the abrasion and adhesion mechanisms.
Tool material must present enough toughness to avoid fracture, especially when operation to perform implies interrupted or intermittent cutting.
The main tool materials are described, starting from the lowest hardness to the highest.
These groups are:
High-speed steels (HSS), including the new powder-sintered grades. However, this material family has not enough hardness for hard machining.
Sintered carbides, usually known as hard metal. They are a compound of submicron tungsten carbide grains with a binder (usually cobalt, 6–12 %) This kind of material in the straight grade or in the coated grades is the most used today for hard machining and high-speed machining.
Ceramics based on alumina (Al2O3) or silicon nitride (Si3N4).
Extra-hard materials, i.e., polycrystalline diamond (PCD) and polycrystalline cubic boron nitride (PCBN), in different grades.
Cutting tool selection for Machining
The cutting tool material is decided by property of the cutting tool material and cutting speed required for machining
The cutting tool must possess various property to fulfill its required function some of them are Strength, toughness, hardness and hot hardness
To understand various properties of materials you can read from the link below
Mechanical Properties of Engineering Materials
We hope this small literature would have helped you to learn about various aspects of cutting tool materials, factors for good tool design, various tool materials and various properties of Materials.
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