Properties of Cutting Tools

Many types of tool materials, ranging from high carbon steel to ceramics and diamonds, are used as cutting tools in today’s metalworking industry. It is important to be aware that differences do exist among tool materials, what these differences are, and the correct application for each type of material.

Cutting tool and the Industry Advancements

 

Cutting tool users can’t afford to ignore the constant changes and advancements that are being made in the field of tool material technology. When a tool change is needed or anticipated, a performance comparison should be made before selecting the tool for the job. The optimum tool is not necessarily the least expensive or the most expensive, and it is not always the same tool that was used for the job last time. The best tool is the one that has been carefully chosen to get the job done quickly, efficiently, and economically.

A cutting tools must have the following characteristics in order to produce good quality and economical parts:

Hardness — Harness and strength of the cutting tool must be maintained at elevated temperatures, also called hot hardness.

Toughness — Toughness of cutting tools is needed so that tools don’t chip or fracture, especially during interrupted cutting operations.

Wear Resistance — Wear resistance means the attainment of acceptable tool life before tools need to be replaced.

The materials from which cutting tools are made are all characteristically hard and strong. Below are the characteristics mentione

 

Plain carbon tool steel is the oldest of the tool materials dating back hundreds of years. However, because it is quickly over tempered (softened) at relatively low cutting temperatures (300 to 500°F), it is now rarely used as cutting tool material except in files, saw blades, chisels, etc. The use of plain high carbon steel is limited to low heat applications.

The hardness of the carbide is greater than the of most other tool materials at room temperature and it has the ability to retain its hardness at elevated temperatures to a greater degree, so that greater speeds can be adequately supported. Two-thirds of all carbide tools are coated. Coated tools should be considered for most applications because of their longer life and faster machining. Coating broadens the application of a specific carbide tool.