The material selection of twist drill bit is mainly divided into three types (high speed steel, cobalt containing high speed steel and hard alloy).
High speed steel twist drill bit: since 1910, high speed steel has been used as cutting tool for more than 1 century. It is the most widely used and cheapest cutting tool material at present. High speed steel bits can be used in electric drill or in a stable environment such as drilling machine. Another reason for the durability of high speed steel is probably because high-speed steel cutting tools can be grinded, because the price is cheap, not only for grinding twist drill bit, but also widely used in turning tools.
Cobalt containing high speed steel twist drill bit: high speed steel containing cobalt is better than high speed steel in hardness and red hardness, and the increase of hardness also improves its wear resistance, but at the same time it also sacrifices a part of toughness. The same with high-speed steel is that they can improve the number of times of use by grinding.
Cemented carbide twist drill bit: cemented carbide is a metal matrix composite. Among them, tungsten carbide is used as the matrix, and some other materials are used as the adhesive. It is made by a series of complex processes such as sintering in the way of hot static pressing. Compared with high-speed steel, it has a great improvement in hardness, red hardness and wear-resistance. But the cost of cemented carbide tools is also much more expensive than that of high-speed steel. Cemented carbide has more advantages in tool life and processing speed than previous tool materials. In the repeated grinding of tools, professional grinding tools are needed.
Material is a key point for twist drill bits. Good tools must start with good materials.
Post time: Mar-18-2022