Process analysis of heat treatment of shrink-handled woodworking twist drill using medium-frequency induction heating power supply

A twist drill is a tool that drills a round hole in a workpiece through rotational cutting relative to a fixed axis. It is named after its chip flute that is spiral-shaped and resembles a twist. During the working process, the twist drill has to withstand huge friction. For this reason, we often use medium frequency induction heating power to heat treat the twist drill. There is a large social demand for mechanical woodworking twist drills. There are many domestic manufacturers and a considerable part of them are exported. The materials and heat treatment processes used by each factory are different. Let’s take the common shrink-handled woodworking twist drill as an example to briefly introduce the medium-frequency heat treatment process.

The hardness of the handle of the shrink-handled woodworking twist drill is required to be 25-30HRC, and the hardness of the blade depends on the specific material. The heat treatment process of shrink-handled woodworking twist drills of different materials is described in the following table:

Process analysis of heat treatment of woodworking twist drills with medium frequency induction heating power supply

Except for high-speed steel twist drills, woodworking twist drills made of other materials are preheated in a neutral salt bath at 620-650°C, and the preheating time is twice the heating time.

Except for high-speed steel twist drills, all woodworking drill bits of other steel grades are cooled by nitrate quenching. The cooling medium temperature is 140-160°C and the cooling time is 1.5-2 minutes. The high-speed steel is tempered in 99% NaNO3, and the rest are tempered in 50% NaNO3. Tempering in KNO3+50%+NaNO2 (mass fraction) solution.

There are many types of twist drills, but due to limited time, the editor can only introduce these to you. If you want to know more about the heat treatment process of twist drills, you can read books on heat treatment. I believe you will have a great understanding. reward.