What kind of drill bit is better for drilling stainless steel?

We all know that the stainless steel is harder and more difficult to break, and it is also more difficult to transform, so it is important to choose the right drill bit. Before understanding the drilling of stainless steel, we need to understand the difficulties of stainless steel processing, and then choose the drill bit according to difficulties.

The challenge of drilling stainless steel

Easy to stick to the knife

Both austenitic stainless steel and martensitic stainless steel have the characteristics of strong chip toughness and high cutting temperature during processing. When the tough chips flow through the rake face, sticking phenomena such as bonding and welding will occur, which will affect the surface roughness of the processed parts;

Severe work hardening

Austenitic stainless steel and some high-temperature alloy stainless steels are all austenitic structures, which have a large work hardening tendency during cutting, usually several times that of ordinary carbon steel. The tool is cut in the work hardened area, which shortens the tool life;

The cutting force is large and the cutting temperature is high.

This type of material has high strength, large tangential stress and large plastic deformation during cutting, so the cutting force is large. In addition, the thermal conductivity of the material is extremely poor, which causes the cutting temperature to rise, and the high temperature is often concentrated in the narrow area near the cutting edge of the tool, thereby accelerating the wear of the tool;

Fast tool wear

The above-mentioned materials generally contain high melting point elements, high plasticity, and high cutting temperature, which speed up tool wear, sharpen and change tools frequently, thereby affecting production efficiency and increasing tool usage costs;

After understanding the above-mentioned processing difficulties, the selection and processing parameters of stainless steel drills in the drilling process of stainless steel are many different from those of ordinary materials.

Suggestions for drills

Carbide stainless steel drill bits

(I) Coating:

⑴The first choice for high-temperature alloys and difficult-to-machine stainless steels;

⑵Good toughness, fine particle material grade and TiAIN coating; excellent red hardness, excellent resistance to chemical and oxidative wear

⑶PVD coating; (Ti, AI) N + TiN.

(2) Drill body: processing at the point, chisel edge, and cutting edge;

(3) The recommended emulsion for cutting fluid, with a concentration of 10%;

Carbide stainless steel special drills have high work efficiency and high hardness, which can cope with harder materials, but the price is more expensive.

Cobalt high speed steel

Coating: high temperature resistance, anti-sticking, abrasion resistance

Drill body: Cobalt-containing high-speed steel body has better toughness

Cobalt-containing high-speed steel drill bits are relatively common in the market. Although their efficiency is not high, it is still possible to drill stainless steel, and the price is relatively low, so they are commonly used drill bits.

Titanium-plated high speed steel drill bit

Titanium-plated high-speed steel drill bits can also be used to drill stainless steel. It can adapt to a relatively fast speed and has a great hardness. It is easier to drill in the face of materials with such hardness as stainless steel.

Precautions for drilling stainless steel

1. When drilling stainless steel, you must not touch the drill bit with your hands. The fast rotating drill bit is more dangerous and easy to hurt your hands.

2. When the drill bit drills stainless steel, due to the rapid friction between the two, a lot of heat will be generated. At this time, the stainless steel and the probe are very hot. Do not touch it with your hands to prevent burns. After use, let the drill bit cool down for a while, and then put the drill bit away after it cools down completely.

3. When drilling stainless steel, be careful to install the drill bit firmly to prevent the speed from flying out too fast and causing danger.

4. The hardness of stainless steel is relatively large. It is not advisable to rush when drilling. Take your time. If you don't drill in one place, you can drill part of it first, and then continue.

The drill bits used to drill stainless steel mainly include cobalt-containing high-speed steel drill bits, titanium-plated high-speed steel drill bits and carbide drill bits. These drills have high hardness and are more suitable for drilling stainless steel.