Spiral air duct is a thin pipe with spiral undercut made of metal strip material roll. It is round without welding. It is often used for air supply and fresh air gas flow transportation to replace the white iron pipe in the past. At present, in the market, stainless steel materials are more favored by the market. The main reason is that most people should understand the characteristics of stainless steel. It is not easy to rust and corrode. But the material with this characteristic will inevitably encounter the difficulty of cutting

1.切割力大，切割温度高。本实用新型材料强度大，切削时切向应力大，塑性变形大，因而切削力大。另外，材料的导热性很差，导致切削温度升高，高温往往集中于刀刃附近较窄的区域，从而加速其磨损。

1. Large cutting force and high cutting temperature. The utility model has the advantages of high material 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 very poor, resulting in the increase of cutting temperature. The high temperature is often concentrated in the narrow area near the blade, so as to accelerate its wear.

2.不锈钢风管加工硬化严重。奥氏体不锈钢及部分高温合金不锈钢均为奥氏体组织，切削时易发生加工硬化，加工硬化倾向于高出普通碳钢数倍，刀具在加工硬化区域内切削，寿命缩短。

2. Severe work hardening of stainless steel air duct. Austenitic stainless steel and some high-temperature alloy stainless steel are austenitic structure, which is prone to work hardening during cutting. The work hardening tends to be several times higher than that of ordinary carbon steel. The service life of the tool is shortened when cutting in the work hardening area.

3.容易粘刀。对于奥氏体不锈钢和马氏体不锈钢，都有切屑强韧、切削温度很高的特点。强力韧性的切屑流经前刀面时，会出现粘合、熔焊等粘刀现象，影响加工配件表面粗糙度。

3. It is easy to stick the knife. Both austenitic stainless steel and martensitic stainless steel have the characteristics of strong and tough chip and high cutting temperature. When strong and tough chips flow through the rake face, there will be adhesion, fusion welding and other adhesion phenomena, which will affect the surface roughness of machined accessories.

4.刀具磨损会加速。以上物料普遍含有高熔点，塑性大，切削温度高，使其磨损加速，磨刀、换刀频繁，从而影响生产效率，提高其使用成本。以降低切割线速度、进给量为主。使用特殊的不锈钢或高温合金加工刀具，钻、攻丝或内冷较好。

4. Tool wear will accelerate. The above materials generally contain high melting point, large plasticity and high cutting temperature, which accelerate their wear and frequently grind and change knives, thus affecting the production efficiency and improving their use cost. Mainly to reduce the cutting line speed and feed rate. Using special stainless steel or superalloy cutting tools, drilling, tapping or internal cooling is better.