How to bend stainless steel capillary tubes

Stainless steel capillary tubes are available in various forms such as round, square, special-shaped, and bent tubes. Today we will introduce how to adjust, cool, and lubricate the tool and precautions when bending stainless steel capillary tubes.

First, the processing form of stainless steel capillary tube fittings

1. Pipe fittings with flanges and round edges. The former refers to the end of the stainless steel capillary tube convex to the inside or outside, and the latter refers to the pipe fittings with ridges or grooves formed in the circumferential direction of the stainless steel capillary tube.

2. Stainless steel capillary tube variable wall thickness stainless steel capillary tube fittings, which change the wall thickness along the length of the tube.

3. Stainless steel capillary tube bending fittings, usually more commonly, turn stainless steel straight tubes into bends with different curvature radii, such as elbows, elbows, etc.

4. Stainless steel capillary tube twisted variable diameter fittings, that is, the diameter of the tube end or a part of the tube becomes narrower.

5. Stainless steel capillary fittings with curling and bottom sealing, improve the total strength of the stainless steel capillary end, curl the outside or inside of the tube, or seal the end of the fitting.

6. Process the cross-section of the stainless steel capillary, and turn the circular cross-section into a square, oval, or polygon.

Second, the difficulty of stainless steel capillary processing

There are many difficulties in processing stainless steel capillaries.

① During processing, the friction between the workpiece and the tool will generate high heat, which makes it easy to wear the tool. Therefore, the requirements for tool materials are relatively strict, and they need to be wear-resistant and high-temperature resistant. And the edge must also be sharp.

② The processing speed is slow because the force will be greater during cutting, resulting in low production efficiency. In addition, due to the high heat generation, it is necessary to choose a good cooling oil, usually sulfur chloride, which will have a better effect. The most difficult thing is drilling deep holes and tapping. Therefore, when processing stainless steel capillary fittings, workers must have excellent experience and skills.

Third, the precautions for stainless steel capillary processing

① It is necessary to pay attention to the processing performance of stainless steel. Stainless steel has high plasticity and toughness during cutting. It consumes a lot of energy during cutting and has a high cutting temperature. The thermal conductivity of stainless steel is low. If the heat dissipation is not handled well, it is easy to cause the tool temperature to rise. Stainless steel has strong bonding and welding properties, and it is easy to generate a built-up edge during cutting. Stainless steel has a strong tendency to work hardening, and it is easy to generate a hardened layer on the cutting surface. Stainless steel is not easy to break chips and will be blocked during cutting, which will affect the smoothness of the stainless steel processing surface.

② The front angle of the stainless steel cutting tool should not be too large. It is usually 12-30°. Grinding a crescent-shaped chip guide groove on the front can improve the cutting conditions. The back angle is 6-10° for carbide turning tools and 8-12° for high-speed steel turning tools. The main deflection angle is 60-75°, and the secondary deflection angle needs to be 8-20°. It should be greater than zero during rough turning and less than zero during fine turning. The tool tip radius is usually 0.2-0.8mm.

③Attention should be paid to cooling and lubrication when cutting stainless steel, and lubricating fluid with good cooling and lubrication performance should be used, which can effectively improve work efficiency.