Points to note when cold-bending stainless steel plates and tubes

The forming and processing of stainless steel plates can use conventional equipment. However, due to the work-hardening properties of stainless steel, the force required is much greater than that of ordinary carbon steel, so the equipment used to form stainless steel plates must have high strength and rigidity. Let’s talk about the cold bending processing of stainless steel plates and stainless steel pipes.

Stainless steel plate cold bending processing

The cold bending process of stainless steel plates is similar to that of ordinary carbon steel, but requires higher power and rigidity of the equipment. Stainless steel plates can be bent at a small radius, but this bending should be limited by the material's fracture stress. Bending with a small radius will cause very large deformation hardening and stress on the stainless steel plate and equipment. The bending radius is not less than twice the thickness of the stainless steel plate. Most specifications require that the minimum bending radius is about three times the thickness of the plate.

In addition, the elastic recovery of stainless steel plates is much higher than that of ordinary carbon steel. Considering the influence of yield strength and thickness of stainless steel plates, the bending angle during cold bending must also be correspondingly larger. The bending radius is twice the thickness of the stainless steel plate. When bending at 90 degrees, the bending angle should be increased by 3-4 degrees. When the bending radius is 20 times the thickness of the stainless steel plate, the bending angle should be increased by 15-20 degrees. For duplex stainless steel 2205, the bending angle will be larger.

Stainless steel plates cannot be hot-bent because the temperature control is strict during bending or heat treatment of the plate. If the heating method is inappropriate or the stainless steel plate is heated to the wrong temperature, the corrosion resistance and mechanical properties of the stainless steel plate will be damaged.

Stainless steel pipe cold bending processing

Due to the strong cold work hardening tendency of stainless steel pipes, stainless steel pipes require greater force than ordinary carbon steel during cold bending. The bending radius used for cold bending of stainless steel pipes is determined by the outer diameter of the stainless steel pipe, the diameter of the pipe and the ratio of diameter to wall thickness.

When cold bending stainless steel pipes, bending tools used for ordinary carbon steel can be used, but all fillers must be kept clean, so the internal supports must be stainless steel or covered with a layer of stainless steel to avoid iron contamination.

If lubricant is used during the cold bending process, it must be wiped clean after the cold bending. The internal and external surfaces of stainless steel pipes should be carefully degreased.

In addition, do not use hot bending. Cold bending will not damage the corrosion resistance and mechanical properties of stainless steel pipes.