Stainless steel profiles, as the name suggests, are stainless steel bars that are formed into different cross-sectional shapes through processes such as hot melting and extrusion. They include stainless steel pipes, stainless steel round bars, stainless steel angle bars, stainless steel flat bars, stainless steel channel bars, and stainless steel square bars.

BIT offers stainless steel bending solutions with section bending machines or plate rolls. Our methods include large-radius bending with a PBH section bending machine, tight-radius bending with a PFB CNC 3D freeform tube bender, helical bending with a PBA CNC aluminum profile bending machine, and induction bending for minimal deformation in wall thickness.

Classification

Stainless steel profiles are favored for their excellent corrosion resistance, combined with mechanical strength and high ductility, making them easy to process and manufacture structural components. This ensures that engineering designs maintain their integrity permanently, meeting the needs of architects and structural designers.

Classification of stainless steel profiles by application

1. Architectural stainless steel profiles: divided into doors, windows, and curtain walls. These are architectural profiles formed by cold bending stainless steel sheets and strips, mainly used in construction areas requiring corrosion resistance or decoration.
2. Radiator stainless steel profiles.
3. General industrial stainless steel profiles: primarily used in industrial production, such as conveyor belts, elevators, dispensing machines, testing equipment, shelves, etc. Widely used in the electronics and mechanical industries, as well as clean rooms.
4. Structural profiles for rail vehicles: mainly used in the manufacture of rail vehicle bodies.

Classification of stainless steel profiles by material structure

1. Austenitic stainless steel.
2. Ferritic stainless steel.
3. Martensitic stainless steel.
4. Duplex stainless steel.
5. Precipitation-hardening stainless steel.

For example: 304L stainless steel

304L stainless steel is an ultra-low carbon austenitic stainless steel developed to address the severe intergranular corrosion tendency of 304 stainless steel caused by the precipitation of Cr23C6 under certain conditions. Its sensitized state exhibits significantly better resistance to intergranular corrosion than 304 stainless steel. Apart from slightly lower strength, its other properties are similar to 304 stainless steel. It is mainly used in corrosion-resistant equipment and components requiring welding and subsequent welding cannot be solution treated (such as manufacturing deep-drawn parts, acid-resistant pipelines, containers, structural components, as well as non-magnetic and low-temperature equipment and components).

Considerations for Bending Stainless Steel Profiles

Due to the high yield point and hardness of stainless steel profiles, the cold hardening effect is particularly evident. Additionally, stainless steel has weaker thermal conductivity and lower elongation rates, requiring greater deformation force during bending. Moreover, the rebound tendency of stainless steel plates is much greater than that of carbon steel, and their lower elongation rates lead to larger bending angles compared to carbon steel.

It is crucial to control the appropriate temperature during the bending process of stainless steel profiles to prevent material hardening or brittleness, which could affect bending quality. Furthermore, attention must be paid to the minimum bending radius limit of stainless steel to avoid material cracking or deformation.

When selecting the bending direction, consideration should be given to the mechanical properties and appearance of stainless steel profiles. Adjusting bending parameters to compensate for rebound effects is also necessary to ensure the final shape meets requirements. Surface treatments such as polishing or plating may be required after bending stainless steel profiles to enhance appearance and corrosion resistance.

Additionally, for a given size, the higher the tensile strength of stainless steel profiles, the lower the elongation rate, resulting in greater required bending force and larger bending angles.

Springback of Bent Stainless Steel

Stainless steel exhibits springback when released from bending force, which is the release of elastic strain and directly related to the material's yield strength. Achieving the desired bending angle may require a larger bending angle, especially for high yield strength stainless steel. The required angle gap increases with the radius, and so does the springback. When the radius is relatively large, the amount of springback may be significant.

As a principal factor, Usual metal bending companies take into consideration the composition of the alloy, material thickness, required bend radius and bend angle when calculating the bending force necessary to avoid a “springback” of the bent stainless steel to its original shape.

At BIT, everything becomes very simple. Just input the actual radius from the first bending test into the PBA profile bending machine, and you will obtain a springback compensation factor. Input it into the bending parameters, and the machine will automatically select the correct bending force, resulting in the correct bending radius and angle.

BIT’s bending machines for stainless steel

At BIT, we can provide section bending machines or plate rolls with a variety of stainless steel bending methods to fabricate your products.

BIT’s bending rolls offer in-house stainless steel rolling capabilities through the following methods:

• Large-radius bent stainless steel is rolled on a PBH section bending machine (also known as a profile bending machine or angle roller).
• Curved stainless steel requiring tight radii is rolled on a CNC 3D freeform tube bender through a technique called freeform bending.
• Helical spiral bending can be performed on any stainless steel section using a PBA CNC profile bending machine. (Inside BIT, we are accustomed to calling it an aluminum profile bending machine. In fact, it is also a powerful and high-precision CNC metal profile bending machine, suitable for various profiles: carbon steel, stainless steel, aluminum, copper, and titanium. When the bending diameter is as high as 500-1500mm, the bending tolerance is only 0.5mm. The Y repeatable positioning accuracy is as high as 0.01mm, offering precision for complex patterns and high-volume tasks.)

Rolled stainless steel tube or pipe requiring a bend with minimal deformation in wall thickness or ovality would be rolled using the induction bending process.