How to Bend Stainless Steel Sheet?

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What Is Sheet Metal Bending?

Sheet metal bending is a series of methods to bend metal into a certain shape profile with the help of machines and tools.

Sheet metal bending can be performed using the press brake, punching machine, ironworker, and other machines.

Usually, these machines use the power system to drive the toolings to exert pressure on the metal sheet to produce deformation.

However, in order to ensure the accuracy of the workpiece, a series of parameters need to be determined before bending the sheet metal.

For example, material thickness, bending radius, bending allowance, bending deduction, K factor, etc.

Also note that different materials have different properties, such as tensile strength, ductility, and so on.

Different machines bend metal sheets into the same profile by different bending methods.

What Are the Methods of Sheet Metal Bending?

The different bending shapes of workpieces are reflected in the different bending angles and bending radii.

The machine can guarantee the precision of the bending workpiece through the standard bending method.

These bending methods are different, but the final profiles can ensure uniform standards.

Let's dive into some of the main bending methods in sheet metal bending.

V-bending

In sheet metal bending, the most common bending process is V-bend. It is named because the punch and die used for this bending are V-shaped. The punch presses the metal plate into the lower die under the drive of the ram, thereby obtaining a V-shaped workpiece.

Roll Bending

The roll bending process is required when bending workpieces with large curls.

Roll bending three rolls are driven by the hydraulic system to bend the sheet.

U-bending

The U-shaped bending process is also a method of bending the workpiece by using the shape of the die.

The punch is driven by the power system to press the metal sheet into the U-shaped die, so as to obtain U-shaped profiles.

Rotary bending

The rotary bending can complete the bending of the workpiece with a degree of more than 90.

Although the workpiece after bending is similar to V-bend, the profile surface bent by this method is cleaner.

Edge bending

The panel bender often uses the edge bending method, usually using the upper and lower molds to move up and down for bending.

This method is usually used to deal with shorter metal sheets, which can reduce the sharpness of the workpiece without damaging the bending edge.

A similar method is to wipe bending. The metal plate is placed on the lower die, and the pressure pad firmly presses the metal plate.

Then the punch then applies pressure to the protruding sheet metal for bending.

What Materials Are Fit for Sheet Metal Bending?

The selection of bending materials is also an important factor to determine the bending effect.

Some material properties are not suitable for bending, which may cause fracture or damage to the mold during bending.

Materials with poor ductility can reduce the risk of material fracture by heating.

Therefore, when selecting bending materials, pay attention to the characteristics of materials.

The following are some common materials that apply to sheet metal bending and their properties.

Carbon steel: Carbon steel is very strong, but it has good ductility and is very flexible. Moreover, carbon steel is an environment-friendly material that can be recycled.

Mild steel: The ductility of mild steel is very good, and it can be bent smoothly without heating.

Stainless steel: Stainless steel is strong and corrosion resistant, and its tensile strength and yield strength are very good.

Stainless steel is a commonly used bending material, which is usually bent with a bending machine.

Titanium: Titanium is also a material with high tensile strength. Improper use will damage the mold. When bending titanium, the internal bending radius needs to be increased to prevent cracking.

Due to its resilience, it is necessary to overbend the material to obtain the desired shape.

Aluminum: It is easy to crack when bending aluminum, so it can be prevented from cracking by annealing. When bending aluminum, be careful not to bend excessively to reduce cracking.

Copper: Copper has strong ductility and is very suitable for bending. The cost of copper is relatively low, and it is widely used in the sheet metal processing industry.

Stainless Steel Sheet Bending

Features of Stainless Steel

Steel is an alloy with the addition of other materials, including small amounts of carbon, manganese, silicon, copper, phosphorus, sulfur, and oxygen.

According to the carbon content, steel is divided into high, medium, low, and ultra-low carbon steel.

Steel can be bent, and the tools for bending steel plates are also made of steel. The force required for bending steel plates is relatively small.

However, the force required to bend stainless steel is relatively large.

Stainless steel has high yield strength, high hardness, and poor ductility, so it needs large tonnage when bending.

The springback of stainless steel after bending is large, so a large bending radius is required to prevent the workpiece from cracking.

Considerations for Bending Stainless Steel Sheet

Plate thickness and bending tonnage. Before bending stainless steel, it is necessary to determine the thickness of the stainless steel plate, and thicker plates need to be processed with a bending machine.

Bending angle and bending radius.

Too big a bending radius will cause excessive material springback, and too small a bending radius will cause bending cracking.

Generally speaking, most of the bending radius is 0.2. For materials like high-carbon steel, a larger inner radius is required to prevent cracking.

The resilience of stainless steel is very large, and the bending angle and internal radius of stainless steel cannot be too small.

Bending Springback

The springback of the metal plate is proportional to the yield strength of the material and inversely proportional to the elastic modulus.

Low carbon steel has less springback, which is suitable for manufacturing workpieces with high precision, while high carbon steel and stainless steel have large springback.

The larger the bending radius is, the greater the springback is. The workpiece with a smaller bending radius has higher accuracy.

Calculate the bending allowance.

The bending allowance (expansion degree of the outer side of the sheet) can be calculated when the sheet thickness, bending angle, and inner radius are known.

This determines the sheet length required for bending.

You can calculate by the formula, BA=(π/180) x B x (IR+K x MT), or use the bending allowance gauge.

Bending with Machines

Next, you can use a machine, such as a press brake, to perform bending processing.

If the metal sheet is easy to crack, it can be hot-formed or annealed.

Annealing improves the ductility of metals by softening them. The hot bending is to make the metal red by heating it and then bending it again.

Conclusion

This blog introduces some basic knowledge of sheet metal bending and several important factors needing attention in stainless steel bending.

Most metal bending is finished by the means of machines, such as press brakes, of course, you can use vises to carry out simple bending.

As a manufacturer of sheet metal processing machines, ADH has 20 years of industry experience.

If you need press brakes or other sheet metal processing machines, you can contact our salesman for more detailed product information and prices.

FAQ

How to Bend Stainless Steel Sheet Without a Brake?

First of all, the materials you need include stainless steel plates, hammers, vises, rulers, protractors, and markers.

Use a ruler to measure the thickness of the plate, determine the K factor and inner radius, and then calculate the bend allowance. The formula is BA=(π/180) x B x (IR+K x MT).

Mark the bending line and bending radius with a protractor and marker.

Cut the stainless steel plate into the corresponding size, and fold the plate into the corresponding angle with a vise.

The metal can be struck evenly with a wooden hammer to achieve the desired angle.

Verify the bend allowance and check the bend angle. If there is a bad bend, the bending can be assisted by heating.

How to Calculate Bend Allowance?

Under pressure, the metal will be compressed internally and stretched externally.

The bend allowance needs to be taken into account when calculating the bending dimension.

To calculate the bend allowance, you need to know the sheet thickness, inner radius, K factor, and bending angle.

The calculation formula is: BA=(π/180) x B x (IR+K x MT)

Where K is the K factor, B is the bending angle, IR is the internal radius, and MT is the plate thickness.

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