Hydroforming Stainless Steel

Hydroforming Stainless Steel: The Complete Guide

In this guide, you will learn everything about hydroforming stainless steel.

Whether you want to learn about the history, benefits, application, or principle of hydroforming – you will find all information right here.

Let’s dive right in

What Is Hydroforming?

Hydroforming is typically used to convert metal sheets into solid and lightweight pieces. High-pressure hydraulic fluids generally are used to form malleable metals like stainless steel.  This method produces parts with even tight tolerance and wall thickness across and cost-effectively.

Hydroforming History

Hotz and Geiger in 1889, undertook extensive development and research that ultimately led to the creation of the hydroforming tools. When the automotive industry started to understand the advantages of hydroforming in the 1900s, it became standard and was utilized all across the US.

Due to a rise in demand for shapes in the 1930s, Cincinnati Milling Company created a hydroforming process acceleration that enabled advanced hydroforming techniques to take shape. Since 1970, it has made its way to aerospace sectors, where it is used to produce spun parts, making hydroforming a widely recommended.

Hydroforming History
Advantages Of Hydroforming Stainless Steel

Advantages Of Hydroforming Stainless Steel

A broader design freedom: it allows the manufacturers the ability to design intricate features and designs. It offers the chance to create whatever part you require out of stainless steel.

High mechanical strength: when stainless steel is hydroformed, strain hardening typically occurs in the sheet, producing pieces with increased strength.

Remarkable precision: the strength increase in the hydroforming stainless steel reduces the risk of spring back, bringing a remarkable precision to the parts.

Reduction of tool cost: because of the fewer parts and absence of the punching and burring operation, the number of tools is considerably decreased.

Limitations Of Stainless Steel Hydroforming

Expensive cost: the cost of hydroforming stainless steel is generally high, and expensive tools are required to complete the process. It will prove costly for the manufacturers and make it difficult for various sectors of the economy to adopt it.

Cycle times: the cycle time for hydroforming stainless steel is typically slower, which causes manufacturers to waste hours trying to make several pieces at once.

Maintenance: since the process involves pricey tools, they require regular maintenance, such as employing suitable materials and sufficient lubrication, to serve you longer. Care must be taken when using the tools.

Limitations Of Stainless Steel Hydroforming
Deep Draw Hydroforming Stainless Steel Vs. Deep Draw Stamping Stainless Steel

Deep Draw Hydroforming Stainless Steel Vs. Deep Draw Stamping Stainless Steel

Deep drawn stamping is often a method that uses radial tensing tangential pressure to shape and size stainless steel to the correct dimensions.  The diameter and length of the blank, such as a flat disc of metal, are reduced by a sequence of specialized punches and dies following the design.

Additionally, the final item has straight, tapered, or a mixture of sides and is hollow or cylindrical. While deep draw hydroforming is a forming technique where a blank metal is dragged radially into a forming die by the mechanical action of the punch, thus, it is a material-based shape modification process.

Stainless Steel Stamping Vs. Hydroforming Stainless Steel

Stainless Steel Stamping
Stainless Steel Stamping

Tool Cost

When comparing expenses, hydroforming usually has a one-time tooling cost, while stainless steel stamping typically has a high setup cost and is frequently repetitive.

Production Quantities

While stamping stainless steel is frequently impractical for prototyping and small runs, hydroforming stainless steel is affordable and appropriate for large, medium, and short production quantities.

Material Wastage

Even with close nesting, stainless steel typically has a more significant proportion of material waste; however, hydroforming stainless steel produces shallow material waste, often as little as 50% to 70% or no scrap.

Process Cost

Extremely high short-run costs for stamping stainless steel only start to go down as production volume rises. The setup, equipment, and development expenses for hydroforming stainless steel might be as low as 80%.

Flexibility

Once the tooling is created for stamping stainless steel, it is typically difficult to change the design. Contrarily, stainless steel hydroforming will provide greater versatility in design modifications.

Lead Time

As opposed to hydroforming stainless steel, which essentially has a short lead time for even large-scale manufacturing, stamping stainless steel has a much longer lead time, reaching up to several weeks for intricate part production.

Hydroforming Stainless Steel Tube Process

Hydroforming Stainless Steel Tube Process
Hydroforming Stainless Steel Tube Process

It is a fabrication and forming technique for stainless steel and usually aids in giving the metal required shapes. Stainless steel metal is shaped using highly pressurized fluids in a relatively affordable technique that can use seamless or welded tubes.

How the procedure operates

  • The device will seal off, allowing the high-pressure hydraulic fluid to shape the stainless steel into the desired shape.
  • At least 400 KPA of fluid pressure will be pumped into the tube by the hydraulic generator.
  • The clamping cylinder will combat the pressure by securely maintaining the negative molds.
  • Next, the hydraulic fluid pressure will drive the tube to expand into the negative mold’s shape.
  • The machine will then release the hydraulic fluid.
  • The technician opens the machine to remove the freshly created tube in the final stage.

The pieces must go through the inspection process after the production process is complete to ensure they adhere to the quality control standards.  It is accomplished by utilizing devices like the Automatic Inspection Vision System or 3D Inspection Vision System. It will be able to find any flaws or inconsistencies in the products.

Hydroforming Stainless Steel Sheet Process

Hydroforming Stainless Steel Sheet Process
Hydroforming Stainless Steel Sheet Process

A hydroforming press, punch, liquid working medium water/oil emulsion, and a die are tools in this process. The following is the hydroforming process for stainless steel.

  • Step one – The blank should be positioned inside the hydroforming press, between the punch and the die.
  • Step Two – The hydroforming press needs to be shut.
  • Step Three – Filling in the blanks with a liquid working medium, such as an oil emulsion, is crucial.
  • Step Four – Pressuring a liquid working medium with punches takes place here.
  • Step Five – The release of pressure from the forming chambers
  • Step Six – It is a stage where punches are retracted.
  • Step Seven – Is the last in extracting the stainless steel’s formed parts.

Factors Affecting Quality Of Stainless Steel Hydroforming

Design Tolerance
Design Tolerance

Although design tolerances are constantly growing tighter, fabricating the assembly doesn’t necessarily require these tolerances. However, engineers do manage to ensure that stainless hydroforming components will fit together flawlessly. It is a significant challenge that often impairs the quality of hydroforming stainless steel.

Tight Corners
Tight Corners

With the correct pressure, stainless steel hydroforming can produce features with acute radiuses. Since the material must flow across the tooling without breaking, it frequently challenges quality.

Lubrication
Lubrication

Not only does the lubricant affect the quality of stainless-steel hydroforming, but also the area and method of application. The lubricant can sometimes distinguish between failure and success when there are thin lines between the wrinkling and breaking sections.

Tool Designs
Tool Designs

It provides difficulties that impact the quality of the stainless steel hydroforming, mainly when it requires multiple tools to create a better component that will match the print tolerance. It typically occurs when transporting stuff into a complex space by doing so will result in material breakage.

Applications Of Hydroforming Stainless Steel

Medical Industries
Medical Industries

In the medical industry, the stainless steel hydroforming is applied in making parts like:

  • Covers
  • Sterilized trays
  • Light reflectors
  • MRI machine components
  • X-Ray machine components.
Aerospace Industry
Aerospace Industry

Some of the applications in the aerospace industry are:

  • Forming pads
  • Air repair station parts
  • Jet engine components
  • Helicopter parts supplies
Automotive Industry
Automotive Industry

Here some of the applications in the automotive industry are such as:

  • Engine cradle
  • Body frames
  • Radiator support
  • Spare parts

Techniques In Hydroforming Stainless Steel

Low-Pressure Hydroforming Stainless Steel
Low-Pressure Hydroforming Stainless Steel

Manufacturers use this technique when they need to slightly tweak the shape of parts rather than drastically change them all at once. Typically, it is a low-cost method that is quick and easy.

Panel Hydroforming Stainless Steel
Panel Hydroforming Stainless Steel

This technology is mainly used in the aerospace and automotive industries. It is carried out under very high pressure to accomplish the proper material flow, which is typically essential in constructing aerodynamic products.

High-Pressure Hydroforming Stainless Steel
High-Pressure Hydroforming Stainless Steel

This approach completely alters the shape and modifies the length to circumference ratio by up to 50%. It often offers excellent control tolerance and is a durable process.

Tube Hydroforming Stainless Steel
Tube Hydroforming Stainless Steel

It is considered a low-pressure technique and the most popular technology now in use with hydroformed tubular sections that enhance performance, integrity, and structural strength.

Hydroforming Stainless Steel

Additional Resources:

Hydroforming Process

Metal Fabrication

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