What Material should I use for my Fastener?

Assembly Design Experience

Designing an assembly for manufacturing can be a tedious process.  Assembly design, functional requirements, and proper fasteners, all make a design engineer’s job stressful.  Through Orbitform’s years of experience in joint assembly, our experts know what it takes to ensure your assembly meets your specifications.

Driving Question

One commonly asked question we have is: “What material should I use for the fastener in my assembly?”  To suggest the best material, one must first understand the design and functional requirements of the joint.  Noteworthy points are:

  • Is this a solid joint, or does it articulate?
  • What is the hardness of the surrounding material?
  • Are there aesthetic requirements?
  • Are there any specifications the joint should adhere to (i.e. torque or pull-out testing)?
  • What is the shape of the rivet (semi-tubular or solid)?

Once the requirements of the joint are fully understood, the best material can then be chosen. 

Cold Heading Standard

The cold heading standard material is 1008 or 1010 mild steel.  This is a low carbon mild steel that forms easily, is particularly resistant to cracking, and is a soft material.  These are the most common types of fasteners to be used for assemblies that have minimal functional requirements. 

Stainless Steel Standard

For assemblies requiring stainless steel, the standard is 18-8.  While tougher than mild steel, this material also forms well with minimal cracking.  This is a good option for assemblies that may be exposed to liquids or seasonal elements. 

Aluminum

Aluminum is a very soft material that is also formable, depending on the alloy.  However, both stainless steel and aluminum materials can cause build up and galling on your tooling.  Orbitform can match the proper coating with the peen tool to extend tooling life and prevent unsatisfactory forming results. 

Case Hardening

In instances where material requires hardening for surface wear, strength, etc., case hardening can cause severe cracking due to the substrate being softer than the surface material.  Through-hardening a rivet makes the material more uniform, and, depending on the hardness, can still be cold formed.

Copper and Brass

Most copper and brass form well, depending on the alloy.  Both materials do not rust and create an aesthetically pleasing finish.  In addition, the added electrical conductivity of copper lends to additional use in electronic components

Materials to avoid include:

  • Resulfurized, rephosphorized free machining steels such as 12L14 and 1144.
  • Most magnesium materials, which tend to crumble when forming.
  • Most powdered metals, which crack and crumble under pressure.

Testing Is Best

Please note that while material recommendations can be made based on the joint functional requirements, the best practice for finding the required material is to test the assembly.  Orbitform offers the one-of-a-kind opportunity to partner with you in the design phase of your assembly, and to form your prototypes in our Solutions Lab.  This unique option allows manufacturers to find the best solution prior to production to prevent costly design changes and assembly failures in the field. 

To find the best material to achieve the functional requirements of your assembly, contact us today.  Our Applications Engineers stand ready to make recommendations for your assembly based on our expertise and 35 years of experience.