Friction Bit Joining

National Laboratory: 
Oak Ridge National Laboratory
Processing/Manufacturing Class: 

Oak Ridge National Laboratory has a unique capability known as friction bit joining (FBJ), a solid-state process for joining dissimilar materials (e.g., aluminum/steel, polymer/steel, or magnesium alloy/steel). The process uses a consumable joining bit that serves as plunging and joining roles during FBJ. During the joining stage, the bit and surrounding sheet materials are heated by friction, leading to solid-state bonding.

Capability Bounds: 

The machine can join different material combinations with a coupon scale. Based on the joining bit’s length, it is possible to join materials with different thicknesses (1~6 mm). The equipment’s maximum tool rotational speed is 4000 rpm, and constant stall torque is 19.4 N·m.

Unique Aspects: 

The FBJ process affords short weld time with no pilot hole or surface preparation needed prior to joining. FBJ can perform multi-stack sheet joining, as well as weld bonding (with FBJ plus adhesive) for corrosion mitigation and increased strength.


The equipment is available for various partnership arrangements with industry.

Single Point of Contact: 

Name: Dr. Yong Chae Lim
Phone: 865-574-4805

  1. Y.C. Lim, L. Squires, T.-Y. Pan, M. Miles, G.-L. Song, Y. Wang, Z. Feng, “Study of mechanical joint strength of aluminum alloy 7075-T6 and dual phase steel 980 welded by friction bit joining and weld-bonding under corrosion medium,” Materials and Design, 69 37-43, 2015.
  2. L. Squires, Y.C. Lim, M. Miles, Z. Feng, “Mechanical properties of dissimilar metal joints composed of DP 980 steel and AA 7075-T6,” Science and Technology of Welding & Joining, 20 (3) 242-248, 2015.
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