IFI UHSFG-1416U-2014

This USCAR – IFI GUIDE provides critical information regarding the manufacturing and evaluation of externally thread fasteners having the following characteristics:

a. Ultimate tensile strength of 1400 MPa and greater.
b. Having bainite micro-structure.
c. That meets the performance requirements of fasteners used in automobile applications.
d. That can be manufactured using existing fastener technology.
e. Meets the economic needs of both the end user and fastener manufacturer. The bolts and screws covered by this GUIDE are M6 through M20 that are suitable for use in service temperature range of -50C to 200C.
Due to the high susceptibility of hydrogen induced delayed fractures, bolts and screws of tensile strengths 1400 MPa and higher should only be used in engine, transmissions, and axle applications where the risk of corrosion is minimal.

This Guide is intended to provide information on expected material and mechanical properties for a bainitic, ultra-high strength steel fastener. The Guide also provides some precautions regarding the processing of ultra-high strength steel fastener products, as well as their possible effect on joint design. This Guide is not a specification, but provides a foundation for ongoing development of ultra-high strength fastener products.