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Title: Evaluating the Upset Protrusion Joining (UPJ) Method to Join Magnesium Castings to Dissimilar Metals

Conference ·
OSTI ID:1395239
 [1]
  1. FCA US LLC, Auburn Hills, MI (United States)

This presentation discusses advantages and best practices for incorporating magnesium in automotive component applications to achieve substantial mass reduction, as well as some of the key challenges with respect to joining, coating, and galvanic corrosion, before providing an introduction and status update of the U.S. Department of Energy and Department of Defense jointly sponsored Upset Protrusion Joining (UPJ) process development and evaluation project. This update includes sharing performance results of a benchmark evaluation of the self-pierce riveting (SPR) process for joining dissimilar magnesium (Mg) to aluminum (Al) materials in four unique coating configurations before introducing the UPJ concept and comparing performance results of the joints made with the UPJ process to those made with the SPR process. Key results presented include: The benchmark SPR process can produce good joints in the MgAM60B-Al 6013 joint configuration with minimal cracking in the Mg coupons if the rivet is inserted from the Mg side into the Al side; Numerous bare Mg to bare Al joints made with the SPR process separated after only 6-wks of accelerated corrosion testing due to fracture of the rivet as a result of hydrogen embrittlement; For the same joint configurations, UPJ demonstrated substantially higher pre-corrosion joint strengths and post-corrosion joint strengths, primarily because of the larger diameter protrusion compared to smaller SPR rivet diameter and reduced degradation due to accelerated corrosion exposure; As with the SPR process, numerous bare Mg to bare Al joints made with the UPJ process also separated after 6-wks of accelerated corrosion testing, but unlike the SPR experience, the UPJ joints experienced degradation of the boss and head because of galvanic corrosion of the Mg casting, not hydrogen embrittlement of the steel rivet; In the configuration where both the Mg and Al were pretreated with Alodine 5200 prior to joining and the complete assembly was powder-coated afterwards, the UPJ process showed substantial improvement in corrosion performance compared to SPR where many SPR joints had separated after only 6-wks of exposure, but none of the UPJ joints had separated even after 8-wis; and In the cases where the Al panel was coated prior to joining to the pretreated Mg coupons, neither the SPR or UPJ joints showed any joint separation or substantial joint performance degradation even after 12-wks of accelerated corrosion exposure.

Research Organization:
FCA US LLC, Auburn Hills, MI (United States)
Sponsoring Organization:
USDOE Office of Energy Efficiency and Renewable Energy (EERE), Vehicle Technologies Office (EE-3V)
Contributing Organization:
AET Integration, Inc.; Automotive Partnership Canada (APC); Canmet materials (CMAT); Henrob; McMaster University
DOE Contract Number:
EE0006442
OSTI ID:
1395239
Report Number(s):
DOE-FCA-0006442-3
Resource Relation:
Conference: 3rd Global Lightweight Vehicle Manufacturing Summit, Detroit, MI (United States)
Country of Publication:
United States
Language:
English