Friction Stir Spot Welding of DP780 and Hot-Stamp Boron Steels

Conference · Tue Jan 01 00:00:00 EST 2008

OSTI ID:1029559

Santella, Michael L ^[1]; Frederick, David Alan ^[1]; Hovanski, Yuri ^[1]; Grant, Glenn J ^[1]

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1. ORNL

Friction stir spot welds were made in two high-strength steels: DP780, and a hot-stamp-boron steel with tensile strength of 1500 MPa. The spot welds were made at either 800 or 1600 rpm using either of two polycrystalline boron nitride tools. One stir tool, BN77, had the relatively common pin-tool shape. The second tool, BN46, had a convex rather than a concave shoulder profile and a much wider and shorter pin. The tools were plunged to preprogrammed depths either at a continuous rate (1-step schedule) or in two segments consisting of a relatively high rate followed by a slower rate. In all cases, the welds were completed in 4s. The range of lap-shear values were compared to values required for resistance spot welds on the same steels. The minimum value of 10.3 kN was exceeded for friction stir spot welding of DP780 using a 2-step schedule and either the BN77- or the BN46-type stir tool. The respective minimum value of 12 kN was also exceeded for the HSB steel using the 2-step process and the BN46 stir tool.

• Research Organization: Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
• Sponsoring Organization: USDOE Office of Energy Efficiency and Renewable Energy (EERE)
• DOE Contract Number: AC05-00OR22725
• OSTI ID: 1029559
• Resource Relation: Conference: 2008 Sheet Metal Welding Conference XIII, Livonia, MI, USA, 20080514, 20080516
• Country of Publication: United States
• Language: English