Gas Metal Arc Brazing and Welding of Advanced High Strength Steels

• Min Kuo, ArcelorMittal

• Tom Natale, AK Steel Corporation

• Stephen Tate, AK Steel

Corporation

• Hassan Ghassemi, ArcelorMittal

• Elliot Biro, ArcelorMittal

• Amanda Davis,

FiatChryslerAmerica US LLC

• Patrick Marchena, Ford Motor

Company

• Mike Palko, Ford Motor Company

• Ted Coon, Ford Motor Company

• Richard Carlson, General Motors

• Weiping Sun, Nucor Corporation

• Justin Hunt, AET Integration Inc.

• Daniel L. Galiher, Tower International

• Vaidyanath B. Rajan, Lincoln Electric

• Michael White, Auto/Steel Partnership

Evaluate the effects of gas metal arc welding (GMAW) and gas metal arc brazing (GMAB) on AHSS and UHSS and to identify the impact of welding and brazing on joint strength.

• Sheets sheared to 6” x 12” were robotically welded in 1F position

• 0.1 mm shims used on faying surfaces of sheet steels

• 0.035” diameter wire

• 90% Argon 10% CO 2  shielding gas(GMAW)

• 100% Argon shielding gas (GMAB)

• X-ray inspection (referencing ISO 17636-2 and ISO 5817)

− for joints made with zinc coated steels

− porosity percentage was measured

• Cross-section examination

• Microhardness traverse

• Quasi-static shear tension

Test specimens were waterjet cut from continuous welded panels in order to eliminate the effects of weld starts and stops.

X-ray inspections were performed to detect imperfections in weld and braze metals

Porosity percentage values are tabulated in the report

• Quality welded and brazed joints were achieved for all test materials.

• A targeted gap of 0.1 mm between faying surfaces was effective in providing a consistent gap and at minimizing porosity in weld metal for coated materials.

• Fracture locations can be in the base metal, HAZ, weld metal, or near the weld fusion line,depending on material grade and thickness.

• For the thin gauge coated steels tested, GMAW and GMAB resulted in similar joint strength.

• Compared to ER70S-6 filler metal, ER100S-G appears to slightly increase the joint strength for the CP780, DP780, and DP1180 materials tested.

• Joint efficiency ranged from 40% (MS1700 Uncoated GMAW) to 105% (BH240 HDGI GMAB) and generally decreased as steel strength increased.

• The test methods used in this study may be used as a basis for developing gas metal arc welding and gas metal arc brazing qualification procedures.