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Resistance Spot Welding Evaluation of Transformation Induced Plasticity 780 (TRIP780) Steel for Automotive Body Structural Applications
Technical Paper
2009-01-0805
ISSN: 0148-7191, e-ISSN: 2688-3627
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English
Abstract
There has been a substantial increase in the use of advanced high strength steel (AHSS) in automotive structures in the last few years. The usage of these materials is projected to grow significantly in the next 5–10 years with the introduction of new safety and fuel economy regulations. AHSS are gaining popularity due to their superior mechanical properties and use in parts for weight savings potential, as compared to mild steels. These new materials pose significant manufacturing challenges, particularly for welding and stamping. Proper understanding of the weldability of these materials is critical for successful application on future vehicle programs. Due to the high strength nature of AHSS materials, higher weld forces and longer weld times are often needed to weld these advanced steels.
In this paper, the weld current lobes, mechanical properties (shear and cross tension), metallographic cross-section and microhardness profile of Transformation Induced Plasticity 780 (TRIP780) 1.6 mm electrogalvanized steel welded to itself in a two-metal stackup are discussed. Weld lobes were developed with Medium Frequency Direct Current (MFDC) equipment, ISO-type B20 tips, weld force of 5.8 kN and hold time of 5 cycles. The weld times were varied at 19, 21 and 24 cycles, with each producing current ranges at or above 2.0 kA. Shear and cross tension samples were made at 19 cycles, with samples showing average loads of 12.30 kN and 5.11 kN respectively. Microhardness assessment using metallographic cross-sections of 21-cycle welds were used to compare short and long hold times. Similar heat affected zones (HAZ) and weld zones were observed for both hold times.
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Koganti, R., Angotti, S., Joaquin, A., Coon, T. et al., "Resistance Spot Welding Evaluation of Transformation Induced Plasticity 780 (TRIP780) Steel for Automotive Body Structural Applications," SAE Technical Paper 2009-01-0805, 2009, https://doi.org/10.4271/2009-01-0805.Also In
References
- AHSS Application Guidelines American Iron and Steel Institute 2004
- Bhadesia H.K.D.H Honeycobe R.W.K. “Steels: Microstructure and Properties” 3rd Edition Cambridge 1995
- Karave, G.S. Zhang, H. “Dependence of impact performance on process parameters and weld attributes for spot welded advanced high strength steels” 2004 ASME World Congress
- Lee M.J. “Advanced high strength steel Technology in the ford 500 and free style, American Iron and Steel Institute, Great Design in Steel Seminar www.autosteel.org March 2005
- Koganti, R. Elliott, A. Coon, T. Joaquin, A. Wexler, A. Bhatnagar, R. Lalam, S. “Resistance Spot Weldability of Three Metal Stack Dual Phase 600 Hot-dipped Galvanized Steel” SAE 2007-01-1363 April 2007
- Koganti, R. Angotti, S. Joaquin, A. Jiang, C. “Resistance Spot Welding (RSW) of Advanced High Strength Steels (AHSS) for Automotive Body Construction” IMECE2007-42675, 2007 ASME World Congress Seattle, Washington DC Nov. 2007
- Bernquist Jonas “Safety cage design in the VOLVO XC90” American Iron and Steel Institute, 2004 Great Design in Steel Seminar www.autosteel.org Livonia, MI
- Mehrkens Michael “Advanced High Strength Steel Technology in the Porsche Cayenne” American Iron and Steel Institute, 2004 Great Design in Steel Seminar www.autosteel.org Livonia, MI
- Bilkey Kevin “Production of a welded assembly for the Hybrid Ford Escape utilizing an intricate drawn DP 1180 component” American Iron and Steel Institute, Great Design in Steel Seminar www.autosteel.org March 2005
- Wielgat Andrea “Vantastic voyage: Toyota Sienna engineers crisscrossed the country to create a minivan that is designed for, built in and exclusive to the American market” Automotive Industries Magazine March 2003