The effect of current on the resistance spot welding of dual phase steels

Year 2024, Volume: 30 Issue: 4, 422 - 428, 30.08.2024

Mesut Özer , Ali Kibar , Mehmet Uçar

Abstract

The effect of current on resistance spot welding joints on metallurgic and mechanical properties is investigated experimentally using galvanized unequal-thickness DP600 steel sheets. The specimens were chosen to be 1.5 and 1.8 mm thicknesses. The parameters of the welding process were preferred as an electrode force at 5 kN, welding currents at 7, 9, 11, 13 and 15 kA and welding times at 180, 240, 300, 360 and 420 ms. The welded joint specimens were subject to tensile-shear strength testing to determine the ultimate tensile strength. Optimal specimens were inspected using optical microscopes and scanning electron microscopy. The effect of spot welding variables on the ultimate tensile strength was determined and the lobe diagram, which shows optimal current-time values, was obtained. The optimal welding parameters were carried out on new sheet metals successfully. The experimental results show that the welding current plays an important role in the especially crash energy absorption and load-carrying capability.

Keywords

Automotive body, Dual phase steel, Energy absorption capability, Resistance spot welding, Weld failure types

Çift fazlı çeliklerin nokta direnç kaynağı ile birleştirilmesinde akım etkisi

Abstract

Nokta direnç kaynaklı birleştrimelerdeki akım değerinin mekanik ve metalurjik özellikler üzerindeki etkisi galvanizli farklı kalınlıklardaki DP600 çelik saclar kullanılarak deneysel olarak incelenmiştir. Numuneler 1.5 ve 1.8 mm kalınlıklarda seçildi. Kaynak proses parametreleri, 5 kN elektrod kuvveti, 7, 9, 11, 13, 15 kA kaynak akım değerleri,180, 240, 300, 360 ve 420 ms kaynak süreleri tercih edilerek gerçekleştirilmiştir. Kaynak birleştirmeli numuneler, en yüksek çekme mukavemetinin belirlenmesi için çekme-makaslama testine tabi tutuldu. Optimal numuneler optik mikroskop ve taramalı electron mikroskobu ile incelendi. Nokta kaynağı değişkenlerinin maksimum dayanım üzerindeki etkisi belirlendi, akım-süre değerlerini gösteren lobe diyagramı elde edildi. Optimum kaynak parametreleri yeni saclarda başarıyla uygulandı. Deneysel sonuçlar gösterdi ki; kaynak akımı özellikle çarpışma enerjisi emiliminde ve yük taşıma kapasitesinde önemli bir rol oynamaktadır.

Keywords

Otomotiv gövde, Çift fazlı çelik, Enerji emme kapasitesi, Nokta direnç kaynağı, Kaynak hata tipleri

References

• [1] Hayat F, Sevim İ. “The effect of welding parameters on fracture toughness of resistance spot-welded galvanized DP600 automotive steel sheets” The International Journal of Advanced Manufacturing Technology, 58, 1043-1050, 2011.
• [2] Wang W, Wei X. “The effect of martensite volume and distribution on shear fracture propagation of 600-1000 mpa dual phase sheet steels in the process of deep drawing”. International Journal of Mechanical Sciences, 67, 100-107, 2013.
• [3] Ramazani A, Abbasi M, Prahl U, Bleck W. “Failure analysis of DP600 steel during the cross-die test”. Computational Materials Science, 64, 101-105, 2012.
• [4] Rashid M, Medley JB, Zhou Y. “Electrode worksheet interface behaviour during resistance spot welding of al alloy”. Science and Technology of Welding and Joining, 14(4), 595-604, 2009.
• [5] Demir B, Elitas M, Karakuş H. “Nokta direnç kaynağı ile birleştirilen DP600 çeliğinin çekme makaslama özelliğinin incelenmesi”. Pamukkale Univ Muh Bilim Dergisi, 28(4), 533-538, 2022.
• [6] Chabok A, van der Aa E, De Hosson JTM, Pei YT. “Mechanical behavior and failure mechanism of resistance spot welded dp1000 dual phase steel”. Materials and Design, 124, 171-182, 2017.
• [7] Pouranvari M, Ranjbarnoodeh E. “Resistance spot welding characteristic of ferrite-martensite dp600 dual phase advanced high strength steel-part ii : failure mode”. World Applied Sciences Journal, 15(11), 1521-1526, 2011
• [8] Sung I, Jin M, Cheol D. “Expulsion Reduction in Resistance Spot Welding by Controlling of welding Current Waveform”. Procedia Engineering, 10, 2775-2781, 2011.
• [9] Zhang H, Wei A, Qiu X, Chen J. “Microstructure and mechanical properties of resistance spot welded dissimilar thickness DP780/DP600 dual-phase steel joints”. Materials and Design, 54, 443-449, 2014.
• [10] Zhou K, Cai L. “Study on effect of electrode force on resistance spot welding process”. Journal of Applied Physics, 116(8), 1-8, 2014.
• [11] Zhao D, Wang Y, Liang D, Zhang P. “Modeling and process analysis of resistance spot welded DP600 joints based on regression analysis”. Materials and Design, 110, 676-684, 2016.
• [12] Aslanlar S, Ogur A, Ozsarac U, Ilhan E, Demir Z. “Effect of welding current on mechanical properties of galvanized chromided steel sheets in electrical resistance spot welding”. Materials and Design, 28(1), 2-7, 2007.
• [13] ULSAB-AVC Consortium. “Advanced Vehicle Concepts Overview Report”. Ulsab-Avc World Auto Steel, Advanced Vehicle Technology Programme, 73, US, 2002.
• [14] Safanama DS, Marashi SPH, Pouranvari M. “Similar and dissimilar resistance spot welding of martensitic advanced high strength steel and low carbon steel: metallurgical characteristics and failure mode transition”. Science and Technology of Welding & Joining, 17(4), 288-294, 2012,
• [15] Zhang H, Senkara J. Resistance Welding, Fundamentals and Applications. 1st ed. Boca Raton, FL, US. Published by CRC Press Taylor & Francis Group, 2006.
• [16] Rao SS, Chhibber R, Arora KS, Shome M. “Resistance spot welding of galvannealed high strength interstitial free steel”. Journal of Materials Processing Technology, 246, 252-261, 2017.
• [17] Chen N, Wang HP, Carlson BE, Sigler DR, Wang M. “Fracture mechanisms of Al/steel resistance spot welds in coach peel and cross tension testing”. The Journal of Materials Processing Technology, 252, 348-361, 2018.
• [18] Alizadeh-sh M, Marashi SPH, Pouranvari M. “Resistance spot welding of AISI 430 ferritic stainless steel: Phase transformations and mechanical properties”. Materials and Design, 56, 258-263, 2014.
• [19] Long H, Hu Y, Jin X, Shao J, Zhu H. “Effect of holding time on microstructure and mechanical properties of resistance spot welds between low carbon steel and advanced high strength steel”. Computational Materials Science, 117, 556-563, 2016.
• [20] Marashi P, Pouranvari M, Amirabdollahian S, Abedi A, Goodarzi M. “Microstructure and failure behavior of dissimilar resistance spot welds between low carbon galvanized and austenitic stainless steels”. Materials Science and Engineering, 480, 175-180, 2008.
• [21] Đurić A, Milčić D, Burzić Z, Klobčar D, Milčić M, Marković B. “Microstructure and fatigue properties of resistance element welded joints of DP500 steel and AW 5754 H22 aluminum alloy”. Multidisciplinary Digital Publishing Institute, 12(2), 1-15, 2022.
• [22] Chung K, Noh W, Yang X, Han HN, Lee MG. “Practical failure analysis of resistance spot welded advanced high-strength steel sheets” International Journal of Plasticity, 94, 122-147, 2017.