Liquid Metal Embrittlement Formation in Galvanized 3rd Generation Steel After Resistance Spot Welding

Abstract

3rd generation steels have been of great importance in the applications of the automotive industry in recent years within the scope of weight reduction efforts. The weldability of 3rd Generation steels with special production methods, along with their forming problems, is being studied intensively. During resistance spot welding (RSW) of these steels, which are generally preferred as galvanized coated, they pass into the liquid phase due to the low melting temperature of the zinc (Zn) element in the galvanized coating. This situation causes liquid metal embrittlement (LME) with the diffusion of molten Zn atoms into the main material after welding. LME sensitivity occurring in the welding area can cause micro cracks in the main material. In addition, LME negatively affects the mechanical properties of the weld area. This study includes a compilation of literature reviews on LME sensitivity that occurs after spot resistance welding. In the study, the effects of the mechanical properties and microstructure of the 3rd generation steel group on the LME sensitivity are explained, and the effects of different galvanized coating types on the LME formation are also presented. Finally, possible mechanisms of LME sensitivity during RSW are discussed and suitable methods to suppress its occurrence are suggested.

Keywords

• 3rd generation steels
• liquid-metal embrittlement
• galvanized coating
• resistance spot welding

Galvaniz Kaplı 3. Nesil Çeliklerde Nokta Direnç Kaynağı Sonrası Sıvı Metal Kırılganlığı Oluşumu

Öz

3. nesil çelikler, ağırlık azaltma çalışmaları kapsamında son yıllarda otomotiv endüstrisinin uygulamalarında büyük bir öneme sahiptir. Özel üretim yöntemine sahip 3. nesil çeliklerin şekillendirme problemleri ile birlikte kaynaklanabilirliği de yoğun olarak çalışılmaktadır. Genellikle galvaniz kaplamalı olarak tercih edilen bu çeliklerin nokta direnç kaynağı (NDK) sırasında, galvaniz kaplamada yer alan çinko (Zn) elementinin ergime derecesinin düşük olması nedeniyle sıvı faza geçmektedir. Bu durum ergimiş Zn atomlarının kaynak sonrası ana malzemeye difüzyonu ile sıvı metal kırılganlığına (SMK) neden olmaktadır. Kaynak bölgesinde meydana gelen SMK hassasiyeti, ana malzemede mikro çatlaklara sebebiyet verebilmektedir. Ayrıca SMK kaynak bölgesinin mekanik özelliklerini de olumsuz yönde etkilemektedir. Bu çalışma, nokta direnç kaynağı sonrasında oluşan SMK hassasiyeti üzerine yapılan literatür incelemelerinin derlemesini içermektedir. Çalışmada 3. nesil çelik grubunun mekanik özelliklerinin ve mikroyapısının SMK hassasiyetine etkileri anlatılmış olup, aynı zamanda farklı galvaniz kaplama türlerinin SMK oluşumuna etkileri sunulmuştur. Son olarak, nokta direnç kaynağı sırasında SMK hassasiyetinin olası mekanizmaları tartışılmış ve oluşumunu bastırmak için uygun yöntemler önerilmiştir.

Anahtar Kelimeler

• 3. nesil çelikler
• sıvı metal kırılganlığı
• galvaniz kaplama
• nokta direnç kaynağı

Kaynakça

1. [1] Yürük A., Çevik B., Kahraman N., Analysis of mechanical and microstructural properties of gas metal arc welded dissimilar aluminum alloys, Mater. Chem. Phys., 273, (2021) 125117.
2. [2] Khan M.I., Spot welding of advanced high strength steels, Master Thesis of Applied Science, Ontario, Canada, (2007) 9-16.
3. [3] Park G., Jeong S., Lee C., “Fusion weldabilities of advanced high manganese steels: A Review. Met. Mater. Int., 27 (2021) 2046–2058.
4. [4] Başer T.A., Resistance Spot Welding of Zn-coated third generation automotive steels using mid-frequency direct current technology, Trans Indian Inst Met, 76 (2023) 49–57.
5. [5] Hıdıroğlu, M., Başer T.A., Tekelioğlu O., Kahraman N., Üçüncü nesil çeliklerin nokta direnç kaynağında sıvı metal kırılganlığı, 10th International Automotive Technologies Congress, OTEKON 2020, September 6-7, Bursa, Türkiye, (2021) 1566-1575.
6. [6] Yang K., Meschut G., Seitz G., Biegler M., Rethmeier M., The identification of a new liquid metal embrittlement (LME) type in resistance spot welding of advanced high−strength steels on reduced flange widths, Metals, 13 (2023) 1754.
7. [7] Karabulut S., Erzincanlıoğlu S., Ünal C. U., Bilici A. Y., Yılmaz İ. Ö., Üçüncü Nesil Çeliklerin Otomotiv Tasarımında Kullanımı, Mühendis ve Makina, (Ağustos 2019) 35-41.
8. [8] Billur E., Dykeman J., Altan T., “Three generations of advanced high strength steels for automotive applications, 3 parça yazı dizisi”, Stamping Journal: Nov/Dec 2013, p.15-16, Jan/Feb 2014, p.12-13, Mar/Apr 2014, p. 12-13.

9. [9] World Steel Association AISBL https://ahssinsights.org/metallurgy/steel-grades/ahss/twinning-induced-plasticity/#:~:text=TWinning%20Induced%20Plasticity%20(TWIP)%20steels,elongation%20typically%20greater%20than%2050%25 Son erişim tarihi: 17.02.2025
10. [10] Horvath C. D., Advanced steels for lightweight automotive structures, Materials, Design and Manufacturing for Lightweight Vehicles, (2010) 35-78.
11. [11] Li W., Yong Z., Weijun F., Xinyang J., Speer J.G., Industrial application of Q&P sheet steels, Proceedings of Intl. Symp. on New Developments in Advanced High-Strength Sheet Steels, (2013) 141-151.
12. [12] Max-Planck-Gesellschaft https://www.mpie.de/3084542/Research_Project_Optimization_Q_P_steels Son Erişim Tarihi: 17.02.2025
13. [13] Huyghe, P., Dépinoy, S., Caruso, M., Mercier, D., Georges, C., Malet, L., Godet, S., On the Effect of Q&P Processing on the Stretch-flange-formability of 0.2C Ultra-high Strength Steel Sheets, ISIJ International, 58(7) (2018), 1341–1350.
14. [14] Steels for cold stamping – Fortiform https://automotive.arcelormittal.com/products/flat/third_gen_AHSS/fortiform Son erişim Tarihi: 17.02.2025
15. [15] Blake K. Zuidema, Introduction to 3rd Generation Advanced High Strength Steels, ArcelorMittal Global R&D, (2017).
16. [16] Liu L., He B., and Huang M., The role of transformation-induced plasticity in the development of advanced high strength steels, Adv. Eng. Mater., 20 (2018) 1701083.
17. [17] Yüce O., Farklı özelliklerdeki otomotiv saclarının lazer kaynak uygulamaları, Yüksek Lisans Tezi, Karabük Üniversitesi Lisansüstü Eğitim Enstitüsü, Karabük, (2023) 15-28.
18. [18] Köle A., Ayan Y., Kahraman N., Markalama ve kesme işlemleri için karbondioksit (CO2) lazer makinesi tasarımı, üretimi ve test çalışmaları, Politeknik Dergisi, 27(2) (2024) 759-768.
19. [19] Dasgupta A. K. and Mazumder J., Laser welding of zinc coated steel: analternative to resistance spot welding, Science and Technology of Welding and Joining, 13(3) (2008) 289-293.
20. [20] Němeček S., Mužík T., Míšek M., Differences between laser and arc welding of HSS steels, Physics Procedia, 39 (2012) 67-74.
21. [21] Bakošová D., Bakošová A., Experimen.tal study of thin steel tubes welded by fiber laser, Manufacturing Technology, 21(1) (2021) 3-13.
22. [22] Yüce O., Hıdıroğlu M., Erdoğan İ., Kahraman N., TBF1180 Çeliğin Fiber Lazer Uygulamaları, Gazi Üniversitesi Fen Bilimleri Dergisi Part C: Tasarım ve Teknoloji, 12(1) (2024) 267-281.
23. [23] Spena P. R., Maddis M. De, Lombardi F., and Rossini M., Investigation on resistance spot welding of TWIP Steel sheets, Steel research int., 86(12) (2015) 1480-1489.
24. [24] Bina M. H., Jamali M., Shamanian M., Sabet H., Investigation on the resistance spot-welded austenitic/ferritic stainless steel, Int J Adv Manuf Technol, 75 (2014) 1371–1379.
25. [25] Kaya İ., Başer T. A., Kahraman N., Mechanical properties and corrosion behavior of similar/dissimilar resistance spot welded automotive aluminum alloys, Materials Science and Engineering Technology (Materialwissenschaft und Werkstofftechnik), 54(11) (2013) 1433-1443.
26. [26] Pouranvari M., Alizadeh-Sh M., and Marashi S. P. H., Welding metallurgy of stainless steels during resistance spot welding Part I: fusion zone, Science and Technology of Welding and Joining, 20(6) (2015) 502-511.
27. [27] Kahraman N., The influence of welding parameters on the joint strength of resistance spot-welded titanium sheets, Materials and Design, 28 (2007) 420–427.
28. [28] Rao S. S., Chhibber R., Aror K. S., Shome M., Resistance spot welding of galvannealed high strength interstitial free steel, Journal of Materials Processing Technology, 246 (2017) 252–261.
29. [29] Vinas J., Kascak L., and Gres M., Optimization of resistance spot welding parameters for microalloyed steel sheets, Open Eng. 6(1) (2016) 504–510.
30. [30] Lin H.C., Hsu C.A., Lee C.S., Kuo T.Y., Jeng S.L., Effects of zinc layer thickness on resistance spot welding of galvanized mild steel, Journal of Materials Processing Tech., 251 (2018) 205–213.
31. [31] Murugan S. P., Vıjayan V., Ji C., and Park Y.-D., Four types of LME cracks in RSW of Zn-coated AHSS, Welding Journal, 99 (March 2020) 75-92.
32. [32] Park Y., Murugan S. P., Liquid metal embrittlement cracks in resistance spot welded advanced high strength steels, Proceedings of the JAAA2018, Kitakyushu, Japan, (November 2018) 27-28.
33. [33] Bhattacharya D., Liquid metal embrittlement during resistance spot welding of Zn-coated high-strength steels, Materials Science and Technology, 34(15) (2018) 1809-1829.
34. [34] Billur E., Çetin B., Gürleyik M., New generation advanced high strength steels: Developments, trends and constraints, International Journal of Scientific and Technological Research, 2(1) (2016) 50-62.
35. [35] Prabitz K. M., Asadzadeh M. Z., Pichler M., Antretter T., Beal C., Schubert H., Hilpert B., Gruber M., Sierlinger R., Ecker W., Liquid metal embrittlement of advanced high strength steel: experiments and damage modeling”, Materials, 14(18) (2021) 5451.
36. [36] Ling Z. X., Chen T., Kong L., Wang M., Pan H., Lei M., Liquid metal embrittlement cracking during resistance spot welding of galvanized Q&P980 steel, Metallurgical and Materials Transactions A, 50(11) (2019) 5128–5142.
37. [37] Sierlinger R., Gruber M., A cracking good story of liquid metal embrittlement during spot welding of advanced high strength steels, Technical report, Linz, Austria: voestalpine Stahl GmbH, (2016) 1-6.
38. [38] Beal C., Kleber X., Fabregue D., Bouzekri M., Embrittlement of a zinc coated high manganese TWIP steel, Materials Science and Engineering A, 543 (2912) 76-83.
39. [39] Meyerdierks M., Zinke M., Jüttner S., Biro E., Determination of LME sensitivity of zinc coated steels based on the programmable deformation cracking test, Welding in the World, 65 (2020) 2295–2308.
40. [40] Ling Z., Wang M., Kong L., Chen K., Towards an explanation of liquid metal embrittlement cracking in resistance spot welding of dissimilar steels, Materials and Design, 195 (2020) 109055.
41. [41] Lalachan A., Murugan S. P., Jin W. S., Park Y. D., Liquid metal embrittlement in Zn-coated steel resistance spot welding: Critical electrode-contact and nugget growth for stress development and cracking, Journal of Materials Processing Technology, 318 (2023) 118009.
42. [42] Kim Y.G., Kim I.J., Kim J.S. et al. Evaluation of surface crack in resistance spot welds of Zn-coated steel, Mater Trans, 55(1) (2014) 171–175.
43. [43] https://www.baosteel.com/en/home Son erişim Tarihi: 17.02.2025
44. [44] Emre H. E., Kaçar R., Resistance spot weldability of galvanize coated and uncoated TRIP steels, Metals (Basel), 6 (2016) 299.
45. [45] Beal C., Mechanical behaviour of a new automotive high manganese TWIP steel in the presence of liquid zinc, Doctoral Dissertation, Intelligence and National Security Alliance, Lyon, France, (2011) 34-67.
46. [46] Siar O., Benlatreche Y., Dupuy T., Dancette S., Fabrègue D., Effect of severe welding conditions on liquid metal embrittlement of a 3rd-generation advanced high-strength steel, Metals, 10(9) (2020) 1166.
47. [47] Ashiri R., Anwarul H. M., Chang-Wook J., et al., Super-critical area and critical nugget diameter for liquid metal embrittlement of Zn-coated twining induced plasticity steels, Scr Mater. 109 (2015) 6–10.
48. [48] Ashiri R., M Shamanian., Salimijazi H. R., et al., Liquid metal embrittlement-free welds of Zn-coated twinning induced plasticity steels, Scr Mater. 114 (2016) 41–47.
49. [49] Yilmaz I. O., Bilici A. Y.., and Aydin H., Resistance spot weldability of TBF steel sheets with dissimilar thickness, Metall. Res. Technol. 117(6) (2020) 620-633.
50. [50] Bhattacharya D., Cho L., van der A E., Pichler A., Pottore N., Ghassemi-Armaki, H. Findley K. O., Speer J.G., Influence of the starting microstructure of an advanced high strength steel on the characteristics of Zn-Assisted liquid metal embrittlement, Materials Science and Engineering: A, 804 (2021) 140391.
51. [51] Wintjes E., DiGiovanni C., He L., Bag S., Goodwin F., Biro E., Zhou Y., Effect of multiple pulse resistance spot welding schedules on liquid metal embrittlement severity, Journal of Manufacturing Science and Engineering, 141(10) (2019) 101001.
52. [52] Dupuy T., A novel electrode tip geometry to mitigate liquid metal embrittlement during resistance spot welding, Welding in the World, 66(9) (2022) 1715–1731.
53. [53] DiGiovanni C., He L., Pan H., Zhou N. Y., Biro E., Predicting liquid metal embrittlement severity in resistance spot welding using hot tensile testing data, Welding in the World, 66(9) (2022) 1705–1714.