نویسندگان
دانشگاه یزد، دانشگاه مهندسی معدن و متالورژی ، یزد، ایران
چکیده
در پژوهش حاضر حساسیت به ترکیدگی فلزجوش راسب شده از الکترود E8010-P1 روی فلزپایه St-52 برحسب تغییرات ضخامت فلزپایه، ریزساختار فلزجوش و دمای بین‌پاسی مورد بررسی و تحلیل قرار گرفته است. بدین منظور نمونه‌های جوشکاری شده در شرایط مختلف (ضخامت فلزپایه و دمای بین‌پاسی متفاوت) مطابق با دستورالعمل بوهلر (SEP-1390) تحت آزمون خمش واقع شدند. بررسیهای انجام شده حاکی از افزایش حداقل دمای بین‌پاسی لازم برای جلوگیری از ترکیدگی فلزجوش E8010-P1 از 80˚C به 120˚C با افزایش ضخامت فلزپایه از 20mm به 30mm بود. افزایش دمای بین‌پاسی علاوه بر کاهش سرعت سردشدن ناحیه جوشکاری و در نتیجه کاهش تنشهای جوشی، موجب کاهش اثر تبریدی (heat sink) فلزپایه شده که در نهایت کاهش حساسیت به ترکیدگی فلزجوش را باعث می‌شود. مطالعات ساختاری نیز نشان داد که عامل اصلی ترکیدگی فلزجوش E8010-P1 ایجاد فازهای نامطلوب از قبیل فریت مرزدانه‌ای و ویدمن‌اشتاتن در فلزجوش می‌باشد. به‌علاوه مدت زمان سردشدن بهینه در محدوده دمایی 800-500˚C (∆t8/5) جهت اطمینان از عدم ترکیدگی فلزجوش مذکور، 180±10s تعیین گردید.
کلیدواژه‌ها
عنوان مقاله [English]
Intercorrelation of Interpass Temperature – Base Metal Thickness – Microstructure and Cracking of Weld Metal Deposited from E8010-P1 Cellulosic Electrodes
نویسندگان [English]
- Masoud Mosallaee pour
- Maryam Sadat Amini
- Mehdi Kalantar
- Seyed Sadegh Ghasemi
Yazd University, Mineral and Metallurgy Faculty, Material Science group
چکیده [English]
In this study, the cracking sensitivity of deposited weld of E8010-P1 cellulosic electrodes as a function of base metal thickness and interpass temperature was analyzed. For this purpose, different welded samples (different base metal thickness and interpass temperature) were subjected to the bending test according to the SEP-1390 bohler specification. Studies illustrated an increase in the minimum interpass temperature from 80˚C to 120˚C is required with increasing base metal thickness from 20mm to 30mm to prevent weld cracking. Increasing of interpass temperature not only decreases the welding cooling rate but also reduces the heat sink effect of base metal and therefore decreases the cracking sensitivity. Structural studies indicated that the main cause of E8010-P1 weld metal cracking is development of undesirable phases such as grain boundary and widmanstaten ferrite in the weld metal. In addition, optimum cooling time between 800-500˚C (∆t8/5) for preventing E8010-P1 weld metal cracking determines to be around 180±10s.
کلیدواژه‌ها [English]
- Cracking
- SMAW
- Interpass Temperature
- E8010-P1
- Pipe Lines
- C.F. Dong, Z.Y. Liu, X.G. Li, Y.F. Cheng, Effects of hydrogen-charging on the susceptibility of X100pipeline steel to hydrogen-induced cracking, international journal of hydrogen energy, 2009, 34 , 9879 – 9884.
- K. Faes, A. Dhooge, P.D. Baets, E. V. Donckt, W. D. Waele, Parameter optimisation for automatic pipeline girth welding using a new friction welding method, Materials and Design, 2009, 30, 581–589.
- G. M. Evans, N. Bailey, Metallurgy of Basic Weld Metal, Abington Publishing, Cambridge, United Kingdom, 1999.
- S.D. Kou, Welding Metallurgy, New Jersy, John Wiley and Sons, 2003.
- M.C. Zhao, K. Yang, Y. Shan, The effects of thermo‐ mechanical control process on microstructures and mechanical properties of a commercial pipeline steel, Material Science and Engineering A, 2002, 335, 14–20.
- R.w. Hinton, R. K. Wiswesser, Estimating welding preheat requirements for unknown grades of carbon and low-alloy steels, Welding Journal, 2008, 87, 11, 273-76.
- H. Okabayasi, R. Kume, Effects of Pre - and PostHeating on weld cracking of 9Cr.-1 Mo-Nb-V Steel, Transaction of the Japan Welding Society, 1988, 19, 2, 85-92.
- K. crostructure and mechanical properties of submerged arc welded HSLA steel joints”, International Journal Advanced Manufacturing Technology, 2008, 36, 475– 483.
- R.A. Farrar, P. L. Harrison, Acicular ferrite in carbonmanganese weld metals: an overview, Material Science, 1987, 22, 3812-3820.
- C.H. Lee, H. K. Bhadeshia, H. C. Lee, Effect of plastic deformation on the formation of acicular ferrite, Materials Science and Engineering A, 2003 , 249_257.
- H. J. Yi, Y. J. Lee, J. Y. Kim, S.S. Kang, Effect of microstructure and chemical composition on cold crack susceptibility of high-strength weld metal, Journal of Mechanical Science and Technology , 2011, 25, 2185- 2193.
- I. Madariaga, I. Gutierrez, C.G. Andres, C. C. Capdevila, Acicular ferrite formation in a medium carbon steel with a two stage continuous cooling, ScriptaMaterialia, 1999, 41, 229-235.
- A. Ghosh, S. Das, S. Chatterjee, P.R. Rao, Effect of cooling rate on structure and properties of an ultra-low carbon HSLA-100 grade steel, Materials Characterization, 2006, 56, 59– 65.
- T. Kasuya, N. Yurioka, M. Okumura, Methods for predicting maximum hardness of HeatAffected Zone andselecting necessary Preheat temperature for Steel Welding, Nippon Steel Technical Report , 1995, 65.
- Welding Handbook, Metals and Their Weldability 7th Edition, AWS, New York, 1982.
- L. H. Hu, J. Li, Z. G. Huang, Y. X. Wu, Effects of preheating temperature on cold cracks, microstructures and properties of high power laser hybrid welded 10Ni3CrMoV steel, Materials and Design, 2011, 32, 1931–1939.
- J. H. Huh, Effect of Weld Metal Microstructures on Cold Crack Susceptibility of FCAW Weld Metal, Metals and Materials International, 2008, 14, 2, 239-245.
- R.C. Junior, T. Maciel, P. Silva, Evaluation of cold crack susceptibility on HSLA steel welded joints, Rev, Metal. Madrid, 2003, 39, 83-89.
- J.S. Seo, H.J. Kim, H. S. Ryoo, Microstructural parameter controlling weld metal cold cracking, Journal of Achievements in Materials and Manufacturing Engineering, 2008, 27, 2, 256-62.
- D.K. Dwivedi, Some investigations on microstructure and mechanical properties of submerged arc welded HSLA steel joints, International Journal Advanced Manufacturing Technology, 2006, 36, 475–483.
- J. Hu, L.X. Du, J. J. Wang, C. R. Gao, Effect of welding heat input on microstructures and toughness in simulated CGHAZ of V–N high strength steel, Materials Science and EngineeringA, 2013, 577, 161–168.
- Z. Tonkovic, M. Peric, M. Surjak, I. Garasic, I. Boras, A. Rodic, S. Svaic, Numerical and Experimental Modeling of a T-joint Fillet Welding Process, 11th International Conference on Quantitative InfraRed Thermography, Naples Italy, 2012.
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