ÓBUDAI EGYETEM BÁNKI DONÁT GÉPÉSZ ÉS BIZTONSÁGTECHNIKAI MÉRNÖKI KAR

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1 ÓBUDAI EGYETEM BÁNKI DONÁT GÉPÉSZ ÉS BIZTONSÁGTECHNIKAI MÉRNÖKI KAR International Engineering Symposium at Bánki IESB 2014 Nemzetközi Gépész és Biztonságtechnikai Szimpózium november 20. A MAGYAR TUDOMÁNY ÜNNEPE TISZTELETÉRE

2 ANYAGTECHNOLÓGIA SZEKCIÓ Elnök: Rácz Pál Danyi József 1 Végvári Ferenc 1 - Béres Gábor 1 Kecskés Bertalan 2 1Kecskeméti Főiskola GAMF Kar, 2 HILTI Szerszám Kft. EXAMINATION OF DEEP-DRAWABILITY OF LASER WELDED BLANKS Lendvai László BME Polimertechnikai Tanszék EFFECTS OF MICROCELLULOSE/LAYERED SILICATE REINFORCEMENT ON STARCH-BASED COMPOSITES Czinege Imre Csizmazia Ferencné- Zsoldos Ibolya Széchenyi István Egyetem, Anyagtudományi és Technológiai Tanszék LASER WELDING OF STEEL-ALUMINUM SHEETS Danyi József 1 Végvári Ferenc 1 - Béres Gábor 1 Kecskés Bertalan 2 1 Kecskeméti Főiskola GAMF Kar, 2 HILTI Szerszám Kft. TUBE EXPANSION WITH POLYURETHANE MEDIUM Csóré András Szabó J. Péter BME Anyagtudomány és Technológia Tanszék DETERMINATION OF DISLOCATION DENSITY IN METALLIC CUBIC SYSTEMS WITH ELECTRON BACKSCATTERING DIFFRACTION Gáspár Marcell Balogh András Miskolci Egyetem Mechanikai Technológiai Intézeti Tanszék EFFECT OF t8.5/5 COOLING TIME ON THE CRITICAL HAZ AREAS OF HIGH STRENGTH STEEL JOINTS Dugár Zsolt 1 Béres Gábor 1 - Kis Dávid István 1 Antalicz Gergely 2 1Kecskeméti Főiskola GAMF Kar, 2 HILTI Szerszám Kft. DETERMINATION OF RECRYSTALLIZATION TEMPERATURE OF VARYING DEGREES FORMED ALUMINIUM, BY DMTA TECHNIQUE 6

3 International Engineerin ng Symposium at Bánki Content EFFECT OF t 8.5/5 COOLING TIME ON THE CRITICAL HAZ AREAS OF HIGH STRENGTH STEEL WELDED JOINTS ME Definition and grouping of high strength steels Welding difficulties of Q+T high strength steels Critical HAZ areas in single and multipass welds Simulation of critical HAZ areas by GLEEBLE 3500 physical simulator Material tests Summary and conclusions Marcell Gáspár, Assistant lecturer Dr. András Balogh, Associate professor áspár, M.; Balogh, A.: Effect of t 85/5 cooling time 1 áspár, M.; Balogh, A.: Effect of t 85/5 cooling time 2 Grouping of highh strength steels Welding difficulties Szakadás Elongati ion, i nyúlás, A Al, % l, % LSS MSS HSS km=10000 km=15000 Mild km=20000 CMn HSLA HSLAQ+T UHSS Quenched and tempered HSS (Q+T) Cold cracks Hydrogen diffusion Tensile stress (limited deformation) High carbon equivalent: 0.5 < CEV S960Q < 0.65 Mn Cr Mo V Cu Ni CEV C MART Tensile Szakítószilárdság, strength, Rm, R m, MPa Márkanév EN R p0,2 [MPa] R m [MPa] A 5 CEV CET T KV [ C] WELDOX 700 E S690QL WELDOX 900 E S900QL WELDOX 960 E S960QL WELDOX 1100 E WELDOX 1300 E Inhomogeneous HAZ Lower toughness Hardened and softened zone Selection of filler metal: Mismat tch ratio nység, [HV] Kemén Lenyomat K G áspár, M.; Balogh, A.: Effect of t 85/5 cooling time 3 áspár, M.; Balogh, A.: Effect of t 85/5 cooling time 4 HAZ properties Structure of HAZ in single and multipass welds Critical areas: Coarse grained: (CGHAZ) Intercritical () Intercritically reheated coarse grained (I CCGHAZ) Subcritically reheated coarse grained (SCCGHAZ) HAZ properties Intercritically reheated coarse-grained zone () Optical microscopic and microhardnesss examination of HAZ in multipass welded d joint (S960QL) (GMAW) - PA position - s = 15 mm - 2% HNO 3 (Nital) - Load: HVM1 áspár, M.; Balogh, A.: Effect of t 85/5 cooling time 5 áspár, M.; Balogh, A.: Effect of t 85/5 cooling time 6

4 Physical simulation in welding GLEEBLE 3500 Definition: physical simulation is the realization of real technological processes in (nearly) real time and geometrical step Application possibilities in welding: HAZ test Hot cracking» Nil strength temperature (NST)» Hot tensile test (HTT) Cold cracking Fusion and pressure welding processes Parameters (function of specimen size): Heating: C/s Cooling: C/s Velocity: 2000 mm/s Maximal force: 100 kn (pressure/compression) Physical simulation in welding HAZ test HAZ simulation: welding heat cycle models F(s,d) => thermocouple measurement or FEM Hannerz v E x R Rykalin-2D TR, x v e 2a 2R Rykalin-3D Rosenthal R x y z a cp Exponential Inhomogeneous HAZ areas The extension of HAZ areas is relatively small due to the low heat input welding, that can be limitedly investigated by conventional material tests. Recommended specimen size: 10x10x70 mm Possible material tests: Optical/electron microscopic methods, hardness tests Charpy-V test (10x10x55 mm), COD testss áspár, M.; Balogh, A.: Effect of t 85/5 cooling time 7 áspár, M.; Balogh, A.: Effect of t 85/5 cooling time 8 HAZ test Simulation steps Precise preparation of HAZ specimens geometrical shape, surface quality Fitting of thermocouples to the surface: Thermocouple welder NiCr-Ni (K type) Positioning of specimens in grips Welding heat cycle: Model: Rykalin-3D Thermo physical properties (JMatPro) Welding parameters Selection of maximal temperature Simulation Evaluation Thermocouples Specimen Grips/jaws Selection of peak temperatures and cooling times HAZ areas (NST = ºC, preliminary simulations): CGHAZ: T max = 1350 ºC : T max = 775 ºC : T max = 1350, 775 ºC t 85/5 8.5/5 cooling times: 5 s 15 s GMAW 30 s Investigated steel category: WELDOX C Si Mn P S Cr Ni CEV 960 0,17% 0,20% 1,23% 0,007% 0,002% 0,20% 0,06% 0,55 Mo V Ti Cu Al Nb B N CET 0599% 0,599% 0041% 0,041% 0003% 0,003% 001% 0,01% 0053% 0,053% 0015% 0,015% 0, 001% 0008% 0,008% 036 0,36 WELDOX 960 RP0,2 Rm A5 KV (-40ºC) MPa MPa % J áspár, M.; Balogh, A.: Effect of t 85/5 cooling time 9 áspár, M.; Balogh, A.: Effect of t 85/5 cooling time 10 HAZ heat cycles in single and multipass welded joint Optical microscopic tests HAZ microstructure by optical microscope: Nital (2% HNO 3 ) t 8.5/5 = 5 s t 8.5/5 = 5 s t 8.5/5 = 15 s t 8.5/5 = 30 s CGHAZ áspár, M.; Balogh, A.: Effect of t 85/5 cooling time 11 áspár, M.; Balogh, A.: Effect of t 85/5 cooling time 12

5 SEM tests Hardness tests HAZ microstructure by scanning electron microscope: Nital(2% HNO 3 ) t 8.5/5 = 15 s CGHAZ Hardness tests: Evaluation: HV max = 450 HV according to EN for the 3 rd group in CR ISO HAZ T max, Hardness, HV10 C t 8.5/5 = 5 s t 8.5/5 = 15 s t 8.5/5 = 30 s CGHAZ Base material HAZ Base material Hardness, HVM0.1 Location t 8.5/5 = 5 s t 8.5/5 = 15 s t 8.5/5 = 30 s grain boundary grain center grain boundary grain center áspár, M.; Balogh, A.: Effect of t 85/5 cooling time 13 áspár, M.; Balogh, A.: Effect of t 85/5 cooling time 14 Toughnesss properties Charpy-V test: Evaluation: 27 J at -40 C (according to EN ) 3 specimens/heat cycle => calculation l of average Charpy energy Base material Summary, conclusions The most critical HAZ areas of WELDOX 960 E (S960QL, EN ) are the CGHAZ and in multipass welded joints. CGHAZ, and were succes sfully performed by our GLEEBLE 3500 thermo mechanical physical simulator for t 8,5/5 =5,155 and 30 s cooling times. The grain size of CGHAZ was 10 times higher than the original Q+T microstructure ( µm instead of µm). The measured max ximum hardness in case of low cooling time was close to the permitted maximum value of EN (450 HV). In there was no significant difference between the hardness values and toughness of the three cooling times. The toughness of CGHAZ, and was much lower than the fine-grained base material. The measured Charpy energy values were close to the required minimum value, 27 J. has the lowest toughness (5 s). For the precise analysis of the toughness properties of HAZ the specimen number should be increased in case of CGHAZ due to the high scatter noticed in impact energy values. On the basis of simulation results the welding technology, including the optimal t 8.5/5 cooling time range can be determined. Further simulations are planned for shorther cooling times (2.5 s). áspár, M.; Balogh, A.: Effect of t 85/5 cooling time 15 áspár, M.; Balogh, A.: Effect of t 85/5 cooling time 16 Literature Gáspár, á M.; Balogh, A.: A hegesztési paraméterek hőhatásövezetre t gyakorolt htáá hatásának kfiiki fizikai szimulációval láió ltötéő történő vizsgálata S960QL acél esetén, Hegesztéstechnika, 2014/1 pp Bhadesia, H. K. D. H.; Honeycombe, R. W. K.: Steels Microstructure and Properties, Third Edition, Elsevier Linacre House, Jordan Hill, Oxford OX2 8DP, UK Nevasmaa, P: Evaluation of HAZ Toughness Properties in Modern Low Carbon Low Impurity 420, 550 and 700 MPa Yield Strength Thermomechanically Processed Steels with Emphasis on Local Brittle Zones, Lisensiaatintyö, University of Oulu, pp Laitinen, R.: Improvement of weld HAZ toughness at low heat input by controlling the distribution of M-A constituents, PhD Dissertation, University of Oulu, pp Węglowski, M.: Modern toughened steels their properties and advantages, Biuletyn Instytutu Spawalnictwa, 2012/02. pp Heikkilä, S. J.; Porter, D.A.; Karjalainen, L. P.; Laitinen, R. O.; Thinen, S. A; Suikkanen, P. P.: Hardness Profiles of Quenched Steel Heat Affected Zones, Materials Science Forum Vol 762, Trans Tech Publications, Switzerland, pp Laitinen, R.; Porter, D. A.; Karjalainen, L. P.; Leiviskä, P.; Kömi, J.: Physical Simulation for Evaluating Heat-Affected Zone Toughness of High and Ultra-High Strength Steels, Materials Science Forum Vol. 762, Trans Tech Publications, Switzerland, pp Palotás, B.: Növelt folyáshatárú acélok keménysége különböző kritikus lehűlési idő esetén, IX. Országos Anyagtudományi Konferencia, Balatonkenese, Magyarország, Paper II/1. Komócsin, M.: Nagyszilárdságú acélok és hegeszthetőségük, Hegesztéstechnika, 2002/1, pp ]Sas, I.: Növelt folyáshatárú acélok hegesztésének gyakorlati tapasztalatai a Ruukki Zrt-ben, Cloos Szimpózium, BMF, ]Rittinger, J.: Termomechanikusan kezelt acélok hegesztése és a hegesztett kötések tulajdonsága, 25. Jubileumi Hegesztési Konferencia, pp ]Kuzsella, L.; Lukács, J.; Szűcs, K.: Fizikai szimulációval végzett vizsgálatok S960QL jelű, nagyszilárdságú acélon, GÉP, LXIII. évf. 4. sz., pp ]Érsek, L.: Alvázak gyártása autódarukhoz nagyszilárdságú acélokból, Hegesztéstechnika, 2008/1. pp ]Kovács, M.: Nagyszilárdságú finomszemcsés szerkezeti acélok hegesztése, Hegesztéstechnika, 1992/3. pp ]Gáspár, M.; Balogh, A.: GMAW experiments for advanced (Q+T) high strength steels, Journal of Production Processes and Systems, Vol. 6 (1), University of Miskolc, Department of Materials Processing Technologies, pp ]Szunyogh, L.: Hegesztés és rokontechnológiák kézikönyv, Gépipari Tudományo os Egyesület, Budapest, 2007 ]LePera, F. S: Improved etching technique to emphasize martensite and bainite in high-strength, Dual-Phase steels, Journal of Metals March, pp ]Lukács, J., Kuzsella, L., Dobosy, Á., Pósalaky, D.: Hegesztési melegrepedés-érzékenység megítélése fizikai szimuláció segítségével, GÉP LXIV. évf. 8. sz pp ]Koritárné Fótos, R.; Koncsik, Zs.; Lukács, J.: A fizikai szimuláció és alkalmazása az anyagtechnológiákban, Műszaki Tudomány az É-K Moi. Régióban, Szolnok, 2012 Thank you for your attention! gasparm@uni-miskolc.hu Acknowledgement The presented research work based on the results achieved within the TÁMOP B-10/2/KONV project and carried out as part of the TÁMOP-4.2.2/A-11/1-KONV project in the framework of the New Széchenyi Plan. The realization of this project is supported by the European Union, and co-financed by the Europea an Social Fund. áspár, M.; Balogh, A.: Effect of t 85/5 cooling time 17 áspár, M.; Balogh, A.: Effect of t 85/5 cooling time 18