1. JOINT HYDROGEN SUSCEPTIBILITY OF 304 SS WELDED WITH TITANIUM EVA MAZANCOVÁ 1, DIMITRIJ OSTROUSHKO 1, KAREL SAKSL 2, ADAM NIESLONY 3 1 VŠB-TU of Ostrava Faculty of Metallurgy and Materials Engineering Czech Republic 2 Institute of Material Research of SAS, Košice, Slovak Republic 3 Opole University of Technology, Faculty of mechanical Engineering, Opole, Poland EPNM2014-Kraków

2. AIM T To show H 2 response of 304 SS and Ti weld in conditions of fatigue test (tensile-pressure) and of the HIC exposition EPNM2014-Kraków

3. EXPERIMENTAL MATERIAL Sheets (110+6Ti) x 2600 x 2600 mm welded by Explomet-Opole 304 SS (wt. %) 304 SS (wt. %)0.03C-0.45Si-1.96Mn-18.4Cr-9.7Ni-0.006P-0.011S Ti (wt. %) 0.01C-0.05Fe-0,05O-0,005N-0.006H EPNM2014-Kraków

4. EXPERIMENTAL PROCEDURE Fatigue bar 90x  10 mm Fatigue bar 90x  10 mm (0.1M solut./8 h–current density of 15 ) (0.1M H 2 SO 4 solut./8 h–current density of 15 mA.cm -2 ) Cyclic fatigue stress (tensile- pressure) at amplitude of 20 Hz (40 Hz HT without H ) - Cyclic fatigue stress (tensile- pressure) at amplitude of 20 Hz (40 Hz HT without H 2 ) - ČSN 42 0363 as-received state 600°C/1.5h (HT) after charging after H-charging Weld Ti EPNM2014-Kraków

5. EXPERIMENTAL PROCEDURE HIC – NACE St. TM0284-2011 HIC – NACE St. TM0284-2011 Samples 20 x 14.5 x 100 mm Crack length ratio CLR Crack thickness ratio CTR Crack sensitivity ratio CSR EPNM2014-Kraków

6. HIC SAMLES + EVALUATION CLR = CLR = 100.  a/w (%) CTR = (%) CTR = 100.  b/T (%) CSR = CSR = 100.  (a.b)/w.T (%) Interface analysis using EDAX and Synchrotron Ti 304 SS a = crack length in w b = crack thickness in T EPNM2014-Kraków

7. MICROSTRUCTURE BIMETAL INTERFACE Ti 304 SS a b EPNM2014-Kraków

8. MICROGRAPH - ADIABATIC BANDS Ti EPNM2014-Kraków

9. MICROGRAPHS – 3 mm AWAY BONDING LINE a b 304 SS Ti EPNM2014-Kraków

10. HIC EVALUATION individual values (%) S CLR (15%) CTR (5%) CSR (2%) 0HT/HT 0HT/HT 0HT/HT 0HT/HT 0HT/HT 0HT/HT 11.04/2.19 2.47/0.14 0.003/0.001 21.25/1.37 2.25/0.13 0.01/0.002 32.04/3.08 1.99/0.62 0.01/0.003 4 3.07/3.68 2.17/0.70 0.01/0.002 53.42/0.50 2.93/0.04 0.01/0.001 6 4.15/2.37 3.75/0.16 0.01/0.002 72.25/1.80 2.30/3.66 0.01/0.012 81.92/1.60 1.90/2.80 0.01/0.005 93.02/1.60 2.51/2.62 0.01/0.013 EPNM2014-Kraków

11. HIC EVALUATION mean values (%) S CLR CTR CSR 11.44/2.21 2.47/0.30 0.01/0.002 2 3 4 3.55/1.52 2.95/0.30 0.01/0.002 5 6 72.39/1.67 2.24/3.00 0.01/0.01 8 9 EPNM2014-Kraków

12. HIC EVALUATION a total cracks: 84 (without the HT) 56 (after the HT) 56 (after the HT) length: 0.01-0.08 mm thickness: 0.01-0.22 mm a b EPNM2014-Kraków

13. INTERPHASE ANALYSES 3 2 41 1-304 SS 2-68-98Ti 3-16Ti-16Cr-57Fe- 8Ni + Al,Si,Mn bal. 5-65-90Ti 4-20Ti-11Cr- 61Fe-6Ni + Al, Si, Mn bal. a b 5 EPNM2014-Kraków

14. FATIGUE TESTS EPNM2014-Kraków

15. FRACTURE SURFACE ANALYSIS EPNM2014-Kraków

16. FRACTURE SURFACE ANALYSIS 2b 3b 1b WHT (without the HT) + the HT) + H-charging H-charging AHT (after the HT) + H-Charging a b EPNM2014-Kraków

17. MarkSiTiCrMnFeNi 1a0.619.216.71.554.97.1 1b0.919.716.71.654.17.0 1c0.921.116.21.553.07.3 2a 97.10.5 2.00.4 2b0.265.54.90.624.34.5 3a0.645.311.31.136.94.8 3b 0.642.211.21.140.34.6 FRACTURE SURFACE ANALYSES (at.%) FRACTURE SURFACE ANALYSES (at.%) EPNM2014-Kraków

18. INTERPHASE ANALYSIS USING SYNCHROTRON Raster step size = 1  m, total length = 401  m X-ray focused to 2.2x34  m, beamline P07 at Petra III (electron storage ring operating at energy of 6 GeV with beam current 100 mA (18) EPNM2014-Kraków

19. CONCLUSIONS Safe load boundary of the HT+H-charged bars (at 20Hz) showed 17% of tensile strength of bimetal weld in clad state and/or 12 % (at 40 Hz) in case of H-charged samples without the HT. Higher amplitude (40 Hz) resulted in threshold level decrease of the HT samples without H-charging approx. by 25 MPa. Fracture surfaces predominanty indicated the rupture in areas where 66–97 at. % of Ti was revealed representing bonding line. On surface, lower portion of Ti a presence of the FeTi and/or Fe 2 Ti with Cr partially substituting the Fe could indicate. EPNM2014-Kraków

20. CONCLUSIONS After the HIC exposition cracks were observed in areas of curls only, where inter- metallic phases of the Fe 2 Ti were detected using monochromatic synchrotron radiation, while the EDAX analysis showed the most frequent mixed phases approx. (in at. %) with 20 Ti, 11 Cr, 60 Fe showed. All HIC parameters were satisfactory and complied with the requirements of NACE Standard and ANSI/API specification 5L. After the HT, results were more satisfactory in average. EPNM2014-Kraków

21. CONCLUSIONS After the HIC exposition, more cracks were detected in samples without the HT unlike the HT ones. Cracks showed 45°-90° orientation towards the bonding line and none ran to any basic material. Cracks were maximally 0.08 mm long and 0.22 mm thick (2 cases). By application of monochromatic synchrotron radiation Fe 2 Ti phase in wave curls was revealed. Presence of Fe-fcc, Fe- bcc and Ti-hcp will be discussed in next paper. EPNM2014-Kraków

22. ACKNOWLEDGMENT Mobilities International Research Teams Specific Research in Metallurgical, Material and Process Engineering Regional Materials Science and Technology Centre – Feasibility Program EXPLOMET This paper was created within the project 7AMB14SK023“ Mobilities “, 02613/2013/RRC „ International Research Teams “ sponsored by Northern Moravian region, within the project SP 2014/62 “ Specific Research in Metallurgical, Material and Process Engineering “ and No. L01203 L “ Regional Materials Science and Technology Centre – Feasibility Program “ founded by Ministry of Education, Young and Sports of Czech Republic. Special thanks belongs to EXPLOMET for an important cooperation. EPNM2014-Kraków

23. THANKS FOR YOUR ATTENTION Slovak Academy of Sciences Institute of Material Research Kosice, Slovakia EPNM2014-Kraków