* - - 100084 Q235B ML15 Ca OH 2 DOI 10. 13204 /j. gyjz201508023 STUDY OF GALVANIC CORROSION SENSITIVITY BETWEEN ANY COUPLE OF STUD WELDMENT OR BEAM Lu Xinying Li Yang Li Yuanjin Department of Civil Engineering Tsinghua University Beijing 100084 China Abstract The corrosion behavior of Q235B steel beam ML15 steel stud and the weldment used in a steel-concrete composite element as well as the galvanic couples referring to the stud body in a simulated rainwater and a saturated Ca OH 2 solution with different amount of chlorions was studied by electrochemical method. The results showed that the weldment was the weakest part to be destroyed in the stud-beam system the stud head was the following one the stud body and the beam were moderate. So the galvanic cells were easily to be established between the weldment and stud or beam in the simulated solutions at the present work and the galvanic current increases with the corrosion strength of the solutions. The galvanic corrosion rate of weldment was at least one order higher than that of the selfcorrosion when the galvanic cell was established. Keywords composite structure stud corrosion 1-1 - 11 - T 1 1a - 1 2 6 7-1 Fig. 1 beam's section 4-11 - - * 2011BAJ09B03 1966 luxy@ mail. tsinghua. edu. cn 2015-01 - 20 3 4 5 - T Schematic of steel-concrete composite T-type Industrial Construction Vol. 45 No. 8 2015 2015 45 8 125
12-1b 13 2 2. 1 7 - T Q235B ML15 Ca OH 2 1 1 Table 1 Chemical composition of specimens % C Si Mn S P Cr Ni Fe 0. 210 0. 092 0. 19 0. 004 3 0. 006 5 0. 010 0. 025 Balance 0. 090 0. 061 0. 38 0. 005 5 0. 007 0 0. 021 0. 028 Balance 0. 091 0. 055 0. 38 0. 005 6 0. 008 0 0. 022 0. 028 Balance NaCl 2 PH 5 15 3 + 0. 5% 10-6 mol /L NaCl + 25 10-6 mol /L C 6 H 12 N 4 30 min NH 4 2 SO 4 15 min CS350 Tafel 600 1000 SCE 5 min 0. 5 mv /s Tafel 25 min ± 250 mv 0. 5 mv /s 0. 2 s 2 1 1. 5 0. 2 cm 2 2. 2 0. 2 s Tafel I 3 3. 1 1 Ca OH 2 CH Ca OH 2 + 50 10-6 mol /L 3 NaCl Ca OH 2 + 250 10-6 mol /L ± 15 mv 2 126 2015 45 8
2 Table 2 Average linear polarization resistance in different simulated solutions kω cm 2 CH CH + 50 10-6 mol /L NaCl CH + 250 10-6 mol /L NaCl 50. 7 35. 6 39. 2 8. 9 22. 1 32. 8 18. 5 9. 2 8. 1 6. 2 7. 7 5. 6 1 12. 2 5. 9 1. 1 0. 85 CH CH + 50 10-6 mol / L NaCl CH + 250 10-6 mol /L NaCl 4 5 ~ 8 kω cm 2 2 Ca OH 2 3. 2 Tafel 2 Tafel Ca OH 2 a CH b CH + 50 10-6 mol /L NaCl c CH + 250 10-6 mol /L NaCl d - - - - 1 Fig. 2 2 Tafel Tafel polarization curves in different simulated solutions 2 Ca OH 2 3 ± 50mV 3. 3 3 3. 4 4 a CH b CH + 50 10-6 mol /L NaCl c CH + 250 10-6 mol /L NaCl d - - - 1 - Fig. 3 3 Galvanic potential in different solutions - - 127
a CH b CH + 50 10-6 mol /L NaCl c CH + 250 10-6 mol /L NaCl d - - - 1 - Fig. 4 4 Galvanic current in different solutions 3 Table 3 Linear polarization resistance of different weldments kω cm 2 Ca OH 2 50 10-6 mol /L NaCl - 6 ~ 10 μa /cm 2 250 10-6 mol /L NaCl Ca OH 2 20 μa /cm 2 4-1 Ca OH 2 Ca OH 2 + 50 55 μa /cm 2 10-6 mol /L NaCl Ca OH 2 + 250 2 10-6 mol /L NaCl Ca OH 2 + 250 10-6 mol /L NaCl 27 μm /a 36 μm /a 2 293 μm /a 644 μm /a 11 18 3 250 10-6 mol /L NaCl 4 - - 1. - J. 1999 32 2 3-8. 3. 5 3 J 3 4 Ca OH 2 + 50 10-6 mol /L NaCl 3 2 3 1 1 /5 1 /10 1 5 10 1 5. 9 2 1. 1 3 0. 62 2. J. 2012 34 2 15-20... 2013 46 2 10-18.. - D. 2011. 5. - D. 2011. 6. - D. 2013. 134 128 2015 45 8
Fig. 14 14 Curve of change in axial force of oblique support 19. 1 MPa 3 1. 71 MPa 10 15 1. 62 MPa 0. 72 MPa 15 1. J. 1998 20 1 112-113. 2. J. 2006 36 691-694. 15 Fig. 15 z MPa z-axis stress cloud of main structure 5 1 2 3. J. 2005 35 11 53-55. 4. Midas J. 2010 26 2 29-31. 5. M. 2009. 6. J. 2005 34 6 42-44. 7. J. 2012 352-354. 8 GB 50017 2003 S. 9. J. 2012 45 1 49-60. 10 GB 50010 2010 S. 128 7. - D. 1-5. 2009. 8. - J. 2013 2 D. 2009. 381-385. 9. - J. 12 Davis J R. Corrosion Understanding the Basics M. Ohio ASM 2009 10 109-111. 11. International 2000. 10. - 13 Davis J R. Corrosion of Weldments M. Ohio ASM J. 2010 7 3 International 2006. 134 2015 45 8