JOINT HYDROGEN JOINT HYDROGEN SUSCEPTIBILITY OF 304 SS SUSCEPTIBILITY OF 304 SS WELDED WITH TITANIUM WELDED WITH TITANIUM

EVA MAZANCOVÁ1, DIMITRIJ OSTROUSHKO1,KAREL SAKSL2, ADAM NIESLONY3

1VŠB-TU of Ostrava Faculty of Metallurgy and Materials Engineering

Czech Republic

2Institute of Material Research of SAS, Košice, Slovak Republic

3Opole University of Technology, Faculty of mechanical Engineering, Opole, Poland

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AIMAIM

TTo show H2 response of 304 SS and Ti weld in conditions

of fatigue test (tensile-pressure) and of the HIC

exposition

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EXPERIMENTAL MATERIAL EXPERIMENTAL MATERIAL

Sheets (110+6Ti) x 2600 x 2600 Sheets (110+6Ti) x 2600 x 2600 mmmm

welded by Explomet-Opole welded by Explomet-Opole

304 SS304 SS (wt. %)(wt. %)

0.03C-0.45Si-1.96Mn-18.4Cr-9.7Ni-0.03C-0.45Si-1.96Mn-18.4Cr-9.7Ni-

0.006P-0.011S0.006P-0.011S

Ti Ti (wt. %)(wt. %)

0.01C-0.05Fe-0,05O-0,005N-0.01C-0.05Fe-0,05O-0,005N-0.006H0.006H

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EXPERIMENTAL PROCEDUREEXPERIMENTAL PROCEDURE

Fatigue bar Fatigue bar 90x90x10 mm 10 mm

 

(0.1M (0.1M H2SO4 solut./8 h–current density of 15 solut./8 h–current density of 15 mA.cm-

2))

Cyclic fatigue stress (tensile-pressure) Cyclic fatigue stress (tensile-pressure) at amplitude of 20 Hz (40 Hz HT at amplitude of 20 Hz (40 Hz HT without Hwithout H2) - ) - ČSN 42 0363

as-received stateas-received state 600°C/1.5h 600°C/1.5h (HT)(HT)after after H-

charging charging

Weld

Ti 

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EXPERIMENTAL PROCEDUREEXPERIMENTAL PROCEDURE

HIC – NACE St. TM0284-2011 HIC – NACE St. TM0284-2011  

Samples 20 x 14.5 x 100 mmSamples 20 x 14.5 x 100 mm

Crack length ratio CLRCrack length ratio CLR

Crack thickness ratio CTRCrack thickness ratio CTR

Crack sensitivity ratio CSRCrack sensitivity ratio CSR

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HIC SAMLES + EVALUATIONHIC SAMLES + EVALUATION

CLR =CLR = 100.a/w (%)

CTR =CTR = 100.b/T (%) (%)

CSR =CSR = 100.(a.b)/w.T (%)

Interface analysis using EDAX andInterface analysis using EDAX and

Synchrotron Synchrotron

Ti 304 SS a = crack length in w b = crack thickness in T

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MICROSTRUCTURE MICROSTRUCTURE BIMETAL INTERFACEBIMETAL INTERFACE

Ti 

304 SS

a b

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MICROGRAPH - ADIABATIC MICROGRAPH - ADIABATIC BANDSBANDS

Ti 

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MICROGRAPHS – 3 mm AWAYMICROGRAPHS – 3 mm AWAYBONDING LINEBONDING LINE

a b

304 SS

Ti

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HIC EVALUATIONHIC EVALUATION individual values (%) individual values (%)

S CLR S CLR (15%)(15%) CTR CTR (5%)(5%) CSR CSR (2%) (2%) 0HT0HT//HTHT 0HT0HT//HT 0HTHT 0HT//HTHT11.04/2.19 2.47/0.14 0.003/0.001 21.25/1.37 2.25/0.13 0.01/0.00232.04/3.08 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 0.01/0.0016 4.15/2.37 3.75/0.16 0.01/0.00272.25/1.80 2.30/3.66 0.01/0.012 81.92/1.60 1.90/2.80 0.01/0.00593.02/1.60 2.51/2.62 0.01/0.013

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HIC EVALUATIONHIC EVALUATIONmean values (%)mean values (%)

S CLR CTR CSR S CLR CTR CSR 11.44/2.21 2.47/0.30 0.01/0.002 23 4 3.55/1.52 2.95/0.30 0.01/0.002 56 72.39/1.67 2.24/3.00 0.01/0.01 89

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HIC EVALUATIONHIC EVALUATIONa

total cracks: total cracks: 84 (without the HT)84 (without the HT) 56 (after the HT)56 (after the HT)

length: length: 0.01-0.08 mm 0.01-0.08 mm thickness: thickness: 0.01-0.22 mm0.01-0.22 mm

ab

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INTERPHASE ANALYSESINTERPHASE ANALYSES

33

22

4411

11-304 SS-304 SS22-68-98Ti -68-98Ti

33-16Ti-16Cr--16Ti-16Cr-57Fe-8Ni + 57Fe-8Ni + Al,Si,Mn bal.Al,Si,Mn bal.55-65-90Ti -65-90Ti

4-4-20Ti-11Cr-20Ti-11Cr-61Fe-6Ni +61Fe-6Ni +Al, Si, Mn bal.Al, Si, Mn bal.

a

b

55

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FATIGUE TESTSFATIGUE TESTS EPNM2014-Kraków

FRACTURE SURFACE ANALYSIS FRACTURE SURFACE ANALYSIS

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FRACTURE SURFACE ANALYSIS FRACTURE SURFACE ANALYSIS

2b

3b

1b

WHT WHT (without(without the HT)the HT) ++ H-charging H-charging

AHT AHT (after the (after the HT)HT) + + H-ChargingH-Charging

a

b

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Mark Si Ti Cr Mn Fe Ni

1a1a 0.6 19.2 16.7 1.5 54.9 7.1

1b1b 0.9 19.7 16.7 1.6 54.1 7.0

1c1c 0.9 21.1 16.2 1.5 53.0 7.3

2a   97.1 0.5   2.0 0.4

2b 0.2 65.5 4.9 0.6 24.3 4.5

3a3a 0.6 45.3 11.3 1.1 36.9 4.8

3b3b 0.6 42.2 11.2 1.1 40.3 4.6

FRACTURE SURFACE ANALYSES (at.%)FRACTURE SURFACE ANALYSES (at.%)

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INTERPHASE ANALYSISINTERPHASE ANALYSISUSING SYNCHROTRONUSING SYNCHROTRON

Raster step size = 1m, total length = 401 mX-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)

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CONCLUSIONSCONCLUSIONS

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 Fe2Ti

with Cr partially substituting the Fe could indicate.

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CONCLUSIONSCONCLUSIONS

After the HIC exposition cracks were observed in areas of curls only, where inter-metallic phases of

the Fe2Ti 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.

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CONCLUSIONSCONCLUSIONS

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 Fe2Ti phase in wave curls was revealed.

Presence of Fe-fcc, Fe-bcc and Ti-hcp will be discussed in next paper.

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ACKNOWLEDGMENTACKNOWLEDGMENT 

This paper was created within the project 7AMB14SK023“MobilitiesMobilities“, 02613/2013/RRC „International Research TeamsInternational Research Teams“ sponsored by

Northern Moravian region, within the project SP 2014/62 “Specific Research in Specific Research in

Metallurgical, Material and Process EngineeringMetallurgical, Material and Process Engineering“ and No. L01203 L “Regional Materials Science Regional Materials Science

and Technology Centre – Feasibility Programand Technology Centre – Feasibility Program“ founded by Ministry of Education, Young

and Sports of Czech Republic. Special thanks belongs to EXPLOMET EXPLOMET for an

important cooperation.

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THANKS FOR THANKS FOR YOUR YOUR

ATTENTIONATTENTION

Slovak Academy of Sciences

Institute of Material Research

Kosice, Slovakia

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