EVALUATION OF CORROSION PROPERTIES OF SUPER

MARTENSITIC STAINLESS STEEL JOINTS USING GAS

METAL ARC WELDING

Visvam Moorthy1 M.E., , T.Prabakaran2 M.E.,(PhD) Assistant Professor1, Assistant Professor2

Department of Mechanical engineering, MIET Engineering College, Trichy , India. 1visvam2k6@gmail.com 2praba244@gmail.com

Abstract— The corrosion process in deep sea waters occurs under very specific conditions and is characterized mainly by low temperature,

high chloride contents, low oxygen content, the presence of CO2 and H2S, microorganisms and high contents of dissolved salts. . Stainless

steels are chosen for their corrosion resistance with the mechanical properties (strength, hardness, ductility) being of secondary importance.

Stainless steels contain more than 10.5 to 12 wt-% chromium, which provides a passive chromium oxide layer that forms on the surfaces when

exposed to air or other oxidizing environments. So it is important when welding stainless steels that the weld metal be protected from sources of

contamination or oxidation. Additionally, the joining of the separate stainless steel plates in some cases is also necessary to meet the actual

needs. Welding is one of the most effective joining methods, which commonly used gas metal arc welding. This work concentrates on welding

of super martensitic stainless steel welding using GMAW and evaluation of corrosion properties

Keywords— GMAW, Super martensitic stainless steel(SMSS), Corrosion, Inert Gas Mixing ,Oil and gas

I. INTRODUCTION

GMAW is an all-position semi –automatic welding process through it automatic versions is also available.

GMAW is a very versatile process and can be used for welding all metals for which compatible filler wires

have been developed .In gas metal arc welding (GMAW) process the shielding gas may be argon, helium,

nitrogen, carbon dioxide, hydrogen, and other mixtures. When inert gas is used the process is more

popularly known as MIG (metal inert gas) welding. During welding 100% CO2, 100%Ar, 80%Ar +

20%CO2, 100%He and 50% He+ 50% Ar gases are used. This work examines the GMAW of super

martensitic stainless steel (SMSS) for different shielding gas proportion.

II. SELECTION OF MATERIAL

SMSS plates have been cut into 250×200×6 mm (15 plate).welds were made using semi-automatic GMAW procedure. All

welding passes were deposited using a Ø1.2mm gas metal (GM410electrode) filler wire by using five different shield gases like

100%Co2, 100%Ar,80%Ar+20%Co2 ,100%He and 50%He+50%Ar,with a gas flow of15 L/ min and stick out length of 20mm, in

the flat position. Preheating and interpass temperature were 1500C .Each and every shield gases they are three different consent

voltage parameters (20, 23&26volts) were used. chemical composition foe SMSS is given table 1.

Chemical composition is given in Table I.

C Si Mn S P Cr Ni Mo Cu Co Ti Nb Al V W Fe

0.036 0.413 0.623 0.004 0.016 12.21 0.377 0.10 0.21

0.013 0.003 0 0 0.062 0.077 85.847

JASC: Journal of Applied Science and Computations

Volume V, Issue XII, December/2018

ISSN NO: 1076-5131

Page No:1310

III. EXPERIMENTAL SETUP

Fig 2. Mixing Chamber setup

IV. WELDING PARAMETERS

TABLE II

WELDING PARAMETERS

Plate

No

Welding parameters

GAS MIXTURE VOLTAGE

(volts)

CURRENT

(amps)

TRAVEL

SPEED

(mm/min)

HEAT INPUT

(kJ/min)

1 100% CO2 20 160 7.4 2.5

2 100%CO2 23 180 7 3.5

3 100% CO2 26 200 6.4 4.8

4 100% Ar 20 160 6 3.2

5 100%Ar 23 180 5.2 4.7

6 100% Ar 26 200 4.7 6.6

7 80% Ar+20% CO2 20 160 6 3.2

8 80% Ar+20% CO2 23 180 5 4.9

9 80% Ar+20% CO2 26 200 4 7.8

10 50% He+50%Ar 20 160 3.5 5.4

11 50% He+50%Ar 23 180 3 8.2

12 50% He+50%Ar 26 200 2.5 12.4

13 100% He 20 160 5.3 3.6

14 100% He 23 180 4.3 5.7

15 100% He 26 200 3 10.4

V. WELDED SPECIMEN

Fig 2.1.Welded With 100%Co2

JASC: Journal of Applied Science and Computations

Volume V, Issue XII, December/2018

ISSN NO: 1076-5131

Page No:1311

Fig 2.2.Welded With 100%Ar

Fig 2.3. Welded With 80%Ar +20%Co2

Fig 2.4. Welded With 100%He

Fig 2.4. Welded With 50%He+50%Ar

VI. CORROSION TEST

Before polarization test samples cut in to (10x10mm) by abrasive cutting followed by polishing.

Sensitization (IGSCC) problem can be overcome by potential dynamic electro chemical polarization curve

measurement test. Test solutions were made using NaCl and deionized water, and the acidity adjusted to pH

4.5 .The ratio of NaCl and deionized water were 1mg/lit. A Standard three electrode set up were used for the

PDECPM test, consisting of working electrode, platinized titanium counter electrode and reference electrode.

A computer controlled potentiostat (IVIUM software) was used for conducting the potentio dynamic

electro chemical polarization curve measurements. The rest potential, Ecorr, of each specimen was

monitored for a period of at least 1 hour prior to the polarization scan. The scan were conducted at a rate of

10mV/min from mV blow the Ecorr to a potential with a corresponding current density value

1mV/cm2 .figure 3 shows polished samples.

JASC: Journal of Applied Science and Computations

Volume V, Issue XII, December/2018

ISSN NO: 1076-5131

Page No:1312

Fig 3.1. 100% Co2

Fig 3.2.00%Ar

Fig 3.3. 80%Ar+20%Co2

Fig 3 .4. 100%He

JASC: Journal of Applied Science and Computations

Volume V, Issue XII, December/2018

ISSN NO: 1076-5131

Page No:1313

Fig 3.5.50%He+50%Ar

VII. RESULT AND DISCUSSION

In Co2, Argon, Helium and mixing gases, the anodic polarization curve is typical for stainless steel in chloride solution and the

pitting potential is easily detectable. The current oscillation occurring in the potential region under the pitting potential is

attributed to nucleation and passivation of metastable pits. The pitting potential, Ep, is plotted against the temperature and the

logarithm of chloride content based on the potentio dynamic polarization data obtained. The pitting potential decreases when

temperature and chlorine content increase in both cases.

Fig 4. Polarization curve

RESULT SUMMARY

Table III

SAMPLE NO SHIELD GAS CORROSION

RATE(mm/y)

1 100%CO2 0.764

3 100%CO2 0.804

5 100%Ar 0.705

6 100%Ar 0.521

7 80%Ar +CO2 0.982

9 80%Ar +CO2 0.921

10 100%He 0.971

12 100%He 0.988

14 50%He+50%Ar 1.214

15 50%He+50%Ar 0.933

JASC: Journal of Applied Science and Computations

Volume V, Issue XII, December/2018

ISSN NO: 1076-5131

Page No:1314

VIII. CONCLUSION

The pitting corrosion resistance of super martensitic stainless steel was affected by the chlorine concentration and temperature in

simulated deep seawater. The pitting potential decreased in a logarithmic relation with the chlorine concentration. The pitting

potential decreased linearly as the temperature increased. Finally potentio dynamic electrochemical polarization tests were carried

out on the welds. Result of corrosion was analyzed between different shield gases. The corrosion rate is difference in different gas

mixture. Based on the experimental test the suitable gas Argon was identified, the corrosion rate is 0.521mm/y.

REFERENCES

[1] Chi- Ming Lee And Stuart Bond & Et Al Corrosion Testing Of Weldable 13%Cr Super Martensitic Stainless Steel (2012)

[2] N. Anselmo, J.E. May, N.A. Mariano , P.A.P. Nascente , S.E. Kuri Corrosion Behavior Of Supermartensitic Stainless Steel In Aerated And Co2-Saturated

Synthetic Seawater (2006)

[3] Herausgeber: & Et Al Numerical Simulation Of Hydrogen Assisted Cracking In Supermartensitic Stainless Steel Welds (2005)

[4] Avoiding Intergranular Stress Corrosion Cracking Of Welds In Supermartnsitic Stainless Steel. For:A Group Of Sponsors(2002) TWI

[5] José Wilmar Calderón-Hernánde & T Al Intergranular Corrosion In A Super Martensitic Stainless Steel Containing 0.06n 0.025nb-0.1v

[6] B Arivazhagan And M Kamaraj The Effect Of Shielding Gas Composition (100%Ar, 100%Co2, 95% Ar+05%Co2 And 80%Ar+20%Co2) And Post Weld

Heat Treatment Of Joining Of P91 Steel Using Fcaw. Journal Of Materials Engineering And Performance 2011; 20(7):1188- 95

[7] Mohamad Ebrahimnia Et Al., The Influence Of Variation In The Shielding Gas Composition (97.5%Ar+2.5%Co2, 90% Ar+10%Co2, 82%Ar+18%Co2

And 75%Ar+25%Co2) On The Weld Properties Of The Steel St37-2 Materials And Design 2009; 30: 3891-95

[8] Martin Et Al The Corrosion Study Of 304l & 316l Weldments Conducted. The AISI 316l Weldment Shows, A Better Pitting Corrosion Behavior Than Aisi

304 Weldment For Every Zone. Corrosion Science2008;

[9] Am Galloway And N Mcpherson Optimum Mechanical Properties Of Weld Metal Were Obtained Using 85%Ar +15%N2 Shielding Gas Mixtures Welding

And Cutting 2006; 5(4): 225- 230

[10] Dr.R.S Parmer Welding Engineering And Technology First Edition: 2004 Published By Khanna Publishers Delhi

[11] Http:// Wikipedia. Org / Wiki/ Corrosion

[12] Xiaoping Ma, Cheng Zhou, Lijun Wang, Chunming Liu, Role Of Nb In 13cr Super-

[13] Martensitic Stainless Steel, Metallurgy And Materials Inox 2010

[14] T. Reyes*, D. L. Olson, B. Mishra Corrosion Of Super Martensitic Stainless Steel Due To Alternating Current In Artificial Sea Water: Dc Response

[15] Colorado School Of Mines, Golden Co, Usa.

[16] S. Hashizume, Y. Inohara And K. Masamura, Corrosion 2000, Paper No. 00130, Nace Int., Houston, 2000.

[17] [15]. C. P. Linne, F. Blanchard, G.C. Guntz And B.J. Orlans-Joliet, Corrosion 97, Paper No. 28,Nace Int., Houston, 1997.

[18] [16]. J.M. Drugli, T. Rogne, M. Svenning And S. Axelsen, Corrosion 99, Paper No. 586, Naceint., Houston, 1999.

[19] [17] J.M. Drugli, T. Rogne, M. Svenning And S. Axelsen, Supermartensitic Stainless Steels 99,Paper No. S99-37, 315, Belgian Welding Institute, 1999.

[20] [18]. S. Sakamoto, K. Maruyama And H. Kaneta, Corrosion 96, Paper No. 77, Nace Int.,Houston, 1996.

[21] [19]. H. Asahi, T. Hara And M. Sugiyama, Corrosion 96, Paper No. 61, Nace Int., Houston,1996. 20]. S. Hashizume, Y. Inohara, Y. Minami And K.

Masamura, Supermartensitic Stainless Steels 99, Paper No. S99-36, 307, Belgian Welding Institute, 1999.

JASC: Journal of Applied Science and Computations

Volume V, Issue XII, December/2018

ISSN NO: 1076-5131

Page No:1315