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ISSN (Print) : 0974-6846 Indian Journal of Science and Technology, Vol 8(31), DOI: 10.17485/ijst/2015/v8i31/84309, November 2015 ISSN (Online) : 0974-5645 Welding Parameters for Inconel 625 Overlay on using GMAW

P. Elango1* and S. Balaguru2 1M-Tech-Machine Design, Bharath University, Chennai – 600073, Tamil Nadu, India; [email protected] 2Department of Mechanical Engineering, Bharath University, Chennai – 600073, Tamil Nadu, India; [email protected]

Abstract alloys are well known for its properties along with high resistance

which finds a very large application in Oil and Petro chemical industries. However due to its prohibitive cost a cheaper alternative of cladding Ni alloys on carbon steel base material is widely used. The Ni may be applied by different methods such as roll bonding, explosive cladding or by weld overlaying. As the weld overlay process is simple and requires a small set up, this is being widely used to improve the corrosion properties of various equipments used in Oil and Petro chemical industries. While the process is simple and easier to apply, enough care need to be applied in controlling the weld chemistry. The most critical element to control is the Fe content in the weld overlay. It is observed that the corrosion properties are not affected when the Fe content is restricted to below 5%. Effort is made in this study to apply the weld overlay using Gas metal arc welding process using soild Inconel 625 wire. Various properties such as cKheemywicoalr cdosm: pBoesnidtion, cracking tendencies, hardness across the weld overlay area etc were also studied in this work.

Test, GMAW(Gas Metal Arc Welding), Hardness Survey, Inconel625, Macro Analysis 1. Introduction below 5%. Effort is made in this study to apply the weld overlay using Gas metal arc welding process using solid Nickel chromium molybdenum alloys are well known for Inconel 625 wire. Various properties such as chemical its creep properties along with high corrosion resistance composition, cracking tendencies, hardness across the which finds a very large application in Oil and Petro weld overlay area etc were also studied in this work. chemical industries. However due to its prohibitive cost a cheaper alternative of cladding Ni alloys on carbon steel base material is widely used. The Ni alloy may be applied by different methods such as roll bonding, explosive cladding or by weld overlaying. As the weld overlay process is simple and requires a small set up, this is being widely used to improve the corrosion properties of various equipments used in oil and petro chemical industries. While the process is simple and easier to apply, enough care need to be applied in controlling the weld chemistry. The most critical element to control is the Fe content in the weld overlay. It is observed that the corrosion properties are not affected when the Fe content is restricted to Figure 1. Inconel cladding on the body.

* Author for correspondence Welding Parameters for Inconel 625 Overlay on Carbon Steel using GMAW

Fusion welding generally involves joining of metals 2. Experimental Setup by application of heat for melting of metals to be joined. Almost all the arc welding processes offer high heat input, 2.1 Process which in turn leads to various problems such as burn Experiments are conducted using the GMAW process. through, distortion, porosity, buckling warping, and grain Industrial pure and commercial grade argon gases with coarsening. Application of appropriate welding process Helium gas (Mixture) used for shielding, Inconel 625 parameters, procedure and technique is essential to avoid welding electrode diameter 1.2 mm used and while the above problems. Gas Metal Arc Welding (GMAW) is welding the inter pass temperature maintained at 300 a good process for weld overlay or cladding, it costs less degree Celsius and it is stress relieved using PWHT (Post compared to the plasma arc welding machine. Volume of Weld Heat treatment)3,4. The effect of weld quality is weld overlay is much higher than plasma welding and Gas studied with reference to input parameters like Voltage, tungsten welding and also it is more flexible than plasma Current, and Height of the torch tip to the base metal. welding in terms of set up such as mounting the torch. Welding was carried out considering the following input Uses a consumable bare metal wire as electrode with parameters. The values of weld input parameters are shielding by flooding arc with a gas. The wire is fed arrived after conducting number of trial experiments. continuously and automatically from a spool through the The tested parameters and their values are described welding gun, Shielding used is Argon or Argon + Helium in the Table 17,8.

for Inconel welding, and CO2 for steel welding, Bare electrode wire plus shielding gases eliminate slag on weld Table 1. bead (Figure 2). Parameter Value Power Source 400 Amp- IGBT machine Type and Polarity DC RP(EP) Mode of operation Manual Filler wire Diameter mm 1.2 Shielding gas% Argon+Helium(80%+20%) Shielding gas flow rate litre/ 18-22 minute (LPM) Operation type Semi Automatic Thickness of base material mm 25 weld metal Thickness 5-6 mm As welded(Machine to 3mm) Mode of Metal spray Spray Amperes A 240 Voltage V 26 Travel speed mm /Min 230 Contact Tube to work distance 15 mm Figure 2. GMAW model. Bead weaving mm Weave- 15 Overlap between passes 1/3 rd It has one disadvantage of having higher dilution level in the parent material than plasma arc welding process. Number of layers 2 For this GMAW process there are few major parameters to control the process such as voltage, current, welding Plate size: 150mm X 150 mm x 25mm speed, arc length, oscillation and gas flow rate. In this Chemical composition for Inconel 625 Filler wire as process the shielding gas used is Argon with helium for per ASME Sec.IX AWs SFA 5.14 – Table 2. better shielding to avoid the oxidation and defects.

2 Vol 8 (31) | November 2015 | www.indjst.org Indian Journal of Science and Technology P. Elango and S. Balaguru

Table 2. below is < 5% to maintain the good corrosion resistance. Elements % max Table 3. c 0.1 Mn 0.5 Elements % max Fe 5 c 0.048 P 0.02 Mn 0.18 S 0.015 Fe 2.22 Si 5 P 0.007 Cu 5 S 0.05 Ni 58Min Si 0.08 Al 0.4 Cu <0.01 Ti 0.4 Cr 20-23 Ni Rem Nb+Ta 2.15-4.15 Al <0.01 Mo 08-10 Ti <0.01 Cr 21.52 Welding Overlay Drawing and Plate bending layout Nb+Ta 3.3 shown in Figure 3. Mo 8.26

2.2.2 Hardness Survey Result Vickers’s hardness testing machine was used to measure the hardness of the weld metal with a 10 Kg load. Hardness survey conducted on overlay Top, Overlay surface (Mid cross section), Base and Heat affected Zone (HAZ-.5mm from the fusion line) with 3 points at each location as per the Figure 4 and as per NACE MR0175/15156-23. The results are presented in Table 4. Table 4. Position Indent Hardness Hardness Hardness Avg. No. As value value value HV above A-A1 B-B1 C-C1 Overlay Top 4,8,12 216 210, 215 212 218, 221, 215 221 209 215 Overlay 3,7,11 207 210, 213 210 215, 210, 210 surface(Mid 206 Lo- 207 210 cross section) cation Figure 3. Base 1,5,9 172 169, 170712 171, 173, 171 175 168 168 2.2 Measurement of Output from the HAZ(0.5 mm 2,6,10 181, 179, 180 178 183, 186, 182 Analysis from fusion 183 185 181 zone) 2.2.1 Chemical Analysis The average value obtained on Overlay Top is 215HV, Table 3 shows the Chemical analysis carried out on the weld Overlay surface 210 HV, Base 171 HV and HAZ 182 HV. metal after machining to 3mm from the base metal and the Figure 5. obtained results5,6. It is noteworthy that the % Fe obtained

Vol 8 (31) | November 2015 | www.indjst.org Indian Journal of Science and Technology 3 Welding Parameters for Inconel 625 Overlay on Carbon Steel using GMAW

Figure 4.

Figure 5.

From Figure 5 it is clear that the hardness values of to bend the specimen is 40mm and the angle of bend is the weld Top is better than parent metal, which indicates 180 degree. As per the Table 5 with specification1. higher strength of the weld overlay. No cracks were found and results were satisfactory and acceptable. Table 5. Thickness 10mm 2.2.4 Macro Structure Examination Width 25 mm Dia 40mm Macro examination conducted on the specimen by using Angle 180 Deg 10 x magnifications refers the Figure 6. It shows the good fusion between parent material and weld overlay and also it is free from abnormal indication. 2.2.3 Transverse side Bens Test

The four number of specimen is taken from the test 2.2.5 Liquid Penetration Examination material as per the Figure 3. The specimen thickness is reduced to 10 mm and width 25 mm. The diameter used Liquid penetration examination conducted on the

4 Vol 8 (31) | November 2015 | www.indjst.org Indian Journal of Science and Technology P. Elango and S. Balaguru specimen as per the following steps as per specifications2. Managing Director, M/s RSL alloy Coating (p) Ltd., First the surface area was cleaned and penetrant was Chennai, Tamil Nadu, India, for their support to carry out applied with the dwell time of 10 min. After that it was experimentation. cleaned using the cleaner with cloth followed by the application of the developer. This result shows that there 5. References is no indication and it was accepted. 1. ASME SECTION IX-welding and brazing procedure qualification. 2. Jebaraj S, Iniyan S, Kota H. Forecasting of commercial energy consumption in India using artificial neural network. Int J Global Energ Issues. 2007; 27(3):276-301. ISSN: 0954-7118. 3. ASME SECTION 5-Non–Destructive examination. 4. Sharmila S, Jeyanthi Rebecca L. GC-MS analysis of esters of fatty acid present in biodiesel produced from Cladophora vagabunda. J Chem Pharmaceut Res. 2012; 4(11):4883–7. ISSN: 0975–7384. 5. Kiran Kumar TVU, Karthik B. Improving network life time using static cluster routing for wireless sensor networks. In- dian Journal of Science and Technology. 2013; 6(S5):4642–7. ISSN: 0974-6846. 6. NACE MR075/15156-2- Hardness survey. 7. Kaliyamurthie KP, Udayakumar R, Parameswari D, Mu- gunthan SN. Highly secured online voting system over Figure 6. network. Indian Journal of Science and Technology. 2013; 6(S6):4831–6. ISSN: 0974-6846. 8. Jeyanthi Rebecca L, Susithra G, Sharmila S, Das MP. Isolation 3. Conclusion and screening of chitinase producing Serratia marcescens from soil. J Chem Pharmaceut Res. 2013; 5(2):192–5. ISSN: Various properties of Inconel 625 weld overlay on carbon 0975–7384. 9. Kimio T, Natarajan G, Hideki A, Taichi K, Nanao K. Higher steel using the GMAW process are studied. The study involvement of sub telomere regions for chromosome rear- reveals that the good overlay is obtained below 5% Fe rangements in leukemia and lymphoma and in irradiated and with appropriate values of process variables that leukemic cell line. Indian Journal of Science and Technolo- includes Ampere, Voltage, Travel speed, Shield gas flow gy. 2012 April; 5(1):1801–11. rate, arc distance. It shows that the corrosion properties 10. Cunningham CH. A laboratory guide in virology. 6th edn. are not affected and it gives the requirement of corrosion Minnesota: Burgess Publication Company; 1973. 11. Sathishkumar E, Varatharajan M. Microbiology of Indian resistance. The hardness values of the weld top are desert. In: Sen DN, editors. Ecology and vegetation of In- better than the parent metal zone which indicates better dian desert. India: Agro Botanical Publ; 1990. p. 83–105. strength of the weld overlay and resistance to corrosion. 12. Varatharajan M, Rao BS, Anjaria KB, Unny VKP, Thyagara- The macrostructure of the weld joint indicates that there jan S. Radiotoxicity of sulfur-35. India: Proceedings of 10th is good fusion between parent material and weld overlay NSRP; 1993. p. 257–8. 13. Available from: http://www.indjst.org/index.php/vision and it is free from abnormal indication.

4. Acknowledgement

I express my sincere thanks to Shri. M. R. Sampathkumar,

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