• Okiemute Grace Erhimona

In this study, the Gas Tungsten Arc (GTAW) and the Shielded Metal Arc (SMAW) welding processes were used to weld a 200mm x 16.53mm thick duplex alloy 2205 stainless steel pipe to determine which of the processes will cause susceptibility of the alloy to intergranular corrosion at the grain boundaries. Duplex stainless steel (DSS) Alloy 2205 containing 22%Cr, 5%Ni, ferritic-austenitic material is an emerging class of stainless steel currently being selected for a variety of applications especially where corrosion is of major concern. They have good mechanical properties and high resistance to all forms of corrosion combined with its high strength-to-mass ratio. These properties allow for savings both in terms of structural weight and maintenance costs. The welding was preceded with the writing of a Welding Procedure Specification (WPS) in accordance with the ASME IX code. The welding was then done using the parameters specified in the WPS for the two processes. Various tests were carried out on transverse specimens cut out from the welds made with both processes. These tests included compositional analysis across the weld profiles, hardness, and tensile test. The test results for the compositional analysis showed an insignificant depletion of chromium from 22.06 at the weld cap to 19.96 at the root of the TIG weld. This depletion is not enough to cause sensitization although there were likely precipitates in the weld and HAZ. The hardness across the welds profile revealed that there was a uniform distribution of hardness across the MMA weldment when compared to the TIG weld which dropped drastically at the weld metal region from 337.2 and 328.7 to 256.5 and 252.0 at the face and root respectively. The mechanical properties of both welds have not shown any major deviations from the standard Alloy SAF 2205 properties. They are within the acceptable range. The test results obtained indicated that with proper control and monitoring of the welding parameters, the SMAW can be effectively used to weld the Alloy 2205 with comparable high quality of properties.

Welding, Stainless Steel, Duplex Stainless Steel, Tungsten inert gas.

"Effect of Welding Processes on Susceptibility of Duplex Stainless Steel Alloy 2205 to Sensitization Using TIG and MMA", International Journal of Emerging Technologies and Innovative Research (www.jetir.org), ISSN:2349-5162, Vol.3, Issue 7, page no.86-91, July-2016, Available :http://www.jetir.org/papers/JETIR1607018.pdf

"Effect of Welding Processes on Susceptibility of Duplex Stainless Steel Alloy 2205 to Sensitization Using TIG and MMA", International Journal of Emerging Technologies and Innovative Research (www.jetir.org | UGC and issn Approved), ISSN:2349-5162, Vol.3, Issue 7, page no. pp86-91, July-2016, Available at : http://www.jetir.org/papers/JETIR1607018.pdf