MECHANICAL AND METALLURGICAL INVESTIGATION ON GAS METAL ARC WELDING OF SUPER AUSTENITIC STAINLESS STEEL

The main purpose of this paper is to present the investigations of the microstructure and mechanical properties of super austenitic stainless steel butt joints made by gas metal arc welding with different shielding gas mixtures. Welding was performed under two sets of optimized parameters employing three different shielding gases, namely 100% argon, 80% argon+20% CO2 and 100% CO2. The microstructure and the mechanical properties of the welds were examined. The fully austenitic base microstructure got transformed into primary dendritic and secondary interdendritic phases in the weld zone. Higher amount of secondary interdendritic phase was observed in the welds made under 100% argon gas whereas a rich amount of long columnar dendritic structures were observed in the welds made under 100% CO2 gas. Welds made under 80% argon+20%CO2 gas under the second set of parameter was found to exhibit comparatively better mechanical properties due to proper amount of the dendritic and interdendritic grain structures in the weld region.

[1]  P. Ferro,et al.  Microstructural, compositional and residual stress evaluation of CO2 laser welded superaustenitic AISI 904L stainless steel , 2006 .

[2]  M. Ohashi.  Extreme value analysis of ductile fracture surface by dimpled rupture associated with fracture behavior of tensile specimens , 2007 .

[3]  A. Cruz-Crespo,et al.  Effect of the O2/CO2 ratio and welding current on the geometry of square groove weld joints in low carbon steels obtained with GMAW , 2010 .

[4]  STUDY OF THE EFFECT OF BEVEL ANGLE AND WELDING HEAT INPUT ON MECHANICAL PROPERTIES OF MILD STEEL WELDMENTS , 2011 .

[5]  K. Rajasekhar,et al.  Microstructural evolution during solidification of austenitic stainless steel weld metals: A color metallographic and electron microprobe analysis study , 1997 .

[6]  Paulo José Modenesi,et al.  Characterization of GMAW arc instability phenomena related to low oxidation potential shielding gases , 2010 .

[7]  S. Senthil Kumaran,et al.  OPTIMIZATIONAL STUDY OF FRICTION WELDING OF STEEL TUBE TO ALUMINUM TUBE PLATE USING AN EXTERNAL TOOL PROCESS , 2011 .

[8]  Paul A. Colegrove,et al.  Comparison of joining efficiency and residual stresses in laser and laser hybrid welding , 2011 .

[9]  A. Durgutlu.  Experimental investigation of the effect of hydrogen in argon as a shielding gas on TIG welding of austenitic stainless steel , 2004 .

[10]  M. T. Liao,et al.  The effect of shielding-gas compositions on the microstructure and mechanical properties of stainless steel weldments , 1998 .

[11]  Structural Steels,et al.  Welding Metallurgy of , 1987 .

[12]  T. Srikanthan,et al.  Static Modeling of GMAW Process Using Artificial Neural Networks , 1999 .

[13]  M. Amuda,et al.  Microstructural features of Aisi 430 Ferritic Stainless Steel (FSS) Weld Produced under varying process parameter , 1970 .

[14]  Xiaoyan Zeng,et al.  Study on microstructure and mechanical properties of 304 stainless steel joints by TIG, laser and laser-TIG hybrid welding , 2010 .

[15]  M. Sheikhi,et al.  Study of the effect of shielding gas composition on the mechanical weld properties of steel ST 37-2 in gas metal arc welding , 2009 .

[16]  Xiaoyan Zeng,et al.  Laser-TIG hybrid welding of ultra-fine grained steel , 2009 .