Effects of Heat Input on the Mechanical and Metallurgical Characteristics of Tig Welded Incoloy 800Ht Joints

Abstract

This study focuses on the effect of heat input on the quality characteristics of tungsten inert arc gas welded incoloy 800HT joints using inconel-82 filler wire. Butt welding was done on specimens with four different heat inputs by varying the process parameters like welding current and speed. The result indicated that higher heat input levels has led to the formation of coarser grain structure, reduced mechanical properties and sensitization issues on the weldments. The formation of titanium nitrides provided resistance to fracture and increased the tensile strength of the joints at high temperatures. Further aging was done on the welded sample at a temperature of 750°C for 500 hours and the metallographic result showed formation of carbides along the grain boundaries in a chain of discrete and globular form which increased the hardness of the material. The formation of spinel NiCr 2 O 4 provided oxidation resistance to the material during elevated temperature service.

Evaluation of radiation shielding potentials of Ni-based alloys, Inconel-617 and Incoloy-800HT, candidates for high temperature applications especially for nuclear reactors, by EpiXS and Phy-X/PSD codes

“…Incoloy-800HT is a variation of Incoloy-800 and 800H. Alloy 800HT is an iron-nickelchromium solid-solution strengthened alloy, one of the featured materials for fourth generation nuclear power plant, with the properties of good resistance to corrosion, oxidation, and appreciable strength at high temperatures [4]. Alloy 800HT can be used as for control rod sheath materials for very-high-temperature reactor and in industrial heating equipment, hydrocarbon processing industry etc.…”

“…Many studies about alloys for different purposes were reported before [6][7][8][9][10][11][12][13][14]. Among the alloys, Ni-based alloys, Inconel-617 and Incoloy-800HT, were also studied by many researchers previously [1,4,[15][16][17][18][19][20]. The researches were generally focused on the oxidation behaviors in different environments, mechanical, metallurgical and tensile properties of the alloys 617 and 800HT.…”