Formation of Ti-Al-N Dispersed Layer on Steel Surface by TIG Melting in a Reactive Environment

Abstract

In this study an attempt has been made to produce titanium-aluminium dispersed hard nitride layer on mild steel surfaces by preplacement of 50 % Ti and 50 % Al powder mixture and then melting with TIG torch under nitrogen environment. Parameter such as heat input of the torch was varied between 540, 608 and 675 J/mm and its effect on the resolidified melt pool was studied. Glazing under all energy inputs produced more than 1mm thick resolidified clad layer. The microstructural analysis revealed the clad layer with dispersion of dendrites of Ti-Al nitrides and Ti- Al intermetallic in ferrite matrix. The concentration of dendrites were found to be maximum near the surface and decreased at deeper depths.The maximum hardness of the modified surface layer was found to be 900 Hv compared to180 Hv of the mild steel substrate.

Overlapping tracks processed by TIG melting TiC preplaced powder on low alloy steel surfaces

“…These types of TiC distribution and segregation have also been reported in laser processed MMC coatings on titanium surfaces 7 and TIG torch processed coatings on titanium and steel surfaces. 21,27,32–35…”

“…These types of TiC distribution and segregation have also been reported in laser processed MMC coatings on titanium surfaces 7 and TIG torch processed coatings on titanium and steel surfaces. 21,27,[32][33][34][35] TiC precipitates of globular, cubic and flower morphologies were seen in many overlapping tracks, but were not uniformly distributed in the melt microstructures. Similar morphologies of TiC precipitates were also reported in single track composite coatings.…”

“…Following the publication of the initial research, [16][17][18][19] an increasing number of papers based on the present work have been reported in the literature. [20][21][22][23][24][25][26][27][28][29][30][31][32][33][34][35] However, there are few reports of investigations that produce significant relationships between the processing conditions and the coating quality, especially on steel substrates. A recent experimental study by Mridha et al 32 incorporated TiC particulates into an AISI 4340 low alloy steel surface, using a powder preplacement technique and melting under a TIG torch to give a single track.…”

“…Depending on the processing conditions used, 0?5-1?0 mm thick defect free composite layers on the substrate surfaces, which had hardness values of about 2?5-4 times the base hardness of 300 HV, were successfully produced. 32 Previously surface engineering work using the TIG technique [20][21][22][23][24][25][26][27][28][29][30][31][32][33][34][35] produced either a small hemispherical volume of modified surface or a single melt track with a width of a few millimetres, running the length of the specimen. However, in many service applications, there is a frequent requirement to modify a much greater surface area.…”

Improving the high-temperature oxidation resistance of H13 steel by laser cladding with a WC/Co-Cr alloy coating

“…Co-based coatings applied using spraying methods are mechanically bonded to the substrate (Wang et al , 2010; Sobolev et al , 1998; Du et al , 2006). Tungsten inert gas (TIG) cladding is an economical surface alloying method, which provides a metallurgical bond between the substrate and the cladding coating (Mridha, 2005; Dyuti et al , 2011). Lei et al fabricated a Co alloy coating on 304 stainless steel via TIG cladding, which improved microhardness and cavitation erosion resistance (Lei et al , 2011).…”