Wear Behavior of Modified Surface Layer Produced by TIG Melting of Preplaced Ti Powder in Nitrogen Environment

The formation of hard surface layer on steel provides a protective coating against wear, thermal loads and corrosion. In the present work a hard composite layer is formed on steel surfaces by preplacement of titanium powder and melted under nitrogen environment. Surface melting was conducted using TIG torch with different energy inputs. The microstructure and the morphology of the melt tracks were investigated using SEM and X-ray diffraction. The in-situ melting of titanium powder in nitrogen atmosphere produced dendritic microstructure of titanium nitride. The melt layer contained dispersed TiN, Ti2N dendrites highly populated at the surface compared to the deeper melt and gave a maximum surface hardness of around 1927 Hv. The wear property of the melt track was investigated using pin-on-disk tribometer at room temperature. The modified surface layer gave a low friction value of 0.12 and wear rate of 0.007895 ×10-4 compared to 1.648 × 10-4 mm3/N/m for the uncoated steel surface.

[1]  E. Bourhis,et al.  Hardness properties and high-temperature wear behavior of nitrided AISI D2 tool steel, prior and after PAPVD coating , 2009 .

[2]  S. Jain,et al.  Erosion wear behavior of laser clad surfaces of low carbon austenitic steel , 2009 .

[3]  A. Nath,et al.  Studies on compositionally graded silicon carbide dispersed composite surface on mild steel developed by laser surface cladding , 2008 .

[4]  J. Tu,et al.  Preparation and tribological behavior of TiN/a-C composite films deposited by DC magnetron sputtering , 2008 .

[5]  H. Kalman,et al.  Thermal stability and wear resistance of hard TiN/TiCN coatings on plasma nitrided PH15-5 steel , 2007 .

[6]  S. Mridha.  Titanium nitride layer formation by TIG surface melting in a reactive environment , 2005 .

[7]  Y. Tian,et al.  Laser surface alloying of pure titanium with TiN-B-Si-Ni mixed powders , 2005 .

[8]  A. Nath,et al.  Characterization of dry sliding wear resistance of laser surface hardened En 8 steel , 2005 .

[9]  P. Cheang,et al.  Intermetallic coatings produced by TIG surface melting , 2001 .

[10]  T. N. Baker,et al.  Study of the surface layer formed by the laser processing of Ti–6Al–4V alloy in a dilute nitrogen environment , 2001 .

[11]  Koji Kato,et al.  Wear in relation to friction — a review , 2000 .

[12]  G. M. Z. Köcker,et al.  Comprehensive tribological characterization of thin TiN-based coatings , 1995 .

[13]  T. N. Baker,et al.  Characteristic features of laser-nitrided surfaces of two titanium alloys , 1991 .

[14]  Eg Kelly,et al.  The metallurgy of welding , 1964 .