Experimental Investigation and Hardness Analysis of Chromoly Steel Multipass Welds Using GMAW

This work presents the result of investigations aimed
at determining the hardness of the welded Chromoly (A 4130) steel
plate of 2” thickness. Multi pass welding for the thick sections was
carried out and analyzed for the Chromoly alloy steel plates. The
study of hardness at the weld metal reveals that there is the presence
of different micro structure products which yields diverse properties.
The welding carried out using GMAW with ER70s-2 electrode.
Single V groove design was selected for the butt joint configuration.
The presence of hydrogen has been suppressed by selecting low
hydrogen electrode. Preheating of the plate prior to welding reduces
the cooling rate which also affects the weld metal microstructure. The
shielding gas composition used in this analysis is 80% Ar-20% CO2.
The experimental analysis gives the detailed study of the hardness of
the material.

• Ramesh S.
• Sasiraaju A. S.
• Sidhaarth K.
• Sudhan Rajkumar N.
• Manivel Muralidaran V.

• Chromoly
• Gas Metal Arc Weld (GMAW)
• Hardness
• Multi pass weld
• Shielding gas composition.

[1] S. Mukhopadhyay, T.K. Pal (2006) Effect of shielding gas mixture on
gas metal arc welding of HSLA steel using solid and flux cor wires. Int J
advanced Manufactured Technology 29: 262-268
[2] Varga T, Konkoly T, Straube H. Investigation on microstructure,
toughness and defect tolerance of gas metal arc weld. IIW Document.x-
1205-90
[3] Vaidya VV (2002) Shielding gas mixture for semiautomatic welds.
Welding J 81(9):43-48
[4] Lathhabai S, Stout RD (1985) Shielding gas and heat input effects on
flux-cored weld metal properties. Welding J 64(11):303-S-313-S
[5] Lesnewieh A (1990) An overview of arc welding process and joining of
HSLA Steels. In: proceedings of the international conference on the
metallurgy, Welding and qualification of microalloyed (HSLA) steel
weldments, Nov 6-8
[6] Barboo FJ, Krauklis P, Easterling KE (1989) Mater Sci Technology
5:1057-1068
[7] Kluken AO, Grong O (1989) Mechanisms of inclusion formation in
AlTi-Si-Mn deoxidized steel weld metals.Metall Trans A 20A:1335-
1349
[8] Farrar RA (1976) The role of inclusion in the ductile fracture of weld
metals. Welding metal Fabrication 44 (8):579-581
[9] Francis RE, Jones JE, Olson DL (1990) Effect of shielding gas oxygen
activity on the weld metal microstructure of GMA welded microalloyed
HSLA steel. Welding J 69(11):408s-415s
[10] Pal TK, Dutta S, Majumdar SK (1997) Effect of shielding gas
composition on chemistry and mechanical properties of gas metal arc
weld metal. Trans Indian Inst Metals 50(2-3):201-208