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Heat input and dilution effects in microalloyed steel weld metals

Journal Article · · Welding Journal (Miami); (United States)
OSTI ID:5363663
 [1];  [2];  [3]
  1. Hunt Integrated Technologies, Oklahoma City, OK (United States)
  2. SINTEF, Trondheim (Norway). Div. of Metallurgy
  3. Colorado School of Mines, Golden, CO (United States). Center for Welding and Joining Research

The sensitivity of weld metal microstructure and mechanical properties to variations in both heat input (i.e., cooling rate) and weld dilution in submerged arc (SA) welding of microalloyed steel was examined. Weldments were prepared with weld metal dilutions of approximately 40% and 70% at heat inputs of 2.0, 3.3, 4.6, and 5.3 kJ/mm, using two commercial welding wires and a basic commercial flux. The high dilution welds, which were ordinary bead-on-plate welds, resulted in microstructures that ranged from ferrite with aligned second phase at low heat inputs to acicular ferrite at high heat inputs. Special over-welding techniques were used to make the low dilution welds, allowing use of the same welding parameters as those for the high dilution welds. The technique involved remelting of weld metal to simulate the effect of multipass welding. The microstructure of these welds was predominantly acicular ferrite, independent of heat input. As a consequence, the low dilution welds had superior toughness compared to the high dilution welds.

OSTI ID:
5363663
Journal Information:
Welding Journal (Miami); (United States), Journal Name: Welding Journal (Miami); (United States) Vol. 73:1; ISSN 0043-2296; ISSN WEJUA3
Country of Publication:
United States
Language:
English