Influence of weld metal alloying additions to extend the heat input range for the submerged arc welding of high strength steels. Final report

Technical Report · Thu Dec 16 04:00:00 EST 1993

OSTI ID:5260595

Liu, S; Olson, D L; Ramirez, J E

Weld metal microstructural development for high strength steels when welded with submerged arc welding process was investigated as a function of consumable composition and thermal experience. Of specific interest is the effect of systematic variations of microalloying additions on broadening of applicable heat input range. Controlled weld metal oxygen content, particularly in the range of 300 to 400 ppm, has been found to improve HY-130 steel weld metal toughness. Molybdenum additions was found to increase the strength of the HY-130 steel weld deposits. Copper additions up to 3.5 wt.pct. were found to strengthen the high strength steel weld metals, in particular, those of higher heat input, 3.6 kJ/mm. Niobium additions alone did not provide as powerful strengthening effect in the high heat input weld metals as the copper additions. In the case of copper-enriched welds, multi-pass welding induced both the precipitation and overaging of epsilon copper precipitates in the reheated weld metal which resulted in non-uniform mechanical properties. When added together, copper and niobium produced the synergistic effect of dual precipitation (Epsilon copper and niobium carbides) which provided the needed strength and thermal stability to the reheated weld metal even at high heat inputs. With this novel approach, the applicable heat input range to produce both adequate weld metal strength and toughness in high strength steels (Sigma y > 690 MPa) can be extended significantly. The optimal additions for copper and niobium were found to be 3.3 and up to 0. 1 wt. pct., Heat input, High strength steel, Precipitation strengthening, Copper, Niobium, Single and multi-pass welding.

• Research Organization: Colorado School of Mines, Golden, CO (United States). Center for Welding and Joining Research
• OSTI ID: 5260595
• Report Number(s): AD-A-274284/9/XAB; CSM-CWR--093-015; CNN: N00014-90-J-1889
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360101* -- Metals & Alloys-- Preparation & Fabrication
360103 -- Metals & Alloys-- Mechanical Properties
ALLOYS
ARC WELDING
CHEMICAL COMPOSITION
FABRICATION
IRON ALLOYS
IRON BASE ALLOYS
JOINING
MECHANICAL PROPERTIES
METALLURGICAL EFFECTS
STEELS
SUBMERGED ARC WELDING
TEMPERATURE DEPENDENCE
WELDING