Pyrometallurgical, Physical, and Mechanical Behavior of Weldments.
Abstract
This research program aimed to achieve a better understanding of pyrometallurgical reactions during welding and process-microstructure correlations. The validity of proposed mechanisms for the formation of weld metal acicular ferrite was tested by using selected surrogate additions with similar chemical behavior but different physical properties compared to titanium-boron additions known to promote acicular ferrite formation. The results suggest that inclusion density and size distribution are the most important factors in acicular ferrite formation. The evolution of inclusions in the weld pool during welding and solidification was modeled. Procedures are reported for the use of shielding gas oxygen content as a welding parameter to optimize weld metal microstructure and properties. Exothermically-assisted shielded metal arc welding consumables were evaluated as a possible means to substitute chemical energy for traditional electrical energy during welding. Exothermic reactions produced up to 40 pct. of the heat required for welding. The influence of electrochemical reactions during welding on weld metal composition was investigated. Evidence of electrochemical behavior in specific welding parameter ranges was found. A search for new non-destructive evaluation techniques and associated procedures to measure specific weld metal compositions or constituents was undertaken. As a demonstration, magnetic property measurements were used to detect phase transformations in Al-Cu alloys.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jan 30, 1996
- Accession Number
- ADA310210
Entities
People
- David L. Olson
- Robert H. Frost
Organizations
- Colorado School of Mines