Effect of rapid solidification on stainless steel weld metal microstructures and its implications on the Schaeffler diagram

Technical Report · Tue Sep 01 04:00:00 EDT 1987

DOI:https://doi.org/10.2172/5957599· OSTI ID:5957599

David, S A; Vitek, J M; Reed, R W; Hebble, T L

An investigation was carried out to determine the effect of rapid solidification on the weld metal microstructure of austenitic stainless steels and its implication on the ferrite constitution diagram. A wide variety of stainless steels were laser welded at different welding speeds and laser power levels. Results indicate that both weld pool cooling rate and the postsolidification solid state cooling rates have a profound effect on the microstructures. For the steels investigated, the microstructures ranged from duplex austenite (..gamma..) + ferrite (delta) to fully austenitic or fully ferritic. These microstructures were found to be sensitive to both cooling rates and composition. The observed results are rationalized based on rapid solidification theory. This investigation indicates that solidification rates and postsolidification cooling rates have a profound effect on the observed microstructures, thus making it impossible to predict the microstructures of rapidly cooled weld metal from the conventional constitution diagrams. The influence of the observations made in this investigation on the Schaeffler diagram is demonstrated, and possible corrections to the constitution diagram incorporating the cooling rate effects are proposed. 23 refs., 17 figs., 4 tabs.

• Research Organization: Oak Ridge National Lab., TN (USA)
• DOE Contract Number: AC05-84OR21400
• OSTI ID: 5957599
• Report Number(s): ORNL/TM-10487; ON: DE88001489
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360101 -- Metals & Alloys-- Preparation & Fabrication
360102* -- Metals & Alloys-- Structure & Phase Studies
ALLOYS
AUSTENITIC STEELS
CARBON ADDITIONS
CHROMIUM ALLOYS
CHROMIUM STEELS
CHROMIUM-NICKEL STEELS
COMPARATIVE EVALUATIONS
COOLING
CORROSION RESISTANT ALLOYS
CRACKS
CRYSTAL STRUCTURE
DIAGRAMS
FABRICATION
FERRITE
FERRITIC STEELS
FILLER METALS
HEAT RESISTANT MATERIALS
HEAT RESISTING ALLOYS
IRON ALLOYS
IRON BASE ALLOYS
JOINING
KINETICS
LASER WELDING
MATERIALS
MICROSTRUCTURE
MOLYBDENUM ALLOYS
NICKEL ALLOYS
NIOBIUM ADDITIONS
NIOBIUM ALLOYS
PHASE TRANSFORMATIONS
REACTION KINETICS
SOLIDIFICATION
STAINLESS STEEL-304
STAINLESS STEEL-308
STAINLESS STEEL-309
STAINLESS STEEL-316
STAINLESS STEEL-347
STAINLESS STEELS
STEELS
WELDING