AN INVESTIGATION OF HOT DUCTILITY OF INCONEL AND INCONEL X (thesis)

Technical Report · Fri Sep 19 04:00:00 EDT 1958

DOI:https://doi.org/10.2172/4298284· OSTI ID:4298284

Pigan, E. A.

Submitted to the Rensselaer Polytechnic Inst., Troy, N. Y. This investigation was undertaken to evaluate the effect of the thermal cycles associated with arc welding in Inconel and Inconel X and to find the cause for the change in properties due to the thermal cycles encountered in arc welding through a metallographic study of the fractured specimens. Modifications on the already built hot ductility time-temperature controller provided for the measurement and recording of the load nccessary to fracture a specimen. Hot ductility and ultimate tensile strength were determined as a function of peak thermal cycles with ductility increasing to a peak value at 2200 deg F. At temperatures above 2200 deg F. ductility decreased sharply until at the embrittling temperature (2450 deg F for Inconel, 2400 deg F for Inconel X) ductility reached zero for both alloys. The ultimate tensile strength was found to decrease uniformly with the temperature of testing. For specimens of Inconel fractured on-cooling from 2450 deg F, the ductility was lowered from the on- heating values but not significantly. The ultimate tensile strength was lowered at the lower temperature of testing but did not vary much from the on-heating values at higher temperatures. Inconel X, on the other hand, exhibited a drastic loss in ductility when the on-heating values are compared to the ductility of specimens fractured on-cooling from 2400 deg F. Corresponding to the drastic loss in ductility the ultimate tensile strength was substantially lowered for all test temperatures. Hot ductility of Inconel fractured oncooling from 2400-F did not vary significantly from the on-heating values; tensile stregnth decreased slightly at temperatures below 2000 deg F. Inconel X specimens exon-cooling from 2350 deg F than when tested on-heating. Some reduction of tensile strength is noted at lower temperatures but the values compare favorably at the higher temperatures. The severe loss in ductility of inconel X is accompanied by gross grain boundary melting. It is possible that meliing of the grain boundaries is a factor in hot cracking in the heat-affected zone when Inconel X is welded in large sections. (auth)

• Research Organization: Oak Ridge National Lab., Tenn.
• DOE Contract Number: W-7405-ENG-26
• NSA Number: NSA-12-016392
• OSTI ID: 4298284
• Report Number(s): ORNL-2571
• Country of Publication: United States
• Language: English

Related Subjects

ALUMINUM ALLOYS-- BRITTLENESS-- CHROMIUM ALLOYS-- CONTROL-- COOLING-- DUCTILITY-- ELECTRIC ARCS-- FAILURES-- HIGH TEMPERATURE-- HOT WORKING-- INCONEL ALLOYS-- MEASURED VALUES-- METALLOGRAPHY-- NICKEL ALLOYS-- NIOBIUM ALLOYS-- SAMPLING-- TENSILE PROPERTIES-- THERMAL STRESSES-- TITANIUM ALLOYS-- WEIGHT-- WELDING
CRACKS-- GRAIN BOUNDARIES-- HEATING-- MELTING
MINERALOGY, METALLURGY, AND CERAMICS