Cobalt-base surfacing of Inconel 718

Journal Article · Sat Dec 01 04:00:00 EST 1973 · Weld. J. (N.Y.), v. 52, no. 12, pp. 550s-556s

OSTI ID:4364706

Douty, R A; Schwartzbart, H

The properties of Inconel 718 suggest its use as a material of construction in the liquid sodium cooled fast breeder reactor. In some of its uses it would be desirable that it be surfaced for hardness with a cobalt base alloy, Because of prior observations of microfissuring in the welding of Inconel 718, a study was completed to determine whether this phenomenon would be encountered in transferred arc plasma surfacing, and, if so, the influence of various metallurgical and process parameters on its occurrence. Six-inch rounds of Inconel 7l8 from different heats and sources were surfaced with CoCrA by the transferred arc plasma process. The variables studied were 718 processing history, composition, grain size, and heat input during surfacing. A prior researcher had proposed the use of fillerless gas tungsten-arc welding (GTAW) to indicate the susceptibility of Inconel 718 to microfissuring. Therefore, this possibility was studied. Of the variables studied, only the grain size of the Inconel 7l8 appeared to have any significant and systematic effect on microfissuring behavior. Coarse-grained material was more prone to cracking than fine-grained material. All of the cracking occurred under the deposit, confined entirely to the grain boundaries in the heataffected zone of the base metal. None of the fillerless gas tungstenarc welds exhibited any cracking. Therefore, GTAW did not serve as an indicator of cracking susceptibility. (auth)

• Research Organization: Rockwell International Corp., Pittsburgh
• NSA Number: NSA-29-013149
• OSTI ID: 4364706
• Journal Information: Weld. J. (N.Y.), v. 52, no. 12, pp. 550s-556s, Journal Name: Weld. J. (N.Y.), v. 52, no. 12, pp. 550s-556s; ISSN WEJUA
• Country of Publication: Country unknown/Code not available
• Language: English

Related Subjects

*CHROMIUM ALLOYS-- DEPOSITION
*COBALT BASE ALLOYS-- DEPOSITION
*INCONEL 718-- PLASMA ARC SPRAYING
*LMFBR TYPE REACTORS-- REACTOR MATERIALS
*TUNGSTEN ALLOYS-- DEPOSITION
CRACKS
GAS TUNGSTEN-ARC WELDING
GRAIN BOUNDARIES
GRAIN SIZE
HEAT AFFECTED ZONE
N50210 --Metals
Ceramics
& Other Materials--Metals & Alloys--Corrosion & Erosion & Surface Phenomena
N50220* --Metals
Ceramics
& Other Materials--Metals & Alloys--Preparation & Fabrication
POWDERS
VALVES LMFBR TYPE REACTORS