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Title: Characterization of Type 304L stainless steel solid-state closure welds for radioactive waste containment

Technical Report ·
DOI:https://doi.org/10.2172/10174815· OSTI ID:10174815

Radioactive wastes, generated during years of nuclear materials production, will be vitrified in glass and sealed in canisters. These cylindrical canisters are fabricated from 0.375 inches (9.5 mm) thick Type 304L stainless steel plate and are 24 inches (61 cm) in diameter and 118 inches (3 m) tall with a forged nozzle. The canisters will be sealed by resistance upset welding a 5 inch (12.7 cm) diameter, 0.5 inch (1.27 cm) thick, slightly oversized plug into the nozzle. A parametric study recommended a range of production welding variables based on mechanical tests and metallography. Intentionally ``cold`` welds produced with low currents and short times exhibited insufficient interface length and lack-of-bonding. At very high currents, long weld times and low force, maximum heating occurred with significant melting at the top, which makes process stability a concern. All welds made between these extremes exhibited predominantly solid-state bonding. Little variation in microstructure between welds was found along much of the interface with changes in current, force and time. Hardness traverses across the welds showed higher values at the interface, indicative of the worked microstructure. Crevices formed at the top and bottom during plastic flow of the material, and grain sizes varied along the interface from differences in dynamic recrystallization and grain growth. The degree of melting at the top was the most significant difference among welds made within the recommended parameter range.

Research Organization:
Savannah River Site (SRS), Aiken, SC (United States)
Sponsoring Organization:
USDOE, Washington, DC (United States)
DOE Contract Number:
AC09-89SR18035
OSTI ID:
10174815
Report Number(s):
WSRC-MS-94-0149; CONF-940793-2; ON: DE94016539; TRN: AHC29501%%102
Resource Relation:
Conference: 27. annual international metallographic society (IMS)/ASM convention,Montreal (Canada),24-27 Jul 1994; Other Information: PBD: [1994]
Country of Publication:
United States
Language:
English