Solidification and aging behavior of Types 308 and 308CRE stainless steel welds

Conference · Wed Aug 01 04:00:00 EDT 1984 · Weld. Res. Suppl.; (United States)

OSTI ID:5191375

Vitek, J M; David, S A

Controlled residual element (CRE) additions of Ti, P, and B to Type 308 stainless steel filler metal have been previously shown to improve the elevated-temperature creep-rupture properties of welds. The solidification and aging behavior of Types 308 and 308CRE stainless steel welds were examined in an effort to identify the mechanism responsible for the improved mechanical properties. Analysis of the as-welded microstructure and thermal analysis of the solidification behavior did not reveal any major differences that could be responsible for the creep-rupture improvement. However, extensive aging studies at 550-850/sup 0/C (1022-1562/sup 0/F) for times up to 10,000 hours revealed significant differences. The transformation of ferrite in the as-welded duplex structure to sigma phase was not retarded by CRE additions. However, the extensive precipitation of M/sub 23/C/sub 6/ at the austenite-ferrite interfaces in the aged Type 308 stainless steel welds was replaced by more homogeneous precipitation of titanium-rich carbides, nitrides, and sulfides in aged Type 308CRE stainless steel. The results are summarized in the form of TTT diagrams. It is proposed that the elimination of a continuous network of carbides is responsible for the improved elevated-temperature properties. The different type of precipitate formed may also play a role.

• Research Organization: Oak Ridge National Lab., TN
• DOE Contract Number: W-7405-ENG-26
• OSTI ID: 5191375
• Conference Information: Journal Name: Weld. Res. Suppl.; (United States)
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360103* -- Metals & Alloys-- Mechanical Properties
AGING
ALLOYS
BORON ADDITIONS
BORON ALLOYS
CHROMIUM ALLOYS
CHROMIUM STEELS
CHROMIUM-NICKEL STEELS
CORROSION RESISTANT ALLOYS
FILLER METALS
IRON ALLOYS
IRON BASE ALLOYS
JOINTS
MECHANICAL PROPERTIES
METALLURGICAL EFFECTS
NICKEL ALLOYS
PHASE TRANSFORMATIONS
PHOSPHORUS ADDITIONS
SOLIDIFICATION
STAINLESS STEEL-308
STAINLESS STEELS
STEELS
TITANIUM ADDITIONS
TITANIUM ALLOYS
WELDED JOINTS