Effect of ferrite transformation on the tensile and stress corrosion properties of type 316 L stainless steel weld metal thermally aged at 873 K

Journal Article · Sat Jul 01 04:00:00 EDT 1995 · Metallurgical Transactions, A

DOI:https://doi.org/10.1007/BF02670773· OSTI ID:87704

Shaikh, H; Khatak, H S; Gnanamoorthy, J B; Rodriguez, P ^[1]; Seshadri, S K ^[2]

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1. Indira Gandhi Centre for Atomic Research, Kalpakkam (India)
2. Indian Inst. of Tech., Madras (India). Dept. of Metallurgical Engineering

The use of austenitic stainless as prime construction materials for liquid metal-cooled fast breeder reactors often necessitates the joining of two or more components by the process of welding. High-temperature delta ferrite is deliberately retained in the weld metal to overcome the problem of hot cracking during weld metal solidification. This article deals with the effect of the microstructural changes, due to transformation of delta ferrite, on the associated variations that take place din the tensile and stress corrosion properties of type 316 L stainless steel weld deposits when subjected to postweld heat treatment at 873 K for prolonged periods (up to 2,000 hours). On aging for short durations (up to 20 hours), carbide/carbonitride was the dominant transformation product, whereas sigma phase was dominant at longer aging times. The changes in the tensile and stress corrosion behavior of the aged weld metal have been attributed to the two competitive processes of matrix softening and hardening. Yield strength (YS) was found to depend predominantly on matrix softening only, while significant changes in the ultimate tensile strength (UTS) and the work-hardening exponent, n, occurred due to matrix hardening. Ductility and stress corrosion properties were considerably affected by both factors. Fractographic observations on the weld metal tested for stress-corrosion cracking (SCC) indicated a combination of transgranular cracking of the austenite and interface cracking.

• Sponsoring Organization: USDOE
• OSTI ID: 87704
• Journal Information: Metallurgical Transactions, A, Journal Name: Metallurgical Transactions, A Journal Issue: 7 Vol. 26; ISSN MTTABN; ISSN 0360-2133
• Country of Publication: United States
• Language: English

Related Subjects

21 SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS
36 MATERIALS SCIENCE
CRYSTAL-PHASE TRANSFORMATIONS
LMFBR TYPE REACTORS
MICROSTRUCTURE
REACTOR MATERIALS
STAINLESS STEEL-316L
STRESS CORROSION
TENSILE PROPERTIES
WELDED JOINTS