Developing optimum postweld treatments of IN625 welds using stress relaxation tests

Conference · Sat Dec 31 04:00:00 EST 1994

OSTI ID:115497

J, Diehl M; Messler, Jr, R W

Inconel 625 is a solid-solution strengthened, nickel-based, chromium molybdenum alloy used for its high strength and excellent corrosion resistance. Corrosion resistance and, to a lesser extent, strength can be enhanced by precipitation of intergranular carbides by appropriate heat treatment. In welded structures, dissolution of carbides near the fusion line in the heat-affected zone render denuded regions susceptible to preferential corrosive attack that is greatly aggravated by residual stresses. To reduce the propensity for stress corrosion in weldments, manufacturing practice typically includes methods for reducing residual stresses, usually using postweld heat treatments. With appropriate heat treatment, grain boundary carbides and general corrosion resistance can be restored at the same time. A series of heat treatments were performed between 1050 and 1800{degrees}F (566 and 982{degrees}C) to determine effectiveness in relieving welding-induced stresses as well as for improving corrosion resistance for a specialized application. Stress relaxation testing of all-weld-metal specimens was compared to residual stress measurement in full-scale weldments using a hole-drilling strain gage technique. The much simpler stress relaxation method provided an excellent measure of residual stresses and proved to be an expeditious way to develop optimum postweld heat treatments.

• OSTI ID: 115497
• Report Number(s): CONF-9404233--
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
CARBIDES
CORROSION RESISTANT ALLOYS
HEAT TREATMENTS
INCONEL 625
MICROSTRUCTURE
PRECIPITATION
STRESS ANALYSIS
WELDABILITY
WELDED JOINTS