Corrosion resistance of GTAW and EBW welded joints of DIN W. Nr. 1.4462 (UNS S31803): Effect of post-weld-heat-treatment

Book · Sun Dec 01 04:00:00 EST 1996

OSTI ID:403625

Brandi, S D; Padilha, A F; Wolynec, S ^[1]

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1. Univ. of Sao Paulo (Brazil). Metallurgical and Materials Engineering Dept.

The duplex stainless steels present better corrosion behavior than the conventional stainless steels. This is due to their chemical composition (Cr, Ni, Mo, N) and a balanced microstructure (50% ferrite). It might be an increase on the volumetric fraction of ferrite, depending on the cooling rate after welding. In the same way the chemical composition can be altered by a loss of the alloying elements during welding, such as N. Both phenomena will decrease the corrosion resistance of the weldment. Autogenous GTAW and EBW were used to join the plates. Several corrosion tests were used to evaluate the behavior of the joints in as-welded (AW) and post-welded-heat-treated (PWHT) conditions. The results were analyzed and correlated to the microstructure of the welded joints. The main conclusion of this work is that corrosion resistance of both joint processes (EBW and GTAW) in as-welded condition is inadequate. PWHT (post-weld-heat-treatment) dissolved the chromium-rich precipitates, restored the equilibrium amount of austenite in the joints and recovered their corrosion resistance.

• OSTI ID: 403625
• Report Number(s): CONF-9606279--; ISBN 0-7918-1492-0
• Country of Publication: United States
• Language: English

Related Subjects

02 PETROLEUM
03 NATURAL GAS
36 MATERIALS SCIENCE
CORROSION RESISTANCE
ELECTRON BEAM WELDING
EXPERIMENTAL DATA
FIELD PRODUCTION EQUIPMENT
GAS TUNGSTEN-ARC WELDING
HEAT TREATMENTS
METALLURGICAL EFFECTS
PRECIPITATION HARDENING
STAINLESS STEEL-318
WELDED JOINTS