The effect of heat treatment on phosphorus segregation in a submerged-arc weld metal

Conference · Fri Oct 01 04:00:00 EDT 1999

OSTI ID:679493

Beere, W B ^[1]; Buswell, J T ^[2]

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1. Magnox Electric plc, Berkeley (United Kingdom)
2. jtb Materials and Design, Stroud (United Kingdom)

Intergranular fracture (IGF) has been observed in carbon-manganese steels after irradiation or high temperature exposure for prolonged periods. The effect is associated with an increase in the ductile-brittle transition temperature and has been related to phosphorus diffusion to grain boundaries. Phosphorus also diffuses thermally at the temperatures used for post-weld heat treatments such that in principle, the slightly different heat treatments given to different parts of a large vessel could lead to differing grain boundary phosphorus coverage and hence susceptibility to IGF. The effect of typical heat treatments on phosphorus coverage has been investigated using a finite difference model based on a theory that has been fitted to a wide range of constant temperature data. Regardless of previous history, the grain boundary coverage of phosphorus was predicted to depend on the final anneal and cooling rate. These differed insufficiently in the typical heat treatments to produce significant differences in segregation. It was concluded that the ductile-brittle transition temperature in submerged-arc welds would be unaffected in vessels that had seen typical post-weld heat treatments.

• OSTI ID: 679493
• Report Number(s): CONF-960643--
• Country of Publication: United States
• Language: English

Related Subjects

22 GENERAL STUDIES OF NUCLEAR REACTORS
36 MATERIALS SCIENCE
EMBRITTLEMENT
FRACTURE PROPERTIES
HEAT TREATMENTS
PHOSPHORUS
PRESSURE VESSELS
REACTOR MATERIALS
SEGREGATION
STEELS
WELDED JOINTS