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U.S. Department of Energy
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Microstructural characterization of autogenous GTA welds in a 12Cr-1Mo-0. 3V steel

Technical Report ·
OSTI ID:6876136

In support of the national fusion energy effort, the weldability of a 12Cr-1Mo-0.3V martensitic stainless steel has been investigated. This alloy is a leading candidate for the first wall/blanket of the ETF (Experimental Test Facility) fusion reactor. The initial investigation has utilized both the continuous cooling transformation diagram and the equilibrium phase diagram to rationalize the microstructures observed in the fusion zone and heat-affected zone of gas tungsten-arc welds. Regions of maximum hardness were observed within the fusion zone and in the coarse-grained region of the heat-affected zone where the predominant microstructural constituent was untempered martensite. Regions of the heat-affected zone which either contained a mixture of untempered martensite and carbides or were not fully reaustenitized during the weld thermal cycle exhibited a lower as-welded hardness. The presence of residual ferrite in an untempered martensite matrix along the weld fusion line also resulted in a localized drop in hardness. The on-heating and on-cooling transformation behavior of the alloy, as determined with the aid of the Gleeble dilatometer, corroborated both the microstructural observations and the hardness data.

Research Organization:
Sandia National Labs., Livermore, CA (USA)
DOE Contract Number:
AC04-76DP00789
OSTI ID:
6876136
Report Number(s):
SAND-80-8236
Country of Publication:
United States
Language:
English