Transformation temperatures, mechanical properties and residual stress of two low-transformation-temperature weld metals

Two low-transformation-temperature weld metals, 12Cr6Ni and 8Cr10Ni weld metals, were devised and their martensite start temperatures were 245 degrees C and 225 degrees C, respectively. Despite a small difference of 20 degrees C in martensite start temperature, the martensite finish temperature of the former was 100 degrees C, while the one of the latter was below room temperature. The difference in martensite finish temperature was due to the stacking fault energy. Lower stacking fault energy accelerated martensitic transformation, thus elevating martensite finish temperature. Owing to difference in martensite finish temperature, the microstructures, mechanical properties and residual stress of low-transformation-temperature weld metals varied correspondingly. Furthermore, experimental and finite-element study indicated that volume expansion strain and martensitic transformation temperature range strongly affected residual stress.