Abstract
Temperature was selected as variable to study phase transformation in weld metal of 12Cr1MoV steel and realized in-situ detection of temperature in weld metal. The maximum temperature and cooling rates during welding were acquired to form the simulation technology of 12Cr1MoV steel in weld metal, and the SW-CCT diagram of 12Cr1MoV steel were obtained by the thermal simulation equipment with extracted cooling rates. When the average cooling rate of t 8/3 is under 1.7 °C/s, the microstructure in weld metal of 12Cr1MoV steel is ferrite (F)+perlite (P)+bainite (B); under 4.7 °C/s, the microstructure is P+B; under 33 °C/s, the microstructure is B; over 33 °C/s, the microstructure is martensite (M). The optical microstructures of typical cooling rates are coincident with the test results of SW-CCT. The Vikers hardness increases with the increasing of cooling rates.