What is the unit of temperature(melting and transition) in the Johnson-Cook model in Abaqus? Which I should use Kelvin or Celcius? For all other parameters like conductivity, I used Kelvin.
You can find in Abaqus Analysis User's Guide, version 6.14, section 1.2.2 Conventions -> Units:
"Abaqus has no units built into it except for rotation and angle measures. Therefore, the units chosen must be self-consistent, which means that derived units of the chosen system can be expressed in terms of the fundamental units without conversion factors."