The catalytic converter operates at very hot temperatures normally. That being said if the temp is becoming excessive (converter glowing for example) this is an indication of excessive unburt fuel entering the catalytic converter. This can be caused by a variety of issues such as spark plugs fowled to a rich air fuel mixture. If the converter is operating this hot you need to have the vehicle repaired. If it is let go and complete meltdown of the cat occurs, you may run the risk of having a fire under the vehicle.