Heat treatment of pipe in a dome electric furnace

Conclusions

• 1. The necessary condition for even heating of pipe in a dome electric furnace is automatic control of the temperature along the length of the furnace, with an even supply of heat along the perimeter of the bundle in each zone, which is ensured with P¹/P²=1.5.

• 2. Proper heating of pipe in a dome furnace depends on the location of control thermocouples, the hot junction of which should be in the area of the heating elements.

  The temperature should be raised in two stages with holding for 25–30 min as an intermediate step.

• 3. It is economically expedient to use dome furnaces for heat treating pipe only in those cases where prolonged holding is required.

  The technicoeconomic indices of dome furnaces can be improved by reducing the weight of the furnace lining by use of lightweight low-thermal-conductivity refractories and also by increasing the rate of heat exchange in the bundle.