Refractory Materials Used In the Bogie Hearth Furnace

Refractory materials used in bogie hearth furnace should comply with the current standards. It is a type of periodic heating furnace. The furnace temperature changes over time according to the heating procedure. It is usually used for the billet heating before forging or workpiece heat treatment. It is the most common furnace in the machinery industry. 

Bogie hearth furnaces can be divided into bogie hearth heating furnace and bogie hearth heat treatment furnace. Bogie hearth furnaces used for drying and baking are also called drying furnace and baking furnace. 

 

A bogie hearth furnace is composed of the hearth, bogie, rail, door and flue. 

 

Hearth

The hearth of the bogie hearth furnace is composed of steel structure, refractory materials and sealing components. 

 

The steel structure is a sealed shell welded with steel columns and steel plates. It is used to prevent the deformation caused by the thermal expansion and contraction of refractory materials and ensure the tightness of the masonry. 

 

The walls consist of the inner refractory bricks, the external bricks and insulation refractory fiber of the hearth. 

 

The roof is an arch composed of arch springing bricks, wedge-shaped bricks and straight bricks. Insulation materials are laid on the arch. Burners are set in the lower part of the walls. 

 

The differences between the refractory fiber hearth and refractory brick hearth include:

a. Refractory fiber hearth is thinner, lighter and has better insulation properties than the brick hearth. 

b. There is no side thrust in the roof and no expansion stress in the furnace body, so the fiber hearth can be lighter. 

c. Since the refractory fiber is lighter, the walls can be hold by the steel and hang, so the bottom has better heat dissipation. 

d. It has several better sealing structures than sand sealing due to the softness and flexibility of fiber.  

 

The passing in and out of the workpieces relies on the dragging under the traction mechanism on the rails. The bogie is composed of refractory materials, frame and running mechanism. The refractory materials in the upper part of the bogie can withstand the load of high temperature and workpieces. The frame has good strength and rigidness under the downward heat transfer of the refractory materials. It is composed of beams and stringers welded with steel. Steel plates and frames on the beams for the refractory laying. Sealing knives are installed on the both sides and seal the furnace during operation. The running mechanism is installed on the stringers. 

 

The rails depend on the form of the running mechanism of the bogie. Wheel bogie runs on monorail, roller belt bogie runs on double rails. 

 

The door is always tall. The door and the door frame are built with heat-resistant iron castings. The door lining is built with refractory fiber or lightweight bricks.

 

Refractory materials used in the flues include:

(1) Bogie hearth heating furnace: high alumina bricks, fire clay bricks, diatomite bricks or calcium silicate board, refractory fiber insulation boards, high-alumina refractory castable and polycrystalline mullite fiber products.

 

(2) Bogie hearth heat treatment furnace: fire clay bricks, diatomite bricks or calcium silicate board, refractory fiber insulation boards, refractory castables, refractory blanket and module.