Industrial Annealing Furnace

Annealing is a metal heat treatment process that involves slowly heating a metal to a certain temperature, holding it for a sufficient time, and then cooling it at a suitable rate, sometimes naturally, and sometimes with a controlled cooling rate.

1. To reduce hardness, soften the workpiece, and improve machinability.

2. To improve or eliminate various structural defects and residual stresses caused by casting, forging, rolling, and welding processes in steel, reducing workpiece deformation, cracking, or tendency to develop cracks.

3. To refine grain size, improve microstructure to enhance the mechanical properties of the workpiece, and eliminate structural defects.

4. To homogenize the material microstructure and composition, improve material properties, or prepare the microstructure for subsequent heat treatments such as annealing and tempering.

In actual production, annealing is widely used. Depending on the purpose of annealing, there are various annealing heat treatment processes, commonly including full annealing, spheroidizing annealing, and stress-relief annealing.

Annealing furnaces are widely used in various industries such as casting, metallurgy, automotive, aerospace, military, shipbuilding, light industry, and power. They can be used for various metal workpieces, including high-chromium and high-manganese steel castings, gray cast iron parts, rolls, bearings, steel balls, and wear-resistant liners, to undergo different annealing heat treatment processes.

The annealing furnace is manufactured with a square or round furnace body structure. The furnace chamber is lined with refractory bricks and aluminosilicate fiber composite insulation, or with a full fiber insulation lining. The workpiece is placed inside the furnace chamber and heated by electric heating, or by fuel oil or gas. The workpiece is heated to the required annealing process temperature under natural or protective atmosphere. After holding at this temperature for a period of time, it is naturally cooled or cooled at a controlled rate.

Due to the wide variety of annealing furnaces, their operation methods also differ. Cart-type annealing furnaces have independently operating loading trolleys, making loading and unloading operations simpler and enabling the loading of large, heavy workpieces. Pit-type annealing furnaces are suitable for vertical loading of workpieces such as shafts, rods, and pipes, and are less prone to deformation during annealing heating.