What are the functions and applications of a mesh-belt normalizing furnace?

2026-03-11

The process is characterized by heating the steel plate to a temperature 30°C to 50°C above the upper critical point of the ferrite–austenite phase transformation, thereby fully austenitizing the steel. After holding at this temperature to ensure uniform austenite homogenization, the plate is then cooled in free air. In conventional normalizing heat treatment, where the workpiece is air-cooled after normalizing, ferrite grains continue to grow, leading to a reduction in the steel plate’s strength. By contrast, when a controlled cooling rate is employed following normalizing, the transformation temperature can be lowered, the transformation mode can be precisely controlled, and the resulting microstructure can be refined. Moreover, the precipitation and growth of microalloying elements such as carbon and nitrogen can be regulated, promoting their fine, low-temperature dispersion and precipitation. This not only enhances the steel’s strength but also helps maintain its toughness. Under conditions of equivalent mechanical properties, the carbon or alloying element content in the steel can be reduced, thereby improving its weldability. Consequently, researchers and manufacturers have conducted extensive exploratory research and development on normalized cooling equipment and processes, achieving notable practical results.

Corrosion resistance performance of the mesh belt annealing furnace:

1. Design appropriately to prevent gaps. For example, welding is preferable to riveting; lap welding is preferable to butt welding; during welding, quality must be ensured to avoid porosity; for bolted connections, low-sulfur rubber washers, sealing packings, and mating surfaces can be protected with coatings. In addition, the design should avoid areas where water can accumulate; during maintenance, dirt and debris should be regularly cleaned and removed.

2. When design measures cannot prevent crevices, cathodic protection may be employed. For example, sacrificial zinc or magnesium anodes can be used in seawater. However, when this method is applied, hydrogen embrittlement must be carefully monitored.

3. Since corrosion inhibitors have difficulty penetrating crevices, a corrosion-inhibiting coating can be applied to the joint surfaces. For example, for steel, a PbCrO4 coating can be used; for aluminum, a ZnCrO4 coating can be applied. Metal sheets coated with these inhibitors can then be separated by packaging paper impregnated with vapor-phase corrosion inhibitors.

4. Use appropriate materials. For certain critical components, materials resistant to crevice corrosion, such as high-chromium, high-molybdenum stainless steels, can be employed.

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What materials are used for the heating elements in belt-type normalizing furnaces?

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What materials are used for the heating elements in belt-type normalizing furnaces?