Heat treatment, such as annealing, changes metals’ physical and chemical properties in industrial and metalworking applications, and it involves severe temperatures, often above 1,700 °F.
The annealing procedure might vary depending on the treated material and the desired outcome, and there are several furnace types with different features and applications.
Annealing Heat Treatment
Annealing is a scientific technique that modifies the microstructure of metal. It can increase metal’s ductility and decrease its internal stress and hardness, allowing the material to be molded without cracking. This method is especially effective for too-hard or brittle steels for shaping.
The annealing heat treating furnaces function by heating the material over its recrystallization temperature but below its melting point. The process eliminates grain stress and slowly cools the material to room temperature, forming ductile grains.
Annealing is used in industries where metals must be complexly shaped or reformed, including:
- Ferrous castings
- Electrical – transformers and motors
Batch Vs. Continuous Furnaces
These heat treatment furnaces differ in how workloads are positioned and interact with the furnace atmosphere.
Aside from annealing, batch furnaces are used for heating and stress-relieving metal heat treatments. In batch annealing furnace type, multiple rolls of wire mesh are loaded and dropped at once. This heat-treating furnace includes box, car-bottom, integral-quench, pit, and vacuum furnaces. This unit reaches temperatures between 1200℉ and 2500℉ and can heat all metals within 24″ wide.
This heat treating furnace involves unrolling wire mesh and running it as a single layer at a constant speed. The charging material is transported through the furnace at a constant speed or step by step and is heated simultaneously. They are used for reheating semi-finished products for subsequent hot forming or heat treatment. Overall, the performance capacities of continuous furnace systems are higher than those of industrial furnaces with the batch-type operation.
6 Types Of Heat Treatment Furnaces For Annealing
Furnace types vary depending on the operation size, the desired temperature, and the features your product requires. It can have a direct or indirect firing system, a continuous or indexing furnace, and operate in batches or a constant heat treating manner.
Roller Hearth Furnaces
Roller Hearth Furnaces are adaptable and have an efficient design for indexing workload baskets. Their temperature can reach 2500℉. Additionally, they can be arranged in an oscillating configuration for lengthy heating cycles on extremely long stock, such as pipe, tubing, strip, and slabs. If enough floor space is available, a rolling hearth furnace can heat, soak, and cool a product continuously for stress reduction.
A pusher furnace processes small and large products in trays and baskets. This furnace type can reach 300ºF to 2,100ºF. It has pulse combustion, one of the most efficient ways to burn gas, and a smooth-running control system.
Box furnaces are batch-operating furnaces that heat up to 2500°F. The product is placed directly into the furnace using front loading or forklift equipment in this furnace type. It has single or multiple door systems that can be lifted vertically or horizontally.
Pit furnaces are used for heating treatment requiring temperatures as high as 2000°F. Compared to other heat-treating furnaces, they perform the most thermal processes. Aside from annealing, they are also applicable for tempering, aluminum-solution, nitriding, steam treating, hardening, carburizing, and vacuum heat-treating.
Conveyor Belt Furnaces
Conveyor belt furnaces heat to 2100°F and have a tunnel-shaped heating chamber divided into heating modules that integrate various heating processes into one continuous procedure. This furnace is effective and economical due to its extended life and low monitoring needs.
The integral quench furnaces’ batch heating system reaches up to 1850°F. They have unobstructed work chambers and high-capacity recirculation fans. Integral-quench furnaces allow you to strategically place heated sources to enable rapid heat transmission, low energy consumption, and suitable temperature and carbon homogeneity.
Annealing Heat Treatment Furnaces At S.M. Engineering & Heat Treating
At S.M. Engineering & Heat Treating, we offer the finest and highest-quality annealing heat treatment furnaces. Our manufactured annealing furnace types ensure a durable, efficient, and unequaled performance to help you have a high production rate with the best outcomes. Contact us or request a quote to know how we can customize your furnace and meet your needs.