What is annealing's primary purpose?

Annealing softens materials, relieving internal stresses, improving ductility and machinability.

What are annealing's stages?

Recovery, recrystallization and grain growth, occurring as temperature increases.

What temperatures are used for annealing?

Varies by material: steel (650-815°C), aluminum (300-410°C), copper (300-650°C) and brass (425-650°C).

What fuels annealing furnaces?

Natural gas, LP gas and electric configurations.

What happens with excessive annealing temperature?

Excessive grain growth, reduced mechanical strength, brittleness and potential oxidation.

What temperature is needed for aluminum annealing?

570-770°F (300-410°C), depending on the alloy.

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Annealing

Annealing furnaces

Q: Is annealing better than quenching?

Annealing and quenching serve different purposes. Annealing softens, while quenching hardens materials.

Q: Is annealing done in a furnace?

Yes, furnaces provide controlled heating and cooling for annealing.

Q: What's the difference between heat treatment and annealing?

Heat treatment alters material properties. Annealing, a specific heat treatment, softens materials.

Precision in Every Detail: Our Annealing Furnaces and Ovens Deliver Reliable Results

Annealing

Definition

Annealing is a heat treatment process in which a material is heated to an elevated temperature and held for a set amount of time and then cooled at a controlled rate. The high temperature cycle (soaking time) is long enough to allow the desired transformation to occur. Cooling is done slowly to avoid warping/cracking due to the thermal gradients and thermoelastic stresses within the metal piece.
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Nutec Bickley annealing heat treatment involves heating a material to a specified temperature and then cooling at a very slow and controlled rate. There are several furnace types to choose from, based on the size of your operation, temperature and features needed for your product.Nutec Bickley’s precision manufacturing and decades of knowledge ensure that your aluminum annealing furnaces will get the job done and stand the test of time.

How does Annealing work?

The 3 stages of the annealing process that proceed as the temperature of the material is increased are: recovery, recrystallization, and grain growth.

Recovery results in the softening of the metal through the removal of primarily linear defects called dislocations and the internal stresses they cause. Recovery occurs at the lower temperature stage of all annealing processes and before the appearance of new strain-free grains. The grain size and shape do not change.

The second stage is recrystallization, where new strain-free grains nucleate and grow to replace those deformed by internal stresses.If annealing is allowed to continue once recrystallization has completed, then grain growth (third stage) occurs. In grain growth, the microstructure starts to coarsen and may cause the metal to lose a substantial part of its original strength. This can however be regained with hardening.

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Working principle of annealing furnaces

An annealing furnace is a vital piece of industrial equipment used to heat materials—most commonly metals —to a specific temperature and then cool them at a controlled rate. The purpose of this process is to alter the physical and sometimes chemical properties of the material, making it softer, more ductile, and relieving internal stresses.

How it works

Heating phase: The material is gradually heated inside the furnace to a predefined annealing temperature. This temperature varies based on the material type but is typically below the melting point. The heating is uniform to ensure consistency throughout the material. 

Soaking phase: Once the desired temperature is reached, the material is held (or "soaked") at that temperature for a specified period. This allows the internal structure to transform and stabilize.

Cooling phase: The furnace then cools the material at a carefully controlled rate—either inside the furnace (furnace cooling) or outside in a controlled environment (air cooling). The slow cooling process is crucial to achieve the desired mechanical properties.

Key benefits

Improves material ductility and toughness

Relieves internal stresses caused by previous manufacturing processes

Reduces hardness for easier machining

Enhances structural stability and grain refinement

Applications

Annealing furnaces are used across various industries, including automotive, aerospace, metalworking, and electronics, for processing materials such as steel, copper, aluminum..

Advantages of Our Annealing Furnaces and Ovens

Custom designed furnaces

Low maintenance refractory systems

State-of-the-art combustion systems

Direct or indirect fired systems

Integration of SCADA

Flexible modular or continuous heat treat systems

Integrated loading and unloading

Controlled cooling

Features of our annealing furnaces

High-performance burners/heating elements
Designed for uniform temperature distribution, our heating systems ensure consistent heat treatment, reducing process variability and improving product quality.

Safety & compliance
Built with safety in mind, all furnaces include over-temperature protection, emergency shut-off, door interlocks, and are compliant with international safety standards.

Precision temperature control
Integrated digital PID controllers provide accurate temperature management with programmable heat-up, soak, and cool-down cycles for optimal process control.

Energy efficiency
Advanced insulation and power management systems minimize energy consumption without compromising performance.

Robust construction
Heavy-duty, insulated steel chambers with corrosion-resistant finishes deliver excellent thermal efficiency and long-lasting durability, even under continuous operation.

Versatile loading options
Available with front-loading or top-loading configurations, adjustable shelving, and customizable chamber sizes to accommodate a wide range of part geometries.

User-friendly interface
Intuitive touch-screen control panel with real-time data monitoring, alarms, and multiple recipe storage for easy and efficient operation.

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Nutec Bickley’s added value

Nutec Bickley is focused on understanding our customers' thermal equipment needs and working to supply the best equipment to meet those needs at the most competitive price.
By applying the latest proven technology, Nutec Bickley is able to provide innovative solutions that meet or exceed our customers' expectations in equipment quality, production efficiency and operational economy.

Industries and Applications of Annealing Furnaces

Industries
Steel forging, automotive, aerospace, foundries, tube manufacturers, aluminum producers, steel bars and rods.

Applications
Furnaces are tailored to each customer’s needs for both ferrous and non-ferrous applications.

Purposes of Annealing Furnaces

Annealing process 
Is used to reverse the effects of work hardening (by recovery and recrystallization) and to increase ductility. Heating is usually limited, in order to avoid excessive grain growth and oxidation.

Stress relief annealing furnaces
Is used to eliminate/minimize stresses arising from plastic deformation during machining, non-uniform cooling and phase transformations between phases with different densities. Stress relief annealing furnaces allows these stresses to relax. Annealing temperatures are relatively low so that the useful effects of cold working are not eliminated.

Normalizing 
Is an annealing heat treatment just above the upper critical temperature to reduce the average grain sizes (of pearlite and proeutectoid phase) and create more uniform size distributions. After complete transformation to austenite (austenitizing) the treatment is completed by cooling to the required microstructure.

Full annealing 
Involves austenitizing and slow cooling (several hours). It produces coarse pearlite-large grains (and possible proeutectoid phase) that are relatively soft and ductile. Full annealing furnaces is used to soften pieces which have been hardened by plastic deformation, and which need to undergo subsequent machining/forming.

Spheroidizing 
Involves prolonged heating just below the eutectoid temperature, which results in the soft spheroidite structure. This achieves maximum softness needed in subsequent forming operations.

Annealing Furnaces Manufacturing Process

Annealing process is a heat treatment that consists of heating a material to a high temperature, holding it for a certain time, and then cooling it slowly, or in a controlled manner.
The objective of annealing is to reduce the hardness of the material, increase ductility, eliminate internal stresses in the material, improve the mechanical and electrical properties of the material, and facilitate the machining of the material

Annealing temperatures required for different metals

Annealing is a heat treatment process that requires precise temperature control to achieve optimal results. The annealing temperature varies depending on the type of metal, its composition, and the desired mechanical properties. Below is a general guide to typical annealing temperatures for common metals:

Common annealing temperature ranges

Metal

Steel (Carbon)

Stainless Steel

Aluminum Alloys

Copper

Brass

Titanium

Nickel Alloys

Annealing Temperature Range

760°C – 870°C (1400°F – 1600°F)

1010°C – 1120°C (1850°F – 2050°F)

345°C – 415°C (650°F – 775°F)

315°C – 650°C (600°F – 1200°F)

425°C – 650°C (800°F – 1200°F)

480°C – 730°C (900°F – 1350°F)

870°C – 1175°C (1600°F – 2150°F)

Notes

Requires slow furnace cooling to prevent distortion and cracking.

Often followed by rapid cooling to avoid carbide precipitation.

Lower temperatures due to aluminum’s lower melting point.

Can be air-cooled or water-quenched after annealing.

Often annealed to restore ductility after cold working.

Requires a controlled atmosphere to prevent oxidation.

Often annealed in vacuum or inert gas to preserve material integrity.

Factors influencing annealing temperature

Material composition and grade

Desired mechanical properties (e.g., ductility, softness)

Initial hardness or work-hardened state

Furnace type and cooling method

Precision is key

Using the correct annealing temperature is crucial for achieving optimal material performance. Overheating can cause grain growth or surface oxidation, while underheating may result in incomplete stress relief.

Related Industries

At NUTEC Bickley we are committed to engineering and design excellence and to delivering the very best equipment to our customers. We assure this by analyzing all of our customers’ needs and complying with rigorous quality standards.

Forging

NUTEC Bickley provides heat treating Forging furnaces for the heating and reheating of large steel ingots, blooms and cast parts.

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Steel & Aluminum

NUTEC Bickley is an international leader in the design, manufacture and installation of innovative energy efficient systems for the Steel and Aluminum industry

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What is the benefit of annealing metal in an annealing furnace or oven?

Annealing is a crucial heat treatment process that enhances the performance and workability of metals. By using a dedicated annealing furnace or oven, manufacturers gain precise control over temperature and atmosphere—ensuring consistent, high-quality results.

Key benefits of annealing metal:

Improves Ductility and Malleability
Annealing softens metal, making it more ductile and easier to shape, bend, or machine. This is especially important in manufacturing processes that involve forming or drawing.

Restores Electrical Conductivity
‍For materials like copper, annealing can restore lost electrical conductivity after work-hardening, which is vital in electrical and electronic applications.

Relieves Internal Stresses
‍During machining, welding, or cold working, metals develop internal stresses. Annealing helps eliminate these stresses, reducing the risk of warping, cracking, or failure in later stages.

Enhances Corrosion Resistance
‍In stainless steels and certain alloys, proper annealing can improve corrosion resistance by redistributing alloying elements uniformly throughout the material.

Refines Grain Structure
‍The controlled heating and cooling cycle refines the metal’s grain structure, improving uniformity and enhancing mechanical properties.

Improves Workability for Subsequent Processing
‍Annealed metals are easier to cut, form, and weld—streamlining downstream manufacturing operations and extending tool life.

Why use an annealing furnace or oven?

Consistent temperature control for uniform results

Improved efficiency and reduced rejection rates

Programmable cycles for different materials and applications

Safe, enclosed environment that protects the material from contaminants

At what point in a metalworking process should an annealing furnace or oven be used?

In the metalworking process, annealing is strategically applied at specific stages to enhance material performance and improve manufacturing efficiency. Knowing when to anneal is key to producing high-quality, reliable components.

Typical points in the metalworking process to use annealing:

1. After cold working or forming
‍Processes like rolling, drawing, stamping, or bending can harden the metal and introduce internal stress. Annealing after these steps:

Material composition and grade

Reduces brittleness

Prepares the material for further shaping or machining

4. After welding
‍Welding introduces intense localized heat that can cause stress and hardness in the heat-affected zone. Post-weld annealing:

Relieves thermal stress

Prevents distortion

Improves structural integrity

2. Between multiple forming stages
‍For complex components requiring several forming steps, intermediate annealing softens the metal between operations, reducing the risk of cracking or failure.

5. Before final heat treatments
‍Annealing is often performed before hardening or tempering, especially when a uniform microstructure is required for the next phase of treatment.

3. Before machining or cutting
‍Softened, stress-free metal is easier on cutting tools and produces cleaner, more precise results—leading to better surface finishes and extended tool life.

Using an annealing furnace or oven at the right stage of production ensures:

Better formability

Reduced risk of defects

Greater structural consistency

Smoother downstream operations

Furnaces we manufacture for annealing heat treatment

Roller Hearth Furnaces

Roller Hearth Furnaces are versatile, efficient and mostly used for index moving of work load baskets. They can also be set up in an oscillating configuration for long heating cycles on very long stock such as pipe, tubing, strip, and slabs.

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Pusher Furnaces

NUTEC Bickley manufactures and supplies pusher furnaces for continuous production in custom designs to meet clients’ production needs and process requirements.

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Car Bottom Furnaces

The flexibility of a car bottom furnace makes it a popular choice for processes that require the handling of large and heavy unusual parts, or multiple configurations loads.

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Box Furnaces

NUTEC Bickley's box furnaces are ideal for intermittent or batch processes where the product is front loaded directly into the furnace with the help of a forklift/handling gear.

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Chain and Mesh Belt Furnaces

NUTEC Bickley's chain and mesh belt furnaces and ovens are designed for continuous production line operations accepting parts ready for heat processing and discharging them ready for the next production step.

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Moving Hood Furnaces

NUTEC Bickley's provides heavy duty moving hood furnaces for the heat treatment process (normalizing, annealing, stress relieving and others) of steel forgings, castings and large steel plate formed parts.

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Rotary Hearth Furnaces

NUTEC Bickley rotary hearth furnaces are integrated with load/unload manipulators to feed forging cells, forming lines, or quenching systems.

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Walking Beam Furnaces

NUTEC Bickley's walking beam furnaces are essentially state-of-the-art heating furnaces that are extremely efficient for processing large/heavy parts in semi-continuous mode.

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Related Resources

Metals Industry - Aluminum Heat Treating

(E-Book)

Date Added:

02/14/2023

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Frequently asked questions about our annealing furnaces

What is the main purpose of annealing?

Annealing is performed as follows:

The material is heated to a high temperature

The material is kept at that temperature for a specific period

The material is cooled slowly and in a controlled manner

Cooling is done slowly to prevent the material from warping or cracking.

What are the three stages of the annealing process?

The 3 stages of the annealing process that proceed as the temperature of the material is increased are:

1. Recovery: Occurs at the lower temperature stage of all annealing processes and before the appearance of new strain-free grains.

2. Recrystallization: Where new strain-free grains nucleate and grow to replace those deformed by internal stresses.

3. Grain growth: The microstructure starts to coarsen and may cause the metal to lose a substantial part of its original strength.

Is annealing better than quenching?

Annealing and quenching serve different purposes, so one isn't inherently "better." Annealing softens materials, improving ductility and relieving internal stresses, making them easier to machine or shape. Quenching, on the other hand, rapidly cools materials to increase hardness and strength. The choice depends on the desired material properties for a specific application.

What is the temperature of the annealing furnace?

Normal Annealing
The material is heated to a temperature between 750º and 980ºC, depending on the carbon content, and then slowly cooled to room temperature.

Soft Annealing
For steel alloys, the temperature is usually chosen between 700º and 900ºC. For copper alloys, the temperature ranges between 300º and 650ºC, and for brass alloys, between 425º and 650ºC.

What is the fuel in the annealing furnace?

Natural gas and LP. Electrical configurations available.

At what temperature is annealing done?

Annealing temperatures vary widely based on the material. For metals like steel, it generally ranges from 1,200°F to 1,500°F (650°C to 815°C), while aluminum typically anneals at 570°F to 770°F (300°C to 410°C). The material is heated to these temperatures, held to allow structural changes, and then cooled slowly to soften, relieve stress, and enhance ductility.

Is annealing done in a furnace?

Yes, annealing is typically performed in a furnace. The furnace provides controlled heating to reach the specific temperature required for annealing, allowing the material to soften and relieve internal stresses. After heating, the material is usually allowed to cool slowly within the furnace or in a controlled environment to achieve the desired properties, such as improved ductility and reduced hardness.

What happens if the annealing temperature is too high?

If the annealing temperature is too high, excessive grain growth can occur, making the material overly soft and reducing its mechanical strength. This can lead to a coarse, brittle structure, diminishing the material's durability and workability. In extreme cases, overheating may cause surface oxidation or melting, compromising the material’s quality and leading to potential defects in further processing.

What temperature is needed to anneal aluminum?

To anneal aluminum, temperatures generally range from 570°F to 770°F (300°C to 410°C), depending on the specific alloy. The aluminum is heated to this range, held for a specified time to allow internal stresses to relieve, and then slowly cooled. This process softens the aluminum, improving its ductility and workability for further processing or shaping.

What is the difference between heat treatment and annealing?

Heat treatment is a process that involves heating and cooling metals or alloys to alter their physical and mechanical properties, such as hardness or strength. Annealing, a type of heat treatment, specifically softens the material by heating it to a specific temperature and then slowly cooling it. This reduces internal stresses, improves ductility, and enhances machinability.

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