Furnaces for Annealing Under Protective Atmosphere by Therelek

Understanding the heating mechanics through Annealing Furnace

The heating mechanics of an annealing furnace, aims at metamorphosis of the microstructure of a material in order to change its mechanical or electrical properties. For example, steel manufacturing units use annealing furnace to bring out desired changes in the hardness of the steel, or increasing its ductility or even some other kind of changes as per requirement.

Read more...

The steel is heated slowly and uniformly to a temperature, holding it there for around 1 to 4 hrs. (or even longer to complete the process of heat penetration), and eventually cooling it down at a controlled rate.

Working routine of an Annealing Furnace 

The mechanism of the heating treatment that goes in an annealing furnace starts off with heating of a material much beyond its recrystallization temperature and then eventually cooling down of the material once it has been held at the temperature, for a certain duration. The material recrystallizes as it cools post some atomic changes that were caused by the heating process with an aim to redistribute and eradicate dislocations in a piece of steel or some other product.

Absolute precision is what an Annealing furnace follows 

The annealing furnace way of heating calls for three different stages, namely the recovery stage, the recrystallization stage and the grain growth stage. Atmosphere furnaces or vacuum furnaces may also be used for the annealing process. 

An absolute control of accurate temperature and the authentic means of preventing decarburization, are some of the essential prerequisites of this unique heating equipment. 

It is important to note that in a box or roller hearth furnace, surface protection is often  attained through application of decarb-resistant coating or by packing the work pieces in pipes, in which they are then surrounded by non-decarburizing material, such as spent charcoal and mica, or cast iron chips. Furnaces with prepared atmospheres frequently are used for the annealing of tool steels.

The packing materials as mentioned above may carburize, decarburize, or just be neutral to the steel, completely depending on the heating temperature, the carbon content of the steel, and the density of the packing or even the particle size of the packing material. The primary task followed by such materials is to debar the decarburizing gases from coming in contact with the steel. If oxygen is to be kept out, the packing must be very tight and the sealing of the container perfect, for most gases can diffuse through ordinary seals at a surprisingly rapid rate at elevated temperatures. 

A precautionary step against the cracking up from thermal shock, is done by loading the furnace at a relatively low temperature in order to allow the furnace load to get heated up slowly with the furnace. Post soaking up at the annealing temperature, the work pieces are to be cooled down in the furnace at 10 to 25 °C/h to 540 °C or even lower. Anywhere below 540 °C (1000 °F), the cooling rate for most tool steels is no longer critical, and the work may be then cooled to the normal room temperature.

Read less..

Furnaces for Annealing Under Protective Atmosphere by Therelek

Pit Type High Temperature Furnace

Pit type sealed retort furnaces are of a cylindrical design vertically erected with a positive sealing mechanism on top in order to contain and preserve heat and atmosphere during a process cycle.

Pit Type High Temperature Furnace

Horizontal Vacuum Furnace

Our Horizontal Vacuum Furnace has cold wall construction with metallic/graphite hot zone. The door swivels sideward and the material is loaded from the front.

Horizontal Vacuum Furnace

Vertical Vacuum Furnace

Therelek’s Bell furnace is designed with optimal performance for high sensitivity and delicate components.

Vertical Vacuum Furnace

Sealed Quench Furnace

Therelek’s Sealed Quench Furnace line consists of preheating and tempering furnaces, washing machines, stationary table, hydraulic lifts and charge transfer systems

Sealed Quench Furnace (SQF)

Continuous Mesh Belt Furnace

A multi-zone control environment is present in a continuous high-temperature furnace, often with a single pre-heating zone,

Continuous Mesh Belt Furnace

Chamber Furnace

Therelek’s chamber furnace can operate up to 1800°C. These furnaces are usually rugged, refractory based construction

Chamber Furnace

Bogie Hearth Furnace

Our standard bogie hearth furnace goes up to 1500°C, however, we make custom designed furnaces for any special requirements

Bogie Hearth Furnace

Bell Jar Furnace

Therelek’s Bell furnace is designed with optimal performance for high sensitivity and delicate components.

Bell Jar Furnace

Bell Annealing Furnace

Bell Annealer brings in excellent temperature uniformity, consistent quality and good production rates.

Bell Annealing Furnace

Continuous Air Circulation Furnace

Continuous air circulation furnace is usually multi-zone controlled for better process control. Individual zones can have preset temperature controls for best process results.

Continuous Air Circulation Furnace

Continuous Roller Hearth Furnace

Roller hearth furnaces are designed for continuous production and easy maintenance to handle large size and weights.

Continuous Roller Hearth Furnace

Interested to know more?

Click on Get Quote, share your details and we will get back to you.

Get Quote