Stress Relieving Furnace Manufacturer in India

What is the Stress Relieving Process?

Stress relieving process is supposed to remove or reduce certain residual stresses induced in tools by heavy machining or while forming. Hence the probability of the tool getting distorted or cracked up during its hardening, gets reduced.

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Stress relieving is a process involving relieving of internal stresses with no changes in the microstructures. The stresses in question are formed within the body due to grinding, surface hammering, cold working, case hardening, electroplated coatings, castings, welding, machining, precipitation and phase transformation are treated in this process.

The adverse effects with internal stress are when steel is under a residual stress and under a corrosive environment, it fails with stress corrosion cracking. Thus by enhancing the tendency of steel for warpage and dimensional instability. In the presence of residual tensile stress, the fatigue strength is reduced. Ductile materials are easily stress relieved when compared to brittle materials.

Ifs and buts of Stress Relieving Furnace 

However, the ground surface of a hardened tool might get highly stressed post grinding but not really faulted. Again, the high stress on its part, might form fine cracks immediately post grinding, before or during use. 

Ground tools with high residual stress can often be salvaged by stress relieving, immediately after grinding, at or just below the tempering temperature in order to maintain the specified tool hardness. Tools also develop high residual stress in use. It is sometimes advantageous to relieve this stress at each redressing of the tool by retempering, only at an appropriate tempering temperature; violating which would cause undesirable softening.

Some Fine Details on the checklist

Stress relieving is most commonly performed in air furnaces. Here, neither the heating nor the cooling rate is much crucial, although the cooling should be slow enough to prevent the introduction of any new stress. 

Usually, protection against the scaling or decarburization is not that critical, unless the stress-relieving temperature is above 650 °C. 

Post stress relieving, some corrections in certain dimensions might be required before hardening, as the relief of stress might end up causing some dimensional changes. Precision tools usually are stress relieved after machining and before hardening. It is often desirable to relieve stress after rough machining but before finishing machining. 

Stress relieving after electrical discharge machining (EDM) work will reduce some of the residual stress but will not be able to remove all of the effects of this machining method.

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Stress Relieving Furnaces by Therelek

Pit Type Low Temperature Furnace

Pit type air circulation furnaces are installed with the opening at ground level or just above it. These are low-temperature furnaces with operating temperatures up to 650°C.

Pit Type Low 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

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

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

Pyromaitre Ovens

With over 1000 Pyros worldwide, these rapid heating ovens are internationally proven to deliver the highest efficiency when it comes to mass production of tempering/stress relieving of your components

Pyromaitre Ovens

Bell Jar Furnace

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

Bell Jar Furnace

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

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

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

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