Annealing

Annealing (normalizing, isothermal annealing, stress-relief annealing)

Dimensional stabilization, reduction of internal stresses and preparation of the material for subsequent operations. We set up annealing to be gentle on tolerances and to fit in with the main heat treatment processes (case hardening, quenching and tempering, nitriding). Precise control of temperature profiles and controlled cooling give us a homogeneous microstructure and predictable results.

What is annealing?

Annealing is the controlled heating of steel according to a defined cycle, followed by controlled cooling. The aim is to refine and homogenize the microstructure, reduce internal stresses and prepare the material for the next production steps. Choosing the right type of annealing improves machinability and dimensional stability and reduces the risk of distortion in subsequent operations.

Main types of annealing we offer

Normalizing
To obtain a fine-grained, uniform microstructure before quenching and tempering or case hardening. Suitable after casting or forging.

Isothermal annealing
Holding in a defined transformation range to obtain a homogeneous microstructure with good machinability and stability. Reduces scatter in properties and facilitates subsequent salt bath quenching.

Stress-relief annealing
Reduces internal stresses after welding, forming or rough machining. Stabilizes dimensions before grinding, measurement and assembly.

Soft annealing
Improves machinability and homogenizes the microstructure before finishing operations.

Recrystallization annealing
Restores ductility after cold forming and eliminates work hardening.

We select the specific cycle according to the drawing, material, previous operations and intended use of the part. We set the parameters to keep the effect on dimensions as small as possible.

Why anneal with Kalírna Zlín

• Integration with the main heat treatment processes – we schedule annealing exactly where it supports the result (before case hardening/hardening/nitriding, after welding, etc.)

• Precision and reproducibility – controlled temperature profiles and controlled cooling

• In-house laboratory – hardness measurement, metallography, checks of the material condition before/after annealing

• Technical advice – we recommend the right type of annealing, protection of sensitive surfaces and inspection points

• Logistics – we offer a collection and delivery service

Typical parts and steels

Parts: shafts, gears, pins, levers, castings, forgings, weldments and machined semi-finished products.
Materials: 42CrMo4, C45E, 16MnCr5, 20MnCr5, 17CrNiMo6 and other structural/case-hardening steels.

When to include annealing

• Before case hardening or hardening, to obtain a uniform initial microstructure

• After welding, forming and rough machining, to stabilize dimensions

• As pre-treatment for nitriding (low distortion, focus on dimensional stability)

Annealing helps reduce scrap rates, shortens the time needed to fine-tune tolerances and improves the final quality of the part.

How we work together

1. Brief and consultation – drawing, tolerances, sensitive surfaces and target properties

2. Choice of annealing type – normalizing, isothermal, stress-relief, soft or recrystallization annealing

3. Process set-up – temperature profile and controlled cooling with regard to dimensional stability

4. Inspection and documentation – hardness measurement, metallography and reports where needed + recommendations for subsequent operations

What we need for an accurate quotation

• drawing with tolerances and functional/excluded surfaces marked

• material and quantity (pieces/batches)

• information on previous/subsequent operations (machining, welding, heat treatment) and the required documentation

Most common combinations

• Annealing → machining → carburizing → hardening → tempering

• Annealing → quenching and tempering (salt bath quenching + tempering)

• Annealing → machining → nitriding