Internal stresses are the invisible enemies of dimensional stability: they are caused by welding, machining, forming or additive manufacturing and can lead to distortion, cracking or reduced service life. With stress-relief an nealing, we reduce these residual stresses in a controlled manner – reproducibly, in line with the material and with complete documentation. As part of our Heat treatment, the processes ensures stable component properties and reliable processes in production and use.
Stress-relief annealing is a heat treatment just below the recrystallization or tempering range of the respective material. The component is gently heated, held at temperature for a defined time and then cooled in a controlled manner. Diffusion and relaxation processes reduce internal stresses without significantly changing the microstructure and strength.
Typical targets:
Minimize distortion and changes in shape (e.g. before precision machining)
Reduce risk of cracking, increase component service life
Ensure dimensional and process stability (welding, machining, AM)
Low distortion and economical: less reworking in fine machining
Process reliability: Reproducible temperature control, documented according to customer requirements
Component service life: Reduced residual stresses lower the risk of cracking
Compatible: e.g. for steel, cast iron, aluminum, titanium, nickel-based materials, etc.
Plannability: Stable mass before finishing, assembly or coating
Normalizing / soft annealing: specifically change the microstructure and mechanical properties – stress relief annealing primarily for stress reduction.
Tempering after hardening: sets hardness/toughness; stress-relief annealing is usually below these temperatures in order to largely maintain strength.
Solution & ageing treatment (aluminum): Structural transformation – stress relief annealing works without any significant change in strength.
After welding of frames, racks, pressure vessels
Before finishing (grinding, honing, lapping)
After high cutting volume or asymmetrical machining
For additively manufactured components (AM) for stress relaxation
For cast components for dimensional stabilization
To minimize risk for safety-relevant parts
(e.g. turbine components and structural components)
(e.g. reactors, pipelines and apparatus engineering)
(Implants and surgical instruments)
(e.g. power plant components and heat exchangers)
(Post-treatment of 3D-printed components)
Generally low. Dimensional changes are possible with high residual stress levels or asymmetrical geometry. We recommend an intermediate measurement before finishing.
With correct parameterization, strength and hardness are hardly affected; the main effect is stress reduction.
We currently have a maximum batch space size of D1500mm x 1800mm with a maximum weight of 2000kg.
It depends on how much oversize the components were manufactured with. Stress relief annealing in air leads to oxidized surfaces, which should then be reworked. To avoid such reworking, stress relief annealing can take place in an inert gas or in a vacuum.
It depends on the material, pre-treatment (e.g. tempering), component history and desired properties. We advise and define the parameters.
Phone: +41 52 245 18 55
Mobile: +41 77 442 46 91
t.bachmann@listemann.com
Phone: +423 375 90 12
Mobile: +423 78 05 401
t.bitschnau@listemann.com
Phone: +48 12 6534 231
Mobile: +48 501 65 22 26
j.brelinski@listemann.com
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