Flame Straightening – Thermal Straightening of Welded Structures and Large Components
Correct welding distortion and dimensional deviations on large components up to 50 t – material-friendly thermal flame straightening without material removal, as a contract service in Lorch.
Straightening without material removal
Thermal straightening restores dimensional accuracy – without removing substance or re-welding.
Even heavy parts up to 50 t
Straightening directly on the 2×25 t crane system – no size limitation from furnaces or fixtures.
Material-friendly temperature control
Controlled heating, limited according to the material – even for quenched-and-tempered and higher-strength steels to S1100.
Everything from a single source
Welding to DIN EN 1090-2 EXC3, flame straightening and machining at one site in Lorch.
DIN EN ISO 9001:2015
Quality management with documented manufacturing processes.
Flame Straightening – Process and Working Principle
In flame straightening, the material is heated rapidly in a locally confined area with a torch. The surrounding cold structure restrains the thermal expansion – the heated zone is upset. On cooling, the upset area contracts and pulls the component into the desired shape. This corrects welding distortion and residual stresses without removing material or re-welding.
Heating figures – spot, line or wedge – let the operator control the direction and amount of shrinkage. Experience and controlled temperature management are essential – especially for quenched-and-tempered and higher-strength steels, whose permissible straightening temperature depends on the material.
Flame straightening complements vibration stress relief. While vibration stress relief (VSR) reduces residual stresses, flame straightening corrects the visible distortion. Combined, the component stays dimensionally stable – the ideal preparation for subsequent precision machining.
We also perform flame straightening as a contract service on customer-supplied components from external manufacturing. Welded structures fabricated in Lorch are straightened directly after welding, before they move on to machining or final assembly – without external logistics and without an interface break.
Suitable Components for Flame Straightening
Flame straightening is suitable for welded structures and steel components with thermal distortion:
- Distorted welded frames and base structures
- Large plates and panels with bulges or waviness
- Beams, profiles and welded box structures
- Machine beds and frames before precision machining
- Components in steel, Hardox, stainless steel and fine-grain structural steel up to S1100
Flame straightening is available as a standalone service or combined with our in-house welding and machining capabilities.
Typical Applications
Flame straightening is used across industries in heavy-component manufacturing:
- Distortion correction after welding of large steel structures
- Straightening of crane, lifting-gear and plant components
- Flatness correction on plates and welded panels
- Dimensional accuracy of frames and structures before machining
- Re-straightening of components after transport or machining
Straightened components proceed directly to precision machining in the same facility – without external logistics or an interface break. Heavy parts up to 50 t are handled on our in-house 2×25 t crane system.
Flame Straightening at Bock – Your Advantages
Bock Maschinenbau offers flame straightening as an integrated step in the manufacturing and quality process:
- Distortion corrected without material removal
- Thermal straightening restores dimensional accuracy without removing substance or re-welding.
- Suitable for heavy parts up to 50 t
- Straightening directly on the 2×25 t crane system – no size limitation from furnaces or fixtures.
- Material-friendly temperature control
- Controlled heating with a material-dependent temperature limit – even for quenched-and-tempered and higher-strength steels.
- Everything from a single source
- Welding to DIN EN 1090-2 EXC3, flame straightening and machining at one site in Lorch.
- DIN EN ISO 9001:2015
- Quality management system with documented manufacturing processes.
Steel fabricators and metalworking companies from the Stuttgart area and the DACH region have us flame-straighten warped welded structures to precise dimensions here in Lorch.
Frequently asked questions about flame straightening
How does flame straightening work?
In flame straightening, the material is heated rapidly in a locally confined area with a torch; the surrounding cold structure restrains the thermal expansion, the heated zone is upset and contracts on cooling. Heating figures – spot, line or wedge – control the direction and amount of shrinkage, so that welding distortion is corrected without material removal and without re-welding.
What is the difference between flame straightening and vibration stress relief?
Flame straightening corrects the visible distortion; vibration stress relief (VSR) reduces residual stresses. Both processes are carried out in the same plant after welding and before precision machining.
Up to what unit weight are components flame-straightened?
Flame straightening is also possible on heavy parts up to 50 t. Straightening is done directly on the 2×25 t crane system, without size limitation from furnaces or fixtures.
Are customer-supplied components also flame-straightened?
Yes. As a contract service, thermal straightening is also carried out on customer-supplied components from external manufacturing. Welded structures fabricated in Lorch are straightened directly after welding, before they go on to machining or final assembly.
Contact
Request Flame Straightening
Tell us the dimensions, weight and material of the component and describe the distortion. We straighten delivered structures as a standalone service or directly after welding in our own production.
