Special curved sections welded by 3D laser for special solutions

PUBLISHED 27 April 2017

Curved sections are used more and more for the rebuildung of oil refineries. But their use is still a challenge which needs designers and manufacturers to be creative.


E section’s blue prints (Click to enlarge)

curved sections


E-shape Profile

Material grade:



laser welded

Industries served:

oil & gas




Solutions for converting an oil reactor

For oil refineries, when retrofitting existing oil reactors, an internal structural modification is applied using curved sections. This avoids having to rebuild the expensive stainless steel reactor.
Nonetheless, according to the type of modification and the new filtering level demanded, the skirt needed might be in form of either an E-shape or an S-shape. The material is nearly always 1.4541 (321).
The different laser fused segments though, that all together build a circle, will be fitted by welding internally to the existing reactor and operate as support for special beams and T-sections that are placed inside and carry the single reactor stages.Skirt-3

3D laser welding of curved sections

In this case the special tailored E-shape profile has a 450mm height and 90mm width, a material thickness of ten millimeters for the webs, and 15 millimeters for the flanges.
So each of the curved sections is assembled from plate stripes laser-cut in an already curved shape in case of the flanges, while the webs are bent to radius prior to assemble.


The segment’s components are stitch-welded together and stiffeners are put on for improvement of handling friendliness during all production steps; from positioning under the laser to laser weld of the parts.
A 5-axis robot that can easily follow the curved path that needs to be fused is doing the welding with our 3D laser technology.We do a full welding penetration and a UT (Ultrasonic Testing) of the welds is performed by qualified personnel according to a special customer’s specification, in order to certify the proper execution.
The sections vary upon the existing reactor’s dimensions and the type of application, generally having a skirt diameter between 2.5 and 4.5m, while the length of the single section is from 1m to 2.2m.

curved sections

All base material was laser-cut to shape prior to assembly and fusing.


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