Specialist welding in stainless steel and aluminium
Welding is one of the operations where experience shows most clearly. Material, part geometry, joint preparation, heat input, clamping and welding sequence affect not only the weld but the whole part.
stainlesstec employs highly qualified specialist welders for demanding structures in stainless steel and aluminium – from thin-walled enclosures through complex welded assemblies to process and pressure vessels.
A clean seam alone does not make a good welded assembly. Before the first weld, essential questions have to be answered:
How is the part clamped?
Which seam is welded first?
Where can heat build up?
Which areas are prone to distortion?
Which surfaces have to be protected?
Which filler metal is required?
Which seams will still be accessible later?
Specialist welding therefore means understanding the whole part. Our welders work closely with production planning and the shop floor to that end.
Experience with demanding assemblies
Welding becomes most demanding where several factors come together:
thin sheet – low heat input, high risk of distortion
long welds – shrinkage and change of shape have to be controlled
complex geometries – accessibility and welding sequence become decisive
high-grade visible surfaces – function is not enough; the appearance has to be right too
pressure and process vessels – welding becomes part of a qualified process
recurring small batches – the result has to work repeatably
Welding stainless steel
Stainless steel places its own demands on heat control, filler metal and post-weld treatment: corrosion resistance has to survive the welding. Heat input that is too high or badly distributed can cause distortion, alter surfaces, produce heat tint and make later dressing harder.
In high-grade applications the weld and the area around it are often part of a defined surface. Our specialist welders therefore consider not only the strength of the joint but the material, the surface and its eventual function. More on welding stainless steel
Welding aluminium
Aluminium behaves fundamentally differently from stainless steel when welded. High thermal conductivity and expansion, plus the oxide layer on the surface, place particular demands on preparation and process control. What matters is:
alloy and delivery condition
clean surfaces
a suitable filler metal
controlled heat input
welding sequence
clamping
distortion control
On thin-walled aluminium structures in particular, experience is decisive. More on welding aluminium
TIG and MIG welding
TIG welding suits cases calling for high weld quality and controlled heat input: stainless steel assemblies, aluminium structures, vessels, thin-walled parts, high-grade visible seams and demanding special designs. Depending on the application we use back purging to protect the weld root in stainless steel.
MIG welding gives powerful joints on suitable aluminium and stainless steel structures. Here too it is not the process alone that decides: material, thickness, joint geometry and the part itself determine which is the better choice. We choose the process to suit the part – not the part to suit the process.More on TIG and MIG welding
Mechanised longitudinal seam welding
On long straight seams, mechanised welding has a particular advantage: even travel and repeatable process conditions. We weld longitudinal seams mechanically up to 2,500 mm long.
Eight axes are available for CNC-controlled 3D laser welding, which allows more complex three-dimensional welding tasks to be automated – of particular interest where low heat input matters, where distortion is to be reduced, where complex contours are welded or where high repeatability is called for.
Here too the technology is only part of the answer: part preparation, joint gap, fixturing and programming largely determine whether the process can sensibly be used. More on 3D laser welding
Distortion begins with heat
Every weld puts heat into a part. The material expands, cools and shrinks. On complex or thin-walled parts that quickly becomes visible or functionally critical distortion. Our specialist welders therefore allow for:
seam sequence
heat input
counter-tacking
clamping
intermediate cooling
symmetry in the design
Where needed, a straightening strategy is added. Good welding does not mean correcting distortion afterwards – it means controlling it from the start.
Clamping and fixtures
An often underrated part of high-grade welding is the fixture. It has to position a part exactly, hold it stable while welding, keep it accessible nonetheless, and take it up repeatably where required.
On small batches in particular, it pays to think about a fixturing strategy with the very first assembly. That is how a successful one-off becomes a repeatable process.
Weld and surface belong together
On visible or hygienically demanding parts the work does not end with the last seam. Depending on the specification, next come:
weld dressing
grinding
blending the surface
removing heat tint
further project-specific surface treatments
What matters is planning welding and finishing together. A badly placed or needlessly large weld cannot simply be ground away later.
Segregated stainless production
For high-grade stainless steel and aluminium parts we work within our segregated production. That supports controlled material handling and protects high-grade surfaces from foreign material.
In food processing, pharmaceuticals and process technology, and on high-grade machine parts and visible components, that is an important part of the whole process.
Qualified welding production
In certain applications personal experience is not enough: procedures, personnel and quality processes then have to be documented and qualified. We hold welding qualifications in connection with DIN EN ISO 3834-3, AD 2000 HP 0 and DIN 2303.
People: experience, a feel for the material, judgement, flexibility. Technology: precision, process control, repeatability, data.
Together they make welding production that is under control – and that is exactly the difference between a machine that welds and a part that fits afterwards.
Experience shows in the result
Thin-walled aluminium enclosure, welded stainless steel assembly or process vessel: the quality of a welded structure comes out of many individual decisions.
Our specialist welders bring experience, materials knowledge and modern welding technology together.
Let’s talk about your project.
Send us your drawing or CAD data by email – together with material, batch size and your requirements. We will come back to you with a sound assessment.
