stainlesstec offers professional TIG and MIG welding of stainless steel and aluminium. Which process we use depends on material, thickness, component geometry, weld requirements and quantity. This is not only about producing a sound joint: heat input, distortion, weld appearance, access and later surface requirements all help decide which process makes technical and economic sense for a part.
In TIG welding (tungsten inert gas), the arc burns between a non-consumable tungsten electrode and the workpiece, with filler metal fed separately. That separation allows very close control of the process, which makes TIG particularly suitable for:
demanding stainless steel joints
aluminium parts
thinner sheet and components
precise weld geometries
visible welds
complex individual parts
small batches with high quality requirements
applications calling for controlled heat input
The advantage lies above all in precise control of the weld pool and the high quality of the weld.
TIG welding stainless steel
TIG welding is one of the key processes for high-quality stainless steel structures. Being controllable, it produces clean welds and lets heat be applied where it is wanted – of particular interest with thinner material, visible welds and parts where distortion and surface quality matter.
stainlesstec processes a range of stainless grades, among them:
1.4301 / AISI 304
1.4307 / AISI 304L
1.4404 / AISI 316L
1.4571 / AISI 316Ti
and other weldable stainless grades as the project specification requires. Base material, filler metal and shielding gas all have to be matched to the application.
TIG is an important process for aluminium too, particularly where a controlled, high-quality weld is required.
Aluminium makes its own demands: the natural oxide layer has a far higher melting point than the base material beneath it, and aluminium conducts heat away from the weld zone very quickly. Clean preparation and suitable process control are therefore decisive.
We process the common weldable aluminium alloys, including materials from the groups:
AlMg
AlMgMn
AlMgSi
pure and low-alloy aluminium
and other aluminium alloys once their weldability has been assessed for the project.
In MIG welding (metal inert gas), the continuously fed wire serves as both electrode and filler metal. That allows higher deposition rates and welding speeds than many manual TIG applications, which can make MIG attractive for:
aluminium structures
heavier material thicknesses
longer welds
larger components
recurring structures
small batches with a corresponding weld volume
Whether MIG really is more economical always depends on the design and the quality requirements.
TIG or MIG – which process is better?
There is no blanket answer: the right process follows from the part.
TIG is particularly advantageous where close control of the weld pool and heat input is required, where thinner material is involved or where a high-quality weld appearance matters. MIG plays to its strengths where higher deposition rates and welding speeds are wanted on suitable designs. In choosing, we consider:
Material
Stainless steel and aluminium make different demands on process and filler metal.
Material thickness
Very thin parts call for different process control than solid structures.
Weld geometry
Length, position and accessibility of the weld influence the choice of process.
Quality requirement
A visible precision weld makes different demands than a purely functional joint.
Heat input and distortion
On sensitive structures, controlling heat input can be decisive.
Quantity
With recurring parts, process time matters alongside weld quality.
We therefore do not choose TIG or MIG on principle, but whichever process suits the job in hand.
Back purging stainless steel – protection on the reverse side too
When welding stainless steel, shielding gas protects the visible side of the weld from the surrounding air. On demanding joints, however, the weld root on the reverse side may need protecting as well.
To do so, the area behind the weld is flushed with a suitable purging gas, displacing the oxygen. This prevents heavy oxidation of the root while welding. Back purging is particularly relevant for:
pipework and vessel structures
welds on the inside
surfaces in contact with media
heightened corrosion resistance requirements
hygiene-critical parts
weld roots that are hard to reach
When welding stainless steel we therefore look not only at the visible weld but at the quality on the reverse side of the joint.
Clean welds start with clean preparation
Whichever process is chosen, preparation is an essential part of weld quality. Joints have to be prepared properly and be free of contamination, and the material and the appropriate filler metal have to be known without doubt.
With stainless steel we pay particular attention to handling the material correctly and avoiding contamination. With aluminium, removing contaminants and dealing with the oxide layer are especially important.
Weld quality is therefore not created when the arc is struck.
Controlling heat input and distortion
Every welding process puts heat into the part: the material expands locally and contracts again as it cools. With thin-walled, large or asymmetrical structures in particular, that can cause considerable distortion. We therefore allow for:
Weld position
Weld length
Welding sequence
Heat input
Material thickness
Fixturing
Structural stiffness
Required tolerances
Choosing between TIG and MIG is therefore always a decision about how the process will affect the part as a whole.
From the weldment to the complete assembly
stainlesstec combines welding with its own sheet metal work, which lets us take on the entire route:
That is an advantage above all on complex welded structures: joints, fits and welding sequences can be taken into account while the individual parts are being made.
We take on demanding one-offs as well as prototypes, small batches and recurring weldments.
With small batches in particular it is not enough to produce a good first assembly: welding sequence, location and process have to be defined so that the required quality is achieved repeatably.
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.
