Welding is one of the most fundamental processes in metal fabrication. It joins metal components permanently, creating structures and assemblies that would be impossible to produce any other way. But welding is not one single process — it is a family of processes, each with different characteristics, different strengths, and different applications.
Choosing the right welding process for a specific application is a decision that affects weld quality, production speed, cost, and the final appearance of the assembly. Get it right and the weld is strong, clean, and produced efficiently. Get it wrong, and you may end up with a weld that is structurally adequate but aesthetically poor, or one that requires extensive rework, or one that is produced at a cost far higher than necessary.
At Raamps Industries, we provide metal welding services using multiple processes, and we work with clients to ensure that the process selected for each job is the right one. This blog explains the main welding processes available, the factors that determine which is most appropriate, and how to approach the selection decision.
The Main Metal Welding Processes
MIG Welding (Metal Inert Gas / GMAW)
MIG welding — formally known as Gas Metal Arc Welding or GMAW — is one of the most widely used welding processes in industrial fabrication. It uses a continuously fed wire electrode that melts and fuses with the base metal, with the weld pool protected from atmospheric contamination by a shielding gas delivered from a separate supply.
MIG welding is valued for its speed and versatility. It can be used on a wide range of materials including mild steel, stainless steel, and aluminium. It produces welds quickly relative to some other processes, and the technique is relatively accessible to train operators in. For structural fabrication, general engineering, and production welding where throughput matters, MIG is often the process of choice.
The limitations of MIG welding include a weld bead appearance that requires grinding or dressing for cosmetically critical applications, and a level of weld spatter that needs to be managed and cleaned. It is also less suited to very thin materials where the heat input can cause distortion or burn-through.
TIG Welding (Tungsten Inert Gas / GTAW)
TIG welding — Gas Tungsten Arc Welding or GTAW — uses a non-consumable tungsten electrode to produce the arc, with filler material added separately by the welder’s other hand. The weld pool is shielded by an inert gas, typically argon.
TIG welding produces the highest quality weld bead of any arc welding process. The welds are clean, precise, and cosmetically excellent — typically requiring little or no post-weld finishing for visual-grade applications. TIG is well suited to thin materials, to stainless steel and aluminium fabrication where appearance is important, and to applications where weld quality standards are demanding.
The trade-off is speed. TIG welding is significantly slower than MIG welding and requires a higher level of operator skill. For high-volume production of structural welds where appearance is not critical, the additional cost of TIG welding is rarely justified. For precision fabrication, food-grade or pharmaceutical equipment, architectural metalwork, and any application where the weld will be visible in the finished product, TIG is typically the right choice.
Spot Welding (Resistance Spot Welding)
Spot welding is a resistance welding process that joins overlapping sheets of metal by passing a high electrical current through them at a specific point, generating heat that fuses the metal at that location. It does not use filler material and does not require shielding gas.
Spot welding is extremely fast — a single weld is produced in a fraction of a second — and is well suited to high-volume production of sheet metal assemblies where the joint design allows for overlapping flanges. It is the dominant joining process in automotive body manufacturing and is widely used in appliance manufacturing, enclosure fabrication, and any application where sheet metal components are joined at multiple points along their length.
Spot welding is not suitable for all joint configurations — it requires access to both sides of the joint for the electrodes, and it works best on thinner sheet metal. It also produces a joint that is strong but not continuous, which means it is not the right choice for applications requiring a sealed weld or a full-strength continuous joint.
Arc Welding (Shielded Metal Arc Welding / SMAW)
Arc welding — also called stick welding or SMAW — uses a flux-coated consumable electrode to produce the arc and the filler material. The flux coating melts during welding and forms a protective slag over the weld pool.
Arc welding is one of the oldest and most widely used welding processes. It requires relatively simple, portable equipment, is tolerant of less-than-perfect surface conditions, and can be used in outdoor and site welding applications where MIG and TIG would be problematic. It is well suited to thicker sections and structural fabrication.
The limitations include a slower deposition rate than MIG, a requirement to remove slag after welding, and a bead appearance that is typically less refined than MIG or TIG. For precision sheet metal fabrication in a workshop environment, arc welding is generally not the first choice — but for structural work, heavy plate, site repairs, and applications where portability matters, it remains highly relevant.
Key Factors in Choosing the Right Welding Process
Material type and thickness
Different welding processes perform differently on different materials and at different thicknesses. TIG is the preferred process for thin stainless steel and aluminium. MIG handles a wider thickness range efficiently. Spot welding is optimised for thin sheet. Arc welding suits thicker sections and structural steel. Matching the process to the material and thickness is the starting point for any process selection decision.
Joint design and access
The geometry of the joint and the accessibility of both sides of the weld influences which processes are practical. Spot welding requires electrode access to both sides of the joint. Butt welds, fillet welds, and corner joints each have their own requirements. If the joint is in a location where access is restricted — inside a box section, at the bottom of a deep channel — the process and technique need to be selected with that constraint in mind.
Appearance requirements
For products where the weld will be visible in the finished item — consumer products, architectural metalwork, food equipment, instrumentation — weld appearance is a design requirement, not just an aesthetic preference. TIG welding produces the cleanest, most refined weld bead. MIG can produce a visually acceptable weld with proper technique and post-weld dressing. Spot welding leaves a weld nugget mark. Arc welding produces a covered bead that requires slag removal.
Production volume and speed
High-volume production applications favour processes that are fast to execute per joint. Spot welding is the fastest for sheet metal lap joints. MIG welding is fast for continuous welds. TIG is slower but may be the only option for quality-critical applications. Arc welding occupies a middle ground. The cost per weld is directly related to the speed of the process, and this relationship becomes very significant at scale.
Strength and structural requirements
All of the main welding processes can produce joints of adequate strength when applied correctly to the right materials with proper procedure. However, the achievable joint efficiency, the behaviour of the weld under different loading conditions, and the inspection methods appropriate to each process vary. For structurally critical welds — pressure vessels, structural frames, load-bearing brackets — the process selection and qualification requirements are more prescriptive.
How Raamps Industries Approaches Welding Process Selection
When a new fabrication job comes to us at Raamps Industries, the welding process is not selected by default — it is selected based on the specific requirements of the job. We consider the material, the joint design, the appearance requirements, the quantity, and the structural demands of the application before recommending and using a specific process.
For clients who are not sure which process is appropriate for their application, we are happy to provide a recommendation as part of our pre-production review. A brief conversation about the end use, the material, and the appearance and quality requirements is usually enough to identify the right approach.
If you have a welding requirement and want expert guidance on the right process for your application, get in touch with the Raamps Industries team. We will give you a straightforward answer and a clear understanding of what to expect from the finished weld.
Frequently Asked Questions
1. Which welding process is strongest?
All major welding processes — MIG, TIG, arc, and spot welding — can produce joints approaching the strength of the parent material when applied correctly. Weld strength is more dependent on correct procedure, filler material selection, and weld quality than on the specific process used. For structural applications, the welding procedure and qualification requirements are defined by the applicable standard or engineering specification.
2. When should TIG welding be chosen over MIG?
TIG welding should be chosen when the highest weld quality and appearance are required — particularly for stainless steel, aluminium, and thin materials. It is the process of choice for food-grade equipment, architectural metalwork, precision instrumentation, and any application where the weld will be visible and cosmetically assessed. MIG is preferred when speed matters more than appearance, or for thicker sections in structural applications.
3. Is MIG welding suitable for stainless steel?
Yes, MIG welding can be used on stainless steel with appropriate filler wire and shielding gas. For applications where weld appearance is not critical, MIG on stainless steel is a practical choice. Where appearance and corrosion resistance at the weld are priorities, TIG welding typically produces a superior result on stainless steel.
4. What is the difference between spot welding and seam welding?
Spot welding produces individual circular weld nuggets at discrete points along a joint. Seam welding is a variation that produces a continuous or overlapping series of weld nuggets by rolling the electrodes along the joint, creating a sealed or near-sealed seam. Seam welding is used where a pressure-tight joint is required on sheet metal, such as fuel tanks or fluid containers.
5. Can different metals be welded together?
Welding dissimilar metals is possible but more complex than welding the same material. The compatibility of the base metals, the selection of appropriate filler material, and the management of the different thermal properties of the two materials all need to be considered. Not all metal combinations can be successfully welded — some require brazing or mechanical joining instead. Discuss your specific material combination with our welding team before proceeding.
6. How does welding affect the properties of the base material?
The heat generated during welding creates a heat-affected zone (HAZ) in the base material adjacent to the weld. In this zone, the microstructure of the material is altered by the welding heat, which can change its mechanical properties — sometimes reducing hardness or toughness compared to the parent material. For materials that are heat-treated or work-hardened, the HAZ represents a zone of reduced performance that needs to be accounted for in the joint design.
7. What post-weld finishing is typically required?
Post-weld finishing requirements depend on the process and the application. MIG welds may need grinding or dressing to achieve an acceptable appearance. TIG welds on stainless steel may need pickling or passivation to restore the corrosion-resistant surface. Arc welds require slag removal. Spot welds typically require no post-weld finishing of the weld itself. For all processes, any spatter needs to be removed from areas where it would affect fit or appearance.
8. Does Raamps Industries offer welding qualification documentation?
For applications requiring welding procedure qualification or welder qualification records, please discuss your documentation requirements with our team at the enquiry stage. We can advise on what documentation is available and what additional qualification activities may be needed for specific standards or client requirements.
9. How does Raamps Industries ensure weld quality?
Our quality approach includes visual inspection of all welds against defined acceptance criteria, dimensional verification of the finished assembly, and — for applications requiring it — non-destructive testing methods such as dye penetrant inspection. Our welders are experienced across all the processes we offer, and our process controls are designed to produce consistent weld quality across production runs, not just on individual samples.
10. Can Raamps Industries handle welding as part of a complete fabrication service?
Yes. Welding is part of our integrated sheet metal fabrication service. We offer laser cutting, CNC punching, CNC bending, and metal welding under one roof. For clients who need components to be cut, formed, and welded into finished assemblies, we manage the complete fabrication sequence, which simplifies your supply chain and ensures quality continuity from raw material to finished part.
