The sequence we use ourselves — start at the joint, choose the process, then size the machine on four numbers. Written by a dealer who carries seven brands and therefore has no reason to push any one of them.
Most welding equipment is bought the wrong way round — a machine is chosen first, and the work is then made to fit it. Every specification we write starts at the other end: with the joint. This page sets out the same sequence we use on the phone, so you can narrow the choice yourself before you ask anyone for a price.
We are the authorised dealer for seven manufacturers rather than one, so nothing below is written to push a particular machine. Where a 300 A set does the job, we say so.
These five answers decide almost everything that follows. If you can answer them, a competent supplier can specify your equipment in one conversation. If you cannot, no amount of comparing brochures will help.
There is no best welding process, only a best process for a given joint. The honest way to read this table is to look at the third column first — most bad purchases come from ignoring what a process is bad at.
| Process | Choose it when | Do not choose it when | Typical thickness |
|---|---|---|---|
| ARC / MMA Stick electrode |
Site and maintenance work, outdoors, wind, awkward positions, mixed jobs, heavy structural steel. Cheapest to buy and nothing to blow away. | Thin sheet under about 2 mm, aluminium, or anywhere a high deposition rate and low cleanup matter. Slag has to be chipped off every run. | 2 mm and up |
| MIG / MAG Solid wire |
In-shop production. Highest deposition rate of the manual processes, easiest to learn, little cleanup, continuous wire so no stub loss. | Outdoors or in a draught — the shielding gas blows away and the weld is porous. Also poor for very heavy single-pass sections. | 0.8–12 mm |
| Flux-cored FCAW |
Heavy fabrication with high deposition needs. Self-shielded wire works outdoors where solid-wire MIG cannot. | Clean, low-fume environments and thin material. Fume volume is high and extraction is not optional. | 4 mm and up |
| Submerged arc SAW |
Long straight or circumferential seams in plate that can be brought to the flat or horizontal position, and cladding. Deposition rates nothing manual comes near, and the arc is buried — no flash, no spatter, almost no fume. | Short, irregular or positional joints, site work and thin sheet. It cannot weld vertically or overhead, and it needs mechanised travel, flux handling and controlled fit-up. | 6 mm and up |
| TIG / GTAW | Stainless, aluminium, thin sheet, pipe root runs, and anywhere the weld is visible or has to pass radiography. The most controllable process there is. | Long production runs on plain steel. It is the slowest process and the most dependent on operator skill. | 0.5–6 mm |
| Stud welding CD & drawn arc |
Fixing threaded studs, pins and fasteners to plate or sheet from one side, in under a second, with no hole through the parent metal. Capacitor discharge for M3–M8 on thin sheet, drawn arc for M3–M16 on plate. | Joining two plates to each other — it is a fastening process, not a seam process. Each stud size needs its own chuck, and drawn arc needs a ceramic ferrule. | 0.5 mm base metal and up |
| Handheld laser | Stainless and sheet metal work where speed and finish decide the cost. Very little distortion, very little grinding afterwards, easy to train. | Poor fit-up. A laser will not bridge a gap the way an arc will. Capital cost is high and enclosure and eye protection are mandatory. | 0.5–8 mm |
Thickness figures are for normal manual work. Anything heavier is welded in multiple passes with edge preparation — and once you are preparing edges, a milling beveller usually pays for itself faster than a bigger welding set.
One process on that list does not belong to the same family as the others. Stud welding does not join two pieces of plate; it fixes a threaded stud, pin or fastener onto one, from the accessible side, in a fraction of a second. If what is slowing your job down is drilling, tapping, riveting or a nut on the back of a panel you cannot reach, no amount of choosing between MIG and TIG will help — the answer is a different operation altogether.
The decision within it is simple. Capacitor discharge discharges in one to three thousandths of a second, so it welds M3 to M8 studs onto thin sheet without marking the far side: panels, enclosures, transformer tanks, cookware. Drawn arc holds an arc for 10 to 600 milliseconds and fuses the full cross-section, which is what you need for M3 to M16 studs on plate where the fastener carries load. See the stud welding page for the ARTECH range and the full comparison.
Submerged arc is the process most often left out of a comparison like this, and it is the one that changes the economics most when it fits. The arc burns under a blanket of granular flux, so nothing is visible: no flash, no spatter, and very little fume. What you get in exchange is a deposition rate several times that of stick or MIG, and deep penetration that lets thick plate be welded in far fewer passes.
It fits when the seam is long, repetitive and can be brought to the flat or horizontal position. That describes a great deal of Indian heavy fabrication:
It does not fit anything short, awkward or out of position. There is no such thing as vertical or overhead submerged arc, the equipment does not go up a structure, and on a one-off bracket the setup time alone will beat you. Fit-up has to be controlled too — you cannot see the arc, so the joint has to be right before the flux goes down.
A power source on its own welds nothing. A working SAW station also needs mechanised travel — a tractor running on track, a column and boom, or turning rolls that revolve the job under a fixed head — plus a flux hopper, and somewhere to keep the flux dry. Agglomerated fluxes pick up moisture the way low-hydrogen electrodes do, so we stock ESAB SAW flux and the 50 kg and 120 kg flux ovens that go with it.
The figure that matters on a submerged arc power source is not peak amps but what it will hold all day, because a SAW seam runs for minutes at a time at currents a manual set would never see. The CPRA 1250i is an IGBT inverter rated 1250 A at 100% duty cycle — the full current, continuously — over a 60 to 1250 A range, on 415 V ±15% three phase at 71.9 kVA. OCV is 84 V, insulation class H, weight 115 kg. That wide mains tolerance matters more in Delhi than the brochure lets on.
It is not a single-purpose machine either: the same source runs manual metal arc and arc-air gouging, which is worth knowing in a shop where the SAW station is not busy every shift.
It comes as a package with the SAW Tractor CPRA, so the travel gear is not a separate purchase. The tractor carries a four-roll drive for 2.0–6.0 mm wire, a 25 kg wire spool and a 6 litre flux hopper; it travels at 0.1–2.2 m/min with wire feed from 0.2–2.5 m/min, and the head swings ±90° around the vertical with ±45° of head and torch inclination, tracked by a mechanical pointer. The package ships with 1.5 m of track, control cable, four welding cables and the tips and feed rollers for 2.4–5.0 mm wire; 2 m track sections extend it.
A tractor on track suits long straight seams and fillets — beams, panels, plate girders. For circumferential seams the head stays put and the job turns instead, so budget for turning rolls rather than more track.
Open the ESAB datasheet — or ask us, and we will send it with the wire and flux recommendation for your plate grade and any impact requirement.
| Material | Usual choice | Alternative | What catches people out |
|---|---|---|---|
| Mild & structural steel | ARC/MMA, or MIG in the shop | Flux-cored on heavy work; submerged arc on long seams | Restrained or crack-sensitive joints need a low-hydrogen basic electrode, not a general rutile one. |
| Stainless steel | TIG for quality and thin work | MIG with tri-mix gas; handheld laser on sheet | Heat input and back purging. Too much heat gives carbide precipitation and a discoloured, less corrosion-resistant weld. |
| Aluminium | AC TIG for control | MIG with a spool or push-pull gun, pure argon | The oxide layer melts far above the metal. Clean it, and never feed soft wire down a long steel liner. |
| Galvanised steel | MIG or MMA | Handheld laser | Zinc fume is genuinely dangerous. Extraction and the right respirator are part of the specification, not an extra. |
| Cast iron | MMA with nickel-iron electrodes | — | Preheat and slow cooling matter more than the machine. Weld short runs and peen between them. |
| Pipe, coded work | Cellulosic electrode for the root, low-hydrogen for fill and cap | TIG root, MMA fill | Cellulosic electrodes run on DC positive only. On the wrong polarity or an AC set they simply will not work. |
Every consumable we sell lists its AWS, EN ISO and IS classification and the approvals it holds — see the consumables page, or download the datasheets from the catalogue library.
Once the process is settled, only four figures on the datasheet actually matter. Everything else is either a consequence of these or a feature you may never use.
Duty cycle is the proportion of any ten-minute period a machine can weld at a stated current before it must idle to cool. 400 A at 60% means six minutes welding and four minutes resting in every ten — not six hours in ten.
Current and duty cycle trade against each other roughly as the square of the current. Drop the current and the permitted time rises sharply. That is why the ESAB ARC 400i is rated 400 A at 60% and 310 A at 100% — it is the same machine, worked less hard.
Duty cycle is rated to IEC/EN 60974-1 in a 40 °C ambient. A shed roof in Delhi in May is hotter than that, and a machine standing in the sun with a dusty filter is hotter again. If your shop runs hot, specify a machine with a 100% rating at or above your working current rather than one that only just reaches it at 60%.
A thermal cutout mid-shift is not a fault. It is the machine telling you it was specified for a lighter job than the one it is doing.
The bottom of the range matters as much as the top. A set that starts at 60 A will not strike cleanly on 1.6 mm sheet; one that stops at 300 A will not gouge. For stick welding the working current is roughly 30 to 45 A per millimetre of electrode diameter — our PIPEWELD 6010R datasheet, for instance, calls for 80–120 A on 3.15 mm and 100–150 A on 4.0 mm. Work out the largest electrode you will genuinely run, add the duty cycle you need at that current, and you have your machine size.
OCV is the voltage across the leads before the arc is struck, and it decides which electrodes the machine can actually run. A general rutile electrode such as ESAB 28 needs a minimum AC OCV of 50 V; a basic low-hydrogen electrode such as ESAB 36H needs 70 V. Buy a set with too low an OCV and you have quietly ruled out the very consumable your code work requires.
Where the work is damp or confined, look for VRD — voltage reduction that holds the idle voltage down to a safe level until the arc is struck.
A welding set is bought once. Electrodes, wire, gas, tips, liners and labour are bought every month, and over any sensible life they dwarf the purchase price. The right comparison is the cost of a finished metre of weld.
These are the shapes of enquiry we see most often, taken through the sequence above.
Mixed positions and a good deal of arc-on time. Stick welding suits the range and the positions; the deciding figure is a comfortable 100% rating at the current the pair actually weld at.
Appearance and distortion decide this one, and the real cost is in the grinding and polishing afterwards. TIG if the volume is modest; handheld laser once finishing labour is the bottleneck.
Portability and tolerance of a rough supply beat every other consideration. Nothing to blow away outdoors, and one electrode covers most of what turns up.
The approval decides the consumable and the consumable decides the machine. Cellulosic roots need DC positive and a set that holds an arc at the end of a long lead; the fill and cap need a low-hydrogen electrode and the OCV to run it.
This is the case where the process choice, not the machine choice, is worth lakhs. Every one of those seams is long, repetitive and can be rolled into the flat or horizontal position, which is exactly the ground submerged arc owns. The deposition rate and the pass count are what pay for it — a joint that takes six stick passes may take two under flux. The CPRA package brings its own tractor and flux hopper, so what is left to budget is the track, the turning rolls and the flux itself.
If you would rather skip the whole exercise, send these and we will do it for you, in most cases the same working day:
You will get back a scope of supply — machine, consumables, protective equipment and anything else the job needs — with the datasheet for every line, so you can check the figures against what we have claimed.
Material, thickness, quantity and delivery location are all we need to begin. We represent seven authorised brands, so the recommendation you receive is the one the job calls for.