Welding Processes & Positions

Welding Processes & Positions

Two variables determine what a welder is actually qualified to do on a given job, and they're independent of each other:

process - the method used to generate the arc, deliver the filler metal, and shield the weld from contamination 

and 

position - the physical orientation of the joint relative to gravity. 

A welder can be highly skilled in one process and one position and genuinely unqualified for a job that requires a different combination of either. Understanding both is the difference between assuming a welder can handle a job and actually knowing they can.

WELDING PROCESSES

The Process Matters.

There is no single “best” welding process.

A process that is ideal for a controlled fabrication shop can be completely wrong for an exposed field repair. A process that produces an exceptional finish may be unnecessarily slow for heavy structural production. A wire that performs beautifully on carbon steel may be completely inappropriate for aluminum or stainless.

Professional welding is therefore not about having one favourite machine.

It is about understanding the available processes, knowing what each one does well, understanding its limitations, and selecting the right combination of process, consumable, shielding, position and technique for the work in front of you.

The four arc processes most commonly encountered in general fabrication and repair are SMAW, GMAW, FCAW and GTAW, but the wider welding industry includes submerged arc, resistance, stud, plasma, laser, friction and other specialized processes.

The sections below explain what they are, where they excel and—just as importantly—where they do not.

SMAW - STICK WELDING

Simple Equipment. Serious Skill.

Shielded Metal Arc Welding (SMAW), commonly called stick welding or arc welding, uses a consumable electrode coated in flux.

The coating performs several functions as the electrode burns, including producing shielding gases and forming slag over the weld. That means the process does not require an external shielding-gas cylinder, which is one of its greatest advantages. Stick welding remains a benchmark for field and structural repair for exactly that reason.

There is no external gas stream to be blown away by wind, the equipment is comparatively portable, and the process can be taken into difficult locations where shop-style equipment is impractical.

The tradeoff is slag. After each weld pass, the slag must be removed before another pass is deposited, and electrode changes interrupt the continuous production possible with wire-fed processes.

There is also a significant skill component. A skilled stick welder is continuously controlling arc length, travel speed, electrode angle, manipulation and puddle size while managing a consumable electrode that is getting progressively shorter. A clean, consistent stick weld is one of the clearest demonstrations of fundamental welding control.

Where SMAW excels

• Structural repair

• Field fabrication

• Outdoor welding

• Heavy repair

• Difficult access

• Remote locations

• Work where wind makes external gas shielding impractical

Common electrodes

Examples include:

E6010 / E6011 - commonly associated with strong arc characteristics and root or field applications.

E6013 - general-purpose electrode with relatively easy operating characteristics.

E7018 - low-hydrogen structural electrode widely used where higher-strength weld metal and controlled hydrogen practices are required.

The electrode classification matters. An “E7018” is not simply a stick that happens to weld steel; its classification communicates characteristics of the electrode and deposited weld metal.

GMAW - MIG WELDING

Speed, Control & Clean Production.

Gas Metal Arc Welding (GMAW) continuously feeds a solid wire electrode through the welding gun while an external shielding gas protects the molten weld pool.

“MIG” is the term most customers know, although technically GMAW encompasses shielding gases beyond strictly inert-gas applications. Where active gases such as carbon dioxide or oxygen are used, the process is commonly referred to as MAG(Metal Active Gas) Welding.

GMAW's major advantages are productivity, continuous wire feed and the absence of the slag layer associated with flux-covered electrodes. That makes it exceptionally useful for controlled fabrication environments where material, access, wind and cleanliness can be managed.

Its biggest weakness is also obvious once the process is understood:

The shielding gas has to stay where the weld is being made.

Wind can disperse the shielding envelope and contaminate the weld pool, which is why conventional GMAW generally favours controlled environments or appropriate wind protection.

GMAW TRANSFER MODES

The Word “MIG” Doesn't Describe One Way of Welding.

GMAW can operate using different metal-transfer behaviours, and those behaviours substantially change where the process is effective.

Short-Circuit Transfer

The wire repeatedly contacts the molten pool, transfers metal and re-establishes the arc.

It is useful for relatively thin material and for out-of-position work because the weld pool can be kept smaller and more controllable.

It is generally less productive than spray transfer but considerably more versatile for general fabrication. CWB notes that short-circuit GMAW can be used across positions and commonly uses CO₂ or argon-based CO₂/oxygen mixtures.

Globular Transfer

Metal transfers in larger droplets.

It can provide useful deposition, but tends to produce considerably more spatter and is generally less desirable when clean, controlled weld appearance is important.

Spray Transfer

The current and voltage are sufficiently high for a fine stream of molten metal to transfer across the arc.

Spray transfer provides high deposition rates and a smooth, productive weld, but the larger and more fluid weld pool generally makes conventional spray transfer best suited to flat and horizontal work.

Pulsed Spray Transfer

Pulsed GMAW alternates between higher peak current and lower background current, allowing spray-type metal transfer while reducing the average heat input enough to expand positional capability.

This is an important distinction:

“Pulsed MIG” is not simply another name for spray transfer.

The electrical waveform is controlling how the transfer occurs.

CWB notes that pulsed GMAW can extend spray-type transfer into all positions.

FCAW - FLUX-CORED ARC WELDING

High Deposition Without Giving Up Field Capability.

Flux-Cored Arc Welding uses a continuously fed tubular wire containing flux.

The major distinction is that there are two fundamentally different forms of FCAW:

FCAW-S - Self-Shielded

FCAW-G - Gas-Shielded (Dual)

The two should not be treated as interchangeable.

FCAW-S — SELF-SHIELDED FLUX CORE

The Wire Carries Its Own Shielding System.

Self-shielded flux-cored welding uses a tubular electrode whose flux generates shielding gases and slag as it burns.

No external shielding gas is required, making FCAW-S particularly useful for outdoor and field work where a conventional gas shield would be vulnerable to wind.

AWS specifically identifies FCAW-S as the self-shielded variation and notes its suitability for outdoor or windy conditions because the flux generates the shielding required around the weld.

It combines some of the mobility of SMAW with the productivity of a continuous wire.

Advantages:

• No external shielding gas

• Excellent field mobility

• Good outdoor capability

• High deposition rates

• Continuous wire feed

• Strong suitability for heavier fabrication

• Excellent productivity in many structural applications

Trade-offs

Like SMAW, FCAW-S produces slag that must be removed between passes.

It can also produce more visible smoke and spatter than some gas-shielded processes, depending on the wire and operating conditions.

The critical distinction

A self-shielded FCAW wire is specifically designed to generate its own shielding.

Running an external shielding gas is not what makes FCAW-S work.

The wire classification and manufacturer's procedure determine the appropriate operating conditions.

FCAW-G - GAS-SHIELDED FLUX CORE

Flux Core With External Shielding.

Gas-shielded FCAW combines a tubular flux-filled wire with an external shielding gas.

This is often what fabricators mean when they refer to dual-shield welding.

The flux contributes shielding and slag formation while the external gas provides an additional shielding environment around the arc and weld pool.

AWS describes FCAW-G as the gas-shielded variation and notes that it is commonly preferred in fabrication environments where the cleaner, controlled process is advantageous.

Why use FCAW-G?

It can provide:

• High deposition rates

• Strong productivity

• Excellent weld quality

• Good fusion

• Useful penetration characteristics

• Reduced dependence on the flux system alone

• Strong suitability for shop fabrication

Why not use it everywhere?

Because the external gas introduces the same environmental issue found with GMAW:

Wind can disrupt the shielding envelope.

That makes FCAW-G much more dependent on environmental control than FCAW-S.

“DUAL SHIELD” — WHAT IT ACTUALLY MEANS

The phrase can be confusing.

Dual-shield is not a completely separate welding process category.

It is a common industry description for gas-shielded FCAW, where the process receives shielding from both the flux system and an external shielding gas.

That makes it fundamentally different from self-shielded FCAW.

A simplified comparison:

Process

Wire

External Gas

Slag

Field / Wind Capability

GMAW

Solid

Required

No

Limited

FCAW-S

Flux-cored

No

Yes

Excellent

FCAW-G

Flux-cored

Required

Yes

Controlled conditions

SMAW

Stick electrode

No

Yes

Excellent

GMAW / FCAW WIRES

The Wire Is More Than Filler Metal.

Wire selection affects the chemistry, mechanical properties, transfer characteristics, deposition behaviour and operating conditions of the weld.

Solid GMAW Wire

Common carbon-steel examples include ER70S-3 and ER70S-6 classifications.

ER70S-6 is widely associated with general carbon-steel fabrication and contains additional deoxidizing elements useful when welding material with some surface contamination or mill scale.

Stainless GMAW Wire

Common classifications include:

ER308L — commonly used for compatible austenitic stainless applications.

ER316L — commonly selected where the base material and service environment call for 316-family stainless.

Aluminum GMAW Wire

Common examples include:

ER4043

ER5356

The appropriate alloy depends on the aluminum base material, required properties, welding characteristics and service requirements.

Flux-Cored Wire

Examples include classifications such as:

E71T-1 — common gas-shielded structural flux-cored category.

E71T-11 — common self-shielded flux-cored category.

There are many specialized FCAW classifications, and the exact designation matters.

A wire should be selected from the required specification and procedure—not simply because it feeds easily or happens to be in the machine.

GAS TUNGSTEN ARC WELDING - GTAW / TIG

Maximum Control. Minimum Compromise.

GTAW uses a non-consumable tungsten electrode to establish the arc.

Shielding gas protects the weld zone, while filler metal, when required, is introduced separately.

Because the filler isn't continuously fed through the torch, the operator has unusually direct control over the weld pool.

That makes TIG particularly valuable where:

• Precision matters

• Weld appearance matters

• Heat control is important

• Materials are thin or sensitive

• Stainless or aluminum require controlled fabrication

• Contamination must be minimized

AWS describes GTAW as a process using a non-consumable tungsten electrode and inert shielding gas, with filler optionally added separately or the joint welded autogenously.

The tradeoff

GTAW is comparatively slow.

Its deposition rate is low, filler addition is often manual and the process demands significant operator control.

That is precisely why it is chosen when control is more valuable than speed.

GTAW AC & DC

TIG also introduces another important distinction.

DC TIG

Commonly used for steels and stainless steels.

AC TIG

Commonly associated with aluminum and magnesium because the alternating current helps manage the oxide layer while providing the arc characteristics required for those materials.

That is one reason aluminum TIG demands a different machine setup and technique from stainless TIG.

WELDING SHIELDING GASES

Gas Is Part of the Welding Process.

Shielding gas isn't simply something that comes out of a bottle.

The gas affects arc characteristics, transfer, penetration, puddle behaviour, bead profile and, in some applications, metallurgical behaviour.

AWS maintains a formal specification covering the classification, purity and composition of shielding gases and gas mixtures used in fusion welding and allied processes.

ARGON

Argon is an inert gas and one of the most commonly used shielding gases.

It is widely used for:

• GTAW / TIG

• Aluminum GMAW

• Stainless GMAW

• Spray and pulsed transfer applications

• Argon-based mixed gases

Its characteristics make it particularly useful when stable arc control and good weld-pool behaviour are required.

HELIUM

Helium is also inert but behaves differently from argon.

It can provide increased arc energy and heat input characteristics and is often used in mixtures, particularly for non-ferrous applications.

Argon-helium mixtures can be useful for aluminum and other applications where additional heat is beneficial. CWB identifies argon or argon-helium mixtures as common shielding choices for aluminum GMAW.

CARBON DIOXIDE — CO₂

CO₂ is an active shielding gas.

It is commonly used for carbon-steel GMAW and in certain FCAW applications.

It can provide good penetration and economical operation, but generally produces more spatter than many argon-rich mixtures.

CWB notes that CO₂ and higher-CO₂ argon mixtures are associated with globular transfer, while CO₂ or argon/CO₂ mixtures can be used for short-circuit GMAW.

OXYGEN — O₂

Oxygen is also an active gas.

Small percentages are sometimes added to argon-based mixtures for steel and stainless applications to influence arc stability, fluidity and transfer behaviour.

It is generally used as a controlled mixture rather than as a stand-alone shielding gas for conventional GMAW.

CWB notes that mixtures such as approximately 2% oxygen in argon can support spray transfer on steel and stainless steel.

ARGON + CO₂

One of the most familiar carbon-steel shielding-gas families is the argon/CO₂ mixture.

Changing the proportion changes the behaviour.

A higher argon percentage generally supports smoother, more controlled transfer and reduced spatter compared with high-CO₂ operation.

A higher CO₂ content can increase penetration and influence arc characteristics but generally produces more spatter.

The correct mixture depends on:

• Material

• Thickness

• Transfer mode

• Position

• Wire classification

• Required appearance

• Productivity

• Applicable procedure

There is no universal “best MIG gas.”

THE SIMPLE GAS RULE

The basic logic is:

GMAW → external shielding gas required

GTAW → external shielding gas required

FCAW-S → external shielding gas normally not required

FCAW-G → external shielding gas required

SMAW → no external shielding gas

SAW → shielding primarily provided beneath granular flux

That single distinction explains why a welding machine that performs beautifully in a shop can be completely inappropriate for an exposed outdoor repair.

Other Welding Processes

SUBMERGED ARC WELDING - SAW

High Deposition for Long, Controlled Welds.

Submerged Arc Welding uses a continuously fed consumable electrode beneath a layer of granular flux.

The arc is submerged beneath the flux, so there is no exposed arc in the same way seen with GMAW, SMAW or FCAW.

The flux protects the weld and contributes to the welding process while allowing extremely high deposition rates.

SAW is especially valuable for:

• Long seams

• Heavy plate

• Structural fabrication

• Large assemblies

• Pressure vessels and tanks

• Repetitive shop production

• Automated or mechanized welding

Its limitation is equally important:

the work generally needs to be positioned so the granular flux can remain over the weld.

That makes SAW a highly productive shop process, but a very different proposition from mobile field welding.

RESISTANCE WELDING

Welding Without a Conventional Arc.

Resistance welding creates heat through electrical resistance while pressure is applied to the workpieces.

Major variations include:

Spot Welding

Frequently used to join overlapping sheet material.

Seam Welding

Uses a rotating electrode arrangement to produce continuous or overlapping welds.

Projection Welding

Uses deliberately formed projections or contact points to concentrate resistance heating.

Resistance welding is highly productive and well suited to repetitive manufacturing environments where components can be accurately positioned and fixtured.

It is fundamentally different from the manual arc-welding processes most customers associate with welding.

STUD WELDING

Fast Attachment of Studs & Fasteners.

Stud welding creates an arc between a stud and the base material and then joins the two under controlled conditions.

It is commonly used for:

• Structural studs

• Fasteners

• Insulation anchors

• Decking applications

• Equipment and fabrication attachments

Its value comes from speed and the ability to attach components without drilling through the base material in certain applications.

PLASMA ARC WELDING — PAW

Plasma Arc Welding is related to TIG but constricts the arc through a small orifice, creating a more concentrated plasma arc.

It offers:

• High energy density

• Precise control

• Deep penetration potential

• Specialized thin-material capability

• Specialized production applications

It is considerably less common in general repair and fabrication than GMAW, FCAW, SMAW or GTAW.

OXYFUEL WELDING

One of the Older Welding Technologies Still Worth Understanding.

Oxyfuel welding uses a fuel gas—commonly acetylene—with oxygen to generate a flame that heats the joint.

Oxyacetylene welding is now far less common for general structural fabrication than arc processes, but oxyfuel equipment remains important throughout the trade for:

• Heating

• Brazing

• Cutting

• Specialized repair

• Maintenance

The associated cutting process is oxyfuel cutting, which should not be confused with welding itself.

HIGH-ENERGY & SPECIALIZED PROCESSES

The welding industry extends well beyond the processes typically used in general fabrication.

Specialized manufacturing can employ processes such as:

Laser Beam Welding — LBW

Extremely concentrated energy for high-speed, precision production.

Electron Beam Welding — EBW

Uses a focused electron beam, commonly in controlled or vacuum environments, for highly specialized applications.

Friction Welding

Creates a solid-state bond through friction-generated heat and pressure rather than melting the materials in a conventional arc.

Friction Stir Welding — FSW

A rotating tool plasticizes and mechanically joins material without conventional melting, particularly valuable for certain aluminum and non-ferrous applications.

Electroslag Welding — ESW

A high-deposition process used for very thick sections and specialized heavy fabrication.

Thermite Welding

Uses an exothermic chemical reaction to produce molten metal for specialized joining applications.

These processes demonstrate an important point:

“Welding” is an entire family of technologies, not one method.

WELDING POSITIONS

The Welder Isn't Always Given the Easy Way.

Position describes the physical orientation of the joint while it is being welded.

For groove and fillet welds, the familiar designations are:

Position

Groove

Fillet

General Description

Flat

1G

1F

Weld performed from above

Horizontal

2G

2F

Weld axis generally horizontal

Vertical

3G

3F

Weld progresses vertically

Overhead

4G

4F

Weld performed from below

Pipe welding adds positions such as 5G and 6G, where a fixed pipe can force the welder through changing orientations during one qualification or weld.

WHY POSITION CHANGES THE DIFFICULTY

Molten metal obeys gravity.

In flat welding, gravity helps keep the puddle where the welder wants it.

In horizontal welding, gravity pulls the molten metal away from the ideal joint location.

In vertical welding, puddle control and travel direction become substantially more important.

In overhead welding, gravity works directly against the operator.

Technique, amperage, travel speed, electrode angle and puddle size all have to be managed accordingly.

Vertical-Up

Generally provides greater control and penetration potential for heavier structural work.

Vertical-Down

Can permit faster travel and lower heat input for appropriate applications and materials.

The direction is not simply personal preference.

It is a process decision based on the material, joint and governing procedure.

PROCESS & POSITION ARE CONNECTED

Not every welding process behaves equally well in every position.

SMAW

Highly versatile across the four basic positions, which contributes heavily to its value in field repair.

GMAW

Short-circuit transfer can be used out of position, while conventional spray transfer is primarily suited to flat and horizontal work.

FCAW-S

Widely valued for positional field work and structural applications.

FCAW-G

Can provide strong positional capability depending on the wire, shielding gas and procedure.

GTAW

Can be performed in multiple positions, but the slower deposition rate makes difficult positional TIG work particularly demanding.

SAW

Strongly associated with controlled, generally flat-position production because the granular flux must remain over the weld.

The process and position therefore cannot be considered independently.

FIELD VS. SHOP WELDING

The Best Process Depends on Where the Weld Happens.

A shop fabricator can often rotate a piece into the most productive position.

A field welder usually cannot.

A fire escape cannot be turned over so the welder can work in flat position.

A railing attached to a building cannot always be removed simply to make the weld easier.

A structural repair may need to happen exactly where the damaged connection already exists.

That changes the process decision.

A welding process that is highly productive on a fabrication table may be a poor choice for an exposed repair ten metres in the air.

Field welding requires the process, consumable and operator capability to adapt to the structure—not the other way around.

PROCESS SELECTION

The Right Welding Process Depends on the Job.

A professional process selection considers:

Base material

What is being welded?

Thickness

How much material needs to be fused and how much heat can it tolerate?

Joint design

What type of connection is being produced?

Position

Can the work be placed in a productive position?

Environment

Is the work indoors, outdoors, exposed to wind or contaminated by existing conditions?

Production

How much deposition and productivity are actually required?

Appearance

Is the finished weld visible and architecturally important?

Access

Can the operator physically reach and manipulate the joint?

Specification

Are there drawings, WPS requirements, engineering requirements or governing standards?

Consumable

What filler or electrode classification is appropriate?

The machine choice is only one part of the decision.

CONSUMABLES & CLASSIFICATIONS

The Electrode Is Part of the Engineering.

Different processes use different forms of consumable.

SMAW

Stick electrodes such as E7018.

GMAW

Solid wires such as ER70S-6, ER308L, ER316L, ER4043 and ER5356, depending on material and application.

FCAW

Flux-cored wires such as structural categories E71T-1 and E71T-11, among many others.

GTAW

Separate filler rods such as ER70S-2, ER308L, ER316L, ER4043 and ER5356, again depending on the material and application.

SAW

Continuous solid or flux-cored electrodes selected in combination with an appropriate granular flux system.

A filler classification identifies properties and intended use.

The correct wire isn't simply the one that creates an attractive bead. It is the one appropriate for the base metal, joint, procedure and service requirements.

WHY “A GOOD WELDER CAN WELD ANYTHING” ISN'T TRUE

Welding skill transfers; Qualification does not automatically transfer.

A welder can be highly experienced and still require specific qualifications, procedures, equipment and consumables for a particular project. Certification and qualification are tied to specified combinations of variables such as process, material, thickness, position and other governing conditions. That is why a credible welding qualification should be treated as a specific technical credential, not a generic statement that someone is “certified.”

For regulated structural work, the applicable Canadian standards and certification requirements need to be determined from the project. CWB certification, for example, can involve company certification, welding procedures and qualification of welding personnel under applicable CSA standards.

THE REAL MEANING OF PROCESS EXPERTISE

Understanding welding processes isn't about memorizing machine settings.

It is understanding why one process is appropriate and another isn't.

A professional welder should be able to look at a job and recognize:

This needs field capability.

This needs gas shielding.

This material needs tighter contamination control.

This joint will require a different sequence.

This position changes what process makes sense.

This wire is appropriate, but that one isn't.

This repair requires engineering input before welding begins.

That judgment is where experience becomes valuable.

THE MCDOUGALL APPROACH

Welding is a means to an end.

The objective is not to use the most advanced process, the fastest process or the process that happens to be loaded in the machine. The objective is to produce the right weld, in the right material, using the right process, consumable and procedure, in the conditions the job actually presents.

McDougall Metalworks

Process knowledge. Practical judgment. Welding built for the application.