If you’re interested in welding and have wondered, “What is SMAW?” we’re here to help explain. SMAW stands for “shielded metal arc welding.” SMAW is a type of welding used in a variety of applications, including maintenance and repair, construction, industrial fabrication, and more.
SMAW is one of the oldest types of welding, dating to 1890 when Charles L. Coffin patented the process. SMAW is a manual arc welding process that remains one of the most commonly used welding processes. It can be used for both repair welding and production, and it can be used in all welding positions on all ferrous metals.
What is Shielded metal arc welding?
Shielded metal arc welding (SMAW), also known as manual metal arc welding (MMA or MMAW), flux shielded arc welding, or informally as stick welding, is a manual arc welding process that uses a consumable electrode covered with a flux to lay the weld.
Shielded metal arc welding (SMAW) is a manual process using a flux-coated consumable electrode with a metal rod at the core. Alternating current or direct current forms an arc between the electrode and the base metal creating the required heat. In the United States, it is the most common method used.
The flux coating disintegrates and gives off vapors that serve as a shielding gas and provides a protective layer of slag. Both protect the weld area from atmospheric contamination. As the metal rod inside the electrode melts it forms a molten pool which becomes the weld.
There are several variables the welder can control that will impact the width and height of the weld bead, the penetration of the weld, and the quantity of spatter. Stick welding is inexpensive when compared with other methods such as TIG. It is portable and works with any thickness and in any position.
The major downside is the slag created during the welding process along with slower speeds (unless you are highly skilled).
SMAW continues to be used extensively in the construction of heavy steel structures and in industrial fabrication. The process is used primarily to weld iron and steels (including stainless steel) but aluminum, nickel, and copper alloys can also be welded with this method.
Now that you know the basics of what SMAW is, keep reading for more details about how it works.
How Does SMAW Works?
SMAW uses the heat of the arc to help melt the top of a consumable-covered electrode and base metal. Both the electrode and the item being welded are a part of an electric circuit. This circuit also includes the power source, welding cables, electrode holder, and ground clamp.
The cables from the power source are attached to the work and electrode holder. Welding begins when an arc forms between the base metal and tip of the electrode. The surface of the work and electrode tip is melted.
Metal then forms on the end of the electrode, transferring from the arc into a pool. Filler is deposited when the electrode is consumed. The arc in SMAW gets extremely hot — temperatures can exceed 9,000 degrees Fahrenheit!
SMAW Voltage
Voltage is one of the main variables in arc welding. Some welding processes are able to use a preset constant-voltage system to maintain this, but with SMAW welds, voltage is regulated manually. This is done by moving the stick closer to or farther from the work.
SMAW Welding Current
Constant current power sources are used for most SMAW and other manual welding processes. This provides a consistent preset current and maintains the amperage setting.
SMAW Polarity
With SMAW welding processes, reverse polarity is almost always used. It helps provide the best bead profile and penetration, and it also reduces excessive spatter, which are droplets of molten material that are generated at or near the welding arc
SMAW Components
Some of the basic tools used when stick welding include:
- Arc welding power source (welding machine)
- Electrode lead cable
- Electrode holder
- Leads
- Cables
- Cable connectors
- Ground clamp
- Chipping hammer
As with any other welding process, safety equipment is used by the welder. This includes a helmet, gloves, and protective clothing.
What Is SMAW Used For?
SMAW can be used for a variety of metal types and various thicknesses. It is often used for heavy-duty work involving industrial iron and steel, like carbon steel and cast iron, as well as work involving low- and high-alloy steels and nickel alloys.
SMAW is used in a variety of industries, including:
- Construction
- Pipelines
- Shipbuilding
- Underwater welding
- Farm machinery manufacturing
SMAW equipment is easily portable and can be used in a variety of environments, from indoors to outdoors to on a ship at sea. And even though SMAW is one of the oldest forms of welding, new technology is always advancing processes and making them increasingly more efficient.
When the SMAW welder is experienced in knowing how to choose the correct electrode, weld speed, and arc length (and is working with clean materials), a SMAW welding job results in reliable welding for a variety of industries.
The Advantages of SMAW
SMAW has many great advantages which make it a continuing staple in most industrial settings. These advantages include:
- Relatively simple equipment
- Most portable of all welding processes
- No need for separate gas shielding
- Can be used in a wide range of environments including outdoors, in fabrication shops, on pipelines and refineries, on ships and bridges, and more.
- Is not sensitive to wind and draft
- Well suited for a wide variety of commonly used metals and alloys
- Can be powered with gasoline or diesel in remote areas without electrical connections
- Equipment and knowledge of technique are already widely in place in most industrial settings
The Disadvantages of SMAW
SMAW has some great advantages, but there are of course also disadvantages, which may not make it the best choice for certain projects. Some of the disadvantages include:
- Is not automated and thus usually has lower productivity rates than automated processes
- Deposition rates are typically lower than for other welding processes
- Requires more operator skill than many other processes
- Isn’t suitable for metals that are reactive including: titanium, columbium, and zirconium
- May spatter and require extra cleanup.
FAQs
What is the difference between SMAW and GMAW?
An SMAW electrode has an external flux covering (one reason why it is known as stick welding), whereas a GMAW electrode has an external shielding gas. Due to its ability to lay down cleaner welds, GMAW promotes better efficiency. SMAW can leave slag deposits on the weld surface due to the vapourizing flux.
What are the 5 essentials of shielded metal arc welding?
Essentials For Proper Welding Procedures
1. Correct electrode size.
2. Correct current.
3. Correct arc length or voltage.
4. Correct travel speed.
5. Correct electrode angle.
What is the purpose of SMAW?
The purpose of SMAW (also known as stick welding) is to perform arc welding using a covered metal electrode to shield the weld. Welding is one of the most popular ways to combine two metal parts into one. The process is simple: apply heat to each metal component.
What metals cannot be welded with SMAW?
Metals with low melting temperatures, such as lead, tin, and zinc, and their alloys are not welded with SMAW. These metals have relatively low boiling points and the intense heat of the SMAW arc immediately cause them to vaporize from the solid state.
Why is MIG preferred over SMAW?
For thinner metals, MIG welding is the better choice for creating a clean, strong joint. On thicker metals — over ⅜ inch — the Stick has better performance. The MIG gun’s ease of use also means it can produce a great volume of work with little downtime.
Is TIG welding a GMAW?
TIG stands for tungsten inert gas welding, also known as GTAW, or gas tungsten arc welding, which means it uses a tungsten electrode to produce the weld. Many other manufacturers use MIG (metal inert gas), also known as GMAW (gas metal arc welding) instead, primarily because it’s faster.