One of the most versatile and commonly used arc welding techniques, manual metal arc (MMA) welding, requires making an arc between a workpiece and a metal-coated electrode.
So, what is MMA welding? Also known as shielded metal arc welding (SMAW), manual metal arc (MMA) welding is a welding process in which the electric arc burns between the workpiece and the coated electrode.
Here, we will discuss everything that you need to know about MMA welding, including what MMA welding is, what it is used for, the MMA welding process, and the 4 types of welding. We will also briefly look at some other questions related to MMA welding. Let’s begin.
What is MMA Welding?
This is perhaps the most important question to answer regarding MMA welding. In MMA welding, the electrode is placed in an electrode holder and contacts the spot to be linked shortly. A short circuit is generated, and the arc begins when the electrode is raised. The electrode, as well as its coating, liquefies and slag is formed above the welded surface during the welding process.
The arc heat melts the electrode and the parent metal that combine together to create a consistent solid mass upon cooling. The core wire or main metal electrode serves as a consumable and provides the welded filler metal. It is possible to join together most cast iron, stainless steels, steels, and other non-ferrous items with MMA welding. It is the ideal joining method for many moderate and high resistance carbon steels.
To produce an arc between the electrode and the metal needing welding, an electric current generated by the welding power supply is utilized. The arc liquefies the electrode’s core to generate drops of molten metal to form the weld. The electrode’s flux coating also melts and creates a shielding gas, which creates a slag layer that shields the weld from degradation in the atmosphere. After each weld, the layer of the slag must be removed.
There are seven different parameters and factors on which the success of MMA welding depending. These include the following:
- Preparing the workpiece to be welded correctly
- The right electrode
- The right travel speed
- The right electrode size for the work
- The right angle of the electrode to work
- The right arc length
- The right welding current
What MMA Welding is Used For?
MMA welding is used for all the advantages that it has over other welding processes. MMA welding has numerous advantages over other welding methods. For instance, it can generate more power than MIG welding.
This means that it can solder stronger materials with an equal level of amperage performance. Tiny, compact MMA inverter welders are therefore capable of welding with up to 4 mm electrodes, which makes them ideal for a wide range of material thicknesses and applications without the hassle of shielding gas or wire feeding.
MMA is also an increasingly portable method thanks to inverter technology, and it is frequently used for field and site activity. Lastly, when compared to TIG or MIG, MMA welding is usually more ‘forgiving’ in the welding of contaminated or rusty materials, making it suitable for maintenance work.
What is the MMA Welding Process?
In the year 1888, MMA welding was first introduced in Russia and it consisted of a bare metal welding rod. After the Kjellberg process was invented in Sweden at the start of the 1900s, the coated electrode was added to the process.
So, how does the MMA welding process work? An electric arc is generated between the workpiece needing welding and a metal electrode that bears a high current.
Once an arc is produced between the workpiece and the electrode, which melts the electrode and the workpiece, the material is connected to form a weld pool. Additionally, the electrode also has an outer coating often referred to as the electrode flux, which often melts and provides a barrier over the weld pool to prevent the molten pool’s contamination and help to build the arc.
This cools and produces a solid slag over the weld, which after completion or before inserting another weld bead, has to be stripped away from the weld Bead. The procedure allows for the creation of only shorter weld lengths due to the length of the electrode before the introduction of a new electrode into the holder. The weld deposit quality is heavily reliant upon the welder’s ability.
A constant current (CC) output is given by the power source and can be either direct current (DC) or alternating current (AC).
The tiny, fairly cheap alternating current (AC) sets are mostly used in DIY or minor maintenance activities. While a few bigger AC sets may also be utilized in the heavier industry, the DC output set is now the most widely used.
It is important to note that not all DC electrodes are able to work on AC power sources. However, AC electrodes can work on both DC and AC. The most widely used of these modes is direct current (DC). AC unit power appears to be shifting switched transformers or iron core.
DC output power sources can be utilized on several types of material and can be generated in wide ranges of current. Such units’ controls range from shifting iron core switches to the new inverter designs.
What is MMA Inverter Welding?
Modern inverter welders can help to solve several problems facing MMA welding, and they offer excellent characteristics and efficiency as the curve can be managed electronically for each operation.
However, the chosen welding inverter power source must have enough strength to melt the weld material and the electrode with sufficient capacity to sustain the voltage of the arc.
The process of MMA welding normally needs a high output (50-350 Amps) at a fairly low voltage (10-50 Volts). While the electrodes used for MMA inverter welding are intended to work on various voltage levels and output power, it is always wise to read the manufacturer’s instructions before use.
MMA inverter welders help to achieve costs savings and other advantages as they:
- Have high control and efficiency levels
- Are extremely lightweight and more compact than their predecessors
- Can provide greater outputs for smaller inputs
- Can provide an extremely energy-efficient power supply
Is MMA Welding a Good Welding Method to Use?
Today, MMA welding is a widely used welding method, which indicates that it is a good welding method to use. MMA welding is being used increasingly today because it provides the following benefits.
Cost
MMA welding devices are relatively inexpensive, and the maintenance costs are much smaller than for other welding methods.
Flexibility and Versatility
Though MMA welding is mainly used for steel and iron welding, a wide range of other metals can also be welded with it. These metals include copper alloys, nickel, and aluminum. Additionally, unlike TIG or MIG welding, MMA welding is less likely to be affected by weather, making it the most efficient welding process for the outdoors.
Simplicity
The equipment can be powered fairly easily, and the technique is easier than certain other welding methods.
Mobility
Compact and light, MMA welding machines are easily portable and suitable for use anywhere.
Final Thoughts
MMA welding includes everything that is detailed above about the process. Using the information provided above, you can determine whether MMA welding is a welding process you’d want to use over the three main types of welding for your specific application.
What are the 4 Types of Welding?
As mentioned at the start, we will briefly look at the 4 types of welding, so you know exactly the welding options you have. The following are the 4 main types of welding.
Gas Metal Arc Welding (MIG)
Also known as MIG welding, gas metal arc welding utilizes a shielding gas across the electrode of the wire which melts the two metals to join. The procedure needs a constant volt and source of direct current. It is the most popular industrial welding technique and has four main metal transfer methods. They include pulsed-spray, spray, short-circuiting, and globular.
Gas Tungsten Arc Gas Welding (TIG)
This method is commonly used for soldering thick sections of non-ferrous metals or stainless steel together. Additionally, it is an arc-welding process that produces the weld using a tungsten electrode. This method takes much longer than the other welding processes and is also much more complicated.
Shielded Metal Arc Welding (MMA)
This is the welding process that we have covered in this article. In this welding process, a manual stick welding method is used by the MMA welder. An electric current is utilized by the stick to create an arc between the joining metals and the stick. This welding process is also used for welding steel and iron in industrial fabrication and steel structures’ construction.
Flux Colored Arc Welding
This is the fourth and final main type of welding. A shield welding alternative, this welding process is frequently used in construction projects. This is because it uses a semi-automatic arc weld and has high portability and speed of welding.