In nearly all commercial-level welding jobs that require structural steel construction or pipe welding, in either the industrial or energy sector, the welding electrodes used are specified in the contract documents and designated welding codes. But what if you are working on a repair job or a construction project not governed by welding codes or the engineer&#;s explicit instructions?
Now it falls to you, the welder, to select the proper welding electrode for the task at hand. This guide will assist with this responsibility by helping you narrow down your selection and pick the welding electrode (commonly referred to as &#;rods&#; in shops and on job sites) best suited to your application.
Let&#;s begin by looking at the two main types of welding rods.
A consumable electrode is effective when the electrode and the filler metal are the same. When the electrode is brought into contact with the workpiece and becomes part of the molten weld puddle where the electrode, flux, i.e., protective coating, and the base metal all are joined together in the weld joint, you are using a &#;consumable&#; electrode. All the welding electrodes that are used with shielded metal arc welding (SMAW) are considered consumable.
Non-consumable electrodes, by contrast, are most generally associated with Gas Tungsten Arc Welding (TIG welding). In TIG welding the non-consumable electrode is secured in the TIG torch and is used to initiate and hold the arc, but at no point is to be consumed into the molten weld puddle. A separate bare metal filler is added to the molten weld metal puddle to complete the weld joint. The common electrodes of such type include Tungsten electrodes.
Welding electrodes are classified based on the numbers printed on the end of each welding rod contained in the package. The numbers will tell the welder at a glance the tensile strength rating, the position the rod can be used to weld in, and the distinguishing characteristics of each welding rod.
The American Welding Society (AWS) put a system for classifying the welding electrodes based on strength, welding positions to be used, flux covering type, and alloying elements if the electrodes are alloyed.
The numerical designations printed on each welding rod available on the market assist us in making an informed decision. For the purposes of this article, we will limit the electrode selection to the shielded-metal arc welding process (SMAW), more commonly known as &#;stick&#; welding. The criteria for selecting welding wires for GMAW (MIG) welding, FCAW (Flux-core) welding, and GTAW (TIG) welding share many of the same fundamental principles.
As per AWS designation, the first two, and in some cases three numbers on the welding rod refer to the tensile strength, i.e., the ability to resist being pulled apart, X 1,000. For example, in the designation , the number &#;70&#; means that a well-made weld made with can withstand 70,000 pounds per square inch (psi) of tensile stress.
A weld using a rod classified as can withstand 110,000 pounds per square inch (psi) of tensile stress. The commonly used welding rod is only rated for 60,000 psi.
The third number refers to the position in which you can use the rod. A &#;1&#; means that the rod can be used in all positions. A &#;2&#; typically means the rod can be used flat and horizontally. Number &#;4&#; is restricted to the flat position only.
The last number in the sequence refers to the class of rod or any particular distinguishing characteristic, especially the flux coverings. For example, on a welding rod, the &#;8&#; means that it is a low-hydrogen rod with basic flux covering.
The &#;0&#; in , , and , are a class of &#;fast freeze&#; with cellulosic flux covering (meaning the molten weld puddle solidifies very quickly), making it well suited to out-of-position welding jobs. The &#;1&#; in the last number of is very similar in characteristics to but is used on AC power sources.
For the low alloyed welding electrodes, the designation may also include the alloy content in the last digit like in the case of E-A1 which means that the electrode contains 0.5% Molybdenum and so on.
So now that we have a baseline understanding of what the numbers mean and how to read the numerical designations of various welding rods on the market, let&#;s discuss how to pick the best one for your specific job requirements by understanding the rod characteristics and pros and cons of the more commonly used welding electrodes on the market.
E is a very popular and commonly used rod, and with good reason. It is easy to initiate the arc, deep penetrating, and given its spray-arc characteristics, allows for high travel speeds. It welds very well in all positions.
is commonly used in pipeline construction, refineries, gas plants, and utility piping along with its variants, and . E is also very forgiving of joint imperfections and surface impurities. Its &#;fast freeze&#; classification (meaning the molten weld puddle solidifies very quickly) allows the skilled welder to fill gaps in joints, within reasonable allowances. Of course, that might prove difficult, if not impossible with other kinds of electrodes. However, because of its &#;fast-freeze&#; characteristics, welds do not have the same ductility as you might get from a electrode, so it would not be a good choice for something under cyclical stress or anywhere ductility is a consideration.
E digs very deep into the base metal, and running it too hot and fast can result in undercut and trapped slag inclusions. is in the cellulose family of welding electrodes and so there is a certain amount of moisture inherent in the rod. If it is allowed to dry out by sitting out too long in a dry, dusty climate, the rod can &#;fingernail,&#; where the flux tends to burn off to one side of the rod, causing the arc to favor one side of the joist over the other. When this happens, it is usually best to dispose of the rod and grab another. is best used on pipes, especially for root passes, railings, and sheet-metal applications. Because of its arc characteristics, it can result in more splatter, cleaning time, and higher costs.
The primary distinction between and is that runs on an AC power source. has long been referred to as &#;farmer rod.&#;
In , James Lincoln made the electric arc welder commercially available and started selling welding machines to farmers throughout the Midwest. The story goes that $100 got you the machine, a box of rods, and a day&#;s lesson in welding.
is an old standby in some light-duty sheet metal applications due to its shallow penetration, high travel speed, and the fact that it is very forgiving of surface impurities.
If one were to repair an old tractor fender or the like, this rod would be well suited to the task. Very forgiving of irregular weld joints and surface impurities like paint and rust, this rod can make quick and easy work out of minor repairs with visually pleasing welds with minimal clean-up. This rod also runs on AC power source machines. These electrodes are known for their easy use and smooth weld profiles but with limited penetration and susceptibility to cracking.
This is another very commonly used welding electrode and falls under the &#;low-hydrogen&#; classification of welding rods.
Decades ago, structural engineers faced issues with sub-surface cracking in steel buildings, bridges, and other structures. After extensive investigation, hydrogen, a key component in moisture, was identified as the culprit and so the &#;low-hydrogen&#; (often referred to in the field as &#;lo-hi) series of rods came into being and has long been a staple in the structural steel welding world.
E will not travel as fast as E but given its &#;fill freeze&#; classification (molten weld puddle solidifies more slowly than fast freeze rods) the welds made by E have greater ductility and should be considered for use in welds where ductility in cyclical stress situations may be a concern. Some examples of this might be structural steel buildings, bridges, and even construction and farm equipment. E, when properly used, can produce some very beautiful welds with very tight, symmetrical ripples and a smooth contour to the finished weld with minimal splatter. One potential drawback is that, if not stored properly in a sealed container or a rod oven, rods can absorb moisture in the atmosphere which can result in porosity in the welds.
E can be turned down to fill in an open root situation or where there is a gap in the fit-up, again, within reasonable tolerances. Careful joint cleaning is essential though because E is susceptible to porosity, often caused by surface contaminants like grease, paints, oils, or dirt. E typically requires DC power sources, although AC versions of this rod can be found in any welding supply distributor.
Commonly known as &#;jet rod&#; in the field due to its high deposition rates, E is a great choice of rod when you need to lay down a lot of metal in a hurry.
Large structural beams, baseplates, columns, and large portions of heavy equipment can be welded very quickly and efficiently with .
As we now know, the &#;2&#; in means that this particular rod is limited to flat and horizontal applications. But if you are on a heavy section of plate with a relatively uniform joint then this rod can be a great choice. It allows the operator to weld with a high travel speed and is very forgiving in travel angle and work angle. Similar to E, the slag will break off rather easily with minimal spatter in a properly completed weld.
One thing that the beginner and intermediate skill level welder should be acutely aware of is that although is very forgiving in work angle and travel angle it is still important to stay focused on the molten weld puddle. E can leave small fusion voids in the weld that you may have to go back and fix, especially in fillet weld joint configurations. DC power source is required with a high amperage range capacity to run this rod, especially larger-sized electrodes.
This is a very versatile welding rod suitable for the welding of more common types of Stainless Steel found on the market. (L refers to low carbon. Too much carbon in a stainless weld can greatly diminish corrosion resistance, a defining characteristic of stainless steel).
Because of its versatility, this rod is commonly used in maintenance and repair situations.
A good choice of electrode if the specific grade of stainless is not known with absolute certainty, E309L offers a very high deposition rate and good crack resistance. Another point worth mentioning here is that if you are ever in a situation of welding carbon steel to stainless steel, 309 has long been the choice of many a welder. Many welders and repair shops keep a small tube of 309 on the shelf for this very reason. E309L makes beautiful welds but can be tricky to run in out-of-position applications.
This is an aluminum welding rod that is highly versatile and can be used with most grades of aluminum you are likely to encounter in minor repair welding jobs. Welding aluminum can be tricky and even tougher out of position. Because of aluminum&#;s ability to conduct heat so rapidly, it might take a little more trial and error in practice than is required with many of the carbon steel electrodes mentioned but it can certainly be done. Since aluminum is a very soft and porous metal, it tends to absorb anything and everything it comes in contact with, especially things like grease and oils. Clean-up and joint prep are therefore particularly important when welding on aluminum. Muriatic acid, a rosebud torch, and a wire brush can all be especially useful tools for this purpose. Very similar to E, aluminum electrodes can attract moisture, so it is important to store them in a warm and dry place.
There are welding size and electrode charts available online that the beginner welder may find very useful when trying to select the proper rod size, but I would emphasize that these should only be used as guides, not hard and fast rules. There are many factors to take into consideration when selecting the right size welding electrode - material thickness, joint design, strength requirements, position to be welded in, etc. - that this topic warrants its own separate discussion. That being said, no guide will ever replace your eye as the judge of a properly made weld. Your completed weld should have reasonable uniformity, with no cracks, lack of fusion to base metal or other weld passes, and have minimal imperfections, like undercut, slag, or porosity.
This all comes with time and practice. Burn rods until you&#;re sick of it, then burn a few more. That is how good welders attain the necessary level of consistency to make the quality welds the customer depends on.
Welding rods should be stored somewhere in a warm and dry environment where the flux or the outer protective coating will not come into contact with moisture or other contaminants that could be detrimental to the ability of the rod to produce sound welds, free from defects.
The E, which is particularly sensitive to moisture contamination, should be stored in a rod-drying oven for some time prior to use as per supplier recommendations. It is a good practice to examine the end of each rod prior to starting the weld. If there is any flux broken off the welding electrode there is the possibility of porosity at the start of the weld pass.
or any of the 10 series rods should never be stored in a rod oven. The 10 series rods are cellulose rods so there is a certain amount of moisture in the flux when they are new and fresh out of the package. A rod oven will dry the rods out so that the flux might fall off and peel away during welding and cause the arc to favor one side of the weld joint. When you encounter this dynamic, it is usually best to throw the rod away and get some new ones.
You absolutely can. There is no standard procedure prohibiting this. If there is enough left of the rod to make the next weld or even a few simple tack welds, and the electrode is still in good condition then there is no reason to waste it.
This depends greatly on several different factors.
If you are on a job working under a welding code, a rod oven will usually be either required or, at least, strongly recommended.
If you are in a cold and damp climate where the rod might come into contact with moisture in the atmosphere then a rod oven is strongly recommended.
If you are in a drier climate where moisture is not a chronic issue and you are not on a job requiring rod ovens, then it may be sufficient to keep the E in a sealed container. Keep a close eye on your welds though.
If you are seeing porosity issues and if the flux on a rod looks cracked, then it may be time to dispose of it and get some new rods.
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Welding consumables are a factor to consider with welding. Several of the different kinds of welding require the use of consumable welding rods. These welding rods, also known as electrodes, are essential to the production of clean, solid, and finished welds. The trouble is there are many different kinds of welding rods. How do you know which one to pick for your project?
Below, we&#;ll discuss those rod types and how they can benefit you in your welding projects. Each variety has different uses and benefits, so read on to learn more about them and their applications.
Consumable Vs. Non-Consumable ElectrodesThe first important information is learning whether your MIG or TIG setup uses consumable or non-consumable electrodes.
Generally, processes like stick welding and MIG welding use consumable electrodes.
TIG welding, in comparison, uses non-consumable electrodes but requires a filler rod in addition to the electrode.
This distinction is vital because most forms of welding have three elements. These three elements are the joined pieces and the filler metal to secure the joint. In these welding processes, the intense heat from the electrical arc melts the metal from both pieces being joined and adds the filler metal to give it more material to fuse into a solid weld.
In stick, MIG, and similar welding processes, the electrode itself is made of the filler material and is melted, often along with flux, into the joint as you weld. In TIG welding, the electrode provides the current, but a secondary rod of filler metal is required to give it additional strength. This filler rod is the consumable part.
Why the Type of Metal is ImportantWhile you can technically grab any old filler rod that fits your welding setup, you must pick the right rod to avoid problems. Choosing the incorrect filler metal leads to all sorts of issues; rusting and corrosion, inclusions and tearing, weakness in the joins or around the weld, or other sources of failure.
Consider an image of a wooden door with a robust deadbolt lock. Breaking through the deadbolt is difficult or impossible, but it would be easy to break the doorframe the lock slots into with sufficient force. So it goes with welding; even picking a strong filler metal doesn&#;t help if the surrounding metal doesn&#;t match and breaks under stress.
There are many different kinds of electrodes or filler rods because there are many different materials you may want to join together. Filler rods are most commonly different kinds of steel but can be other metals, including aluminum and bronze, depending on the welder&#;s needs.
The list goes on and on, but one thing&#;s for sure: if you don&#;t know what kind of metal you&#;re working with, chances are you won&#;t know what type of welding rod to use yet.
Considerations When Choosing a Welding RodThere are many factors to consider when picking the correct welding rod for any project.
First, and among the most critical factors, is the materials being joined. As mentioned above, your filler metal needs to match your base materials. Picking the wrong filler will result in everything from burn-through to weakened welds to a non-functional joint.
Second, the position can be significant. Whenever possible, it&#;s ideal first to rotate the materials, so you&#;re working on a flat, horizontal surface for welding. If that&#;s not possible, and you must weld on a vertical or overhead position, certain filler materials won&#;t work. Instead of pooling and cooling, the materials can drip off the joint and further damage the surface.
Third, there may be external requirements for specific fillers in particular applications. These can come from many sources. For example, industry regulations may specify certain materials used in a given application, either for their chemical or physical properties or for their strength. Welding in construction, for example, needs to be robust for safety reasons, whereas welding for artistic projects may not have any regulations.
Fourth, the shielding gas used for your weld also makes a difference. In particular, various densities of CO2 in your shielding gas can make a significant difference, intended or otherwise. The gas choice is essential because certain gasses react to certain metals, which can compromise the weld if that reaction is present.
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All of these must be considered when picking a welding rod because different rods have different properties. So, how do you identify what rod is helpful for what?
Decoding Welding Rod CodesWelding rods are classified by their properties and are assigned an alphanumeric code. This code is one or two letters followed by four or five numbers. Each has a meaning.
The first code is the letter. Most welding rods start with E, which stands for Electrode, and indicates that the rod is the current-carrying electrode. R means it is a welding rod of filler material but not an electrode. ER means it is both in flux-core or stick welding, where the electrode and the rod are the same (this is a consumable electrode rod.) RB stands for a brazing rod used in brazing rather than welding or usable in both.
Next, you have the first two or three digits of the number. If the number is five digits (such as E), then the first three digits are significant. If the total number is four digits long (such as E), then the first two digits are meaningful.
These digits specify the capacity or tensile strength of the material and are in kPSI, or thousand pounds per square inch. So the E has 60,000 PSI strength, while the E has 100,000 PSI strength. The most common steel welding rods usually have a 60 or 70.
The following single number will typically be a 1, 2, or 4. This number indicates the position of the material you can use in welding. Remember above we mentioned that the position is essential and that some materials will stay hot for too long and will drip away from overhead or vertical welds. This digit is the number that specifies this information. A &#;1&#; indicates that you can use the rod in any position. A &#;2&#; shows that you can only use it in flat or horizontal welding, and a &#;4&#; means that you can use the rod for flat, horizontal, vertical down, or overhead welding. A &#;3&#; would indicate a vertical-only material, but these are not commonly seen.
The final number will be somewhere between 0 and 8 inclusive. This number specifies two things: the coating of the rod (the flux) and what current can be used on it. Sometimes, the last two digits are used instead of just the one.
Here&#;s an idea of what you might see:
&#; High Cellulose Sodium Flux
&#; High Cellulose Potassium Flux
&#; High Titania Sodium Flux
&#; High Titania Potassium Flux
&#; Iron Powder and Titania Flux
&#; Low Hydrogen Sodium Flux
&#; Low Hydrogen Potassium Flux
&#; High Iron Oxide, Iron Powder Flux
&#; Low Hydrogen Potassium, Iron Powder Flux
&#; The same as X0
&#; The same as X1
&#; High Iron Oxide Flux
&#; The same as X8
The content of the flux also determines whether it should be AC, DC+, DC-, or DC±. This information is typically found on the packaging of welding rods and can be found on charts like this.
Coating ThicknessAnother factor you may need to consider is the thickness of the coating of flux on your electrode. This measurement is indicated by a coating factor, which is the ratio of the rod&#;s diameter and the coating&#;s diameter. There&#;s some margin of error, but the three ranges center around these values:
A coating factor of around 1.25
A coating factor of around 1.45
A coating factor of 1.6-2.2.
Light-coated rods offer less shielding gas and are more prone to slag and inclusions. Hence, they are less widely recommended for many applications, particularly those where purity and strength are paramount.
Medium-coated rods are usable in any position and are easier to remove slag than many other types. They are often used in large-scale projects like offshore drilling, pipeline welding, and bridge construction, among other uses. They&#;re also common for hobbyist applications.
Heavy-coated rods are the most guaranteed to shield a weld and produce superior results. They are used wherever extreme purity is necessary but are overkill in many situations.
Tungsten Electrode Color CodesAnother factor you may encounter is rods coded by color. These are tungsten electrodes that are non-consumable and used in TIG welding.
They come in four primary varieties:
is pure tungsten.
is tungsten with around 1% thorium.
is tungsten with around 2% thorium.
is tungsten with some zirconium percentage, between 0.3% and 5%.
Though, you may see others, such as:
is tungsten with around 0.5% thorium.
is tungsten with around 3% thorium.
is tungsten with around 4% thorium.
is tungsten with around 0.75% zirconium.
is tungsten with around 1% lanthanum.
is tungsten with around 1.5% lanthanum.
is tungsten with around 2% lanthanum.
is tungsten with around 2% lanthanum.
is a non-standardized tungsten with various mixed oxides.
is also a non-standardized tungsten with various mixed oxides.
There are also carbon electrodes, but the carbon arc welding process is rarely used today outside of very specific military applications. It is an outdated process that creates more extensive and more difficult-to-control arcs.
The Most Popular Types of Welding RodsWelding typically follows the 80/20 rule. That is, 80% of your welding will be done using 20% of your rods. In reality, given the vast array of possible niche rods, it&#;s more like a 99/1 rule. In most arc welding processes, there are typically only about six rods in everyday use.
They are:
E. Among the most popular electrodes, these require DC and a narrow arc. They are common in steel welding applications that require deep penetration, such as shipbuilding, steel storage tanks, and other large-scale applications.
E. These are similar to E but can be used with AC as well. They are one of the most common go-to electrodes for thick welding materials, with a bit more leeway and ease of use than E. Their primary drawback is that their weld beads tend to be flatter and leave waves, so they may not be as aesthetically pleasing as other welds.
E. These welding rods support both AC and DC current and are ideal for welding with minimal spatter and slag. They create a stable arc and are great at shallow penetration. As such, they are best for repair, cosmetic, non-critical welds, and welds of certain materials like oxidized carbon steel. They also produce thick welds, which may need cleaning after.
E. Another of the most popular electrodes, this composition is easy to use and creates very little spatter. It&#;s commonly used in mid-penetration welding and for mid-thickness materials. It&#;s also good for short runs and multiple welds, where consistency between welds is necessary during a repositioning.
E. Perhaps the most popular electrode, this is one of the best multipurpose rods available and a staple of every welder&#;s kit. It&#;s mostly used for welding low and medium-carbon steel and can create a significantly stronger weld than any of the E60XX rods. The flux coating on the rod is also essential for preventing inclusions in the weld itself. E is found in many kinds of construction and other joinery.
E. This rod uses a high iron content in its flux, which makes it very quick in heating and deposition. This characteristic makes it ideal for fast, high-speed welds but risks issues if your process is too slow. They&#;re also ideal for smooth, flat-surfaced, or finely-waved finished welds.
Further ReadingAll of this only scratches the surface of electrodes and welding rods. There are many, many other rods out there, many of which have specific purposes. Design specifications, industry regulations, or directives often identify distinct rods necessary for individual projects. Most of this doesn&#;t need to be memorized, though knowing the basics of how the rods are categorized can give you immediate insight into what you&#;re working with.
Remember, too, that this is primarily about welding rod electrodes. Filler rods can have other numbers to identify them. For example, aluminum filler rods have numerical codes to specify the aluminum alloy used in the rod so that you can match it as closely as possible to the joined materials.
The rabbit hole is deep, and there&#;s always more to learn, even among experienced welding veterans. Feel free to contact us with questions about which rods are ideal for your projects or welding equipment requirements. We&#;re happy to help.
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