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The Importance of Low-Hy Rods in a Welding Job
Low-hydrogen welding rods are the backbone of structural welding. Known as "low-hy" to welders in the field, this versatile electrode is manufactured to contain less than 0.6% of moisture in the covering and is required by currently acceptable welding standards and procedures to be stored in an environment that maintains factory quality dryness.
Its low hydrogen content ensures a smooth, strong weld that is very ductile, making it the welding rod of choice for structural welding jobs.
It is well known that prior to beginning a structural welding job that low-hydrogen electrodes must be conditioned properly to avoid damaging defects in the welds.
One of the ways utilized to protect the low-hydrogen coating is to double coat using a titania layer to help avoid defects when low hydrogen deposits are required.
But problems such as porosity, hydrogen embrittlement, lack of fusion and cracking can result if standard low hydrogen rods are not stored according to the manufacturer's specifications.
Specifically, hydrogen can adversely affect a weld and some steels under a variety of conditions.
The primary source for the presence of hydrogen is moisture in the electrode coating picked up through exposure to the atmosphere. For this reason with any welding job proper storage, handling and treatment of low hydrogen electrodes is critical to prevent a defective weld.
This is especially important in the construction and erection of multiple story buildings which rely for their support and inner structure on welded steel beams.
A defective weld can result in the collapse of a building or during subsequent inspection rejection of the weld.
This requires rebuilding a portion of the metal inner structure of a skyscraper or other building sometimes at a cost of many millions of dollars.
Welding electrodes are manufactured to be within acceptable moisture limits consistent with the type of covering and strength of the weld metal to be used with the electrode.
They are then packaged in a container which has been designed to provide the degree of moisture protection considered necessary by the industry for the type of covering involved.
A common mistake is opening the container from the wrong end, or tossing them around which can crack the low hydrogen coating on the welding rods rendering them useless.
With any welding job it is very important to maintain your rods or electrodes within a temperature range of 100°F and 300°F. This temperature range has been determined by the welding industry to be adequate to prevent atmospheric moisture from entering the welding rod coating and subsequently entering the weld during the welding process.
In particular, maintaining low-hydrogen electrodes in a dry, consistently heated environment is a must.
Ask any welding professional and they will recommend that low-hydrogen electrodes be stored in a rod oven. Any other rudimentary method such as utilizing an old refrigerator or microwave with a 100 watt light bulb is laughable and is in no way acceptable for today's welding professional.
Welding Rod info
AWS Classifications Explained
The American Welding Society (AWS) numbering system can tell a welder quite a bit about a specific stick electrode including what application it works best in and how it should be used to maximize performance. With that in mind, let's take a look at the system and how it works.
The prefix "E" designates an arc welding electrode. The first two digits of a 4-digit number and the first three digits of 5-digit number indicate tensile strength. For example, E6010 is a 60,000 psi tensile strength electrode while E10018 designates a 100,000 psi tensile strength electrode.
E 60 1 "10"
Electrode Tensile strength Position Type of Coating and Current
The next to last digit indicates position. The "1" designates an all position electrode, "2" is for flat and horizontal positions only; while "3" indicates an electrode that can be used for flat, horizontal, vertical down and overhead. The last 2 digits taken together indicate the type of coating and the correct polarity or current to use. See chart below:
Digit Type of Coating Welding Current
10 High cellulose sodium DC+
11 High cellulose potassium AC or DC+ or DC-
12 High titania sodium AC or DC-
13 High titania potassium AC or DC+
14 iron powder titania AC or DC- or DC+
15 low hydrogen sodium DC+
16 low hydrogen potassium AC or DC+
27 iron powder iron oxide AC or DC+ or DC-
18 iron powder low hydrogen AC or DC+
20 High iron oxide AC or DC+ or DC-
22 High iron oxide AC or DC-
24 iron powder titania AC or DC- or DC+
28 Low hydrogen potassium iron powder AC or DC+
As a welder, there are certain electrodes that you will most likely see and use time and time again as you go about your daily operations. A DC machine produces a smoother arc. DC rated electrodes will only run on a DC welding machine. Electrodes which are rated for AC welding are more forgiving and can also be used with a DC machine. Here are some of the most common electrodes and how they are typically used:
DC only and designed for putting the root bead on the inside of a piece of pipe, this is the most penetrating arc of all. It is tops to dig through rust, oil, paint or dirt. It is an all-position electrode that beginning welders usually find extremely difficult, but is loved by pipeline welders world-wide. Lincoln 5P+ sets the standard in this category.
This electrode is used for all-position AC welding or for welding on rusty, dirty, less-than-new metal. It has a deep, penetrating arc and is often the first choice for repair or maintenance work when DC is unavailable. The most common Lincoln product is Fleetweld® 180 for hobby and novice users. Industrial users typically prefer Fleetweld 35.
This all-position, AC electrode is used for welding clean, new sheet metal. Its soft arc has minimal spatter, moderate penetration and an easy-to-clean slag. Lincoln Fleetweld® 37 is most common of this type.
A low-hydrogen, usually DC, all-position electrode used when quality is an issue or for hard-to-weld metals. It has the capability of producing more uniform weld metal, which has better impact properties at temperatures below zero. The Lincoln products are typically Jetweld® LH-78 or our new Excalibur® 7018.
Typically used to make a large weld downhand with AC in plate that is at least ¼" thick, but more commonly used for plate that is ½" and up. Lincoln has several electrodes in this category that are called Jetweld® 1, 2, or 3.
Although not nearly as common, an electrode may have additional numbers after it such as E8018-B2H4R. In this case, the "B2" indicates chemical composition of the weld metal deposit. The "H4" is the diffusible hydrogen designator, which indicates the maximum diffusible hydrogen level obtained with the product. And "R" stands for the moisture resistant designator to indicate the electrode's ability to meet specific low moisture pickup limits under controlled humidification tests.