June 13, 2006
Knowing which rods tend to do what in the field can save you time and make for better results when the job is through.
|Photo courtesy of Hobart Brothers Co., Troy, Ohio.|
Editor's Note: This article first appeared on www.thefabricator.com on April 15, 2002.
The student was terrified.
"They're giving us 6011 instead of 6010!" he whispered.
"Don't worry, it's just like 6010," I reassured him.
We were at our regional Vocational Industrial Clubs of America (VICA) competition. My students just had been debriefed and were going out to the shop to begin their welding skills contest. They calmed down and ended up sweeping first through fourth places.
I teach high school structural welding. I had stressed 6010 and 7018 while neglecting to inform the students of the other electrodes out there. In high school classes I try to stick to the fundamentals. I've been welding 25 years, and I still feel overwhelmed when I think of all the different processes out there.
On the way home from our contest, I explained that although 6010 and 6011 were different electrodes, their similarities outweighed their differences. Both are fast-freeze rods, meaning that the weld puddle changes from liquid to solid rapidly. They also have deep penetration; produce a flat, rippled bead; and leave little slag. They are great for all positions, and they are used primarily by pipefitters, pipeliners, and boilermakers.
Although I've almost exclusively used 7018 as a structural welder, I've also burned my share of 6010 and 6011. These two rods are used for many applications in the field. They do have technical differences, such as different flux compositions; however, I'm going to give you my nontechnical, self-proclaimed expert opinion of the rods. I'm proclaiming myself an expert because I believe using the rods while standing on scaffolds, balancing on 2-inch beams 30 stories high, hanging in boatswain's chairs, lying upside down under vessels, and cramming myself claustrophobically into vessels while welding qualify me.
I've also fallen off some of those buildings, but that's another story.
The "60" in 6010 means 60,000 pounds' tensile strength (the ability to resist being pulled apart) per square inch. The "1" means it can be run in any position—flat, horizontal, vertical, or overhead.
The last number, 0 or 1, is some kind of technical jargon that I have never used in my 25 years as a journeyman or instructor. But for you engineer types, you know it has to do with flux composition, slag type, and power supply.
Both 6010 and 6011 are good electrodes. In my opinion, they are the only rods to tack with. They strike very easily and leave little slag to chip off. They also are very good when you need full penetration. They are a prime choice for welding decking, an application in which you must penetrate through the gauge metal into the joist or beam.
Crank up the machine to warp 10, and you have a portable torch. It doesn't cut that pretty, but it gets the job done in a pinch when you don't have access to an oxyacetylene rig and need to cut something in a hurry. Make sure the area around you is clear, especially below if you are working up high. Cutting with these electrodes produces big-time sparks and large globs of molten metal.
6011 runs on AC and direct current electrode positive (DCEP), while 6010 runs only on DCEP. This gives 6011 an advantage if you have an AC-only machine. I have found, and think most welders will agree, that 6010 runs more smoothly. The slag chips off better than 6011, and this is one reason it is used more often than 6011 in root passes on pipes.
Another advantage of these electrodes is the speed at which they burn. This makes them ideal for welding joists and bridging, especially the stiffening angle going from joist to joist for bracing. These two electrodes have enough strength to do the job and are much faster than 7018. They run great downhill passes where not a lot of penetration or structural strength is required.
The 7018 is the backbone of structural welding. This rod runs completely different from the 6010 and 6011 rods—it is much smoother and easier. More of a "drag" rod, the 7018 is also referred to as a low-hydrogen, or "low-high," rod in the field. The flux contains almost no hydrogen, and the rod produces smooth, strong welds that are very ductile.
For this reason, these rods are used extensively in structural welding. I've used them on shopping centers, factories, powerhouses, nuclear weapons assembly plants, high-rise office towers, dams, and bridges. I've also used them on about a billion "neighbor-friend" projects.
The key word for the 7018 is versatility.
A 7018 rod literally should be dragged across the metal when welding. Along with dragging, a welder can weave it back and forth or oscillate it to feather it in on both sides. In vertical welding, some welders will count repetitions on each side of the weld pool, but this is a really bad habit to get into. As my old instructor used to scream into my ear, "Relax your hand and watch the puddle!" As long as you watch the puddle and relax your hand, you should be able to see and feel it tie into the steel. Counting doesn't guarantee a good tie-in; seeing and feeling do.
Shops, field welders, and home hobbyists often do not store 7018 rods properly. Being a low-hydrogen rod, 7018 requires an environment in which no moisture is allowed to get into the flux.
This is achieved by using a rod oven. I have seen all sorts of ovens used. I once saw a refrigerator that was converted into a makeshift oven by placing a high-wattage light bulb inside. This is done all too often and is in no way acceptable—7018 rods should be kept at 250 degrees F. If they are out in the open for less than four hours, they can be rebaked at 700 to 800 degrees F for an hour.
It all depends on the code (for instance, AWS D1.1 92 Steel Structural Welding Code) and what you are welding. I've seen only a few jobs in which the rods were stored correctly, if at all.
Another common mistake is opening the wrong end of the box. Another is throwing the boxes around during storage. Both break the flux off the rods. These damaged rods usually end up being wasted. If the flux is broken only off the tip, they can be long-arced and used. But if the flux is broken in other areas, the rod is useless. It's bad enough tossing away rods only halfway burned, but it is worse to throw away rods that have never been used at all.
If you were to ask a Ford fan, Chevy fan, or Dodge fan which truck is the best, you'd be there for hours. All three are good trucks with different pros and cons.
The same can be said of the different brands of rod. When it comes down to it, almost all are good. Some seem to run more smoothly; like most welders, I do have a preference, but can make do with any of them.
The 6010 and 6011 rods intimidate many first-time welders. Because they require more manipulation, they are a bit harder to run than 7018.
Many instructors teach only the "whip method," while others believe only in "circles" for rod manipulation. I don't care if you stand on your head gargling peanut butter, as long as your weld is sound.