When I’m out on a structural job or tackling thick plate, there’s one thing I’ve learned the hard way: not every electrode gets the job done. Some rods are fine for farm repairs, light fabrication, or quick fixes, but when the weld really matters — pressure vessels, heavy beams, critical joints — I reach for low hydrogen electrodes.
A lot of welders, especially when moving from MIG or TIG into stick, ask me, “What makes these rods different? Why not just use the same 6013 or 7014 I’ve always run?” The answer comes down to hydrogen control. Too much hydrogen in the weld puddle can lead to cracking, brittle welds, or costly rework — and I’ve seen welds fail under stress because the wrong filler rod was used. That’s where low hydrogen rods like 7018 shine. They’re designed for structural strength, thicker metals, and high-strength steels where safety and durability are on the line.
If you’ve ever wondered when to grab a low hydrogen rod, how they affect weld quality, or why proper storage even matters, stick around. This guide will break down exactly what low hydrogen electrodes are used for and how you can get the best results whether you’re in the shop or out in the field.
Image by cinmagazine
What Is a Low Hydrogen Electrode?
A low hydrogen electrode is a type of stick electrode used in shielded metal arc welding (SMAW), also known as stick welding. These rods have a flux coating that’s formulated to keep hydrogen levels super low in the weld metal. Hydrogen is the enemy here because it can get trapped and cause cracks as the weld cools.
How does it work? The flux coating on these electrodes is basic in nature, often containing minerals like limestone that don’t absorb much moisture from the air. When you strike an arc, the flux melts and shields the weld pool from contaminants, while keeping diffusible hydrogen under control—usually below 8 ml per 100g of weld metal, as per AWS standards.
You’ll see them classified under AWS codes like E7018 or E7016, where the “70” means 70,000 psi tensile strength, and the last digits tell you about position and flux type. I remember my first time using an E7018 on a high-strength steel beam; the arc was smooth, and the bead looked pro right off the bat.
Why Use Low Hydrogen Electrodes?
Why bother with these over regular rods? It’s all about weld integrity and safety. Low hydrogen electrodes are your best bet when welding materials prone to cracking, like high-carbon or low-alloy steels. Hydrogen can sneak in from moisture in the flux or contaminants, leading to hydrogen-induced cracking—also called cold cracking or delayed cracking. This happens when hydrogen atoms get trapped in the metal lattice, making it brittle.
In the real world, this matters big time. Think about welding a pipeline or a bridge support; a crack could mean leaks, collapses, or worse. I’ve seen jobs where skipping low hydrogen rods led to failures under load, costing thousands in repairs. Using them reduces the need for high preheats, saves time, and boosts cost efficiency by minimizing rework.
Plus, they offer better mechanical properties, like higher toughness and ductility, which is crucial for applications under stress or impact. If you’re a pro welder following ASME or AWS codes, these electrodes often meet stringent requirements for critical welds.
When Should You Use Low Hydrogen Electrodes?
You should reach for low hydrogen electrodes when the job involves crack-sensitive materials or high-stakes applications. For instance, if you’re welding thick sections of structural steel, restrained joints, or anything in offshore, power generation, or construction, these are ideal.
Why? Because higher-strength steels are more susceptible to hydrogen embrittlement. I’ve used them on pipeline repairs where the code demanded low hydrogen to ensure no leaks under pressure. They’re also great for welding in humid environments or when you can’t control moisture perfectly.
Don’t use them for everything, though. For thin sheet metal or non-critical DIY stuff, a standard rod might suffice and be cheaper. But if safety and longevity are on the line, low hydrogen is worth it.
Types of Low Hydrogen Electrodes
There are several types, each suited to different needs. The most common is E7018, which has iron powder in the flux for high deposition rates and works in all positions except vertical down. It’s versatile for structural work.
Then there’s E7016, similar but without the iron powder, offering deeper penetration for root passes. E7028 is for flat and horizontal positions only, with even higher deposition for faster welding on thick plates.
Look for suffixes like H4 or H8, indicating hydrogen levels—lower is better for critical jobs. Some have an “R” for moisture-resistant, allowing longer exposure times. I always check the AWS classification on the box; it tells you everything about strength, position, and flux.
For example, on a recent job welding low-alloy steel, I grabbed E7018-H4R because it held up in the shop’s humidity without picking up moisture.
How Do Low Hydrogen Electrodes Work in SMAW?
In SMAW, you connect the electrode to your welder, strike an arc, and the core wire melts into the joint while the flux shields it. The low hydrogen part comes from the flux composition—it releases minimal hydrogen gas during the process.
The arc stability is top-notch; it’s smooth and quiet, with low spatter. This makes it easier for beginners to control. The slag is easy to remove, leaving a clean bead.
Practically, set your machine to DC electrode positive (DCEP) for best results. For a 1/8-inch E7018, start at 90-140 amps, adjusting based on material thickness. Keep a short arc length to avoid porosity.
I once taught a trainee who was long-arcing; the weld looked rough with inclusions. Shortened the arc, and boom—perfect bead.
Step-by-Step Guide to Using Low Hydrogen Electrodes
Let’s break it down step by step, like I’m showing you in the shop.
First, prep your joint: Clean the base metal of rust, oil, paint, or mill scale. Use a grinder or wire brush—contaminants introduce hydrogen.
Second, set up your equipment: Grab your SMAW welder, set to DCEP. For 3/32-inch rod, try 70-110 amps; 5/32-inch, 120-180 amps. Test on scrap.
Third, handle the electrode: Take it from the oven or sealed pack. Don’t let it sit out more than 4 hours (9 for R types).
Fourth, strike the arc: Use a scratch or tap start, maintain a drag angle of 10-15 degrees.
Fifth, weld: Move steadily, keeping the arc short. For vertical up, weave slightly.
Sixth, clean: Chip off slag between passes.
Seventh, inspect: Look for cracks or porosity. If needed, preheat the metal to 200-300°F for thick sections.
Follow this, and your welds will be solid.
Storage and Handling Tips for Low Hydrogen Electrodes
Storage is crucial—these rods hate moisture. Keep them in a rod oven at 250-300°F to drive off any absorbed water. I have a portable oven in my truck for field jobs.
When you open a pack, use them within the exposure limit. If they get damp, rebake at 500-800°F for an hour, but check manufacturer specs—overbaking cracks the flux.
Handle with clean gloves; oils from your hands can contaminate. Store sealed packs in a dry area. I’ve lost a batch to humidity once; the welds cracked, lesson learned.
Common Mistakes When Using Low Hydrogen Electrodes
One big mistake: Ignoring storage. Leaving rods out overnight picks up moisture, leading to underbead cracking. Fix: Always oven-store.
Another: Wrong amperage. Too high causes spatter and burn-through; too low, poor fusion. Fix: Dial in mid-range and adjust.
Improper prep: Dirty joints introduce hydrogen. Fix: Clean thoroughly.
Rushing restarts: Chipping the end wrong exposes flux unevenly. Fix: Rub on a rough surface to expose the core.
I’ve made these errors early on; now, I double-check everything.
Pros and Cons of Low Hydrogen Electrodes
Here’s a quick table to compare:
| Pros | Cons |
|---|---|
| Reduces cracking risk | More expensive than basic rods |
| Smooth arc, low spatter | Requires careful storage |
| High deposition rates | Limited exposure time |
| Good for all positions | Needs rod oven for handling |
| Meets strict codes | Not ideal for vertical down |
Applications of Low Hydrogen Electrodes in Welding
In the USA, these are staples for structural steel under AWS D1.1, like buildings and bridges. I’ve used them on I-beams where integrity is non-negotiable.
For pipelines, per API 1104, they prevent leaks in high-pressure lines. Offshore platforms rely on them for corrosion-resistant welds.
DIYers: Great for fabricating trailers or repairs on farm equipment with high-strength steel.
Students: Practice with E7018 to learn control.
Industry workers: Power plants use them for boiler repairs, ensuring no failures under heat.
Machine Settings for Low Hydrogen Electrodes
Settings vary by rod size and material. For mild steel with 1/8-inch E7018: 110-140 amps, 20-25 volts.
Thicker alloy steel: Bump to 150 amps, preheat to 250°F.
Use AC for some, but DC for better stability. Test on scrap—too hot, and you get undercut; too cool, slag inclusions.
Joint prep: Bevel edges for thick plates, ensure good fit-up.
Filler compatibility: Match to base metal, like ER70S for mild steel backups.
Safety Considerations with Low Hydrogen Electrodes
Safety first: Wear PPE—gloves, helmet, jacket. Fumes from flux can irritate, so ventilate.
Radiation from arc: Shield your eyes.
Hydrogen risks: Proper use prevents cracks, but watch for signs like porosity.
Follow OSHA guidelines for welding in confined spaces.
I’ve had close calls with poor ventilation; now, I always use a fan or extractor.
Comparing Low Hydrogen Electrodes to Other Rod Types
Vs. cellulosic rods (E6010): Those dig deep but introduce more hydrogen—great for root passes, but switch to low hydrogen for fills.
Vs. rutile (E6013): Easier for beginners, but higher hydrogen for non-critical work.
Low hydrogen wins for toughness in high-stress jobs, though costlier.
I mix them: E6010 for root, E7018 for cap.
Low Hydrogen Electrodes for Different Materials
For mild steel: E7018 all day.
High-carbon: Preheat and use low hydrogen to avoid brittleness.
Aluminum? Not typically—stick to GTAW rods, but some low hydrogen variants exist for alloys.
Stainless: Specialized low hydrogen like E308L.
Match the rod to material properties for compatibility.
Tips for Beginners Using Low Hydrogen Electrodes
Start slow: Practice stringer beads on flat plate.
Watch your angle: Drag, not push.
Keep rods dry: Invest in a small oven.
Learn codes: AWS basics help.
I started with scrap; built confidence before real jobs.
Advanced Techniques with Low Hydrogen Electrodes
For pros: Use weaving for wider beads, control heat input.
Multi-pass: Clean each layer.
Phased array UT for inspection on critical welds.
I’ve used them in vertical up on pipes—slight weave prevents sagging.
Cost Efficiency of Low Hydrogen Electrodes
They cost more upfront, but save on repairs. High deposition means fewer rods used.
For shops: Bulk buy and proper storage cuts waste.
DIY: Worth it for durable projects like gates.
Weld Integrity and Low Hydrogen Electrodes
Integrity boils down to no cracks, good fusion. Low hydrogen ensures that by limiting diffusible hydrogen.
Test with bend or X-ray for codes.
I’ve had welds pass inspection first try thanks to these rods.
Conclusion
Wrapping this up, you’ve got the lowdown on what low hydrogen electrodes are used for—preventing cracks in critical welds, boosting safety, and ensuring strong, durable joints on everything from structural steel to pipelines. Whether you’re a DIY welder fixing up your rig, a hobbyist building custom pieces, a student practicing arcs, or a pro on the job site, you’re now ready to pick the right rod like E7018 and handle it properly for top-notch results. Go ahead, grab those electrodes with confidence, and lay down some beads that’ll last.
FAQ
What is the difference between low hydrogen and regular electrodes?
Low hydrogen electrodes have flux that minimizes hydrogen in the weld to prevent cracking, ideal for high-strength steels. Regular electrodes like E6013 are easier for general use but can introduce more hydrogen, risking brittleness in critical applications.
How do you store low hydrogen welding rods?
Store them in a rod oven at 250-300°F to keep moisture out. Limit exposure to 4 hours once opened, and rebake if needed per manufacturer guidelines to maintain low hydrogen properties.
Can low hydrogen electrodes be used for all welding positions?
Most like E7018 work in all positions except vertical down, making them versatile for overhead or vertical up welds. Check the AWS code for specifics.
Why do low hydrogen electrodes prevent cracking?
They reduce diffusible hydrogen in the weld metal, which can cause embrittlement and cracks as the metal cools. This is key for materials prone to hydrogen-induced issues.
What amperage should I use for E7018 electrodes?
For a 1/8-inch E7018, start at 110-140 amps on DCEP. Adjust based on material thickness and test on scrap for smooth arc and good penetration.
I’m Darrell Julian, the founder, lead writer, and hands-on welding enthusiast behind ArcWeldingPro.com. With more than 15 years of real-world welding experience, I created this platform to share what I’ve learned in the field, in the shop, and in the heat of the arc.
