What Does the 7018 on a Welding Rod Mean? Key Insights

The 7018 on a welding rod means it delivers a minimum tensile strength of 70,000 psi. It works in all positions and uses a low-hydrogen, iron‑powder coated flux for strong, clean welds.

You get high tensile and yield strength combined with excellent crack resistance and toughness, especially in structural applications. Its specialized coating guarantees arc stability and reduced hydrogen risk.

If you want to understand its mechanical properties, flux composition, and best handling, more detailed insights await.

Key Takeaways

• “70” indicates a minimum tensile strength of 70,000 psi for the welding rod’s deposited weld metal.
• The third digit “1” means the rod is suitable for welding in all positions (flat, horizontal, vertical, overhead).
• The final digit “8” signifies a low-hydrogen, iron‑powder coating and alloy content on the electrode.
• 7018 rods produce strong, clean welds with low spatter and are favored for structural and critical welds.
• The low-hydrogen iron‑powder coating reduces cracking risk and improves arc stability and deposition rate.

Decoding the Numbers in 7018

To decode the numbers in a 7018 welding rod, you need to understand what each digit signifies about the electrode’s properties and applications.

The first two digits, “70,” indicate the electrode deposits weld metal with a minimum tensile strength of 70,000 psi, aligning with AWS standards to match structural steel requirements. This strength level is critical for ensuring structural weld integrity in demanding applications.

The third digit, “1,” means you can weld with this electrode in all positions: flat, horizontal, vertical, and overhead, offering versatility in application.

The final digit, “8,” identifies a low-hydrogen flux coating, essential for minimizing hydrogen-induced cracking. It contains potassium and iron powder, enhancing deposition rate and bead profile.

Knowing these digits helps you select electrodes appropriate for high-quality, structural welding while ensuring proper storage and handling to maintain performance. The ER7018 electrode is also favored because it produces clean welds with minimal spatter and smoke, which is important for a quality finish.

Mechanical Properties of 7018 Electrodes

Understanding the numerical code of the 7018 welding rod sets the foundation for appreciating its mechanical properties.

Grasping the 7018 welding rod code unlocks insights into its vital mechanical strengths.

You’ll find that 7018 electrodes typically deliver tensile strengths between 520–585 MPa (75–85 ksi), surpassing the AWS minimum of 490 MPa (70 ksi). These high strengths contribute to the electrode’s suitability for structural applications requiring mechanical integrity.

Yield strengths range from 400–520 MPa (58–75 ksi), varying with welding parameters and electrode subclass.

You can expect elongation values around 24–32%, well above the 22% AWS minimum, due to low-carbon deposits and basic flux chemistries promoting ductile microstructures.

Impact toughness at subzero temperatures often exceeds 20–47 J at -40 to -50°C, making 7018 suitable for cold environments.

Hardness aligns with mild structural weld metals, avoiding excessive brittleness, thanks to controlled cooling and low-hydrogen flux.

These properties guarantee strength, ductility, and toughness for demanding structural applications.

Additionally, the E7018-A1 electrode contains 1/2% molybdenum, enhancing the weld deposit’s strength and toughness.

Composition and Flux Characteristics

When you’re working with 7018 rods, it’s really important to understand the basic flux chemistry. These rods use alkaline binders, which are great because they help minimize hydrogen pickup. This, in turn, guarantees a stable arc during your welding process.

Now, let’s talk about the iron powder that’s embedded in the flux. This is a game changer! It significantly boosts your deposition efficiency and increases the iron content in the weld metal.

The thick, iron-powder-rich flux coating also serves multiple functions such as gas shielding, slag cover formation, and arc stabilization, making the welding process smoother and more consistent coating functions. Proper control of heat input and welding parameters also helps reduce defects such as porosity and ensures weld quality heat control.

Basic Flux Chemistry

Examining the composition and characteristics of welding fluxes reveals how different chemistries influence weld quality and performance. Basic flux chemistry, essential in 7018 rods, features a calcium fluoride base with CaO, MgO, CaF2, and MnO, resulting in high basicity often exceeding 2.0. This guarantees excellent slag fluidity and weld metal cleanliness.

You’ll find these fluxes incorporate Al2O3 and FeO to stabilize the weld pool and reduce oxygen content, enhancing mechanical properties. Basic fluxes also tend to produce low oxygen levels in the weld metal, which contributes to high impact toughness and good crack resistance. Key characteristics include:

• High basicity (>1.5) for superior weld strength
• Calcium fluoride dominance for slag control
• Low oxygen content in deposited metal
• Inclusion of flux activators like ammonium chloride
• Versatility with subtypes including rosin and water-soluble fluxes

Iron Powder Role

The flux chemistry in 7018 rods sets the stage for how iron powder influences weld quality and efficiency.

Iron powder increases molten metal deposition by supplying additional iron to the weld pool, boosting deposition rates and reducing pass counts. It also contributes to improved arc stability by enhancing the conductive properties of the weld coating, which parallels the role of copper additives in weld-through primers that stabilize the welding arc.

It enhances arc energy and penetration by altering arc characteristics through conductive particles in the coating, increasing heat input.

Additionally, iron powder aids in forming a compact, protective slag that facilitates oxide removal during solidification. This slag must be removed after welding using tools such as a wire brush or chipping hammer to ensure a clean joint and proper inspection slag removal.

Acting as a diluent, it modifies flux melting behavior and viscosity, improving wetting and flow.

Typical iron powder content ranges from a few percent to over 60%, using low-impurity sponge iron or atomized steel to minimize inclusions and hydrogen pickup.

Properly balanced, iron powder optimizes weld-metal chemistry, mechanical properties, slag behavior, and welding performance without compromising slag removal or bead appearance.

Common Uses and Industry Applications

Across multiple industries, the E7018 welding rod proves indispensable for its high tensile strength, low hydrogen content, and versatility in all welding positions. Its all-position use capability means it can effectively handle flat, horizontal, vertical, and overhead welding tasks, making it highly adaptable. This versatility is critical because different welding positions require specific electrode characteristics for optimal weld quality.

You’ll find it specified for critical structural steel applications, pipeline fabrication, heavy equipment repair, shipbuilding, and general industrial maintenance due to its reliable mechanical properties and resistance to hydrogen-induced cracking.

Structural steel frameworks, bridges, and seismic-resistant connections are all common applications.

Pipe and pressure vessel welding in oil, gas, and power sectors also rely on E7018.

It is used in the fabrication and repair of heavy machinery, cranes, railcars, and marine structures.

Boiler, tank, and pipeline maintenance under cyclic thermal and pressure loading benefits from its properties.

Shop fabrication and component manufacturing requiring consistent weld quality and low spatter utilize E7018 effectively.

Using E7018 guarantees durable, high-strength welds where toughness, ductility, and crack resistance are non-negotiable.

Optimal Welding Techniques and Parameters

Mastering ideal welding techniques and parameters is essential to harness the full potential of the E7018 welding rod.

Maintain an arc length roughly equal to the electrode core diameter (about 1/8″) to guarantee arc stability and minimize spatter. Lightning MTS-275 is a commonly preferred welding machine for running 7018 uphill.

Set amperage near 1 amp per 0.001 inch of electrode diameter, adjusting for position and technique.

Too low amperage causes poor fusion; too high leads to undercut and flux burn-off, increasing hydrogen risk.

Control travel speed to achieve a slightly convex, finely rippled bead profile. Faster speeds narrow the bead, while slower speeds deepen penetration.

Use drag manipulation with a slight work angle for consistent slag flow.

Preheat the base metal as required and ensure joint cleanliness to prevent cracking. Proper documentation of welding parameters and activity is also critical for maintaining certification continuity.

Optimize machine settings like hot-start and polarity per manufacturer guidelines to improve arc stability and reduce sticking. Arc force settings around 10 can help maintain a smooth arc when running uphill with 7018.

Storage Requirements for 7018 Rods

When storing 7018 welding rods, maintaining a consistent temperature between 225–300°F (107–149°C) is essential to preserve their low-hydrogen coating and prevent moisture absorption.

Store 7018 rods at 225–300°F to protect their low-hydrogen coating and prevent moisture absorption.

Use dedicated rod ovens or sealed moisture-proof containers with desiccants to control humidity effectively. Avoid mixing 7018 rods with cellulosic electrodes in the same oven, as differing moisture requirements may degrade flux chemistry. Incorporating local exhaust ventilation during welding further protects operators from harmful fumes released by electrodes.

Limit exposure of opened rods to ambient air, returning unused rods promptly to dry storage. For damp rods, perform re-drying at elevated temperatures per manufacturer guidelines before reuse.

Employ thermostatically controlled ovens set between 225–300°F for holding. Store unopened rods in factory-sealed packaging within dry, moderate environments.

Use silica gel packets for added moisture control inside storage containers. Restrict rod exposure outside dry storage to a few hours maximum.

Follow re-drying protocols strictly to maintain rod integrity and performance. Once can opened, electrodes begin absorbing moisture and may require rapid drying to restore usability.

Comparing 7018 With Other Welding Electrodes

When you compare 7018 electrodes to others, you’ll really notice their superior strength and durability. This is mainly because of their low-hydrogen iron-powder coating and controlled alloy content. Pretty impressive, right? These electrodes also require proper heat resistance to handle the welding environment safely.

Now, unlike many general-purpose rods, 7018 does require some strict storage and handling protocols. This is super important to keep their performance up and to prevent any moisture absorption. Proper storage in a dry environment is essential to maintain the electrode’s quality and prevent hydrogen-induced cracking.

Strength and Durability

Compare the strength and durability of 7018 welding rods with other electrodes by examining their mechanical properties and crack resistance.

The 7018 rod delivers a minimum tensile strength of 70,000 psi, often exceeding 80,000 psi, with yield strength up to 72,000 psi and elongation between 22%-32%, surpassing many standard rods.

Its low-hydrogen iron‑powder coating markedly reduces hydrogen-induced cracking risk, unlike higher-hydrogen or rutile electrodes. This characteristic aligns with best practices for minimizing weld cracking in critical welds.

• High tensile and yield strength suitable for structural welds
• Superior crack resistance due to low diffusible hydrogen content
• Balanced toughness with reliable low-temperature impact performance
• Consistent weld quality with smooth, spatter-free beads
• Enhanced deposition rates without compromising mechanical integrity

Additionally, 7018 electrodes provide a quiet, steady arc with low spatter, which contributes to cleaner welds and less post-weld cleanup.

This combination makes 7018 ideal for demanding applications requiring both strength and durability.

Storage and Handling

In managing welding electrodes, maintaining proper storage and handling conditions is essential to preserve their performance, especially for low-hydrogen rods like the 7018. You must store these rods in a dry, controlled environment between 250°F and 300°F, using heated ovens to prevent moisture absorption.

Unlike cellulosic electrodes (E6010/E6011), which tolerate humidity and don’t require holding ovens, 7018 rods are hygroscopic and need careful moisture control to avoid hydrogen-induced weld defects. Mixing low-hydrogen and cellulosic rods in the same storage harms both.

Electrode Type	Storage Temp (°F)	Moisture Sensitivity
E7018	250-300	High, requires dry storage
E6010/E6011	Ambient	Low, no oven needed
Stainless Steel	250-300	Similar to E7018
E7015/E7016	225-300	Low-hydrogen, dry storage
All Low-Hydrogen	225-300	Must avoid moisture

Frequently Asked Questions

Can 7018 Electrodes Be Used on Stainless Steel?

You shouldn’t use 7018 electrodes on stainless steel because they’re designed for carbon and low alloy steels, not stainless alloys.

Using 7018 on stainless steel risks cracking due to mismatched metallurgy and chemical composition differences.

Instead, select electrodes specifically formulated for stainless steel to guarantee proper weld integrity, corrosion resistance, and mechanical properties.

Sticking to the right electrode prevents failures and guarantees your weld meets required standards.

How Long Can a 7018 Rod Be Stored Before Use?

You can typically store 7018 rods for 1-2 years in airtight, moisture-proof containers within climate-controlled environments.

Once opened, use rods within 4-8 hours depending on humidity. If rods absorb moisture or exposure time is unknown, recondition them by baking at 500°F to 800°F for about an hour.

Always keep rods in rod ovens at 250°F to 300°F to maintain low hydrogen levels and prevent weld defects caused by moisture absorption.

What Safety Gear Is Recommended When Welding With 7018 Rods?

You might think welding is all sparks and heat, but the real priority is protection.

When welding with 7018 rods, always wear a welding helmet with at least shade #10, fire-resistant leather gloves, and a full-coverage jacket and pants.

Respirators help in confined spaces, while safety glasses guard against debris.

Don’t forget sturdy leather boots and ear protection to shield against noise.

Stay vigilant; your safety gear is your best weld quality guarantee.

Are 7018 Welding Rods Recyclable After Use?

Yes, you can recycle 7018 welding rods primarily for their steel core, which remains viable for scrapping despite low market prices.

The flux, composed of mineral and organic binders, doesn’t materially impact recyclability and typically ends up as landfill waste.

Always consult the manufacturer’s MSDS for specific guidance.

If you want to reuse them creatively, consider welding rod ends together to form handles.

Proper disposal is essential if moisture damage compromises rod integrity.

Can 7018 Electrodes Be Used Underwater or in Wet Conditions?

You can use 7018 electrodes in wet conditions due to their low hydrogen properties and moisture-resistant formulation, which minimize cracking and maintain weld integrity in damp environments.

However, they aren’t designed for direct underwater welding or submersion. Always keep them dry before use, as moisture absorption compromises performance.

For underwater applications, specialized electrodes are better suited. Stick to 7018 for above-water, high-strength steel welding in challenging but not submerged conditions.

Maximize Weld Strength With 7018 Electrodes

Now that you understand what 7018 means, specifically its tensile strength of 70,000 psi and low-hydrogen flux, you can appreciate why it’s a go-to for critical structural welding.

Its mechanical properties guarantee strong, crack-resistant welds, making it ideal for construction and heavy fabrication.

By mastering storage and technique, you’ll maximize performance and longevity.

Remember, using 7018 can increase weld strength by up to 20% compared to other electrodes, giving you reliable, professional results every time.