The 7018 welding rod isn't just another electrode – it's a game-changer. With its unique strength, versatility, and ease of use, this remarkable tool has transformed how welders approach their craft. From its low-hydrogen composition that minimizes the risk of cracking to its ability to produce high-quality welds in all positions, the 7018 rod stands out as a true all-rounder. In this guide, we'll explore the unique characteristics of the 7018 rods.
What is the 7018 Welding Rod?
The 7018 welding rod is a type of stick electrode widely used in arc welding processes, particularly in shielded metal arc welding (SMAW). The numbering system "7018" provides key information about the rod's characteristics. The "70" indicates the tensile strength of the weld metal in thousands of pounds per square inch (70,000 psi). The "1" signifies that the rod can be used in all positions, and the "8" denotes that the electrode has a low-hydrogen potassium coating. This coating helps produce smooth, stable arcs and reduces the risk of hydrogen embrittlement in the weld. Known for its excellent weldability and high-quality results, the 7018 rods are favoured in various industries, including construction, shipbuilding, and pipeline fabrication, especially for critical welds that require high strength and crack resistance. 
Specification of 7018 Welding Rod
The 7018 welding rod boasts unique specifications that contribute to its popularity and versatility in welding applications. Let's break down these specs in detail:
7018 Welding Rod Specs
Tensile Strength: As the "70" designation indicates, the 7018 rod produces welds with a minimum tensile strength of 70,000 psi (pounds per square inch). This high strength makes it suitable for welding structural steel and other applications requiring robust joints.
Yield Strength: The yield strength of welds made with 7018 electrodes typically ranges from 58,000 to 70,000 psi, providing excellent resistance to deformation under load.
Elongation: Welds created with 7018 rods exhibit an elongation of about 22% to 30%, offering good flexibility and the ability to withstand stress without fracturing.
Impact Strength: The 7018 electrode produces welds with high impact strength, typically around 20-80 ft-lbs at -20°F, making it suitable for low-temperature applications.
Hydrogen Content: The "8" in 7018 indicates a low-hydrogen coating, with typical hydrogen levels below 8 ml per 100 grams of deposited weld metal. This low hydrogen content helps prevent hydrogen-induced cracking.
Deposition Rate: 7018 rods have a moderate deposition rate, typically ranging from 1.6 to 2.8 kg/hr (3.5 to 6.2 lbs/hr), depending on the welding parameters and rod diameter.
Diameter Options: These electrodes are available in various diameters, commonly ranging from 2.0 mm (5/64") to 6.4 mm (1/4"), allowing for versatility in different welding scenarios.
Length: Standard lengths for 7018 rods are typically 350 mm (14") or 450 mm (18"), though other lengths may be available for specific applications.
Current Range: The recommended current range varies based on the rod diameter but generally spans from 65-85 amps for a 2.4 mm (3/32") rod up to 230-300 amps for a 6.4 mm (1/4") rod.
Composition and Coating
The 7018 welding rod consists of a solid wire core made primarily of low-carbon steel, typically containing small amounts of manganese and silicon. This electrode's distinguishing feature is its thick flux coating, which is rich in iron powder (up to 50% by weight) and contains potassium silicate as a binder. This coating also includes various minerals and alloys contributing to arc stability and weld quality.
The low-hydrogen potassium coating serves multiple purposes:
It creates a protective gas shield around the arc, shielding the molten metal from atmospheric contamination.
It adds alloying elements to the weld pool, enhancing the mechanical properties of the finished weld.
It forms a slag cover that protects the cooling weld and helps shape the bead.
It stabilizes the arc, allowing for smooth operation in various welding positions.
Weld Penetration
The 7018 electrode provides moderate penetration, which is ideal for many applications. This characteristic allows effective fusion without the risk of burn-through on thinner materials. The penetration depth can be controlled by adjusting welding parameters such as current and travel speed. The iron powder in the coating contributes to a stable arc and smooth metal transfer, resulting in consistent penetration across the weld.
Welding Positions
The "1" in the 7018 designation indicates that this electrode suits all welding positions. This includes:
Flat (1F/1G): Horizontal welding on a level surface.
Horizontal (2F/2G): Welding on vertical surfaces with the electrode held horizontally.
Vertical (3F/3G): Welding vertically, either upward (preferred) or downward.
Overhead (4F/4G): Welding on surfaces above the welder's head.
The slag's fast-freezing characteristics and the weld pool's controlled fluidity allow us to weld in all positions. This versatility makes the 7018 rods an excellent choice for various applications.
7018 Welding Rod Settings
1. Amperage Settings
The amperage setting for 7018 welding rods is crucial for achieving optimal weld quality. The correct amperage depends on the rod diameter, with larger rods requiring higher amperage. Generally, use 1 amp per 0.001 inch of rod diameter. For example, a 1/8-inch (0.125-inch) rod typically requires 115-165 amps. However, this can vary based on welding position and material thickness.
Start at the lower end of the range and adjust as needed. Too low amperage can lead to poor penetration and stick electrodes, while too high amperage may cause overheating, excessive spatter, and burn-through on thinner materials. Always consult the manufacturer's recommendations for specific amperage ranges.
2. Current Type: AC or DC
One of the most frequently asked questions is whether to use AC or DC with a 7018 welding rod. So the answer is: The 7018 welding rod is versatile in terms of current type, as it can be used with both Alternating Current (AC) and Direct Current Electrode Positive (DCEP or DC+). DCEP is generally preferred as it provides deeper penetration, a more stable arc, and slightly better mechanical properties in the weld. However, AC can be advantageous in certain situations, such as when welding magnetized materials or when trying to minimize arc blow. AC also produces a more comprehensive, shallower weld bead than DC.
The choice between AC and DC often depends on the available power source, the specific application, and the welder's preference. Many welders find that DCEP offers the best overall performance for 7018 rods.
3. Arc Length and Travel Speed
Maintaining the correct arc length and travel speed is essential for producing high-quality welds with 7018 rods. The ideal arc length is typically about the same as the diameter of the electrode's metal core (not including the flux coating). This usually translates to about 1/8 inch for most common rod sizes. A too-long arc can lead to excessive spatter and poor weld quality, while a too-short arc may cause the electrode to stick or inadequate shielding.
Travel speed should be adjusted to maintain a weld pool width of about 2-3 times the rod's core diameter. Moving too fast can result in insufficient penetration and a narrow, ropy bead. Moving too slowly can lead to excessive heat input, a wide bead, and potential distortion of the base metal. The key is to find a balance that allows the weld pool to flow smoothly behind the arc while maintaining consistent penetration.
4. Electrode Angle
The angle at which you hold the 7018 electrode significantly affects weld quality and penetration. For flat and horizontal welds, maintain a "drag" or "backhand" technique with the rod tilted 5-15 degrees in the direction of travel. This angle helps the slag flow behind the weld pool, resulting in better penetration and a smoother bead appearance.
Use a slight upward angle of about 5-10 degrees for vertical up welds. In overhead positions, a nearly perpendicular angle works best. A consistent electrode angle throughout the weld helps ensure uniform penetration and bead appearance.
5. Preheating and Interpass Temperature
Preheating the base metal and controlling interpass temperature can be crucial when welding with 7018 rods, especially on thicker materials or those prone to cracking. Preheating helps reduce the cooling rate, minimizing the risk of hydrogen-induced cracking. The exact preheat temperature depends on the base metal composition and thickness but typically ranges from 200°F to 400°F (93°C to 204°C) for carbon steels.
Maintain a similar interpass temperature when making multiple pass welds. Use temperature-indicating crayons or an infrared thermometer to monitor and control these temperatures. Proper heat management ensures the low-hydrogen benefits of the 7018 rods are fully realized, resulting in stronger, crack-resistant welds.
Applications of the 7018 Welding Rod
1. Structural Steel Fabrication
The 7018 welding rod is widely used in structural steel fabrication due to its high strength and excellent crack resistance. It's precious in constructing buildings, bridges, and other load-bearing structures where weld integrity is crucial. 
In these applications, the rod's ability to produce solid and ductile welds helps ensure the longevity and safety of the structures. Its low-hydrogen characteristics also minimize the risk of hydrogen-induced cracking, which is especially important in thick structural members.
2. Pipeline Construction and Repair
In the oil and gas industry, 7018 rods are frequently employed for pipeline construction and repair. The electrode's ability to produce high-quality welds in all positions makes it ideal for joining pipe sections in various orientations.
The rod's low hydrogen content is particularly beneficial in this field, as it reduces the risk of hydrogen embrittlement in the heat-affected zone. This characteristic is crucial for maintaining the integrity of pipelines that transport corrosive or high-pressure fluids.
3. Shipbuilding and Marine Applications
The shipbuilding industry relies heavily on 7018 welding rods for many welding tasks. The electrode's resistance to moisture absorption and ability to produce solid and crack-resistant welds make it suitable for marine environments.
From hull construction to internal structural components, 7018 rods help ensure the seaworthiness of vessels. Their versatility in welding various steel grades commonly used in shipbuilding further enhances their value in this industry.
4. Heavy Equipment Manufacturing
Heavy equipment manufacturers, such as construction machinery, agricultural implements, and mining equipment, often use 7018 rods in their welding processes. The electrode's high strength and impact resistance are crucial for components subjected to heavy loads and harsh operating conditions.
The ability of 7018 rods to weld thick materials effectively makes them particularly useful in fabricating large, robust parts. Their all-position welding capability also allows for efficiently producing complex equipment shapes.
5. Pressure Vessel Fabrication
7018 welding rods are a common choice in manufacturing pressure vessels for industrial applications. Their ability to produce high-integrity welds with excellent mechanical properties is essential for vessels that withstand high internal pressures.
The low-hydrogen characteristics of 7018 rods are essential in this application, as they help prevent hydrogen-induced cracking that could lead to catastrophic failure. The electrode's versatility in welding various steel grades used in pressure vessel construction adds to its utility.
6. Automotive Industry
While not as commonly used in modern automotive manufacturing as other welding processes, 7018 rods still find applications in some regions of the automotive industry, particularly in repair and custom fabrication.
The 7018 rod's strength and versatility make it a valuable tool for chassis repairs, custom frame modifications, and fabrication of specialized components. Its ability to produce clean, strong welds in various positions is particularly useful in repair scenarios where access may be limited.
7. Power Generation Equipment
7018 welding rods are often employed in the fabrication and repair of power generation equipment, such as turbines, boilers, and generators. The high strength and crack resistance of welds produced with these electrodes are crucial in components subjected to high temperatures and pressures.
The rod's low-hydrogen characteristics are particularly beneficial in this application, as they help prevent hydrogen embrittlement that could lead to premature failure of critical components. The electrode's ability to weld in all positions facilitates on-site repairs and maintenance of large, complex equipment.
8. Railway Industry
The railway industry utilizes 7018 welding rods in various applications, from track construction and repair to the fabrication and maintenance of rolling stock. The electrode's high strength and impact resistance are valuable for components that must withstand the cyclic loading and vibration inherent in railway operations.
In track welding, the 7018 rod's ability to produce solid and crack-resistant welds helps ensure the safety and longevity of rail joints. For railcar and locomotive fabrication, the electrode's versatility in welding different steel grades and its all-position capability make it a valuable tool in manufacturing and repair.
Advantages and Disadvantages of Using the 7018 Rod
Benefits of 7018 Welding Rod
• High Strength: Produces welds with excellent tensile and yield strength.
• Low Hydrogen: Minimizes the risk of hydrogen-induced cracking.
• All-Position Welding: Can be used in flat, horizontal, vertical, and overhead positions.
• Smooth Arc: Offers stable arc characteristics and easy slag removal.
• Versatility: Suitable for a wide range of steel types and thicknesses.
• Crack Resistance: Produces welds with good resistance to cracking under stress.
Cons of 7018 Welding Rod
• Moisture Sensitivity: Requires careful storage and handling to prevent moisture absorption.
• Lower Deposition Rate: Deposits weld metal at a slower rate compared to some other electrodes.
• Preheating Requirement: The base metal often needs preheating, especially for thicker sections.
• Limited Use on Thin Materials: Not ideal for welding very thin steel due to its penetration characteristics.
• Cost: Generally more expensive than some other common electrodes.
• Skill Requirement: Demands good technique for optimal results, especially in out-of-position welding.
Storage and Handling of 7018 Rods
Proper storage and handling of 7018 welding rods are crucial to maintain their low-hydrogen characteristics and ensure optimal welding performance. These electrodes are hygroscopic, meaning they can absorb moisture from the air, leading to porosity, cracking, and other weld defects if not managed correctly.
Ideally, 7018 rods should be stored in a clean, dry environment with a controlled temperature. Many welding suppliers and manufacturers recommend keeping these electrodes in heated rod ovens or storage cabinets maintained at temperatures between 250°F to 300°F (121°C to 149°C). This helps to keep the rods dry and prevents moisture absorption. Portable rod ovens can maintain the necessary temperature and humidity conditions for short-term storage on job sites.
When removing 7018 rods from their packaging, it's essential to only take out the amount that will be used within a reasonable timeframe, typically within 4-8 hours, depending on the ambient conditions. Unused rods should be promptly returned to their sealed container or rod oven. If rods have been exposed to moisture or humid conditions, they should be reconditioned in a rod oven at temperatures around 500°F to 800°F (260°C to 427°C) for about an hour before use.
It's worth noting that 7018 rods that have absorbed moisture can often be recognized by a "popping" or "sizzling" sound during welding. These rods may produce porous welds with excessive spatter. If these signs are observed, welding should be stopped, and the electrodes should be properly dried before continuing.
Handling 7018 rods with clean, dry gloves can help prevent the transfer of oils and moisture from the welder's hands. Additionally, care should be taken to avoid mechanical damage to the flux coating, as this can affect the rod's performance and the resulting weld quality. By following these storage and handling practices, welders can ensure that their 7018 electrodes maintain their low-hydrogen properties and consistently produce high-quality welds.
Safety Precautions When Using 7018 Rods
1. Proper Personal Protective Equipment (PPE)
When using 7018 welding rods, it's crucial to wear appropriate PPE. This includes a welding helmet with the correct lens shade to protect your eyes from intense arc light and harmful UV radiation. Wear flame-resistant clothing that covers all exposed skin to prevent burns from sparks and spatter.
Use leather gloves designed for welding to protect your hands, and wear safety boots with metatarsal guards to shield your feet from falling objects and hot metal. Don't forget ear protection if working in noisy environments, as prolonged exposure to welding noise can cause hearing damage.
2. Ventilation and Fume Extraction
Adequate ventilation is essential when welding with 7018 rods. The welding process produces fumes and gases that can be harmful if inhaled. Ensure your workspace has proper ventilation, ideally with a local exhaust system or fume extractor close to the welding area.
If working in confined spaces or areas with poor ventilation, wear a respirator designed for welding fumes. Certain base metals and coatings can produce particularly toxic fumes, so always be aware of the materials you're working with and take appropriate precautions.
3. Fire Prevention and Control
Seven thousand eighteen welding rods produce sparks and spatter that can ignite flammable materials. Before welding, remove all flammable materials from the work area or cover them with fire-resistant blankets. Keep a fire extinguisher rated for electrical fires (Class C) within easy reach.
Be aware of your surroundings and check for potential fire hazards, including areas where sparks might fall out of sight. After welding, monitor the area for at least 30 minutes to ensure no smouldering fires develop. Sometimes, a fire watch may be necessary for an extended period after completing welding.
4. Electrical Safety
Since 7018 rods are used in arc welding, electrical safety is paramount. Ensure your welding equipment is properly grounded and in good condition. Inspect all cables and connections regularly for signs of wear or damage. Never weld in wet conditions or while standing in water, as this increases the risk of electric shock.
When changing electrodes, be aware of the risk of electric shock from the open-circuit voltage. Always use dry, insulated gloves when handling the electrode holder. If you need to adjust your welding machine, turn it off and unplug it first.
5. Proper Handling and Storage of Electrodes
Handle 7018 rods with care to prevent damage to their flux coating. Damaged coatings can lead to poor weld quality and increased fume generation. Store the rods in a dry environment, ideally in a rod oven, to prevent moisture absorption. Moisture in the flux can lead to hydrogen embrittlement in the weld, potentially causing cracks.
When working at heights or confined spaces, secure your electrode holder and rod container to prevent them from falling and potentially injuring someone below. Always dispose of stub ends and packaging properly to keep the work area clean and safe.
6. Awareness of Surrounding Environment
Be conscious of your surroundings when welding with 7018 rods. The bright arc can harm bystanders, so use welding screens or curtains to protect others in the area. Be aware of reflective surfaces that might redirect the arc light.
Consider the impact of your welding on nearby equipment or processes. The electromagnetic fields generated by welding can interfere with electronic devices, including pacemakers. If working in an industrial setting, communicate with others to ensure your welding doesn't create hazards for ongoing operations or compromise the safety of other nearby workers.
Comparison of 7018 Rods with Other Welding Rods
In this section, we'll compare the 7018 welding rod with other common electrodes used in arc welding. We'll examine how the 7018 compares to these alternatives in terms of strength, usability, and specific applications, highlighting the unique characteristics of each rod type. 
Comparative Analysis of 7018 vs. 6010
The 7018 and 6010 welding rods are popular choices, but they have different purposes and distinct characteristics. The 7018 rod produces high-strength welds with low hydrogen content, making it ideal for structural applications and situations requiring crack-resistant welds. It operates smoothly with minimal spatter and can be used in all positions.
Related: 6010 Welding Rod
In contrast, the 6010 rods are known for their deep penetration and ability to cut through rust, paint, and other contaminants. It's often used for root passes in pipe welding and for welding in dirty or less-than-ideal conditions. The 6010 runs on DC+ only, while the 7018 can use AC or DC+. Compared to the 6010, the 7018 produces a smoother bead appearance and generally easier-to-remove slag. However, the 6010 is less sensitive to moisture and doesn't require the careful storage that 7018 does.
Comparative Analysis of 7018 vs. 6011
The 7018 and 6011 welding rods are similar but designed for different welding scenarios. The 7018, with its low-hydrogen coating, produces strong, ductile welds with excellent crack resistance. It's preferred for critical structural welds and applications requiring high-quality results.
The 6011 rod, like its cousin, the 6010, offers deep penetration and can burn through contaminants. However, unlike the 6010, the 6011 can run on both AC and DC, making it more versatile as a power source. The 6011 is often used for general-purpose welding, especially in field work where base metal cleanliness may be an issue. While the 7018 produces smoother, more aesthetically pleasing welds, the 6011 is less sensitive to moisture and doesn't require special storage conditions, making it more convenient for some applications.
Comparative Analysis of 7018 vs. 7024
The 7018 and 7024 welding rods are both in the 70-series, indicating similar tensile strength, but they have different operational characteristics. The 7018 is an all-position rod with a low-hydrogen coating, suitable for critical welds in various applications. It offers good arc stability and produces welds with excellent mechanical properties.
The 7024, often called a "jet rod," is designed for high-speed, high-deposition welding only in flat and horizontal positions. Its coating has a higher iron powder content, allowing for faster travel speeds and higher deposition rates compared to the 7018. The 7024 is ideal for large filler metal applications, such as heavy plate welding. However, it lacks the all-position capability and low-hydrogen characteristics of the 7018, making the 7018 more versatile for a more comprehensive range of welding tasks.
Takeaway
The 7018 welding rod is versatile and reliable for many welding applications. Welders should practice using the 7018 rods to master their smooth arc characteristics and slag removal techniques. Proficiency with this electrode opens up opportunities in industries where high-quality, crack-resistant welds are essential.
