When it comes to joining thick sections of carbon steel efficiently and with exceptional quality, few processes rival submerged arc welding (SAW). And at the heart of a successful SAW operation is the choice of consumable. For countless fabricators working with common low-carbon steels, EA2 wire is the go-to choice.
But what exactly is EA2 submerged arc welding wire, and why is it so widely trusted? This guide will dive deep into everything you need to know—from its chemical composition and mechanical properties to its best applications and how to use it effectively.
What is EA2 Submerged Arc Welding Wire?
EA2 wire is a standard copper-coated, low-carbon steel wire used specifically for the submerged arc welding process. The “E” indicates it is an electrode, and the “A2” denotes its chemical composition classification according to standards like AWS A5.17 / A5.17M (Specification for Carbon Steel Electrodes and Fluxes for Submerged Arc Welding).
It is designed to be used with a compatible fused or agglomerated flux, which shields the arc and molten weld metal from the atmosphere, prevents spatter, and helps shape the weld bead. The combination of the EA2 wire and the right flux is crucial for achieving the desired weld metal properties.
Key Properties and Characteristics of EA2 Wire
Understanding the properties of EA2 welding wire helps in selecting it for the right job.
- Chemical Composition: EA2 wire is a manganese-molybdenum low-alloy wire. A typical analysis is:
- Carbon (C): ~0.10%
- Manganese (Mn): ~1.50% – 1.90%
- Silicon (Si): ~0.05% – 0.30%
- Molybdenum (Mo): ~0.45% – 0.65%
This composition provides a good balance of strength and toughness.
- Mechanical Properties (As-Welded with Appropriate Flux):
- Tensile Strength: Typically produces weld metal with a tensile strength of 80,000 – 95,000 psi (550 – 655 MPa).
- Yield Strength: Approximately 65,000 psi (450 MPa).
- Impact Toughness: Offers good Charpy V-Notch impact properties at low temperatures, often meeting requirements for applications down to -30°C (-22°F) or lower, depending on the flux used.
- Copper Coating: The thin copper coating on EA2 wire provides critical benefits:
- Corrosion Resistance: Prevents rusting during storage.
- Electrical Conductivity: Improves current pickup, leading to a more stable arc.
- Feedability: Reduces friction in the welding guide tubes, ensuring smooth wire feeding.
Common Applications of EA2 SAW Wire
Thanks to its versatility and reliable performance, EA2 submerged arc welding wire is a workhorse in heavy fabrication industries. You’ll commonly find it used in:
- Construction of Bridges and Buildings: For welding thick plates, girders, and structural components.
- Shipbuilding and Offshore Structures: Ideal for long, continuous hull seams and critical joints that require high integrity.
- Pressure Vessel and Boiler Manufacturing: Used for longitudinal and circumferential seams where strength and leak-tight integrity are paramount.
- Line Pipe and Storage Tanks: For manufacturing large-diameter pipes and welding the shells of storage tanks.
- Heavy Equipment and Mining Machinery: Fabrication of frames, booms, and other high-stress components for excavators, bulldozers, and cranes.
Essentially, EA2 wire is perfect for multi-pass welding of ASTM A36, A516 Gr. 55/60/65/70, and similar carbon and low-alloy steels.
Choosing the Right Flux for EA2 Wire
The EA2 welding wire alone doesn’t determine the final weld metal properties. The flux plays an equally important role. Fluxes are classified as neutral or active.
- Neutral Fluxes: These fluxes do not significantly alter the chemical composition of the weld metal. They are preferred for multi-pass applications as they allow for consistent properties across many layers. They are an excellent general-purpose choice for EA2 wire.
- Active Fluxes: These fluxes add manganese and silicon to the weld metal, which can help improve resistance to porosity, especially on steels with mill scale or slightly contaminated surfaces. However, they can change the chemistry on subsequent passes.
Always consult the flux manufacturer’s recommendations for the best wire-flux combination to achieve your specific mechanical property requirements.
Best Practices for Welding with EA2 Wire
To get the most out of your EA2 submerged arc welding wire, follow these expert tips:
- Cleanliness is Key: While SAW is forgiving, always remove heavy rust, oil, grease, and moisture from the joint area. Moisture in the flux is a primary cause of hydrogen-induced cracking.
- Proper Flux Storage: Store flux in a dry, sealed container. Bake flux according to the manufacturer’s instructions if it has been exposed to humid air to drive off moisture.
- Optimize Parameters: Use the correct voltage, amperage, and travel speed for your joint design and thickness. A higher voltage will create a wider, flatter bead, while higher amperage increases penetration.
- Maintain Stickout: Keep the electrical stickout (the distance from the contact tip to the arc) consistent. Changes in stickout can significantly alter the welding current and deposition characteristics.
- Use the Correct Polarity: EA2 wire is most commonly used with Direct Current Electrode Positive (DCEP or Reverse Polarity), which provides deep penetration and stable arc conditions.
FAQs About EA2 Submerged Arc Welding Wire
Q: Can EA2 wire be used for single-pass welds?
A: Absolutely. It is effective for both single-pass and high-quality multi-pass welds.
Q: What is the difference between EM13K and EA2 wire?
A: EM13K is another common SAW wire, but it is a carbon-manganese wire without molybdenum. EA2 wire, with its molybdenum content, generally provides higher tensile and yield strength.
Q: How do I store EA2 welding wire?
A: Store it in a cool, dry place in its original packaging. The copper coating offers good rust resistance, but prolonged exposure to high humidity should be avoided.
Conclusion: Why EA2 Wire is a Fabrication Staple
EA2 submerged arc welding wire remains one of the most popular and reliable choices for a reason. Its excellent blend of strength, toughness, and versatility makes it suitable for a vast range of critical applications in heavy industry. By understanding its properties, pairing it with the correct flux, and adhering to sound welding practices, you can achieve strong, clean, and efficient welds time after time.