AK-707Q Ultra-Low Hydrogen Electrode for High Toughness Bridge Welding.
A low-hydrogen sodium coated electrode designed for all-position welding of critical low alloy steel bridge structures with high toughness and excellent mechanical properties.
Product Overview
AK-707Q is a low-hydrogen sodium type covered electrode for manual metal arc welding, formulated for all-position welding with DC reverse polarity. It delivers high toughness and consistent mechanical performance in critical structural applications.
The electrode meets EN ISO 18275 B E 6918 N3M2, AWS A5.5 E10018M, and GB/T 5118-1995 E7015-G classifications, ensuring compatibility with international standards for low alloy steel welding in demanding environments.
Application: lt is used for important low alloy seel bridge welding structures.
Key Benefits
Ultra-Low Hydrogen for High Toughness.
The sodium-based coating minimizes hydrogen content in the weld metal, reducing the risk of cold cracking in high-strength low alloy steels, especially in thick sections and low-temperature service.
High Mechanical Strength and Ductility.
Deposited metal achieves tensile strength of at least 690 MPa, yield stress of at least 590 MPa, elongation of at least 15 percent, and impact energy of at least 47 J at minus 40 degrees C.
All-Position Welding Capability
Suitable for flat, horizontal, vertical, and overhead positions, allowing continuous welding on complex bridge structures without changing consumables.
Stable Arc with Controlled Penetration.
DC reverse polarity operation ensures a stable arc and consistent weld pool control, ideal for precision welding in critical structural joints.
Where It Is Used
- Critical low alloy steel bridge structures requiring high toughness and crack resistance.
- Welding of thick-section components in heavy steel structures.
- Structural fabrication where low hydrogen and high impact strength are essential.
- Maintenance and repair of existing bridge and structural steelwork.
Who It Is For
- Welding consumable distributors supplying high-performance electrodes for structural projects.
- Bridge and heavy steel structure fabricators requiring certified low-hydrogen electrodes.
- EPC contractors working on infrastructure projects with stringent welding code requirements.
Problems It Solves
- Weld cracking in low alloy steel structures due to high hydrogen content in the weld metal.
- Failure to meet impact toughness requirements at low temperatures in critical joints.
- Need for multiple electrode types to cover different welding positions on complex structures.
Specifications
Published by the factory for AK-707Q. Values not shown are not published on the datasheet and are marked as such rather than estimated.
| Standard | Designation |
|---|---|
| Classification | EN ISO 18275 B E 6918 N3M2 A AWS A5.5 E10018M GB/T 5118-1995 E7015-G |
| Element | Content |
|---|---|
| C | 0.10 |
| Si | 0.6 |
| Mn | 1.0-2.0 |
| S | 0.015 |
| P | 0.020 |
| Ni | 0.8-1.7 |
| Mo | 0.10-0.40 |
| Property | Value |
|---|---|
| Tensile strength (MPa) | ≥690 |
| Yield Stress (MPa) | ≥590 |
| Elongation (%) | ≥15J |
| Impact values (J) | ≥47J/-40℃ |
| Diameter | Current range |
|---|---|
| 2.5mm | F/H-70-110A V/OH-50-80A |
| 3.2mm | F/H-90-130A V/OH-80-110A |
| 4.0mm | F/H-140-180A V/OH-130-170A |
Technical Features
- Low-hydrogen sodium coating for reduced risk of cold cracking.
- Deposited metal tensile strength at least 690 MPa, yield stress at least 590 MPa.
- Elongation at least 15 percent and impact energy at least 47 J at minus 40 degrees C.
- Supplied in 2.5 mm, 3.2 mm, and 4.0 mm diameters with published current ranges for all positions.
Use Guide
- Select diameter by joint thickness and position: 2.5 mm for thin sections, 3.2 mm for medium, 4.0 mm for thick sections.
- Use DC reverse polarity for stable arc and optimal weld metal properties.
- Set current within the recommended range: 2.5 mm - 70-110 A flat/horizontal, 50-80 A vertical/overhead; 3.2 mm - 90-130 A flat/horizontal, 80-110 A vertical/overhead; 4.0 mm - 140-180 A flat/horizontal, 130-170 A vertical/overhead.
- Keep electrodes dry in sealed packaging; re-bake if exposed to moisture before use.
- Clean joint surfaces from rust, oil, paint, and moisture before welding to prevent porosity and hydrogen pickup.
How It Compares
AK-707Q and E7015 both weld low alloy steel with high toughness and low hydrogen, but AK-707Q is specifically formulated for bridge structures with enhanced impact resistance at low temperatures. E7015 electrodes may have different chemical compositions and are not always optimized for the same low-temperature performance. For applications requiring higher nickel content and improved toughness, AK-707Q offers a tailored solution with Ni content between 0.8 and 1.7 percent.
Related Grades
Other welding electrodes in the same family.
AK-707Q Questions
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What mechanical properties does the deposited metal achieve?
What welding positions are supported?
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