AK-S70/ AK-AF207 Submerged Arc Welding Wire and Flux for 700MPa High Strength Steel.
A submerged arc welding system combining AK-S70 wire and AK-AF207 flux, designed for high strength low alloy steel with stable arc, easy slag removal, and good low temperature impact toughness.
Product Overview
AK-S70 is a submerged arc welding wire for low alloy high strength steel, and AK-AF207 is a fluorine-base type sintered flux. The combination is used for welding high strength steels up to 700 MPa, commonly in shipbuilding, machinery, chemical plants, bridges, and steel structures.
The system delivers stable arc performance, easy slag removal, and good crack resistance. Deposited metal achieves impact toughness of at least 27 J at minus 40 degrees C, meeting requirements for low-temperature service.
Application: Ak-S70 is a submerged arc welding wire for low alloy high strength steel, AK-AF207 is a fluorine-base type sintered flux. The combination of Ak-S70 and AK-AF207 has the advantages of good welding technology, stable arc, easy slag removal and good low temperature impact toughness and crack resistance. Suitable for 700MPa high strength steel welding, commonly used in ships, machinery manufacturing, chemical industry, bridges, steel structures and other low-alloy welding of corresponding strength.
Key Benefits
Stable Arc and Easy Slag Removal.
The AK-AF207 flux produces a stable arc and slag that detaches easily, reducing inter-pass cleaning time and minimizing the risk of slag entrapment.
Good Low Temperature Impact Toughness.
Deposited metal meets a minimum impact value of 27 J at minus 40 degrees C, suitable for applications requiring toughness in cold environments.
High Strength and Crack Resistance.
The system is designed for 700 MPa strength steel, with mechanical properties including tensile strength of 690-830 MPa and yield stress of at least 610 MPa, and good resistance to cracking.
Controlled Chemical Composition
Chemical composition includes low carbon (0.028%), controlled sulfur (0.006%) and phosphorus (0.010%), and alloying elements such as nickel (2.01%) and molybdenum (0.44%) to support strength and toughness.
Where It Is Used
- Welding of 700 MPa high strength low alloy steel in shipbuilding.
- Machinery and equipment manufacturing requiring high strength and toughness.
- Chemical plant and pressure vessel construction.
- Bridge and steel structure fabrication.
- Welding of thick-section components where crack resistance and low-temperature performance are critical.
Who It Is For
- Shipbuilding yards requiring high strength, low-temperature resistant welds.
- Fabricators of heavy machinery and industrial equipment.
- Contractors working on bridges and large steel structures.
- Manufacturers of pressure vessels and chemical plant components.
Problems It Solves
- Achieving consistent weld metal properties in high strength low alloy steel without cracking or reduced toughness.
- Managing slag removal and arc stability in automated submerged arc welding processes.
- Meeting low temperature impact requirements in critical structural applications.
- Ensuring proper preheat and post-weld heat treatment for high strength steel welds.
Specifications
Published by the factory for AK-S70/ AK-AF207. Values not shown are not published on the datasheet and are marked as such rather than estimated.
| Standard | Designation |
|---|---|
| Classification 1 | EN ISO —— AWS A5.23M F69A4-EM4-M4 |
| Classification 2 | GB/T 36037 SA FB 1 |
| Element | Content |
|---|---|
| C | 0.028 |
| Si | 0.35 |
| Mn | 1.60 |
| S | 0.006 |
| P | 0.010 |
| Ni | 2.01 |
| Cu | 0.06 |
| Cr | 0.26 |
| Mo | 0.44 Mechanical |
| Tensile strength (MPa) | 690-830 |
| Yield Stress (MPa) | ≥610 |
| Elongation (%) | ≥16 |
| Impact values (J) | ≥27J/-40℃ |
| Recommended | —— |
Mechanical property data for this grade is not published on the factory datasheet. Ask our technical team for the test record before you qualify it.
Note: 1. before the use of flux must be 300 ~ 350 ° C baking 1-2 hours, welding wire should be dry before use, no oil, Rust State 2. welding should be strictly removed before the welding area of oil, rust, moisture and other impurities, 3. When welding, preheat 150 ~ 300 ° C (depending on plate thickness and material) . 4. Recommended welding specification (taking Φ4.0 wire as an example) I = 500 ~ 550A, U = 28 ~ 32V, welding speed V = 50 ~ 55cm/min, inter-pass temperature 150 ~ 180 ° C. 5. To ensure the plasticity of deposited metal, it is necessary to dehydrogen at 200 ~ 240 °C for 2 ~ 4 hours after welding. Flux Quality Requirements: 1. Flux water content ≤0.10% 2. Mechanical inclusions ≤0.30. 3. In flux, flux s 0.050% 4. Flux p content ≤0.060% Deposited metal x-ray detection requirements : Grade I
Technical Features
- AK-S70 wire used with AK-AF207 flux for submerged arc welding.
- Deposited metal tensile strength: 690-830 MPa, yield stress: ≥610 MPa.
- Elongation: ≥16 percent, impact toughness: ≥27 J at minus 40 degrees C.
- Chemical composition: C 0.028%, Si 0.35%, Mn 1.60%, S 0.006%, P 0.010%, Ni 2.01%, Cu 0.06%, Cr 0.26%, Mo 0.44%
- Flux water content ≤0.10%, mechanical inclusions ≤0.30%, sulfur content ≤0.050%, phosphorus content ≤0.060%
- Deposited metal x-ray detection: Grade I.
Use Guide
- Pre-bake AK-AF207 flux at 300 to 350 degrees C for 1 to 2 hours before use.
- Ensure AK-S70 wire is dry and free of oil, rust, or moisture before welding.
- Clean the joint area thoroughly to remove oil, rust, and moisture prior to welding.
- Preheat the base metal to 150 to 300 degrees C, depending on plate thickness and material.
- For Φ4.0 mm wire, recommended parameters are current 500 to 550 A, voltage 28 to 32 V, welding speed 50 to 55 cm/min, inter-pass temperature 150 to 180 degrees C.
- After welding, perform dehydrogenation at 200 to 240 degrees C for 2 to 4 hours to ensure deposited metal plasticity.
How It Compares
AK-S70/ AK-AF207 is a submerged arc system for high strength low alloy steel. It differs from standard carbon steel SAW systems by including alloying elements like nickel and molybdenum to achieve higher strength and toughness. Compared to basic flux systems, it offers easier slag removal and more stable arc, though with slightly higher hydrogen content. For applications requiring the lowest possible hydrogen, a basic flux system would be preferred instead.
Related Grades
Other welding wire in the same family.
AK-S70/ AK-AF207 Questions
What are the recommended preheat and inter-pass temperatures?
What is the required post-weld heat treatment?
What are the mechanical properties of the deposited metal?
What are the flux quality requirements?
What packing is AK-S70/ AK-AF207 supplied in?
Can we test AK-S70/ AK-AF207 before placing a production order?
Request a Quotation for AK-S70/ AK-AF207
Send the diameter, the quantity and the destination port. Our technical team replies with packing, pricing and the data you need to qualify the grade.