SJ501 Submerged Arc Welding Flux Empowers the Revolution of High-Speed Welding: Key Advantages and Practical Guide to Enhancing Efficiency and Quality

Introduction to SJ501 Submerged Arc Welding Flux

SJ501 is an aluminum-titanium type acidic sintered welding flux with an alkalinity of approximately 0.5-0.8 and a particle size of 10-40 mesh (2.0-0.45mm). Its main chemical components include Al₂O₃ (44%-46%), TiO₂ (10%-15%), MnO (15%-18%), and CaF (≤6%). This flux can be used with both alternating current (AC) and direct current (DC). When using DC for welding, the welding wire should be connected to the positive electrode. It is suitable for welding low-carbon steel, low-alloy steel, and steel for pressure vessels, such as materials like 16Mn, X65, X70, 14MnNiq, and Q345C. When used with welding wires such as H08A, H08MnA, H08MnMoA, or H10MnSi, its application range covers submerged arc welding scenarios in boiler pressure vessels, ships, bridges, and oil pipelines, among others.

Advantages in Handling High-Speed Welding

SJ501 flux has been specially optimized for high-speed welding performance, with a stable welding speed of over 70m/h. It is suitable for multi-wire rapid welding, twin-wire single-pass welding, flat welding, and butt welding, and is particularly well-suited for thin-plate welding. Its core advantages are as follows:

1. Arc stability and high-speed adaptability: The flux has a relatively high content of Al₂O₃ and TiO₂. These neutral and weakly acidic oxides have low oxygen potential and are not easily decomposed under the high temperature of the arc, preventing oxygen increase in the weld metal. This enables high-speed welding without sacrificing stability. Compared to SJ101 or SJ301 fluxes, SJ501 has better welding performance, achieving a welding speed increase of more than 30%.

2. Excellent resistance to porosity and rust: By reducing oxides with high oxygen potential and enhancing deoxidation, SJ501 effectively solves the common porosity problem in high-speed welding. At the same time, it has good resistance to impurities such as rust, oil stains, and moisture on the welded plate, ensuring defect-free welds and excellent impact toughness of the deposited metal.

3. Weld bead formation and slag detachability: The weld bead is smooth and shiny, with extremely easy slag removal. The relatively high melting point of Al₂O₃ improves the physical properties of the slag, avoiding undercut defects. It is particularly suitable for thin-plate welding of steel cylinders and boiler water wall pipes, improving overall welding efficiency and aesthetics.

4. Alloy penetration and compatibility: It has a certain ability to penetrate manganese. When used with welding wires with low manganese and silicon content, the manganese burnout rate is low, ensuring stable chemical composition of the weld. It is suitable for multi-layer welding and narrow gap welding, significantly improving production efficiency.

These advantages make SJ501 the first choice for industrial high-speed welding, with an annual export volume of over 3000 tons, widely used in high-efficiency manufacturing fields.

Precautions for Use

To ensure that SJ501 flux performs optimally, users must strictly adhere to the following operating specifications:

1. Pre-welding preparation: The flux must be baked at approximately 350°C for 1 hour, and used immediately after baking to avoid moisture absorption affecting performance. The surface of the welded parts must be thoroughly cleaned of impurities such as rust, oil stains, and moisture to prevent defects.

2. Welding process control: Adopt short arc operation and maintain a narrow weld bead. During high-speed welding, monitor current and voltage parameters to avoid overheating leading to undercuts. The twin-wire single-pass welding mode is recommended, with the welding speed controlled within 70m/h, and fine-tuned according to the plate thickness.

3. Power supply and polarity selection: When using DC welding, the welding wire is connected to the positive electrode; both AC and DC can be used, but DC is more stable. Avoid leaving the flux exposed to the air for a long time, and seal and store it promptly after use.

4. Safety and maintenance: The welding environment must be well-ventilated, and protective equipment should be worn. Regularly check the uniformity of the flux particle size; if there is caking, re-bake it. When the manganese content of the matching welding wire is >1.7%, pay attention to monitoring the burnout rate to avoid deviations in alloying elements.

5. Storage recommendations: Store in a dry and ventilated place, and use within the shelf life. In high-speed applications, if signs of porosity appear, prioritize checking the welding wire compatibility and environmental humidity.