Welding Process and Requirements for Steel Structures

The welding process plays a crucial role in the fabrication of steel structures, directly impacting the safety, stability, and longevity of the structure. With 14 years of experience in the industry, Ellermann Steel is committed to delivering high-quality welding services that meet international standards. Below, we outline the key welding processes and requirements, supported by specific examples and technical parameters.

1. Overview of Steel Structure Welding

Steel structure welding involves connecting steel parts through heat or pressure to form a unified structure. Common welding methods include manual arc welding, CO2 gas shielded welding, and submerged arc welding. The choice of welding technique depends on the type of steel, the complexity of the joints, and the project environment.Example:When welding a 10-meter long steel beam, we may use manual arc welding (MMA) for the joints. For thinner, more precise components, CO2 gas shielded welding (MIG/MAG) may be selected, with currents typically set around 200 amps for a high-quality weld.

2. Key Welding Requirements

Selection of Welding Materials

The choice of welding material is critical for ensuring strong, durable welds. It must be compatible with the base material to avoid issues like cracking or brittleness.Example:For welding a bridge structure, we use E7018 low-hydrogen electrodes to ensure high tensile strength (typically 70 ksi). In colder climates, we may opt for E7016 electrodes, which perform better in low-temperature environments.
Pre-Welding Preparation

Proper surface preparation is essential to ensure clean and smooth welding surfaces. This includes removing contaminants like rust, oil, and oxides and ensuring precise joint alignment.Example:For a warehouse frame, steel joints are cleaned using grinders to remove oxide layers, ensuring the edges are smooth and free of debris. The joint gap is tightly controlled, with a permissible deviation of less than 0.5mm.
Control of Welding Parameters

Proper control of welding parameters such as current, voltage, and welding speed is essential to achieving optimal weld quality.Example:
- Current: For a 5mm thick steel plate using CO2 welding, we set the current at 180-200 amps to ensure a stable weld pool without overheating.
- Voltage: The voltage is typically set between 22-26 volts to maintain a consistent arc while minimizing spatter.
- Welding Speed: For the same plate thickness, the welding speed is set at 20-30 cm/min to ensure uniform bead formation and avoid overheating.
- Welding Position: For vertical welding, the current may be adjusted to 210 amps to maintain the stability of the molten pool and prevent bead sagging.
Welding Monitoring and Inspection

Continuous monitoring during the welding process ensures that the correct parameters are maintained. After welding, non-destructive testing (NDT) methods such as X-ray or ultrasonic testing are used to detect defects.Example:After welding a steel structure for an industrial building, we perform X-ray inspection to detect any internal defects like cracks or air pockets. The exposure time is adjusted according to the material thickness, with 2-3 seconds of exposure for 20mm thick steel to ensure deep inspection.
Post-Welding Treatment and Testing

Post-welding treatments such as stress relief, cleaning of weld slag, and heat treatment are necessary to enhance the mechanical properties and appearance of the welds.Example:After welding a high-rise building’s steel structure, the joints undergo stress relief annealing at 350-400°C to reduce residual stresses. Tensile tests are also performed to ensure the weld strength meets design requirements, typically achieving a tensile strength of 500 MPa or higher.

3. Ellermann Steel's Welding Advantages

Expert Team

Ellermann Steel’s welding engineers have extensive experience and can tailor welding solutions to meet the specific needs of each project. For example, when welding steel for offshore oil platforms, we select welding materials and techniques that ensure the structure’s durability in harsh environments.
Advanced Equipment

We use state-of-the-art welding equipment, including automated CO2 welding machines and laser welding technology, to ensure precision in every weld. These machines are programmed to control parameters like current, voltage, and speed, reducing human error and improving weld quality.
Rigorous Quality Control

Our quality control processes ensure that each welding project adheres to international standards. Every weld undergoes strict inspection, including X-ray, ultrasonic, and tensile testing, to confirm the structural integrity and safety of the final product.
Environmental and Safety Commitment

We prioritize worker safety and environmental protection during the welding process. High-efficiency smoke and fume extraction systems are in place to ensure a safe working environment, while we use eco-friendly welding materials to minimize our environmental footprint.

4. Conclusion

Steel structure welding is a fundamental aspect of construction, directly affecting the safety and performance of the structure. With over 14 years of experience, Ellermann Steel is dedicated to providing high-quality welding services. From precise parameter control to strict quality inspections, we ensure that each welding project meets the highest standards, delivering reliable and durable steel structures.