What are the operating procedures of submerged arc welding machine?

Submerged Arc Welding (SAW) is a commonly used welding process known for its high efficiency and deep penetration. Operating a submerged arc welding machine requires adherence to specific safety and operational procedures to ensure high-quality welds and prevent accidents. 

Submerged arc welding machine operating procedures

1. Pre-Operational Setup

a. Inspection and Preparation

Check the Equipment: Ensure the welding machine, power source, and wire feeder are in good working condition. Inspect cables, connections, and the welding gun for any damage.

Clean the Workpiece: Ensure the surfaces to be welded are clean, free of rust, oil, dirt, or other contaminants that may affect weld quality.

Select Proper Filler Wire: Choose the appropriate wire electrode based on the material type and thickness to be welded.

Select Proper Flux: Ensure that the flux is dry and suitable for the welding process. The flux must match the welding wire and workpiece material.

Setup Welding Parameters: Set the welding machine's parameters (voltage, current, and travel speed) based on the welding specifications and the thickness of the material.

b. Check Safety Gear

Personal Protective Equipment (PPE): Wear the necessary PPE, including:

Welding helmet with appropriate shade lens

Flame-resistant gloves

Flame-retardant clothing

Welding boots

Safety glasses or goggles

Ventilation: Ensure adequate ventilation in the work area, as fumes from the welding process can be hazardous.

Fire Extinguisher: Have a fire extinguisher nearby, as welding can pose a fire hazard.

2. Machine Setup and Calibration

a. Set the Electrode Wire

Load the Electrode Wire: Load the wire electrode spool into the feeder. Ensure the wire passes smoothly through the guide tube and into the welding gun.

Check Wire Feed Speed: Set the wire feed speed according to the required weld specifications. The wire feed speed will determine the amount of filler material deposited in the weld pool.

b. Prepare the Flux

Load the Flux Hopper: Fill the flux hopper with the required flux. Make sure that the flux is dry and clean.

Check Flux Delivery System: Ensure the flux delivery system is properly functioning, providing an even layer of flux over the weld joint during the welding process.

c. Set Welding Parameters

Adjust Current and Voltage: Set the welding current and voltage according to the material type, thickness, and joint design. Current and voltage settings should align with the welding procedure specification (WPS).

Adjust Travel Speed: Set the travel speed of the welding head (for automatic or semi-automatic machines). The travel speed should match the heat input requirements for the specific material and joint design.

d. Set Up the Workpiece

Position the Workpiece: Secure the workpiece in place on a welding table or fixture, ensuring proper alignment of the joint to be welded.

Ground the Workpiece: Attach the ground clamp to the workpiece to establish a complete circuit for the welding process.

3. Operational Procedure

a. Start the Welding Process

Start the Arc: Begin welding by engaging the welding arc, either by pressing the trigger on the welding gun (manual welding) or initiating the automatic welding system.

Monitor Flux Coverage: Ensure that the flux is properly covering the arc during welding to avoid exposure to air, which could cause weld defects like porosity or oxidation.

b. Monitor the Welding Process

Arc Stability: Observe the arc stability, and adjust parameters if necessary. A stable arc will produce a consistent, high-quality weld.

Flux Recovery: For automatic systems, monitor the flux recovery unit to ensure it is working correctly and recycling unused flux for further use.

Weld Bead Inspection: Continuously inspect the weld bead for uniformity and penetration. Look out for any signs of weld defects such as undercutting, slag inclusions, or excessive spatter.

4. Post-Welding Procedures

a. Stop the Welding Process

Turn Off the Arc: At the end of the weld, disengage the arc by releasing the welding gun trigger or stopping the automatic welding system.

Remove Slag: After the weld has cooled slightly, remove the slag layer formed by the flux using a chipping hammer or wire brush.

Inspect the Weld: Perform a visual inspection of the weld bead for any surface defects. For critical welds, non-destructive testing (NDT) such as ultrasonic or radiographic testing may be required.

b. Shutdown Procedure

Turn Off the Machine: Switch off the power source and welding machine. Disconnect the wire feeder and any auxiliary equipment.

Clean the Welding Area: Remove any excess flux, wire trimmings, and other debris from the welding area.

Store Equipment Properly: Coil up cables and wires, store the welding gun and flux properly, and ensure the machine is ready for the next use.

c. Post-Weld Treatment

Post-Weld Heat Treatment (if necessary): If required by the welding procedure specification, perform post-weld heat treatment (PWHT) to relieve stress in the welded joint and improve its mechanical properties.

Final Inspection: Perform a final inspection of the weld and surrounding area to ensure it meets the required standards and specifications.

5. Safety Considerations During Operation

Avoid Overheating: Monitor the temperature of the welding machine and electrodes to prevent overheating.

Handle Flux Carefully: Avoid inhaling flux dust and ensure proper handling, as it can be hazardous to health.

Check Grounding Continuity: Ensure the workpiece is properly grounded throughout the welding process to avoid electrical shocks.

Arc Protection: Maintain a proper distance from the arc and ensure that others nearby are also protected from exposure to the welding arc.

Conclusion