FOCUS ON WELDING
Image: @ Babcock International. and poor gas coverage. Inspect and replace contact tips when the bore becomes enlarged or oblong. Clean or replace nozzles when spatter buildup restricts gas flow.
During welding
1. Maintaining consistent arc length and travel speed: A consistent travel speed is essential for a uniform weld bead and to prevent defects.
2. Proper welding technique for different joint types: The angle of the electrode or torch must be held correctly to ensure adequate penetration and fusion.
3. Controlling heat input to minimise distortion: Managing heat input is crucial to avoid warping the workpiece or causing burn-through.
Preparation is everything
Clean your base metal thoroughly: Surface contaminants are the enemy of quality welds. Remove all rust, mill scale, oil, grease, paint and moisture from the welding area. Use a wire brush, grinder or appropriate solvent cleaner. Even invisible contaminants can cause porosity, cracking and weak joints.
Proper joint fit-up: Take time to ensure accurate alignment and appropriate gap spacing for your welding process. Poor fit-up leads to excessive filler metal use, distortion and potential defects. Use clamps, jigs or tack welds to maintain proper positioning throughout the weld.
Select the right filler material: Match your filler metal to the base material composition and application requirements. Consider factors like strength, corrosion resistance and service conditions. When in doubt, consult the manufacturer’ s specifications or our technical team.
Environmental control
Maintain a clean, draft-free workspace: When welding in windy or dusty conditions,
the work area must be enclosed or shielded to prevent shielding gas dispersion and weld contamination. Even gentle air currents can compromise gas coverage, particularly with TIG and MIG processes.
Control temperature: Be aware of ambient temperature and base metal temperature. Cold base metal can cause hydrogen cracking in some materials. Consider preheating when working with thick sections or high-carbon steels.
Gas and consumables’ management
Use fresh, appropriate shielding gas: Verify you’ re using the correct gas mixture for your material and process. Check for adequate flow rate( typically 15-25 CFH for most applications). Contaminated or depleted gas cylinders should be replaced promptly.
Store electrodes and wire properly: Keep filler materials in dry, controlled environments. Moisture-absorbed electrodes cause porosity and cracking. Follow storage recommendations, especially for low-hydrogen electrodes that may require re-baking.
Regularly replace contact tips and nozzles: Worn consumables cause erratic arcs, spatter
4. Maintain a clean, draft-free workspace: When welding in windy or dusty conditions, the work area must be enclosed or shielded to prevent shielding gas dispersion and weld contamination.
Process control
Use correct welding parameters: Follow recommended voltage, amperage, wire feed speed and travel speed for your specific process and material. Too much heat causes burn-through and distortion; too little creates insufficient penetration and weak bonds.
Maintain proper torch angle and travel speed: Consistency is key. For MIG welding, a 10 – 15-degree push or drag angle typically works best. Keep your travel speed steady to ensure uniform bead appearance and penetration.
Watch your arc length: Maintain the appropriate stick-out distance for your process. Too long creates an unstable arc and poor gas coverage; too short risks stubbing and irregular deposition.
Post-welding
1. Effective cooling techniques to prevent cracking: Controlled cooling is necessary for some materials to prevent the formation of brittle structures that could lead to cracks.
2. Inspection procedures to identify defects: Non-destructive inspections such as visual, magnetic particle and ultrasonic testing during and after welding are common methods to identify defects like cracks, porosity or undercut.
28 | ismr. net | ISMR June 2026