Superior quality welding processes deliver two distinct competitive advantages: weld integrity and welding repeatability. With the right processes in place, you should be able to consistently deliver strong, durable welds that are free from cracking, distortion, spatter, undercut, porosity and erratic beads.
High-quality welding is built on a foundation of skilled labour, cleanliness, preparation, correct storage of consumables and materials, the type of welding and the type of gas used, as well as the integration of automation into job planning.
To drill down on these key factors a little more, we’ve compiled 10 tips on how to improve the quality of your welding processes.
1. Skilled Labour
The skill level of the welder is an important factor in the delivery of high-quality welds. This is particularly true of labour-intensive welding techniques (such as TIG / GTAW and gas metal arc welding ), as well as complex, sensitive welding techniques (such as hybrid laser arc welding and laser beam welding). Not just anyone can pick up a welding torch and perform a strong, durable weld that is free from cracking, spatter, undercut, porosity and erratic beads. Perfecting one’s welding technique to deliver repeatable high-quality welds requires time, practice and in-depth technical knowledge.
Automating welding processes has the potential to provide enormous gains, in terms of productivity, profitability and quality. The automation of travel speed, current and other key variables reduces the likelihood of human error in the welding process, delivering consistent, repeatable weld profiles. In fact, a well programmed automated welding system will provide highly consistent weld quality almost indefinitely. This allows for a much higher degree of adherence to weld procedures and quality assurance standards, and can reduce the reworking processes such as grinding, machining and re-welding. In comparison, manual welding requires a high degree of concentration over sustained periods, inevitably resulting in welder fatigue and increasing the likelihood of defects.
Cleanliness plays a key role in welding quality. If a welder does not properly clean the components being welded, the results can be disastrous. Contaminants such as dirt, dust, grease or even the oils in skin introduced during a weld can cause incomplete fusion, porosity, cracking and poor bead appearance. These issues compromise the weld’s performance, longevity, and its ability to resist corrosion. This is particularly problematic in the ASME vessel fabrication and nuclear welding sectors, where high quality welds are required to ensure adherence to strict guidelines.
As such, your welding process should always include cleaning the components to be welded so that all surfaces are spotless and smooth, and ensuring your work area and consumables are clean and contaminant-free. For some materials, such as titanium, you may need to take additional cleanliness precautions—nitrile gloves should be worn while handling and cleaning filler rods and all other parts.
4. Type of Welding
The type of welding you choose to use in your welding process greatly influences the quality of the weld. Each type of welding offer both advantages and disadvantages in terms of weld quality.
For instance, welding with the GMAW process can be subject to lack of fusion. Additional potential issues include spatter and inter-pass cleaning.
In comparison, Gas Tungsten Arc Welding (GTAW) is typically the cleanest type of welding. Where high quality welding is non-negotiable, workshops tend to use GTAW because of the high-quality results it delivers. Eliminating slag, flux and spatter results in a much higher quality weld and eliminates the potential for inclusions.
K-TIG’s advanced welding technology delivers high quality, single pass, full pentration GTAW welding.
5. Multiple Passes
When the welding of thicker materials requires multiple passes, the likelihood of porosity, inclusions at the toes of the passes, and lack of fusion all significantly increase. In addition, cleaning and grinding is required between each pass, increasing the likelihood of inclusions.
Reducing the number of passes can be key to improving overall weld quality. K-TIG welds, for instance, can be completed in a single pass in titanium up to 16mm, and in stainless steel up to 13mm. K-TIG welds therefore have no fusion lines, and require no inter pass cleaning or grinding, greatly reducing the potential for defects.
6. Consumable Storage
An often-overlooked tip for improving the quality of your welding processes is properly storing your consumables to ensure they remain free from contaminants. This will help prevent quality issues such as excessive slag fluidity, porosity, rough welding surfaces, difficult slag removal and, perhaps most importantly of all, increased diffusible hydrogen that often leads to cracking. As such, filler wire, your grinding wheel and even the gloves with which you handle your materials should be stored in a dry location, out of the elements. In particular, ensure that the manufacturer’s storage instructions for your electrodes and wires are adhered to—many electrodes must be stored below a certain temperature, and some wires must be stored below a recommended humidity level.
7. Materials and Workpiece Storage
The way in which you store your materials and workpieces is just as important as how you store your consumables. So, be sure to store all the workpieces that you plan to weld in a dry area that is out of the elements and free from contaminants.
8. Gas Selection
It is imperative that you select the right gas for the welding process to be applied. The right gas offers a range of benefits—it protects the weld pool from exposure to the atmosphere, promotes a stable arc, and significantly impacts the quality of the weld deposit.
For instance, when using GTAW to weld stainless steel, a mixture of argon and hydrogen delivers impressive results. By increasing heat of the arc and thus increasing penetration. When welding duplex and super duplex, nitrogen additions help maintain a phase balance between the austenite and ferrite within the material.
When choosing the right gas, you need to consider: the type of material being welded; whether deep penetration is a must (as opposed to reducing burn-through in the joint); and whether weld appearance (and therefore spatter) are important.
To deliver the best possible quality welds consistently, preparation is essential. If components are presented for welding in a repeatable way, the quality of the welds is greatly enhanced—there are no unnecessary changes that a welder must account for each time. Consistent input affords consistent output. Quality fit-up affords quality results.
During the welding preparation process, fabricators and welders should always check for external contaminants before presenting a component for welding. All dust, grease and grime must be removed, leaving the area to be welded as clean as possible. You will also need to prepare the edges of the material being welded for the joint required. For instance, if the material requires a butt weld, you will need to ensure both the root face and root gap are properly prepared prior to welding.
10. Job Planning
Proper job planning can greatly improve your welding process, particularly for large-scale projects that feature repeatable components. For instance, when planning for a job, you should consider what is both the easiest welding position, and the welding position which is likely to provide the highest quality results. You should also consider whether the job can be performed with automation. If it can, incorporating automation as much as possible into your job plan has the potential to significantly improve output, consistency and repeatability.
An automated welding process like K-TIG can complete a full penetration butt joint in 10-inch schedule 40 pipe to x-ray quality in under 3 minutes. The welding time and quality is transferable between circumferential welding and longitudinal welding, with outstanding repeatability. The use of a high-productivity process such as K-TIG can greatly improve the output, quality and profitability of your projects.