I’m currently supporting this function of welding visual examinations temporarily until we qualify more inspectors in the longer term.
The basics cover the need for each weld joint to be marked with a welder symbol. This is because a job may contain more than a few joints and involve multiple welder shifts, its important to be able to trace which weld joint done by which individual welder should the need to investigate arises.
Although weld spatter is not covered in ASME B31.1 or ISO 17637 or ISO 5817 as a weld defect, it is highly recommended to be removed completely under AWS D1.1 to ensure the surface is clean for further processing such as surface examinations like LPT, MT or applications of coatings.
Weld spatter is the most commonly condition found during my share of visual weld inspections albeit the removal process is quite easy – welders tend to take this lightly and wait for the final inspection to detect all instead of cleaning after every joint completed.
Weld spatter is created during the welding process and is essentially small droplets of molten metal that are expelled from the weld pool. Several factors contribute to the formation of weld spatter:
High Welding Current
Using excessive welding current can result in a larger weld pool, increasing the likelihood of spatter formation.
Incorrect Shielding Gas Flow
Insufficient shielding gas or improper gas flow rates can lead to inadequate protection of the weld pool, causing spatter.
Electrode Extension
Keeping the electrode too far from the workpiece can contribute to spatter formation. Maintaining the correct electrode extension helps in achieving a stable arc and reduces spatter.
Electrode Polarity:
Incorrect polarity can affect the welding process, leading to unstable arcs and increased spatter. Ensuring the correct polarity for the welding process being used is crucial.
Welding Technique
Poor welding techniques, such as weaving too wide or moving too slowly, can result in excessive spatter. Proper technique involves maintaining a consistent travel speed and maintaining a steady arc length.
Base Metal Contaminants
Contaminants such as rust, paint, or oil on the base metal can vaporize and cause spatter during welding. Proper cleaning and preparation of the base metal before welding can help reduce spatter.
Electrode Quality
Using low-quality or contaminated electrodes can contribute to spatter formation. Using clean, high-quality electrodes appropriate for the welding process and base metal can help reduce spatter.
Gas Composition
The composition of the shielding gas used can affect spatter formation. Using the correct gas mixture for the welding process and material being welded is essential to minimize spatter.
Welding Position
Welding in certain positions, such as overhead or vertical-up, can increase the likelihood of spatter due to the effects of gravity on the molten metal.
To minimize weld spatter, it’s important to control these variables carefully, maintain proper welding techniques, and ensure the equipment and materials used are suitable for the specific welding process and application. Regular maintenance and inspection of welding equipment can also help identify and correct issues that may contribute to spatter formation.
Until then, write to you later.
Mohd Firdaus Rahiman