Wednesday, August 12, 2015

5 Tips to Avoid Porosity in Welding

Find out tips to avoid porosity in welding, making sure of your weld look and durability.

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Porosity in Welding: Causes and Preventions (Part 1)

There are many welders jobs now in the market and there need more people to fill the seats. Many countries tend to reduce the flow of immigrant workers though, welding industry has wholeheartedly welcomed laborforce with this skill. To this end, job placement agencies often play a good role in helping companies find abroad workers with certain qualities they need. Employers with an eye for productivity often expect your hires to possess those traits: dedication, hard work, ability to create quality welds with minimized defects – weld porosity, for example. Just the same as the cavity in the mouth, weld porosity worsens your weld look and the repair is sometimes frustrating.

Porosity in welding occurs when a gas – often oxygen, nitrogen and/ or hydrogen, or a contaminant gets absorbed into the weld puddle. This fault would cause weak, hole-filled, bubbly welds that don’t meet code and can even make pieces of the project collapse. That's why there is no alternative but to redo such faulty welds. And it will be the best if welders can save that work by knowing how to prevent weld porosity. Below are 5 tips that may help with weld porosity prevention, especially during Mig (Gas Metal Arc Welding).


1. Keep It Clean

The material surface must be dry and clean. Oil, moisture, rust and grease are big enemy to welding. They can find ways to mix with weld puddle when the welding temperature rises, trapping gas which leads to bubbles as the material cools down.

Keep an eye on possible chemical reactions that could also cause porosity if your material gets coated with paint, zinc or other laminates. The trapped gas might be in T joints when you weld on both sides. Specially, before you begin aluminum welding, clean the outside layer of oxide.

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2. Check gas flow

Watch for the flow of shielding gas. You will have trouble if it’s too low or too high. The power of the flow is associated with the air quantity disturbed at the weld site that contaminant can mix with weld puddle.

3. Check equipment

Make sure there is no kink or leak to the hose, which can affect your shielding gas flow. Ensure the hose isn’t contaminated.

Check your gun liner to know whether it is clean and properly sized. Employ the contact tip of right size on your weld gun. Sometimes, the tip of your weld gun can be clogged, then make sure to check.

4. Maintain calm conditions

A breeze seems nice in a workshop that welding temperatures can surpass 2,500°F, but turns out to be bad for welding. Instead, keep calm conditions. Watch for strong currents and air flows, the arc length. If the gun is further away from your weld site, the gas shield can become weaker. This makes gas and air to seep into weld puddle and bubbles often appear.

5. Take it slow and steady

In Mig welding, the wire feed should seamlessly come off the reel. Check to see whether your wire feeding system has an easy-to-adjust brake and set the appropriate tension for the wire not to coast. When welding, take it slow and steady. Any haste can often induce weld porosity as the wire feed malfunctions can decelerate production.


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