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Porosity in welding is a result of dissolved gases or gases released during the welding process, being trapped in the metal when there is insufficient time to escape prior to solidification. If in the shape of rounded holes, the gas is called spherical porosity or just porosity. However, if elongated the terminology is wormholes or piping. Causes of porosity are;
- excessively long or short arc length
- welding current too high
- insufficient or moist shielding gas
- travel speed to fast
- base metal covered with oil, grease, moisture etc.
- wet, unclean or damaged electrodes.
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What is girth weld?
circumfrencial weld is sometimes referred to as Girth weld. its just another term.
Can you weld steel to steel?
Yes, you can weld steel to steel. You can use steel welding rod.
What is a weld symbol?
A weld symbol is the shape drawn on a Print to tell the welder: how to prepare a welding joint, what process can be used to weld (mig, tig, arc, etc) what filler rod to use, how wide and long the weld should be, how to deal with the weld after your done (grind flush, brush clean, or nothing) and a million other things.... Its a tool that design engineers use to communicate what the weld needs to be to meet their design specifications.
Why is it important to strike the arc only on the weld joint?
why is it important only to strike the arc in the weld joint
What is definition of the under run in filet weld?
A fillet weld in any single continuous weldmay underrun the nominal fillet weld size specified by2 mm [1/16 in] without correction, provided that theundersize portion of the weld does not exceed 10% of thelength of the weld. On the web-to-flange welds on girders,underrun shall be prohibited at the ends for a lengthequal to twice the width of the flange.
What does porosity mean in welding?
Porosity is the formation of bubbles in the weld.
What is porosity in welding applicaton?
Porosity is nothing more than bubbles in the weld. Surprisingly a weld can contain quite a bit of porosity without affecting the strength.
What is high wind velocity can cause porosity in weld?
hardiflex
What should the welder watch if the view of the weld is obstructed by the shielding gas nozzle?
Porosity
What are the welding defects in sheet metal?
Porosity is the most common weld defect. For beginners don't rule out lack of penetration and non-compatible welding rod or filler wire. It all depends on how the weld failed if it has. Proper prep and preheat is required in many types of welding. So a little more detailed question can help me give you a more detailed answer. Trapped slag is also a common problem. It creates a void in the weld. Although porosity is the most common defect some porosity doesn't necessarily affect the weld strength.
Where does silica come from when tig welding carbon steel?
Silicon is added to the tig rods in production. Use a gas weld rod which does not have the silicon and the weld will be full of porosity.
If electrode use in welding has moisture what effect will it have on the weld?
Electrodes with too much moisture may lead to cracking or porosity.
What is porosity on metal welding?
Weld porosity is gas formations that did not escape prior to the weld solidification. These gases can be formed from water (which breaks down to hydrogen and oxygen atoms), oil, paint, rust or many other contaminants. The welding contamination can be on your welding materials as well as on the base metal (damp welding electrodes, etc.).
What is 4g welding?
4G is a welding position. The '4' means the weld is to be made in the overhead position. The 'G' means the weld is a groove weld.
What is the difference between premeability and porosity?
The word is spelled 'Permeability'. Porosity means something can take water into itself but Permeable means it will allow water to pass through it
How is porosity caused in welding?
Hi porosity is the gas pores (or) gas pocket travel deep in the solidified weld bead. Major causes $ Inadequate shielding gas $ Poor welding technique $ Damaged welding accessories $ Natural effects like wind flow
What is submerged arc welding?
Sub arc welding is a process in which the welding actually occurs while submerged under a layer of flux. Not only does this prevent oxygen from entering the weld and thus porosity, but it also keeps the dangerous arc from sputtering and spattering from the weld.
