Re: Problem solving

ArtMetal
Bramblebush


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Posted by Valerie on November 20, 1997 at 17:35:43:

In Reply to: Oxyacetylene Set-up posted by Valerie on September 17, 1997 at 13:18:58:

Oxyfuel Problems and How to resolve them

POPPING SOUND at the torch ( sometimes flame going out also) This is called a BACKFIRE. Causes of a backfire are:

Incorrect pressures at the regulator for the torch tip size

Loose connections at the torch or hose connections

Incorrect pressure adjustment at the torch valves

Dirty torch tip opening

Holding the tip of the flame too close to the metal

Sticking the filler rod into the inner cone of the flame

Welding in an inside corner joint with insufficient oxygen at torch

HIGH-PITCHED WHISTLE, VERY HOT TORCH HANDLE. This is called a FLASHBACK

This can be a very dangerous situation. When this happens, it means that the flame is traveling up inside the torch. Many times, you are still able to see a flame at the tip of the torch. The flame will still be traveling up inside the torch, through the hoses and into the regulators. If this happens, turn off the oxygen immediately at the torch valve. This extinguishes the flame in the torch (In extreme cases, the brass torch body becomes the fuel.). Next shut off the acetylene torch valve and then the cylinder valves. A flashback is caused by the same situations as in a backfire. Thoroughly check over your equipment before resuming work. If a flashback occurs again, notify your supervisor or find a qualified repair person to check it over.

BURNING THROUGH METAL RATHER THAN WELDING Possible causes:

Torch tip too large for the thickness of metal

Too much pressure at the regulators

Incorrect flame adjustment

Holding the torch in one place for too long

Incorrect flame-to-metal angle. If the torch is 90 degrees to metal, it will overheat

Metal may not be the type you think it is (might be copper or other metal)

METAL WILL NOT JOIN TOGETHER Solutions:

Get the pieces of metal hotter before adding the filler rod. The edges to be joined should be molten at the point where the flame is pointed before adding filler rod.

When the metal is just about molten, get the filler rod hot by holding it near the flame. Do not get it so hot that it drips onto the metal.

Filler rod is properly added to the joint by touching it into the molten puddle. Don't drip the filler metal onto the weld area. Add the filler to the front of the puddle.

WELDS ARE BRITTLE AND WEAK Welds are usually weak because of dripping the filler rod onto the metal to be joined and then "pushing" it around in an attempt to get a decent-looking weld. Another reason that the weld may be brittle is the type of metal or filler rod used. Another possible reason for weld brittleness if the type of flame used. An oxidizing flame creates a bubbly puddle and porous weld. Carburizing also makes it brittle.


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