Can you over heat a weld or metal in general?

[AliciaT]

So I have recently become the happy owner of an o/a set up. Love it.
I am doing quite good with my welds and am in process of making an anvil stand.

Anyways yesterday I was toying with different flames thinking
I could really get a good puddle with any of them but I found one that didn't work for me.

It was a neutral flame just very rich in both so I can only surmise it was to hot.

Instead of a nice molten puddle I could push around I got puddles that were boiling and ugly.
So clearly that did work wont try it again but what happened did I boil the metal? and is that bad?
I had no chance of welding with it as stuff was just happening to fast and I couldn't control the
puddle since it wasn't staying flat and smooth.

The fellow who has shown me the basics has been welding for 35yrs but as a farrier has only
needed it for quick applications so hasn't really studied it.

I am a farrier too but I want to be a blacksmith and farrier so need more info. :)

[Old N Rusty]

oh yes you most certainly overheat steel when gas welding and there is no practical cure for the bubbles that come out call it scrap and start over localise the heat do not let the whole piece get very hot and it will do right well good luck!

[macbruce]

If you stay in one place too long with the puddle it will begin to break down and spoil (bug holes). Normally you get the puddle established, add filler rod and move on..................................mb

[Steve H]

Bruce- good point. The coating on filler rod contains copper and trace elements which act to de-gas the puddle and help it settle down. I have noticed when Tig welding as well as oxy-acet that when you start getting porosity, adding filler before it gets too full-blown helps it fuse and can sometimes cure the porosity.

[AliciaT]

Okay I went out a did a bit more with a less rich flame and it was fine so I will just avoid that flame, and I do have a bit of a tendency to stall in one area so I will watch that.

thanks

[John B]

For welding you need a "neutral" flame, silver soldering and brazing, a "carburising" flame, which means nothing without an explanation, try here for basic info http://www.twi.co.uk/content/jk3.html there are also basic safety techniques and operation sequences to be followed when using O/A

The following is from a handout I give to students being introduced to gas welding here in the UK, regulations and terms may differ elsewhere.


Terminology

Snifting; The practice of opening and closing the cylinder’s valve quickly to remove any debris before fitting a Regulator

Regulator; A device fitted to the cylinder outlet to reduce the cylinder pressure to that required for welding, brazing or cutting (Fuel gas LH thread Oxygen RH thread)

Flashback Arrestor; This prevents a flame front (from a backfire) from reaching the cylinder

Backfire; Return of the flame into the cutter/torch, usually accompanied by a hissing sound or a bang

Pressure Relief Valve; Vents excess pressure from the regulator when system pressure exceeds a predetermined level

Hose assemblies; Used to connect the regulator to the cutter/torch hoses are colour coded to match the gas type

Non Return Valve; Also known as Hose check valve prevents reverse gas flow.

Cutter/torch/blowpipe; A piece of equipment that facilitates the mixing and control of the gases to perform a welding, cutting or brazing operation

Purging; The process of allowing the gas to remove any air or other gases present in hoses/torches

SAFETY
• Trained personnel only should use gas welding and cutting equipment.
• Always make sure cylinders are safely secured in an upright position
• Ensure hoses are in good condition and when in use kept tidily on the floor to reduce the risk of tripping over them
• Ensure working area is well ventilated (Carbon Monoxide poisoning and danger of explosion)
• Ensure working area and surrounds are clear of any flammable materials
• In the event of a Flashback, immediately turn off the Oxygen followed by the fuel gas at the cylinder valves and check for overheating, hot spots or vibrations if in any doubt call fire brigade and evacuate area, keep cylinders cool if possible (hoses or into a tank of water)
• Ensure no oil or grease is present in any parts of the equipment
• Wear protective clothing, gauntlets, and eye protection
• Keep fire extinguishers nearby, sand or water buckets
• Be aware of others nearby
• Use a spark igniter to light the torch


CONNECTING THE EQUIPMENT
• Remove covers on regulator mounting valves
• Check cylinder valves are clean and threads are in good condition, Snift the valve to remove any debris (Unless a hydrogen bottle, NEVER snift Hydrogen)
• Check threads and mating surface on the regulator are clean, check it is correct for the fuel being used, and that it can cope with the pressure in the cylinder
• Ensure the regulator Knob is fully unscrewed
• Connect the flashback arrestor to regulator outlet
• (For hoses with a bore greater than 6.3mm or longer than 3metres, it is recommended that; Non return valves fitted to the torch end of the hose, and a flashback arrestor connected to the regulator outlet that has the following functions Flame arrestor, temperature activated cut off, pressure activated cut off
• Connect hose to flashback arrestor outlet, connect non return valve (if needed) to the torch end, connect torch, ensure fittings are tight and secure
• Select and fit correct nozzles/cutter head is fitted, and ensure control valves on torch are closed
• Slowly open each cylinder valve (Acetelyne only needs 1 full turn maximum) and adjust its regulator to the correct reading for the operation to be carried out. DO NOT STAND IN FRONT OF THE REGULATOR WHEN OPENING CYLINDER VALVES
• Check the system for leaks using soapy water, then recheck the pressure setting with the gas flowing
• Purge each hose to ensure the hoses and torch are primed with gas. Ensure this is done in a well ventilated place away from ignition sources. Purging should be carried out after each period of non use.

OPERATING PROCEDURES

Different thicknesses of materials require different sized nozzles, there are charts that advise on these, and there should be references in the boxes the equipment originally came with, the proceedure is the same for all welding torches, cutting torches differ slightly in use in the fact you need two settings for the Oxygen supply, (preheat and burn, preheat is similar to welding pressures, burn is much greater and kicks in when lever on torch is depressed/opened)

Lighting up
• Check all valves on the torch are closed
• Open the fuel gas knob (Red) and light the gas using a spark lighter and adjust the gas flow until the flame just stops smoking
• Open the oxygen knob (blue) and adjust the flame to a neutral condition
• If using for cutting, depress the cutting lever and adjust the flame as necessary

Shutting down
• Close the fuel gas control on the torch
• Close the oxygen gas control valve on the torch
• Close both cylinder valves
• Reopen both control valves on the torch to vent the gas in the system
• When the system is fully relieved of pressure, unscrew the regulator gauge’s pressure adjusting knobs, and close the gas control knobs on the torch
• Store equipment safely

Practice is needed and work safe, potentially you have a bomb next to you and under your control.

[HWHII]

You have 3 types of oxy-acetylene flames, neutral, oxydizing, and carburizing. Your netral flame has equal amounts of oxygen and acetylene and is prefered for welding. A oxydizing flame has slightly more oxygen so there is a feather that extends beyond your inner cone and this flame is generaly use in brazing applications and finally we come the carburizing flame and sometimes called a reducing flame which burns more acetylene.The feather is reduce to inside the inner cone. This flame helps remove oxygen from iron oxides that may be present. In other words it works better on rusty steel.

If you are burning up your material you might have to large of a tip. Your working line presures sould be 5 psi for your acetylene 7 psi for oxygen. You should have a neutral flame for welding clean steel and cutting.

[John B]

IMHO you must have different methods over in the US, here we balance pressures for neutral flames, excess oxygen(oxidising) is not as effective as a carburising flame for brazing/silver soldering, too fierce.

But I will agree to the tip size comment, they should also be kept well cleaned.

Each to their own and what works for them.

[clinton]

You are correct John- a carburizing flame is used for brazing- more acetylene and equal pressure, but 2 psi will not make much difference, as long as you have a neutral flame you can weld.
The question that was asked here had to do with overheating a weld or metal, and in my opinion yes you can, but I believe for the project that you are working on will be fine, it does not sound like you continued trying to weld when you saw that it was not working well. Your best quality control with any welding is a visual inspection- look at the weld- is there lack of fusion? porosity? undercut? cold lap? If you see any of these defects you should grind them out and re-weld. An anvil stand does need to be strong it will be put through lots of abuse, I prefer a tripod myself with the legs rather straight not angled too much

[HWHII]

You are correct John- a carburizing flame is used for brazing- more acetylene and equal pressure, but 2 psi will not make much difference, as long as you have a neutral flame you can weld.
The question that was asked here had to do with overheating a weld or metal, and in my opinion yes you can, but I believe for the project that you are working on will be fine, it does not sound like you continued trying to weld when you saw that it was not working well. Your best quality control with any welding is a visual inspection- look at the weld- is there lack of fusion? porosity? undercut? cold lap? If you see any of these defects you should grind them out and re-weld. An anvil stand does need to be strong it will be put through lots of abuse, I prefer a tripod myself with the legs rather straight not angled too much

I am sorry guys. I have to stand by what I read. I teach welding and the text book we use Welding Principles and Practices states a slightly oxydizing flame is prefered for brazing.

[doc]

Hi John and HWHII you are both right. It depends on what type of brazing you are doing .
check out this link http://www.google.com/url?sa=t&source=web&cd=2&sqi=2&ved=0CCgQFjAB&url=http%3A%2F%2Fwww.embraco.com%2FDesktopModules%2FDownloadsAdmin%2FArquivos%2FHjmk2nyG9t.pdf&ei=EHyWTaXWGtG20QGvutjxCw&usg=AFQjCNFxOGJ7CZkTFkkFzEHmcARkl2uDEg&sig2=q90nzgSnc7dXeyB8Wj3cog

[John B]

Thanks for that clarification Doc, Many years ago I had to make some curved tube brass handrails and got a stress crack in them on the final bend, like all new experiences I had to experiment and did in fact end up with a slightly oxidising flame to complete the task, adjusting the flame until it worked on a couple of samples, using a sliver of the original tube as a filler rod and saliva reduced borax as the flux.

Not sure whether I welded the piece or brazed it, I would consider it welded as the metal fused and joined as opposed to uniting ... but thats probably a whole new thread. I was told at the time (by "experts")I couldn't weld brass, but you have to try don't you? Cant scrap a weeks work just 'cos someone says it can't be done. Very slight discolouration at the time, but 30 years on it still looks well and I have great difficulty in making out where it was repaired.



Anyway its all good stuff, and hopefully some will benefit by it, that was the point of putting in the handout details as AT had already discovered the answer to the original post.

[ciladog]

Your netral flame has equal amounts of oxygen and acetylene and is prefered for welding.

In the complete combustion of acetylene there are two molecules of acetylene to five molecules of oxygen (2 H2C2 (g) + 5 O2 (g) --> 4 CO2 (g) + 2 H2O (g)) so not equal just neutral.

[Old N Rusty]

wow some brains here! for T.I.G. bubbles ( sugar) as we pipe welders called it, a tiny drop of 308 ss cures it AND it will x-ray clean, not a ASME approved procedure at all!and dont be letting cats out of bags by bragging to the welding inspector it works is all we care after all i dont live near that plant and the paycheck is ALL i care about. we all carried a short piece of 308 ss tig wire in shirt pocket. ssssshhhh! PAX

[Nakedanvil - Grant Sarver]

Old and Crusty: yeah, been there, done that. That sure calms down the puddle.

Back to the OP, get moving and keep moving! And don't look back!

[Old N Rusty]

Mr. Grant i figgured you might have a bit of experience in the welding field, heck as old as we are, we been there, and done that, so many times a gas weld in the overhead position dont fase us at all. I heard on anvilfire you got a little shop too, with some small pieces of equipment.

[Ten Hammers]

My nickles worth. Tip selection is the key but proper setup of pressures is the absolute starting point. I weld single stage OA with a dillon torch and have for I guess 10 years. Prior to that I used whatever I had ( Victor mostly). The Dillon torch gives me absolute control of the flame with proper tip selection. Setup is simple. Roughly 5/8 feather with the number 3 tip. I could care less what the regulators say ( healthy good regulators with arrestors ). Normally around 4psi per each. I gas weld a fair amount of forgings with scale on them. I also weld new metal edge fillet welds as well as tee and other configurations. Yes I sometimes wire weld a piece and then heat that piece to torch welding heat, blend a bit and then forge that weld ( 2 steps to the anvil). My experience has shown that yes you can overheat but YES you can underheat. My hearing is shot. This said the flame should sound pretty close to the same with each tip change ( the more noise, the more oxygen to remove until you have a true neutral flame). I use a Smith gas saver. Pick it up and light the torch. Your eyes and ears should tell you that you have a proper flame. During the weld you may hear ( if you can hear) the weld in low gas pressure ( meaning that you have a hot tip and WILL BACKFIRE ). You may not hear this, you may only experience it ( if that makes sense). Proper gas ( fuel) pressure keeps the tip cool. Learn your own specific tip selection feather perameters and live within them. ABSOLUTELY practice proper safety procedures. If you are not trained, get trained. Oxy fuel welding is the way I do most things but I also MIG and stick and forge weld. I should have a scratcher for the stick welder simply because stainless welds nicer with that technology ( TIG also has a much lower heat signature and would be handy for me in that regard ). I do weld stainless occasionally with the torch. I do hard solder a few things ( Harris 1200º ) but very few. By the way CLEAN TIPS are also the trick. I have gas welded rusty tractor wheels ( half soled on some 12 ga to a rusted out place ) with absolute success. If you are boiling I might suggest back to setup and different tip selection. Me, expert ? Not a chance. I only have my experience. Properly setup, 14 ga 90º outside fillet welds lay down like a saddle on a sow. Experienced tig welders wonder how you can do that without electricity. Really it is quite simple. Yes I now work second shift for the man. My shop time is limited. I do yes sometimes use the big tip on the torch for a forge when setting up some tooling or a new R&D piece. Yes I sometimes use the torch to light the solid fuel forge. I have a couple of weed burner heads for LP that I sometimes use for heat or finish work but nothing will ever replace OA in my shop ( or the gas saver ). No M'am, I don't crawl under horses. Get yourself some 16,14,12,10 and 7 ga previously cut steel pieces. Lay them 90º ( same ga to same ga ) and weld the outside fillets. Try some butted seams ( leave a smidge of a crack). Get some coat hanger for filler. Try some unplated brace wire. Burn some gas. Your instructor sounds like a smart guy. Listen to him. As time goes on, buy some E70-S6 welding rods for filler. Get some shade 5 glasses that feel good and protect you. Weld uphill. Weld downhill. Weld horizontally. Weld through mill scale. Grind prep some pieces. Weld rust. Have fun. The professionally trained and tested ( yes I have pulse welded and production welded thousands of pieces for the man in years past ) of the crew here will also have some suggestions for coupons to improve your skills. Cold weather is tough on regulators. Take very good care of your regulators. Sorry for being so windy.

[Ten Hammers]

Will see if I can fix the multipost. B)

[HWHII]

Sorry folks. Haven't checked this thread in a while. Thanks Doc for the info. Ciladog I stand corrected, not sure if I can remember the chemical equations though. Good stuff there.