Rusty4242
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bought a splitter blade from northern tool and they want me to use a low hydrogen rod to weld it onto the splitter beam with. why won't 6011's do? thanks, Larry
6011 instead of 7018
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Farmerford
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Moisture in the weld puddle introduces hydrogen which reacts with molten metal that has a high carbon content and leads to embrittlement of the weld. "Hydrogen embrittlement" to be more precise, or hydrogen cracking.
The splitter blade probably has more carbon (for strength and hardness) than typical structural steel, which may have only 0.10 to 0.20% carbon. Low carbon structural steel does not have enough carbon for hydrogen embrittlement to be a serious problem.
The flux on 6011 electrodes requires moisture to function properly. That is why it can generally be stored in a less than airtight container. Even the small amount of moisture in the 6011 flux produces enough hydrogen to cause embrittlement in high carbon steel.
7018 electrodes, in contrast, have a "dry" flux. That is why they have to be stored in air tight containers. In critical production work, the welder may be furnished fresh electrodes every few hours so that they are not exposed to the atmosphere for very long before they are used.
So, to avoid hydrogen embrittlement, high carbon steel is welded with low hydrogen (ie, low moisture) electrodes.
If it is a non-critical use, there is no great risk in trying 6011. You can reduce the risk of hydrogen embrittlement by preheating the pieces and by covering the weldment with sand to slow the cooling. Preheating to 300-400 deg F will not hurt. Since 6011 electrodes usally absorb moisture from the air (which they do not need since moisture is in the original material), you might reduce the hydrogen by cooking the 6011's in the oven (I forget the temperature and time; it is on Lincoln's website).
But can't you pick up a small package of 7018 at Lowes for a few dollars. They should be sealed and fresh, and if you use them a few hours after opening they should do fine.
The splitter blade probably has more carbon (for strength and hardness) than typical structural steel, which may have only 0.10 to 0.20% carbon. Low carbon structural steel does not have enough carbon for hydrogen embrittlement to be a serious problem.
The flux on 6011 electrodes requires moisture to function properly. That is why it can generally be stored in a less than airtight container. Even the small amount of moisture in the 6011 flux produces enough hydrogen to cause embrittlement in high carbon steel.
7018 electrodes, in contrast, have a "dry" flux. That is why they have to be stored in air tight containers. In critical production work, the welder may be furnished fresh electrodes every few hours so that they are not exposed to the atmosphere for very long before they are used.
So, to avoid hydrogen embrittlement, high carbon steel is welded with low hydrogen (ie, low moisture) electrodes.
If it is a non-critical use, there is no great risk in trying 6011. You can reduce the risk of hydrogen embrittlement by preheating the pieces and by covering the weldment with sand to slow the cooling. Preheating to 300-400 deg F will not hurt. Since 6011 electrodes usally absorb moisture from the air (which they do not need since moisture is in the original material), you might reduce the hydrogen by cooking the 6011's in the oven (I forget the temperature and time; it is on Lincoln's website).
But can't you pick up a small package of 7018 at Lowes for a few dollars. They should be sealed and fresh, and if you use them a few hours after opening they should do fine.
allengentry
New member
6011 DOES NOT require excessive moisture to "function properly".
6011 is MORE TOLERANT of moisture, and should be reconditioned if the manufacturer recommends it if exposed to more than 70% humidity.
7018 is less tolerant of moisture due to the iron content/flux chemistry. It needs to be stored between 250-350*F 24/7.
Moisture content/contamination of the flux has little or a lot of impact in the amount of hydrogen introduced into the base metal. The flux/filler metal chemistry also determines that.
The splitter blade absolutely has more carbon than A36, and likely is heat treated as well.
If you want to weld this properly, preheat both your splitter blade and base material you are welding to. In order to give you a proper pre-heat, I need to know the thickness of the base material.
And ABSOLUTELY use 7018.
60XX will result in hydrogen being introduced into the base metal and weld, and will subsequently crack and break.
Allen
6011 is MORE TOLERANT of moisture, and should be reconditioned if the manufacturer recommends it if exposed to more than 70% humidity.
7018 is less tolerant of moisture due to the iron content/flux chemistry. It needs to be stored between 250-350*F 24/7.
Moisture content/contamination of the flux has little or a lot of impact in the amount of hydrogen introduced into the base metal. The flux/filler metal chemistry also determines that.
The splitter blade absolutely has more carbon than A36, and likely is heat treated as well.
If you want to weld this properly, preheat both your splitter blade and base material you are welding to. In order to give you a proper pre-heat, I need to know the thickness of the base material.
And ABSOLUTELY use 7018.
60XX will result in hydrogen being introduced into the base metal and weld, and will subsequently crack and break.
Allen
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SPYDERLK
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Farmerford: Wow, very interesting! From the sound of it maybe you can answer this. When you dry rods by heating and the flux cracks, does that mean that they were too wet? - or that they were dried too quickly/too hi T? Can you get good slow drying with dessicant with [monitored] less than 5% H @ ambient T?
Thx, larry
Thx, larry
SPYDERLK
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My experience is that I get better welds with 6011 rods stored at 50%H than at 5%. Perhaps you know the reason for this.allengentry said:
How does a dry 6011 introduce hydrogen? Is hydrogen inherent in the rod coating independent of water?
Magnesium ribbon can burn underwater by decomposing water. It seems to me that an electric arc is hot enuf to do this as well, thereby freeing hydrogen from a moist coating......??
larry
I will add, as allengentry said, ABSOLUTELY use 7018 and do at least 3 passes (assuming the blade is approximately 1 inch thick), let it cool some after each set of passes, you need pretty high heat. The 7018 welds will actually give to a bending force and act like spring steel, one could weld a leaf spring with this rod.allengentry said:
here is something for everyone.
6011 rods dipped in 30w motor oil for underwater welding. (DC)
source = Oceaneering International
exposed underwater welding is rarely used today, only for emergency temp repairs. reason is the welds qwench to rapidly increasing brittleness. Habitat welding is the norm, but bolt on repairs are the most common.
EDIT: Do Not Jump into the pool and try this. Get proper training, I did!
Rhett
6011 rods dipped in 30w motor oil for underwater welding. (DC)
source = Oceaneering International
exposed underwater welding is rarely used today, only for emergency temp repairs. reason is the welds qwench to rapidly increasing brittleness. Habitat welding is the norm, but bolt on repairs are the most common.
EDIT: Do Not Jump into the pool and try this. Get proper training, I did!
Rhett
Last edited:
allengentry
New member
SPYDERLK said:
Allright, I'll give the lengthy explination after dinner. It's complex. Genreally, my first statement is factual, but not 100% correct. You will see when I explain.
I give you guys credit, you understand way more than most boards, which is good.
Went thru almost the same thing as you are doing about a month ago.
Refer back to page 5, " Welding Help Needed". There's picts there for what 1 pass, 6013 and no preheating will getcha.
These folks gave very good advise at that time and I followed it as closely as I could. Preheating, 7018 and multiple passes. Cool slowly.
As a postscript, I split two more face (24") cord yesterday with mine and is holding fine. Some knarly maple and cherry.
Refer back to page 5, " Welding Help Needed". There's picts there for what 1 pass, 6013 and no preheating will getcha.
These folks gave very good advise at that time and I followed it as closely as I could. Preheating, 7018 and multiple passes. Cool slowly.
As a postscript, I split two more face (24") cord yesterday with mine and is holding fine. Some knarly maple and cherry.
Farmerford
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Allen and Gizmo make several good points, but I don't fully agree with them on a couple.
Hydrogen is indeed present in certain fluxes. 6010 and 6011 have a high cellulose (wood powder/flour) flux because at welding arc temperatures the cellulose produces a large quantity of gas that both completely shields the weld pool against atmospheric contamination and makes the arc penetrate more deeply due to the blowing effect of the gas and the hydrogen produced by the cellulose (which increases the strength of the arc). These fluxes have about 5% moisture which is necessary for the flux to function properly.
6013 replaces a large part of the cellulose in 6010/6011 with more rutile (titanium dioxide), and does not penetrate as deeply. The flux has about 2% moisture. The reduced cellulose and moisture in 6013 produce about only half the hydrogen as the 6010/6011.
7018 uses a primarily lime flux with iron powder to furnish more weld metal. It has virtually no moisture and the lime flux produces about 1/8 the hydrogen of the combined moisture and cellulose flux of 6010. Unfortunately the lime flux readily absorbs moisture from the air, and will absorb enough moisture to increase the hydrogen available to above the limits for embrittlement of high carbon steels.
This was demonstrated to me once in the 1960's by a Lincoln instructor. He took two pieces of mild steel and two Lincoln 7018 electrodes (I think they were called "Fleetweld Blue Dot" back then). One electrode had been in proper storage (250deg F, I think) and the other had been lying on the bench in the open shop for several days. He ran a heavy bead on each piece and doused it in water instantly. The he put both pieces in clear oil (mineral oil, I think). The bead made with the 7018 that had been exposed to the air for several days begin to emit small bubbles and continued to do so for quite some time. The bead made with the "fresh" rod emitted no bubbles. He explained that the gas bubbles were hydrogen resulting from the decomposition of water into hydrogen and oxygen as it was exposed to the arc. That was proof enough for me of the need to properly store low hydrogen electrodes if they were going to be used on critical work.
It will make the professional welders cringe, but before I use old 7018 electrodes that I know are almost certain to have absorbed moisture on medium to high carbon steel (like fork lift forks, scraper blades, ), I stick the electrode and let the weld current flow through it until it begins to steam. That's not scientific, but it seems to work for my jackleg welding.
I was trying to show the original poster how he might get by with cellulosic flux rods (6011) on his splitter wedge. My experience with Northern Tool suggests that the wedge is not heat treated because of the significant additional expense and because the subsequent welding would be likely to remove the heat treatment in the heat affected zone. If the wedge is 0.50% carbon (typical for an ax-head), he may be able to use 6011 rods if he allows the weld to stay above 450 deg F long enough for much of the hydrogen to diffuse out of the weld. At 450deg F and above the hydrogen is able to diffuse through the weld metal fairly rapidly. By preheating to around 400 deg F (which will not materially affect the heat treatment, if any, if done for only several minutes) the weld itself, particularly with the multiple passes Allen and Gizmo recommend, can stay "hot"long enough for much of the hydrogen to diffuse and escape. We were tought to make the cap pass a wide weave for the very purpose of keeping the underlying weld metal hot for a longer period to allow more hydrogen to escape. Recall that I suggested to the original poster that the cover the completed weldment with sand. That was to slow the cooling.
Not long ago when welding brackets onto some 3" X 6" forklift forks I left a propane weed burner on them to maintain the weld at (about) 500 deg F for about 30 min. I used 6010 for the root pass to get the penetration I needed, and then used 7018 for the hot passes and cap (with a "temper bead"). According to the charts, the hydrogen in the root pass diffused up through each of the upper weld layers during the welding process (because of the elevated temperatures) and the post weld heating allowed the residual amounts to diffuse out of the cap. I guess time will tell.
As Allen and Gizmo correctly point out, fresh 7018 rod produces the strongest weld, and preheating is advisable for several reasons: it drives any moisture out of the metal, its reduces stress cracking from uneven cooling, it reduces the chance of forming large needle martensite in the HAZ, and it keeps the weld metal above 450 deg F for longer to allow more hydrogen to diffuse out of the weld.
Spydylk: I am not sure why the flux sometimes cracks. I seems most likely that we get it too dry. It might also come from differential expansion. I suspect it is initially put on the rod as a slurry and then dried to the required moisture content. The rod and slurry are probably at room temperature. But when drying at 400-700 Deg F (depending on the material) the metal rod may expand more than the flux and create stress concentrations (particularly axially) that cause the cracks. Slow heating might allow the stresses to build more slowly and to dissapate without cracking.
As you have probably guessed, I use the rods as long as at least a reasonable amount of the flux is left, particularly if no is going to see the weld.
Rhett: 30W motor oil for underwater welding. Wonder what that does. If I am out of cutting/chamfering rods and must cut or gouge metal with the stick welder, I use 6010 that has been soaked in water. All that extra moisture adds to the blowing effect that gets rid of the molten metal
Hydrogen is indeed present in certain fluxes. 6010 and 6011 have a high cellulose (wood powder/flour) flux because at welding arc temperatures the cellulose produces a large quantity of gas that both completely shields the weld pool against atmospheric contamination and makes the arc penetrate more deeply due to the blowing effect of the gas and the hydrogen produced by the cellulose (which increases the strength of the arc). These fluxes have about 5% moisture which is necessary for the flux to function properly.
6013 replaces a large part of the cellulose in 6010/6011 with more rutile (titanium dioxide), and does not penetrate as deeply. The flux has about 2% moisture. The reduced cellulose and moisture in 6013 produce about only half the hydrogen as the 6010/6011.
7018 uses a primarily lime flux with iron powder to furnish more weld metal. It has virtually no moisture and the lime flux produces about 1/8 the hydrogen of the combined moisture and cellulose flux of 6010. Unfortunately the lime flux readily absorbs moisture from the air, and will absorb enough moisture to increase the hydrogen available to above the limits for embrittlement of high carbon steels.
This was demonstrated to me once in the 1960's by a Lincoln instructor. He took two pieces of mild steel and two Lincoln 7018 electrodes (I think they were called "Fleetweld Blue Dot" back then). One electrode had been in proper storage (250deg F, I think) and the other had been lying on the bench in the open shop for several days. He ran a heavy bead on each piece and doused it in water instantly. The he put both pieces in clear oil (mineral oil, I think). The bead made with the 7018 that had been exposed to the air for several days begin to emit small bubbles and continued to do so for quite some time. The bead made with the "fresh" rod emitted no bubbles. He explained that the gas bubbles were hydrogen resulting from the decomposition of water into hydrogen and oxygen as it was exposed to the arc. That was proof enough for me of the need to properly store low hydrogen electrodes if they were going to be used on critical work.
It will make the professional welders cringe, but before I use old 7018 electrodes that I know are almost certain to have absorbed moisture on medium to high carbon steel (like fork lift forks, scraper blades, ), I stick the electrode and let the weld current flow through it until it begins to steam. That's not scientific, but it seems to work for my jackleg welding.
I was trying to show the original poster how he might get by with cellulosic flux rods (6011) on his splitter wedge. My experience with Northern Tool suggests that the wedge is not heat treated because of the significant additional expense and because the subsequent welding would be likely to remove the heat treatment in the heat affected zone. If the wedge is 0.50% carbon (typical for an ax-head), he may be able to use 6011 rods if he allows the weld to stay above 450 deg F long enough for much of the hydrogen to diffuse out of the weld. At 450deg F and above the hydrogen is able to diffuse through the weld metal fairly rapidly. By preheating to around 400 deg F (which will not materially affect the heat treatment, if any, if done for only several minutes) the weld itself, particularly with the multiple passes Allen and Gizmo recommend, can stay "hot"long enough for much of the hydrogen to diffuse and escape. We were tought to make the cap pass a wide weave for the very purpose of keeping the underlying weld metal hot for a longer period to allow more hydrogen to escape. Recall that I suggested to the original poster that the cover the completed weldment with sand. That was to slow the cooling.
Not long ago when welding brackets onto some 3" X 6" forklift forks I left a propane weed burner on them to maintain the weld at (about) 500 deg F for about 30 min. I used 6010 for the root pass to get the penetration I needed, and then used 7018 for the hot passes and cap (with a "temper bead"). According to the charts, the hydrogen in the root pass diffused up through each of the upper weld layers during the welding process (because of the elevated temperatures) and the post weld heating allowed the residual amounts to diffuse out of the cap. I guess time will tell.
As Allen and Gizmo correctly point out, fresh 7018 rod produces the strongest weld, and preheating is advisable for several reasons: it drives any moisture out of the metal, its reduces stress cracking from uneven cooling, it reduces the chance of forming large needle martensite in the HAZ, and it keeps the weld metal above 450 deg F for longer to allow more hydrogen to diffuse out of the weld.
Spydylk: I am not sure why the flux sometimes cracks. I seems most likely that we get it too dry. It might also come from differential expansion. I suspect it is initially put on the rod as a slurry and then dried to the required moisture content. The rod and slurry are probably at room temperature. But when drying at 400-700 Deg F (depending on the material) the metal rod may expand more than the flux and create stress concentrations (particularly axially) that cause the cracks. Slow heating might allow the stresses to build more slowly and to dissapate without cracking.
As you have probably guessed, I use the rods as long as at least a reasonable amount of the flux is left, particularly if no is going to see the weld.
Rhett: 30W motor oil for underwater welding. Wonder what that does. If I am out of cutting/chamfering rods and must cut or gouge metal with the stick welder, I use 6010 that has been soaked in water. All that extra moisture adds to the blowing effect that gets rid of the molten metal
Nice Farmerford,
I store my rods in an older aluminum (inside and out) ice chest. I mounted a humidistat with 120vac contacts in the chest along with a light socket and made an airtight hole through the wall for a wiring connection so I can plug the chest into 120vac. I installed a 25w light bulb in the socket and when humidity gets too high the bulb comes on, goes off when the humidity is just right. Don't want to be buying silver and stainless rods too many times.
I store my rods in an older aluminum (inside and out) ice chest. I mounted a humidistat with 120vac contacts in the chest along with a light socket and made an airtight hole through the wall for a wiring connection so I can plug the chest into 120vac. I installed a 25w light bulb in the socket and when humidity gets too high the bulb comes on, goes off when the humidity is just right. Don't want to be buying silver and stainless rods too many times.
JL Sargent
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Not for tool steels I suspect, but I weld structural all the time while working off a service truck. 6011s are really hard to beat in this setup. If welding larger sections I will run a root pass of 6011 and then subsequent passes with the 7018.
Log spitter wedges: Ten years ago I fabbed a wedge out of structural scrap. Still works fine after 20+ cords of mostly Hickory wood. No need for tool steels on a splitting wedge.
Log spitter wedges: Ten years ago I fabbed a wedge out of structural scrap. Still works fine after 20+ cords of mostly Hickory wood. No need for tool steels on a splitting wedge.
