Rusty4242
Bronze Member
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
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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.