what is the purpose of the use of a low hydrogen rod? does the low hydrogen content make it flow better?
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what is the purpose of the use of a low hydrogen rod? does the low hydrogen content make it flow better?
Hydrogen is an enemy of welding. Steel and hydrogen have an affinity for one another. The result is called Hydrogen embrittlement. The effect that you will normally see form hydrogen introduction into the weld is sudden failure or cracking.
Water as we all know is loaded with hydrogen. Moisture in certain rods causes a lot of issues, when the hydrogen is broken down into its elemental form through electrolysis via the welding arc, it will get trapped into the weld and cause problems.
7018's are considered low hydrogen due to their manufacturing technique and metal composition. These are exceptionally smooth welding rods capable of beautiful welds and are strongly joined.
However, lo-hi rods such as the 7018 are only truly low if they are kept from moisture and in a rod oven until they are ready to be used. Typically 7018's will only be low high for about 8 hours outside the oven.
The paper boxes and platic boxes that so many lo-hi rods come in are NOT designed to keep moisture out. Tedius prebaking and drying out of the rods must be done to restore the Lo-hi properties. I don't recommend buying them in this form...although they will weld fine, you don't get the lo-hi benefits. Buy only sealed metal cans. Typical rods like this are found in the Lincoln Excalibur series. Once the can is opened the rods must be used within 8-10 hours or put into a rod oven for long term storage.
A 7018 is a good choice for a beginner as it welds smooth and nearly as flawlessly as a 6013 or 7014 rod. But it can be difficult and like to stick from time to time as well.
WHAT??? So 7018 used in pipeline welding is only for beginners??? Somebody is smoking crack or I need to start smoking it too make sense of this comment!
Performance didn't say 7018 are only for beginners. He said that they are good for beginners.
I would say that he pointed out that they are best for experts because average joe's don't have rod ovens.
I have seen moisture resistance 7018 rods advertised but I haven't used them or talked to any one who has. I also don't know how moisture resistant they are.
Eric
E7018-1 h4r is a very low hydrogen rod. The 4 is for the ml's of difussable (whatever that means...I believe it is referring to actual H20) hydrogen in 100 grams of weld metal, which is the lowest rating. The r is for moisture resistant.
A r rod is good for a 10 hour shift out of the oven or fresh from the can. A regular 7018 is good for only 2.
No, I wasn't trying to say a 7018 is for beginners only.
I was saying it is a good rod for a beginner to weld with. Even if he or she cannot provide a suitable storage environment for the rods... I.E. anything that comes from a box or plastic sleeve, will still be good to make good "looking" welds. The manipulation will remain basically the same whether the rod is dry or not. The only thing different will be the end strenth of the weld and the possibility of hydrogen cracking in the root of the weld.
Ah thanks for clarifying. Guess I don't need to smoke crack now!
Please do not smoke crack, weld cracks.
Glad you guys got into this little debate. My son wants to TIG in the morning and I thought I would throw a little MMA in there for fun. This reminded me to throw some (yes) 7018 in the oven for a bit. Since it is new to him, I think the 7018 is good for him to start. Maybe a couple 6011 or 6010 for fun as well.
By using an oven, is the water content you're trying to get rid of in the rod or flux?
I was just wondering if I could just knock the flux off my 7018 and use it for TIG?..or do I still have to put it in the oven?
The moisture gets in the flux. The oven will dry them out.
You are trying to keep out the moisture. But rebaking rods that have been wet is ticklish at best....Many times what you have happen is that the rebaked flux will fall off with the slightest contact.
No, don't reuse 7018 for tig. Tig rods have special deoxidizers in the rod that make them suitable for use in tig. Don't use it unless you are practicing, and then, you probably won't get the same kind of results. Now, Mig wire yes, you probably could use it since it is very similar. But I would not use STick electrodes without the flux, not 7018 at least. (I have used cast rods to stick a little bit of cast back together after knocking the flux off, but that is another ball of wax).
OK, Got about 20 lbs left in the can and put it in the oven last night. Brought it up to 300* for a while and turned the oven off. I'll test it today.
Rebake must be done higher than that or no good. Must reach about 600 degrees. This is NOT and endorsement of their products, but you can see what I mean. This is helpful and accurate info, even if it is on a commercial site selling ovens. http://www.keenovens.com/articles/7018-storage.htm
Read parts 1 and 2
I read the keen article and the guy is absolutely clueless when he says a home oven needs a fire extinguisher to go up to 600 degrees. It appears the author doesn't know that most modern home ovens are self cleaning and will reach well over 900 degrees in self cleaning mode and that the self cleaning ovens have an interlock that will not let you open them above 600 degrees.Quote:
Originally Posted by performance
He is talking about toaster ovens I believe, as many of them are what is used to rebake rods. At least from what i took it to mean.
be it 6010 7018 6012 6013 all rod is manufactured using the same core wire the only difference is the flux coatingQuote:
Originally Posted by jtybt
600 deg some are 800 deg and the time in oven depends on if its 70 80 90 series rod i doubt your toaster oven is going to hit 600-800 degrees mind you these are rebake temps and not maintiance temps and can only be rebaked one time as per aws codeQuote:
Originally Posted by performance
I guess things have changed. The 60 and the 70 is in thousands of pounds of tensile strength.Quote:
Originally Posted by Wookie
To store my rods I'm cheap so I open a can of rods and put them in a vacuum sealer bag.
The packs are from 5 to 25 rods.
I roll out about 5-6 inches longer than the rods and seal one end for the bottom. Then place 5-25 rods in a column and use my temp controlled solder iron at 445 degrees and seal next to the first column then add the next 5-25 rods and do the seal job till the bag is full about 4-6 columns then seal the top entry.
They won't vacuum seal well but seal as individual sleeves, need 5 rods cut that column open and so on.
It takes a while to do but doesn't come close to the cost of 10-50 pounds of rod!!
Thanks
dwdw
Wookie,Quote:
Originally Posted by Wookie
I can assure you that is NOT correct. 60, 70,80, and 100 prefixes refer to tensile strength, and composition of filler metal according to the AWS who helped define the current system we use in the US.
Here is the difference between tig/mig metal and stick welding rods. The info came from Esab's website.
This is for a regular 7018.
C 0.045 %
Mn 1.1 %
Si 0.4 %
P 0.015 %
S 0.014 %
This is for ER70s-6.
C 0.08 %
Mn 1.40 %
Si 0.80 %
P 0.010 %
S 0.001 %
Cu 0.10 %
The Mn (Manganese) and Si (Silicon) act as deoxidizers and take care of any oxygen in the weld metal.
I heard that aboard any navy ship that if they open a can of 7018 rod, they use what they need and if the whole can don't get burnt they toss it overboard. Anyone know if thius is true?
Quote:
Originally Posted by Mikeymetal
I’m pretty sure that’s not any kind of policy, but on a carrier and probably any ship, anything you didn’t need or want was disposed of that way, full steam ahead, move ahead operation kind of thing.
The military in general is pretty wasteful in my opinion, it’s about getting the job done. So I do not doubt it at all.
Where you hail from?
I'm not military so I don't know the full answer, but you could sure see the rod's useful life deteriorating quickly in a high humidity or high salt spray environment. Who knows, there may be a long and detailed regulation in place to store a newly opened can. Friends have told me that cleverly side stepping rules is almost a religion among certain military types, so it may be easier to complete a form that says "electrodes accidentally dropped into a puddle" or "accidentally fell overboard again, the fourth time this week" than to re-bake rods.
Quote:
Originally Posted by DaveO
You hit it on the head DaveO.
Humidity is a big factor, and even on a huge carrier space is at a premium. Unless it’s part of a “weapons system” it’s not tightly tracked, the guy keeping track of the rod has no clue what it is or does it’s just “Used” so the welders didn’t have to explain why it took 50 l/b’s of rod to do the 3’ square deck repair, nor would they care. I wasn’t a Navy welder but if you needed anything it was just handed to you. Unless it was even remotely related to something that goes boom.