Arc rods

  1. Brad93

    Brad93 M J B Engineering

    Messages:
    10,367
    Location:
    Essex
    Edit: Al has beat me to it, I’m on the Ninth edition.

    The presence of hydrogen in the weld metal will only lower it’s tensile strength if the hydrogen moves towards the grain boundary’s and Has the propensity to cause a crack.

    for this you need to have a weld under stress and a susceptible microstructure. Majority of hydrogen is going to permeate out of the weld during the cooling and following 48 hours.

    This hydrogen, it’s not like nitrogen embrittlement in steel or hydrogen pores in aluminium. It’s absolutely microscopic, occupying the spaces between the crystal lattice. Room temperature just happens to be the temperature when hydrogen gets trapped in the lattice and tends to accumulate in the free space at grain boundaries.

    it’s been some time since I really researched and read into this subject so I may be incorrect here, so Al please correct me if I’m wrong.
     
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  2. Robert Mullins Member

    Messages:
    109
    Location:
    Salisbury, uk
    This has opened a whole can of worms, a welding engineer where I used to work, said that the new practise within the oil refinery/pipe line is to remove, and reweld butt welds as steel continues to absorb hydrogen with the passage of time: but according to what your saying, this is a temporary and the hydrogen will escape within 72 hours
     
  3. TechnicAl

    TechnicAl Member

    Messages:
    8,232
    Location:
    Rotherham
    Unless the weld is frozen the hydrogen will escape with time....heat will speed it up....72 hours is the usual time allowed between welding and NDT....usually any cracks will have appeared by then.........Ive never heard of welds having to be cut out and replaced because they have absorbed hydrogen........the vast majority of the hydrogen comes from the welding

    Are you referring to sour pipe lines where H2S Hydrogen Sulphide is present......if so thats corrosion....http://himipex.com/the-problem-of-protection-of-metal-from-the-hydrogen-sulfide-corrosion
     
  4. Robert Mullins Member

    Messages:
    109
    Location:
    Salisbury, uk
    I was told about this in the late 90's, and from memory it was as I said, refinery, oil line work: i'mi' still in contact with Malcolm, I'll ask him
     
  5. Munkul

    Munkul Jack of some trades, Master of none

    Messages:
    3,144
    Location:
    Cumbria
    Sounds like he's maybe picked up the wrong end of the stick? Only reason to cut out and reweld is if they used the wrong filler metal to start with, or if the welds carried out are subject to sulphide stress cracking at a different rate to the rest of the pipework parent metal... possibly a combination of both reasons...? If it's sour service then usually the pipe material AND the weld procedures would be NACE approved. It could be because the original welds should have been post heat treated, and they left it too late, so as a precaution they're rewelding the lot...
     
  6. Mpm welding

    Mpm welding Member

    Messages:
    26
    Location:
    Cheshire
    One thing I've always noticed is that you all get wrapped in the technical aspect of a given electrode, metallurgy and properties etc etc. The gentleman would find 7018's wholly unsuitable for one reason, you have to use the lot and can't store them properly, unless you have a rod oven and a quiver to heat them before using. Or ALL these magic properties are for nought. Hence why we all in the UK love are smooth 6013's. Plus 7018's are a swine on re-strike, although I just crank up my amps to counter this. I have a plethora of makes/types, enough for TechnicAl to be in his element in fact, plus I know Mjb knows his stuff, but I have been reading posts on here for a while now and it was one of the things I remember, as a novice, I was blinded with esoteric info. Rods, all day everyday the best? Esab ok46.00 6013's of what dreams are made ! If you had a hand in the ok46.00 electrodes development TecchnicAl I'll buy you a pint or 3! Any newbs reading don't confuse these with the ok46.30, although they're pretty good too.
     
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  7. Lewis_RX8

    Lewis_RX8 Member

    Messages:
    468
    Location:
    Scotland
    Im no expert myself but get on very well with the BOC Premium rods get from a local industry welding supplier £12 for 5kg including vat and a lot better than machine mart specials
     
  8. Mpm welding

    Mpm welding Member

    Messages:
    26
    Location:
    Cheshire
    Been meaning to try them, got an account with BOC so I'll give them a go as ok46.00 ain't cheap!
     
    metalmelt likes this.
  9. Lewis_RX8

    Lewis_RX8 Member

    Messages:
    468
    Location:
    Scotland
    Have not tried esab ok rods heard good words about them however only i can only compare the BOC to Machine Mart and some old SIP rods.

    Have seen they are a bit pricy however :whistle:
     
  10. TechnicAl

    TechnicAl Member

    Messages:
    8,232
    Location:
    Rotherham
    Sorry to say that I never worked for Esab but I know a story about the 46........Lincoln bought a Spanish manufacturer called KD who made a KD46 for many years...It was considered one of the best 6013s on the market....so much so that one or two others launched products with 46 in the name. I was told that the guy who developed it left KD and joined Esab not long before they launched the 46.00

    Do I still qualify for the pint or 3?
     
  11. Mpm welding

    Mpm welding Member

    Messages:
    26
    Location:
    Cheshire
    Knew you'd know something about them! Lol I'm a bit of an electrode saddo, in that I've tried all processes and love stick welding, don't know why? Stick, tig then mig for me. Due to that fact the few years I've been into this welding malarkey, I've tried a LOT of different types, ALL types not makes of course used. Helps that I can get 304, 316 and steel in general quite cheap, ok really cheap, that I can play about.
    Yes, pint qualifies. I must've read a load of posts with you in anyway so I owe you for teaching me stuff. YouTube and forums are good tools to get into this complex thing called welding. Goodnight all got work tomorrow, oh well !
     
  12. metalmelt Member

    Messages:
    589
    Location:
    UK
    Christmas soon, get the wife to treat you to a box, you will notice the difference after MM specials (cheapest they can get) sold purely for profit.
     
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  13. Munkul

    Munkul Jack of some trades, Master of none

    Messages:
    3,144
    Location:
    Cumbria
    Plenty people use 7018 without a rod oven for general purpose work. They're still stronger and tougher than 6013 on mild steel.

    You've just lost the "h4" or "h5" designation that you'd need for highly restrained weldments, or low alloy steel, etc, which is susceptible for hydrogen cracking. Obviously no good for code work, either.

    They are a pain to re-strike, though! I knock the glassy end off on concrete usually.
     
    metalmelt likes this.
  14. TechnicAl

    TechnicAl Member

    Messages:
    8,232
    Location:
    Rotherham
    I remembered a bit more later on.........KD in Spain (who made the KD46) actually made the Esab OK 46.00 for many years, until they were bought by Lincoln. So both Lincoln KD and Esab had a problem......KD needed to sell them elsewhere and Esab had to get a replacement....thats when they recruited the Technical guy from Spain....
     
  15. Robert Mullins Member

    Messages:
    109
    Location:
    Salisbury, uk
    I know pipe welders that only ever strike a rod up once, no matter how much remains, it's discarded
     
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  16. TechnicAl

    TechnicAl Member

    Messages:
    8,232
    Location:
    Rotherham
    If you notice most 7018s and 7016s have a graphite tip.....we used to metal spray some but its only possible on the bigger diameters (too many smaller ones get missed),,,,thats to help striking but obviously not restrike.....its good policy on critical work to only use full rods, too easy to make restrike defects

    Some even use "nobbling" where they strike outside the joint and create a "nobble" of weld
     
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  17. Gingle

    Gingle We are all in the same boat

    Messages:
    136
    Location:
    Cambridge
    WOW
     
  18. Tangledfeet

    Tangledfeet #1 Fan of 3M's VHB tape

    Messages:
    1,662
    Location:
    St Andrews, Fife, Scotland
    Do you ever visit Dundee? Highland Industrial Supply is the closest ESAB welding supplier to me as I'm at t'other end of Fife. Never tried BOC rods but do have some Nikko 7018's to try.

    I've also found that the price on the shelf/label is usually more than you actually pay at the desk...

    esab.jpg
     
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  19. Lewis_RX8

    Lewis_RX8 Member

    Messages:
    468
    Location:
    Scotland
    I am up that way, some times will have to give that shop a try seem a lot more reasonable on the pricing there and as the BOC dealer, I go to indeed is normally cheaper than shown on the web.

    Not sure on 7018's for me as my old welder is at 50v Open circuit which I understand is on the low side for 7018's however I can think of a good solution for this problem :whistle:
     
    Tangledfeet likes this.
  20. Tangledfeet

    Tangledfeet #1 Fan of 3M's VHB tape

    Messages:
    1,662
    Location:
    St Andrews, Fife, Scotland
    Must crack open the pack and give them a whirl as my inverter shouldn't struggle with 7018's.

    Aah, new welding machine time! :thumbup:
     
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