Little technical question (maybe for @TechnicAl ? )
The 72 hours rule is valid for fatigue and static stresses conditions or only for
static stresses? (Please forgive me if the terms are wrong)
i have never known it change....72 hours is standard fir EEMUA etc etc....I once convinced an Inspector to reduce it to 24 hours but i had to show tesr rrsults from consumables with less than 1ml and 0 after 24 hours.....consistently
Have a nice evening, welding people.
Sart0
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Memmeddu
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With my new welder now i can buy E7018 because now I can use them without set up and start on my genset engine driven welder ,i have a friend which have some citobasico stored that he doesn't sell anymore because it's difficult find someone that can run 7018 here where I live
So they are opened since something like five years i will put them into an homemade oven , insulated
So when they are something like 100°C the oven turn off than it starts cooling down,but very slowly because the insulation than warm up again very quickly , i will do this for something like a month than i start the oven the day before use them
Think that can works for me because I don't really need 7018 it's only personal upgrade to my skills and also because they are always better than 6013
So they are opened since something like five years i will put them into an homemade oven , insulated
So when they are something like 100°C the oven turn off than it starts cooling down,but very slowly because the insulation than warm up again very quickly , i will do this for something like a month than i start the oven the day before use them
Think that can works for me because I don't really need 7018 it's only personal upgrade to my skills and also because they are always better than 6013
Munkul
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We use them on the farm, keep em warm and in sealed rod containers, and re-dry them now and again in the oven at 250deg for a few hours. I also look after coded weld repairs with contractors who start with a new vac packet every job, no exceptions.
We prefer 7018's for the positional welding ability - overhead and vertical up, it still amazes me how easy they are to run vertical up. If it wasn't for this, I'd stick with 6013 because they leave a "better looking" weld bead.
But when you really look into the "low hydrogen" bit, even a 7018 left out in a cold damp garage for a month will produce welds similar or better to a 6013 in terms of hydrogen - therefore producing a similar strength weld. The caveat being that we are ONLY talking about mild carbon steels, S275 structural strength.
Once you go to stronger carbon or low alloy steels, the combination of metallurgy and higher strength means the amount of hydrogen in the weld and HAZ is really critical, and you might start getting cold cracking. I'm talking things like hardened bucket edges, or dozer blades. I have no experience with it but I wonder if maybe even S355 structural steel could be susceptible.
While I dont have the answers as to where the line stops, I do believe that doing it my way on the "farm" is fine where it's 95% all S275 grade, but for any high strength steels or pressure code work, you HAVE to do it properly, and adhere to the guidelines. A £25 pack of rods is cheaper than having to reweld cracked jobs, and at worst it's a safety issue.
We prefer 7018's for the positional welding ability - overhead and vertical up, it still amazes me how easy they are to run vertical up. If it wasn't for this, I'd stick with 6013 because they leave a "better looking" weld bead.
But when you really look into the "low hydrogen" bit, even a 7018 left out in a cold damp garage for a month will produce welds similar or better to a 6013 in terms of hydrogen - therefore producing a similar strength weld. The caveat being that we are ONLY talking about mild carbon steels, S275 structural strength.
Once you go to stronger carbon or low alloy steels, the combination of metallurgy and higher strength means the amount of hydrogen in the weld and HAZ is really critical, and you might start getting cold cracking. I'm talking things like hardened bucket edges, or dozer blades. I have no experience with it but I wonder if maybe even S355 structural steel could be susceptible.
While I dont have the answers as to where the line stops, I do believe that doing it my way on the "farm" is fine where it's 95% all S275 grade, but for any high strength steels or pressure code work, you HAVE to do it properly, and adhere to the guidelines. A £25 pack of rods is cheaper than having to reweld cracked jobs, and at worst it's a safety issue.
Thank you Munkul, I really appreciate you taking the time to share that. I decided like yourself that it's not a huge amount of money vs sorting out a problem, so I'm going to continue using properly stored rods for anything I need to arc weld as I only require this occasionally. Almost everything I do currently can be moved indoors and I'd use my tig, but occasionally a job needs to be done away from the workshop.
Munkul
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quite a good article:
https://www.twi-global.com/technica...ks-in-steels-prevention-and-best-practice-046
there's a graph halfway down showing potential hydrogen (of which is quite high in MMA electrodes) vs actual weld metal hydrogen level. The weld metal hydrogen level is directly related to cracking, in any particular steel grade:
Draw your own conclusions.
https://www.twi-global.com/technica...ks-in-steels-prevention-and-best-practice-046
there's a graph halfway down showing potential hydrogen (of which is quite high in MMA electrodes) vs actual weld metal hydrogen level. The weld metal hydrogen level is directly related to cracking, in any particular steel grade:
Draw your own conclusions.
Never seen a graph like that before....."potential" hydrogen level?????. ml/100g of wire ???......anyway ignoring the potential part the other bits are simply wrong. Ive never seen over 10ml in a MIG / MAG weld.......If my memory serves me well the highest Ive ever tested (and ive done thousands) has been 5ml.......never seen 30ml in a flux core wire and 30 ml is what you can expect from Cellulosic.......its possible with a Rutile but extremely rare unless its dripping wet.
Also Hydrogen alone wont make it crack......you need the combination of steel structure, stress and hydrogen......if 2 are low the 3rd has to be extreme to cause cracking.....its highly unlikely that 30ml will cause cracks in an unrestrained mild steel joint............They even join the highly susceptible CrMo pipe with cellulosics by keeping the joint hot long enough for even the 30ml to escape.
I used to have a video showing what 5ml looks like escaping from a crack.....basically gassing lemonade.....we also used to freeze a weld immediately after its finished...and place it in a jar of glycerine....you would be amazed how many bubbles 5ml makes.
Also Hydrogen alone wont make it crack......you need the combination of steel structure, stress and hydrogen......if 2 are low the 3rd has to be extreme to cause cracking.....its highly unlikely that 30ml will cause cracks in an unrestrained mild steel joint............They even join the highly susceptible CrMo pipe with cellulosics by keeping the joint hot long enough for even the 30ml to escape.
I used to have a video showing what 5ml looks like escaping from a crack.....basically gassing lemonade.....we also used to freeze a weld immediately after its finished...and place it in a jar of glycerine....you would be amazed how many bubbles 5ml makes.
Brad93
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That graph is a load of rubbish as Al pointed out.
The terminology is all wrong.
Hydrogen levels are calculated after the weld has been deposited and the units are:
“Millilitres of hydrogen per 100grams of weld metal”
Most basic electrodes even unbaked are 5-15ml, rutile up to 25ml, cellulosic 25-50ml/100g Weld Metal
The terminology is all wrong.
Hydrogen levels are calculated after the weld has been deposited and the units are:
“Millilitres of hydrogen per 100grams of weld metal”
Most basic electrodes even unbaked are 5-15ml, rutile up to 25ml, cellulosic 25-50ml/100g Weld Metal
Munkul
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You guys obviously have more experience than I do of weld metal hydrogen so are probably better qualified to judge this...
I'm also not sure what they mean by "potential" hydrogen - I'm guessing it means when the consumable gets damp, there is more available hydrogen? but it obviously doesn't all go into the weld metal.
But ... Both of you state ml/100g figures from your experience DEPOSITED weld metal which agrees with the graph. The only part that looks really wrong is the FCAW area. Not sure what is going on there, since like you say, it's a low-hydrogen process whatever way you look at it.
I mean, they're only a welding institute, who helped develop ISO, ASME and API codes... what do they know. Clearly you read their graph right the first time round, and they are wrong
I also said quite clearly, in my above post:
"Once you go to stronger carbon or low alloy steels, the combination of metallurgy and higher strength means the amount of hydrogen in the weld and HAZ is really critical, and you might start getting cold cracking. I'm talking things like hardened bucket edges, or dozer blades. I have no experience with it but I wonder if maybe even S355 structural steel could be susceptible"
Getting back to the point of the thread: no-one is offering proof that using damp 7018's on S275 steel will lead to hydrogen cracking failures, and I am showing research that suggests it's not an issue...
I'm also not sure what they mean by "potential" hydrogen - I'm guessing it means when the consumable gets damp, there is more available hydrogen? but it obviously doesn't all go into the weld metal.
But ... Both of you state ml/100g figures from your experience DEPOSITED weld metal which agrees with the graph. The only part that looks really wrong is the FCAW area. Not sure what is going on there, since like you say, it's a low-hydrogen process whatever way you look at it.
I mean, they're only a welding institute, who helped develop ISO, ASME and API codes... what do they know. Clearly you read their graph right the first time round, and they are wrong
I also said quite clearly, in my above post:
"Once you go to stronger carbon or low alloy steels, the combination of metallurgy and higher strength means the amount of hydrogen in the weld and HAZ is really critical, and you might start getting cold cracking. I'm talking things like hardened bucket edges, or dozer blades. I have no experience with it but I wonder if maybe even S355 structural steel could be susceptible"
Getting back to the point of the thread: no-one is offering proof that using damp 7018's on S275 steel will lead to hydrogen cracking failures, and I am showing research that suggests it's not an issue...
You guys obviously have more experience than I do of weld metal hydrogen so are probably better qualified to judge this...
I'm also not sure what they mean by "potential" hydrogen - I'm guessing it means when the consumable gets damp, there is more available hydrogen? but it obviously doesn't all go into the weld metal.
But ... Both of you state ml/100g figures from your experience DEPOSITED weld metal which agrees with the graph. The only part that looks really wrong is the FCAW area. Not sure what is going on there, since like you say, it's a low-hydrogen process whatever way you look at it.
I mean, they're only a welding institute, who helped develop ISO, ASME and API codes... what do they know. Clearly you read their graph right the first time round, and they are wrong
Believe it or not, it happens. They have never made welding consumables and they have never tested as many as those who have
I also said quite clearly, in my above post:
"Once you go to stronger carbon or low alloy steels, the combination of metallurgy and higher strength means the amount of hydrogen in the weld and HAZ is really critical, and you might start getting cold cracking. I'm talking things like hardened bucket edges, or dozer blades. I have no experience with it but I wonder if maybe even S355 structural steel could be susceptible"
Getting back to the point of the thread: no-one is offering proof that using damp 7018's on S275 steel will lead to hydrogen cracking failures, and I am showing research that suggests it's not an issue...
It is highly unlikely to get H2 cracking in S275 because the structure is not susceptible. You would need extremely high hydrogen levels and very severe restraint. I have seen it on Sellafield Thorpe where they were welding with water running by the weld, also on the running gear for channel tunnel built by Brush Electric where the final weld was so severely restrained and on a bridge over the river Wharfe at Bolton Abbey where they were very close to the water and it was highly restrained. So it can happen but it is very unlikely. I once tried to create some cracks using sub arc and welding what was virtually a tekken test...I couldnt do it and in the end the flux was almost liquid.
PS..API, ASME etc are written by Americans as far as I know....on the inside cover it lists the participants...as far as I recall TWI arent on that list.
Brad93
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You guys obviously have more experience than I do of weld metal hydrogen so are probably better qualified to judge this...
I'm also not sure what they mean by "potential" hydrogen - I'm guessing it means when the consumable gets damp, there is more available hydrogen? but it obviously doesn't all go into the weld metal.
But ... Both of you state ml/100g figures from your experience DEPOSITED weld metal which agrees with the graph. The only part that looks really wrong is the FCAW area. Not sure what is going on there, since like you say, it's a low-hydrogen process whatever way you look at it.
I mean, they're only a welding institute, who helped develop ISO, ASME and API codes... what do they know. Clearly you read their graph right the first time round, and they are wrong
I also said quite clearly, in my above post:
"Once you go to stronger carbon or low alloy steels, the combination of metallurgy and higher strength means the amount of hydrogen in the weld and HAZ is really critical, and you might start getting cold cracking. I'm talking things like hardened bucket edges, or dozer blades. I have no experience with it but I wonder if maybe even S355 structural steel could be susceptible"
Getting back to the point of the thread: no-one is offering proof that using damp 7018's on S275 steel will lead to hydrogen cracking failures, and I am showing research that suggests it's not an issue...
No the graph says per potential H2 per 100g of wire on the Y-axis which is stupid and makes no sense. The hydrogen doesn’t come from the wire it comes from the flux.
The deposited figures are still wrong whichever way you look at it. Rutile, basic, flux core, all wrong.
I think your should pay a little respect to TechnicalAl. He has been in the welding industry for decades and has worked for world leading electrode manufacturers. This may be a small forum but there are some members who are well respected and very knowledgable in the industry on here.
The TWI isn’t the be all and end all of welding mate. As they say, those who can do and those that can’t, teach.
The people who write a lot of welding books are ex ESAB and Lincoln employees. David Widgery being one.
The specialists out there are consultants to TWI. Gene Mathers is another.
Munkul
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....so basically you're agreeing with me, about S275
I know for a fact that some members of TWI sit on some of the API panels. They even offer API accredited courses - of which I have done several - fitness for service, weld repair, etc. The guy that taught the FFS course actually helped write the last two versions of the API 579, which is not to be sniffed at. I can't actually confirm the ASME bit. Anyway I was just trying to make a point.
don't worry, I know they aren't the be-all and end all, I talk to plenty people who don't have a good word to say about their practices, and I do take what comes from them with a pinch of salt (like I do with everybody) , BUT, I'm just saying - they aren't daft. There is some reason behind that graph, and if you blindly just don't want to understand it, then that's your call I guess. You DO get a small amount of hydrogen with solid wire, btw, but I guess I don't need to tell you that?
....so basically you're agreeing with me, about S275
I know for a fact that some members of TWI sit on some of the API panels. They even offer API accredited courses - of which I have done several - fitness for service, weld repair, etc. The guy that taught the FFS course actually helped write the last two versions of the API 579, which is not to be sniffed at. I can't actually confirm the ASME bit. Anyway I was just trying to make a point.
don't worry, I know they aren't the be-all and end all, I talk to plenty people who don't have a good word to say about their practices, and I do take what comes from them with a pinch of salt (like I do with everybody) , BUT, I'm just saying - they aren't daft. There is some reason behind that graph, and if you blindly just don't want to understand it, then that's your call I guess. You DO get a small amount of hydrogen with solid wire, btw, but I guess I don't need to tell you that?
Yes I am agreeing with you about s275....I think I said so earlier...or maybe that was a different thread.
I really dont know what that graph is trying to show. I have spent 40 years making welding consumables and Ive never seen that before.
Just had a look at the TWI website and they show representation on API committees.....Im wrong again.....Surname starting C
I also did some BSI committee work many years ago....until the pressure of commerce made it worthless.....I was invited on many committes but some f them I knew nothing about....In those days it was looked at as prestigious for the company to have representation on Standards but that changed due to commercial pressure and trends. To the point where BSI etc couldnt get enough people through Industry and Trade Organisations....I knew people who spent most of their working life on these comittees (eg those named by Brad) but many of them ended up out of work when the welding industry in Europe hit hard times and cheap imports. There were a lot of Academics in the industry when I started back in 70s but by the 90s most had gone or become consultants. My point is that these committes are often made up of the willing rather than the informed.
I also did some BSI committee work many years ago....until the pressure of commerce made it worthless.....I was invited on many committes but some f them I knew nothing about....In those days it was looked at as prestigious for the company to have representation on Standards but that changed due to commercial pressure and trends. To the point where BSI etc couldnt get enough people through Industry and Trade Organisations....I knew people who spent most of their working life on these comittees (eg those named by Brad) but many of them ended up out of work when the welding industry in Europe hit hard times and cheap imports. There were a lot of Academics in the industry when I started back in 70s but by the 90s most had gone or become consultants. My point is that these committes are often made up of the willing rather than the informed.
Munkul
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By the way i am sorry for going in hard, I've been a couple of years away from forums only recently posting here and there again, and I'd forgotten how easy it is to get wound up and punch back a retort over a keyboard. It doesn't do anyone any favours and just makes me look like a d!ck.
I realise you have actual first hand experience of this whereas I don't. Maybe someone chucked that graph together to look good for a presentation and no-one has actually verified it... it wouldn't surprise me. It certainly looked good from my point of view where I don't know everything, but know just enough to be dangerous
I realise you have actual first hand experience of this whereas I don't. Maybe someone chucked that graph together to look good for a presentation and no-one has actually verified it... it wouldn't surprise me. It certainly looked good from my point of view where I don't know everything, but know just enough to be dangerous
feel free...we all have opinions and most of us think we are right....a good argument is good for everyone as long as it doesnt get personalBy the way i am sorry for going in hard, I've been a couple of years away from forums only recently posting here and there again, and I'd forgotten how easy it is to get wound up and punch back a retort over a keyboard. It doesn't do anyone any favours and just makes me look like a d!ck.
I realise you have actual first hand experience of this whereas I don't. Maybe someone chucked that graph together to look good for a presentation and no-one has actually verified it... it wouldn't surprise me. It certainly looked good from my point of view where I don't know everything, but know just enough to be dangerous
