"E7018": a rant to designers.
"E7018": a rant to designers.
2
HgTX (Civil/Environmental)
(OP)
"You keep using that word. I do not think it means what you think it means." (Princess Bride)
I am posting this in this particular forum because bridge welding is more likely than structural welding to have long machine welds.
Almost every set of plans I see requires E70XX or E7018 electrodes. But just because your undergraduate steel design textbook used E70XX electrodes in the design example does not mean that is all there is to welding with 70-ksi electrodes.
Designers seem to intend "E70XX" to generically mean "filler metal with a minimum tensile strength of 70 ksi". But it does not mean that. E70XX means something very specific. It means filler metal with a minimum tensile strength of 70 ksi, welded by the shielded metal arc welding process. That is stick welding. With rods. Manually. With stops and starts every foot or so.
If you want the fabricator to be able to use any machine or semi-automatic wire-fed process such as submerged arc welding, flux-cored arc welding, etc., you cannot say "E70XX". Moreover, if you are designing to a specification that requires SAW for certain types of joints (AREMA and certain DOTs), you create a spec conflict by using that term. If you are using weathering steel, the corresponding weathering filler metal is in fact 80 ksi (a side effect of the alloys, not because more strength is needed), and if you require E70XX for a weathering steel structure you have now guaranteed non-weathering properties for your welds.
The best way to get the weld metal you want is to call for filler metal of matching strength to the base metal; this is covered very well in the AWS D1.1 and D1.5 welding codes. Otherwise you can talk about the minimum required weld metal tensile strength.
But don't say "E7018". The fact that you've gotten away with it so far just means people have been ignoring you. But "we knew what they meant" is not the optimal way to go about one's business.
Rant over. Thank you for your time.
Hg
I am posting this in this particular forum because bridge welding is more likely than structural welding to have long machine welds.
Almost every set of plans I see requires E70XX or E7018 electrodes. But just because your undergraduate steel design textbook used E70XX electrodes in the design example does not mean that is all there is to welding with 70-ksi electrodes.
Designers seem to intend "E70XX" to generically mean "filler metal with a minimum tensile strength of 70 ksi". But it does not mean that. E70XX means something very specific. It means filler metal with a minimum tensile strength of 70 ksi, welded by the shielded metal arc welding process. That is stick welding. With rods. Manually. With stops and starts every foot or so.
If you want the fabricator to be able to use any machine or semi-automatic wire-fed process such as submerged arc welding, flux-cored arc welding, etc., you cannot say "E70XX". Moreover, if you are designing to a specification that requires SAW for certain types of joints (AREMA and certain DOTs), you create a spec conflict by using that term. If you are using weathering steel, the corresponding weathering filler metal is in fact 80 ksi (a side effect of the alloys, not because more strength is needed), and if you require E70XX for a weathering steel structure you have now guaranteed non-weathering properties for your welds.
The best way to get the weld metal you want is to call for filler metal of matching strength to the base metal; this is covered very well in the AWS D1.1 and D1.5 welding codes. Otherwise you can talk about the minimum required weld metal tensile strength.
But don't say "E7018". The fact that you've gotten away with it so far just means people have been ignoring you. But "we knew what they meant" is not the optimal way to go about one's business.
Rant over. Thank you for your time.
Hg





RE: "E7018": a rant to designers.
I'm probably guilty as charged.
RE: "E7018": a rant to designers.
Thanks for the information, I will definitely follow up on that.
RE: "E7018": a rant to designers.
Hg
RE: "E7018": a rant to designers.
RE: "E7018": a rant to designers.
RE: "E7018": a rant to designers.
I need to do some more research about the use of E70XX electrodes since most of the welds I specify is in conjunction with M270W steel.
RE: "E7018": a rant to designers.
Or do I need go hear your rant? *blush*
RE: "E7018": a rant to designers.
I really want to thank you for your post. I've been educating myself more about welding as a result. How common is flux cored arc welding for machine welding? The only fab shop I've visited used SAW for their long weld passes like flange to web welds.
I found this document from the Ohio DOT about types of weld filler materials. I think it really explains it well. https://www.google.com/url?sa=t&rct=j&q=&a...
I think the general note I usually use says something to the effect of "all welds shall have weathering characteristics". After all the reading I've done it would seem you can't really specify an electrode unless you know the type of welding that will be done (SMAW, GMAW, SAW or FCAW).
RE: "E7018": a rant to designers.
Your link is a good one--it shows examples of different classifications for different welding processes and how they differ.
Weld all around really means weld all around, no stopping at corners (and certainly no welding 3 sides of an overlapping joint but not the 4th). If a rant is warranted, I should start a new topic. Is this the right ET forum or should I pick a different one?
Hg
Eng-Tips policies: FAQ731-376: Eng-Tips.com Forum Policies
RE: "E7018": a rant to designers.
RE: "E7018": a rant to designers.
Seal welds are another rant entirely, though there is a published rant by the esteemed Duane Miller of Lincoln Electric that is of much better quality than any rant I could rant. And in an unranty style, even better. (Short version: seal welds don't know they're just seal welds, will still take load, and if they're undersized or of nonstandard quality they can still cause problems.) I should post that somewhere as well.
Hg
p.s. Hi Tom!
RE: "E7018": a rant to designers.
RE: "E7018": a rant to designers.
RE: "E7018": a rant to designers.