Hi all
I have a quastion on welding of building structure .The base metal is
ASTM A36 (DIN ST37),
Is it allowed to use E6010 electrode for welding root pass of complate penteration of groove joints, Acording to AWS D1.1 or NOT.
I could not find it in this standard cleary.
Thanks for any help.
I hear that 60 series is used a lot in the field for root passes. It would depend on what is in the contract documents, which usually stipulate the use of E70XX electrodes on structural projects. I would think that a good welder can weld the root without using 60 series.
Looks like Azimi is using DIN ST37 steel, whose APPROXIMATE ASTM equivalent is A-36. Please take a look at the response I've posted to Sean's question "How European steel grades are named" on the Technical section of this Forum, regarding the "equivalence" between European and American steel grades.
ST 37 steel has an ultimate tensile strengh of 37 kgf/square millimeter, and hence the name. 37 kgf/sq mm equals about 52,650 psi.
On the other hand, the E6010 electrode produces a welded metal with an ultimate tensile strength of 60,000 psi. So, there's no reason for which Azimi can not use E6010 for the root and subsequent passes.
E6010 has a very good penetration and this is good for welding structural steel. However, it has a bad looking appearance, and this is bad when the weld will be seen by the general public, as in structural steel.
Back in my days of erector engineer what I used to do was the following:
Give the root and subsequent passes, except the last, with E6010.
Then, give the last pass with E6012, whose appearance is fine.
Giovanni S. Crisi
Sao Paulo - Brazil
6010 produces a weld metal with a "minimum" tensile of 60,000psi.
To use Lincoln 6P+ as an example, the typical as welded tensile will run between 72,900 and 86,000psi.
JTMcC.
Is 6P+ a new Lincoln product?
JTMcM,
Very acccurate concerning tensile strength. As you just did, maybe Mr. Crisi should have noted the ultimate tensile strength as 60K minimum. Didn't you mean 5P+? Maybe there is a 6P+.
English being not my mother language, sometimes I get confused with
English wording.
I've always understood that "ultimate tensile stength" is the stress at which the specimen breaks when subjected to tensile test. If this isn't so, please explain me what "ultimate tensile strength" means.
Anyway, JTMcM is right in saying that this strength is the minimum one.
So, I'll put my former phrase in this way:
E6010 produces a welded metal that will break at 60,000 psi minimum. On the other hand, DIN ST37 steel breaks at 37 kgf/square mm minimum, far less that 60,000 psi. So, there's no reason why E6010 could not be used to weld ST37 steel.
Giovanni S. Crisi
I may be mistaken, but the DIN ST37 isn't quite as strong as the ASTM A36 grade. If the ST37 steel's tensile strength is 52,650 psi, that is somewhat less than the A36 whose tensile is 58-80ksi, or 400-550 MPa.
Mr. Meadows,
you're perfectly right. That's why I said in my first posting, which is right up here, that ST 37 is an APPROXIMATE (with capital letters) equivalent to A 36. I also asked the readers to take a look at the answer I've given to Sean's question on equivalence of American and European steels on the Technical section of this Forum. There, I explain how Equivalence Tables of steel grades should be considered.
I believe that azimi is using ST 37. Why? Because if he were using A 36,
he wouldn't bother in mentioning "ST 37" on his question.
Azimi, would you tell us what steel are you using?
Giovanni S. Crisi
I agree with swnorris in the stipulation of the 70 series (70K tensile strength) for structural welding. I agree also with your ability to use the 60 series for the root pass, but then going to the 70 series for the completion is usually the norm on virtually all applications I've experienced.
CM
6P+ is part of the Lincoln Pipeliner series of consumables.
JTMcC.
JTMcC is correct about the 6P+ and there is also a 8P+ for supplemental applications.
Why ask why?
"supplimental application"???
And here I thought we were using that rod for hot pass/fill/cap.
JTMcC.
The main reason that joints are not welded out with 6010 electrodes is the high hydrogen content. This greatly increses the risk of hydrogen cracking. This is not to say that 6010 cannot be used for fill passes of structural welds, but preheat, thickness, and joint restraint must be considered before they can be used. The hastle of justifying their use, additional steps (such as preheat), and the added risk of cracking is not usually worth the effort in my opinion.
I fully agree with Mr. Roberts. That is why I suggested, as many other designers do, in using a low hydrogen filler metal like a 7018. I believe the 6010 is quite adequate for the root pass, but then to switch to the 7018. Like everyone else, that is my opinion.
azimi has put the same question on the Certification & Qualification section of this board.
There's an answer there posted by "thcqci" saying that Table 3.1 of the 2004 Edition of AWS D1.1 allows the use of E60xx (hence 6010)eletrodes for welding A36 steel up to and including a thickness of 3/4 inches.
If D1.1 allows it, why shouldn't we?
Giovanni S. Crisi
By -
Date 07-19-2005 19:41
In my experience, the Code gives minimum requirements. It is certainly not against the Code to upgrade to higher variables. Because the Code allows an E60xx does not mean that there are not conditions that should be considered when using that grade. Mr. Roberts made such conditions that should be considered.
Chuck
I worded my response there carefully to say it is allowed. I too agree that while allowed, E60XX may not be the best choice. Other factors may make E70XX a better choice. I am not necessarily qualified to make that judgement, especially without more details.
Mr. Meadows and thcqci,
you're perfectly right. We all know that codes, standards and specifications make minimum requirements, and nobody will forbid you to use a better quality material to make a better quality product.
Giovanni S. Crisi
I only have a 2000 copy of D1.1
"Section 5.10 Backing"
"Roots of groove or fillet welds may be backed by copper, flux, glass tape, ceramic, iron powder, or similar materials to prevent melt thru. They may also sealed by means of root passes deposited with low hydrogen electrodes if SMAW is used,...."
Does this mean that all (SMAW) complete penetration joint root passes must be made with low hydrogen electrodes?
Re: Azimi's initial post, for welds in A36 base metal, 60 series is not prequalified in the SMAW process if the base metal thickness is greater than 3/4". See Table 3.1 Prequalified Base Metal - Filler Metal Combinations for Matching Strength.
Re: Bill Mc's post, to me, the two most common base metals in structural applications are ASTM A 36 and ASTM A992. Again, 60 series is not prequalified in the SMAW process if the base metal thickness is greater than 3/4". 60 series is also not prequalified for A992. Low hydrogen electrodes are prequalified for A992. Also refer to Table 3.1. That's not to say that a procedure couldn't be qualified to use 60 series in either case.
Our structural jobs and I guess most all structural jobs require E70XX electrodes. I think that anyone considering using 60 series electrodes in a similar situation should get an engineer's approval before using them, because his design criteria is based on 70 series weld metal tensile and yield properties, which are greater than that of 60 series.
I still stand by my statement in my initial post that a good welder doesn't need to resort to using a 60 series rod.
