Well, first off, none of the standard AWS welder qualification tests required by the structural welding codes are without backing. Next, 6010 is not an electrode permitted by AWS D1.5. Low hydrogen electrodes or low hydrogen welding processes must be used for all the approved steels under the auspices of D1.5 and for the performance qualification tests.

It makes little sense to require the welder to take an open root test with E6010 for the root pass since the E6010 is not permitted and it does not qualify the welder for welding with low hydrogen electrodes. E6010 and E7018 have different F numbers and the F number is an essential variable in the structural welding code.

You might ask your instructor for a copy of the WPS to see exactly what is called for. There are mandatory qualification tests included in the structural welding codes. The contractor, if they go through the effort of qualifyng the welding procedure, can then require any additional tests they want, but as I said, the bridge code does not permit the use of SMAW electrodes that do not meet the requirements of a low hydrogen electrode. I would be hard pressed to accept a welder qualification test that used E6010 with an open root and no back gouging operation. Its a bird without wings, it doesn't fly.

Good luck - Al

Devin,

Open root 6010 root pass w/ lo-hy hot pass, filler and cap is a standard, widely used welding procedure in numerous and varied industrial applications.  Success in performing the weld requires hands on instruction from a competent welding instructor able to demonstrate and explain several aspects of correct performance including: correct joint geometry, bevel angle, root opening, landing width, amperage, rod angle, travel speed and "keyhole" opening.  Without ever seeing it done it is difficult to explain in any helpful manner for you to visualize it.  You are essentially depositing weld on the opposite side of the plates you are joining or more commonly the inside of the pipe joint from the outside. There are a tons of You Tube videos to peruse that will give you the general idea, however learning to make this weld will be largely a matter of technique, practice and adjustments after you have been instructed in the basics mentioned above.  For example, some welders use a wider or narrower root opening, some a wider or thinner face, higher or lower amperage, faster or slower travel speed.  Commonly in trade schools, practicing this weld on plate is a precursor for preparation in learning to perform this weld on pipe in the 6G position which is the test position, covering all positions, that most contractors/employers will use when testing welders in open root applcations.

The open root weld w/out backing can also be done using 7018 for the root pass, however it is an uncommon welding procedure to encounter or to be tested in.  In 38 years practicing this trade I can only remember being asked to qualify to an open root 7018 root pass 3 times [out of at least 100 testing scenarios].  The single time I took the test the procedure was never used on the job.  Most welders would consider it an impractical weld procedure for all but very specific project requirements.  I do need to qualify however that the vast majority of my work history has been in the pipe trade, not structural steel and there are regions and jurisdictions that do commonly require 7018 open root qualifications

AWS D1.1, one of the few structural codes I am even vaguely familiar with, permits the use of 6010 open roots at least in so far as their SWPS Welding Procedure Specification permit.  My general understanding of D1.1 is that under Clause 4, any Welding Procedure Specification tested successfully can be used as a Qualified Procedure.  I am not at all familiar with AWS D1.5 Bridge Code requirements [other than its stringency, having watched Bridge Welding Inspectors examine a weldment with the scrutiny one would expect from a Bald Eagle Mother finding a parrot in her nest] but that is to be expected and appreciated as we don't want bridges built incorrectly or by incompetent welders.  I do know that Pilebucks welding Pipe Piling will use a 6010 open root but whether that is done in bridge construction I do not know.  I would be surprised and somewhat exasperated to learn that AWS D1.5 does not have a similar Weld Qualification Clause that permits the use of a Qualified Weld Procedure that meets testing requirements without backing, but I am speaking out of my league here and perhaps a senior member, more qualified in AWS D1.5 intricacies can explain why this might be so.  Possibly it is due to the Grade and strength of steel used in bridge construction but that is just speculation. 

You'll enjoy this new open root weld procedure you are embarking on learning.  It's really challenging and will step your game up to a new level.  New welders are often intimidated by gap in a weld joint.  Learning to open root a weld will help overcome that trepidation and further test your skill and resolve to be a welder.  However it not something you can really learn from an internet forum, you will be best served by listening and watching your instructor carefully and a whole lot of practice.