practice tips for a 3g SMAW structual test

Date 10-27-2008 04:34

Hello lewis grimes, a lot of the structural tests that many will take for SMAW 3G will probably be done on 1" plate as this will qualify you for unlimited thickness. If in fact this is a 3/8" plate you will be qualified for a 3/4" thickness for flat, horizontal, and vertical. It is also likely that the plates will each be beveled to 22 1/2 degrees so that the included bevel angle is 45 degrees. The 1/4" root opening with either a 1/4" or 3/8" backing strip also sounds correct. I believe you might also be using 1/8" E7018 from root to cap, vertical-up progression. There can certainly be variations to the scenario that I have included above, yet the one that I have listed here is along the lines of many D1.1 welder qualifications. Look for others to have additional suggestions for you to consider. Best regards, aevald

By swnorris (****)

Date 10-27-2008 13:39

For the type of fabrication we do, I really don't see a lot of structural applications requiring vertical groove welds, regardless of whether it's limited or unlimited thickness, or whether it's in the shop or the field. Typically, when it's a groove weld, it's a 2G weld. In my experience, a lot more vertical fillets than vertical grooves, especially in the field. 3G adds another degree of difficulty. Do you really need a 3G cert.? Last week we had five guys in here certifying on a job they'll be erecting for us and they all wanted to take a 3G unlimited thickness test using the SMAW process. It took a total of 14 tests to get all five guys certified, and there's not one vertical groove joint on the entire 800 ton project.

By lewis grimes Date 10-27-2008 17:34

Thanks guys for your help. I had only assumed it would be the v groove 22.5 degree like the other structual unlimited spray WPS Im also workin on.

The contractor did state I would need a 3G. As it stands now, he has enough folks on site since I spoke with him last so I wont be taking thier test. Still it be great to be more prepared next time. I haven't picked up a stick in a year so yeah the 3G Im antcipating to be tuff, but I need the experience.

One last thing as for as practice technique, my plan was to run stringers, but on the cap run a weave; however, some do run stringers all the way ..right?
Thanks again

By aevald

Date 11-03-2008 07:44

Hello lewis, you could be expected, or given the option to do, either of the methods that you mentioned. Some will like to see stringers all the way out, others will allow for stringers or weaves in combination. Be sure to ask if they don't give you a WPS(welding procedure specification) that spells it out for you. Good luck when that opportunity presents itself. Best regards, aevald

By mcphilly Date 11-04-2008 05:08

I would run a mild weave on your root pass and your hot pass just to make sure you dig into the sides of the root really good. You wont be able to make a full pass with a weave bead on a single rod so make sure you stop in the middle of the plate . They wont cut any coupons out of the middle so it is safe to stop there. After your Hot pass just run stringers the rest of the way out making sure you dig good into the sides. From my experience you should have a little more than an inch of rod left after a good stringer. Just make sure you let your plates cool down a bit before running to many passes. A lot of people will use temp crayons. For the 3g I like to run my machine between 110 and 120 depending on the machine. Good luck man and I hope this helps you out.

By aevald

Date 11-04-2008 06:43

Hello mcphilly, as you are new to the forum, first-off let me say welcome. In order for lewis grimes to receive notification of your post you need to hit the reply button on his post. In this case, I received notification of your post so unless he looks through this thread in it's entirety at a later time he might not know that you replied and had suggestions for him. This is definitely NOT a criticism, so please know that I am only trying to explain how the notification system works on the forum. Best regards, aevald

By mcphilly Date 11-05-2008 01:52

thanks aevald

By Chris Nichols Date 11-04-2008 08:16

Another suggestion I will throw at you is to make sure your backing bar extends about 1" beyond the beginning and end of your test plate. This will allow you to add "dog ears" to your plate to help with filling the plate evenly all the way through. Also, whether the plate gets x-rayed or bend tested, be sure to get ALL of the slag out between passes. It's been a few years since I did mine, but I remember having a pick set with me to get into areas I couldn't get slag out by just using a slag hammer. Good luck on your next opportunity!!!!

By Cumminsguy71 (*****)

Date 11-08-2008 17:50

Your plate has to be seven(7) inches tall and two three(3) inch wide with the 22.5 degree bevel. The backing strip shall be no less than 1/4" and I think it said the minimum width of your backing strip is three(3) inches unless it is being removed to inspect the root then it's no less than 1 inch.

I just did mine the other night, same position. Just ran a stringer root, maybe a very very slight weave just to tie in the edges. Ran a small weave hot pass, a filler pass, a filler pass and a weave cap pass. Have the machine set right and you really won't need your chipping hammer, my slag would roll right off the fillers and the cap. Some say use a grinder, others say no. I used the grinder just enough to knock off the high spot on my restarts and just barely hit those.

Practice, what I did, ran stringers on old scrap plate getting real tight welds. Actually did the same working on my cap. Just ran on flat plate trying to pick what one of the different styles I liked. Kinda got a weave I guess. Also played with the heat alot, up and down. Run a rod see what it does, look at the spatter, listen to the arc, watch the slag, then turn the knob and do it again.

Good luck with it!!