plate test ?

admin

Good EveningThe guys that will be taking the test will be tested on 1” thick x 8” long plate without backing strip. They will have strong backs on them and when the front side is welded they will either grind or gouge the back side and weld it. The will use Lincoln Welding Machines with wire feeders with E71T-1 wire, wire size 0.045” with Argon/CO2 75/25 gas, metal will be preheated 100°F.  if there anything that is need please feel free to contact me.This is email i got from hr.my question is if there's no back up strip is it an open root? And wth is strong backs?
Reply:It sounds like a tight root since you are running flux core.  It is expected that the root pass is a bad pass then you will turn over and back gouge to sound metal and fill in from back side.  The strongbacks are pieces of flat bar likely 3 by 3/8 or heavier to stop the plate from pulling.  they would be tack welded to the ends standing across the joint.  If there are run off tabs then the strongbacks would have mouse holes cut so that the weld can run off the end of the 8 inches.
Reply:Thanks for your replySo strongbacks lay across both ends of the plate! And not up the plate as a backing strip!thanks iotechman.
Reply:Yes  I am wondering though if the strongbacks he is referring to are in the same plane as the test plate and they double as run off tabs.  Traditionally a strongback stands up on edge at 90 degrees to the centerline of the weld joint to provide the maximum rigidity.
Reply:make sure they gouge deep enough on the second side to see that line under/within the first pass they make on the first side go away, otherwise everything past that is pointless fill.  I would STRONGLY suggest to gouge and then grind as opposed to grind and grind.  It is way easier to chase the back of a weld out with a gouger than it is with a grinder.  Clean up the gouge after gouging and fill the second side in.  Probably wouldn't hurt to die pen or mag particle the second side after gouging and grinding.