Downhill welding is a bit more difficult to get penetration than uphill, but can still produce a sound weld. Filler deposition rate is typically much lower, but you will find it easier to make welds on thinner materials by welding downhill.

 

hello everyone, i am at the end of my first year of welders training, and i know this topic has not been visited lately, but i thought i would give my description of some of the many proper testing techniques. these are what they test us with in school.

concerning the bend test with a backing strip, the joint should look something like


I /

the I represents one side of your joint, left square, the / should be between 33 and 37 degree bevel. teh backing strip, 1/4 thickness is adequate, your tacks should not be inside of the joint, but on the back of the plate and the backing strip should connect the two plates. the distance between the bevelled adn square edges varys according too weld position. with wirefeed, flat, it should be about 1/2", although opening it a little more would not hurt. this joint isnt really going to be used for anything but structural steel, so maybe with a frame repair. your first pass can go one of two ways, a fillet weld into the square edge that should reach about a 1/4" towards the bevelled edge. or you can weave between the two pieces of steel. the fillet is probably best. be sure to watch to see that you are digging into the backing plate when you weld and not jsut riding on top. you should be pulling the weld along. produces a rounder bead, but better penetration. alos watch your bead is not so round that you are going to have voids in your weld. after the joint has been welded, the backing strip should be gouged off, and hte back of the weld ground flat. thats your basic finish, some cases you may gouge into your weld and then reweld outwards to ensure complete penetration.

a single v weld has no backing strip. should look like a V. both plates should be bevelled, the edge of the bevel should be ground/ filed down so that you have a 1/8" land on the edge of your plate. a 1/8" gap between plates is your root gap. then just weld it up trying all you can too ensure complete penetration and no voids.

\ / bevelled section
| | about 1/8"
1/8"

the testing method is to grind and polish both sides of the weld flat. then cut strips across the weld about 1 1/2" wide. you dont want it any narrower than 1" but not much wider than 2".

we have a hydraulic press that is used specifically for the testing of welds, the jig that we put our coupons into looks something like


|
V downward force

_____ weld coupon
| | coupon holder


in a perfect world, your welds do not break, you end up with a bunch of U's before you grind your welds down, mark some cap and some root. bend the caps so that the top of your weld is pushed outwarsd, and roots vice versa. this way you are testing the top and bottom of your weld. the surface of your coupon should be smooth, if there are any opening or cracks bigger than 1/8" square, it is a fail.


i think that is all you need to know in order too test your structural welds. hope it helps. i know it doesnt really apply to much of whay you discuss here, but it does sort of apply to frame repair, although i dont reccommend welding ona frame, if you have to get a ticketed welder. but if you are just curious how your welds hold up, this may interest you.

i would also just like to say this is a great topic , ive enjoyed catching up on it all, thankyou. hope this helps you

 

That's a pretty accurate description, but keep in mind that the joint design can vary a lot. You may have to do a double J bevel, single J, double V, single V, maybe with a backing strip, maybe a consumable insert, etc.

The bending technique doesn't change a lot though. AWS specs do call out for different bend radius for different thicknesses, and also allows for side bends.