welding speed

Lets say I am MIG welding 3/16 steel. A butt joint. With a proper set up machine for heat and wire speed, how long should it take me to weld an inch?

I have a feeling I am trying to move the puddle too fast and not getting enough penetration.

 

There's no set amount of time that it should take to run an inch of weld. It depends on several factors.

First, the machine setting. Define "proper set up". It is different for different people's welding techniques.

Secondly, the technique used makes a difference. Some guys just push on ahead, in a straight line. This would take the least amount of time to perform.

Someone else might oscillate ( weave right/left ), or weave side-to side ( north/south) as they move along. This would be more time consuming.

The best way to tell if the bead is good, is to know what a good bead is supposed to look like. If it is too narrow, with a peaked crown, you're going too fast.

What you could do, is to do a practice piece (butt joint). Take 2 pieces of 3/16" thick steel, about 6" long, grind the weld area clean, and tack them up ( I recommend a 1/16" gap between the pieces, or better yet, bevel the pieces).

Weld them up, one side only. After it's cooled, put one of the pieces of steel in a vise, so that the weld, and the other piece of steel is just above the jaws of the vise. NOW, PUT ON YOUR SAFETY GLASSES! Then take a BFH and smack the top piece of steel, from the BACKSIDE...the side that you DID NOT WELD. You're trying to separate them. If they don't break after several gallant attempts, consider the weld a success.

If they DO break, look and see where the break occured. If the weld broke IN the weld joint, the weld wasn't too good. If the weld stayed together, and the base metal tore, then the weld was good.

 

Another test is to make apractice coupon and then cut it in half perpendicular to the weld. Look at the crossectiin for penetration. I like to pull the weld, in other words, aim the wire at the puddle and drag it backwards. The downside to mig welding is you can get a perfect looking weld with little penetration. As stated above, try to bend your weld. The weld should bend with the substrate . One of the tests done by certified welders is to butt weld a pipe, then put it in a bender, and bend 90 degress at the joint.
If it bends and doesn't crack, it passes.
If you feel your not getting enough penetration , increase the heat . The charts on the machines are just general. For a full pen weld, you should be able to see the weld burn in the backside of the coupon.