Welding Tips and Tricks

If you were welding a fillet weld and didn't change your settings, assuming that the settings are within reason, at what angle or pitch does a weld start to loose its penetration and strength? Just a question that crossed my mind today and figured I'd have a good chance at getting the right answer here. Thanks.

Do you mean, "At what angle of 'downhill' does the penetration begin to be affected?"

That's a hell of a tough question without serious experimentation and empirical evidence.

The answers likely also depend on the joint design, tee versus groove, tee with beveling, etc.

Steve S

Yes, I meant angle of downhill. I know there are a lot of factors to consider like the joint and size of material but I was wondering if there was some kind of formula or something that someone had come up with in a class or something. You know, one of the things you might hear in welding school. Where I work my boss is totally against a downhill weld. Even if its noncritical he wants us to uphill.
I was just curious as to the losses in a downhill since we weld things on many different angles.

It would help to know what rod you are using, not all rods are rated to weld vertical down.

MinnesotaDave wrote:It would help to know what rod you are using, not all rods are rated to weld vertical down.

Mig Bro.

There are miles and miles of high pressure cross country pipelines welded every day with a downhill progression with very few failures. We don't have rivers and streams running full of oil products so it must have some strength. Throughout my life I've heard it said that uphill is 7 times stronger than downhill, uphill penetrates better, downhill traps slag, to all these things I say nonsense. Every process has it's place and if it's done correctly it can meet or exceed the strength of the parent metal without slag inclusion and get 100% penetration. What more can you ask of a weld?

There are some flux core wires that are made to run downhill and should be run that way, same goes for SMAW rods. Some are not.

Biggest thing to consider is if your boss, who I assume pays you, wants it done uphill then it's uphill. If there's a WPS involved then he's responsible to make sure it's done accordingly and is liable if it's not. There are codes in place to address and qualify almost any kind of weld dealing with pressure or strength that dictate progression. The good news is if your boss pays by the hour then you should be glad he wants all uphill because it's generally slower than downhill. If you're asking the question because you can produce a nicer looking weld downhill than you can an uphill one, then you need to change your end of the bargain.

I know that doesn't really answer your question directly but it might be as good as you're going to get because like Steve said, there's a lot of variables that come into the question.

Len

Ah, did not notice this is in the mig section, just hit the "new posts" button.

General rule of thumb for mig - vertical down only for 1/8" and thinner - vertical up for anything thicker.

Although vertical down can be used for the root pass of an open butt weld - Jody demonstrated it in a weld video recently.

Bottom line for me - boss says go up, and it's a well accepted practice - so up it is