Welding Tips and Tricks

I am a mechanic on trucks and heavy equipment so i am around alot of welding and fabing. Today a guy was hard surfacing a bucket and every few minutes he would hit the weld he had just done with a hammer not to chip slag but to just hit the weld. I asked him what he was doing that for and he said it made the weld stronger. now i have been in this field for twenty years and i have weld alot of things and been around alot of welders and this is the first time i have ever heard of that.My question is did he know what he is talking about or is he full of it.

I don't know if it works with the hard facing rod. But with other materials, Copper, Aluminum, Brass and some steels beating it will work hardening it.
After working copper you have to anneal it to bring it back from the harden state.
This dead soft state lets you work the material, so it will not crack. With certain things when you are done working copper, brass and some alloys of aluminum. You can work harden the pieces to add some strength and rigidity. This is accomplished by hitting the piece with repeated blows, or a shot tumbler.

I have also head and seen people hitting the weld area with a hammer to relieve the heat induced stresses in the weld zone. I don't think whacking it once or twice with a hammer is going to do much.

But that is probably were it comes from.
glen

I've been a repair welder for over 31 years, most of it heavy equipment and logging. That definitely pegged my B S meter.
aflap

I believe what the fellow was welding was Cast Iron. I took an engine block with a crack in to be welded after getting a few reccomendations. I inquired as to the procedure and was told that the block had to be heated then welded with a cast iron compatible rod. Weld an inch and peen (hit the weld with a hammer) and continue for an inch and peen. Supposedly it stress relives the area. The block never reopened the crack so there must be some truth in this theory.

It may have something to do with the work-hardening thing. I know forging steel will harden and strengthen the metal.

You said he was welding "hard-face", he probably thought that peening the weld would keep it from cracking.
We have a "cutter-rebuild" department where I work. Those guys burn M-7 and 102-G hardface wire all day (and night) long without peening their welds. Sometimes they get some cross-checking but nothing that affects the end result.
I have heard of peening/stress-relieving to reduce weld shrinkage and cracking but it is not a commen thing.

go to lincoln's website and go to resources and you'll find an article about cracks in hardfacing process. its actually a good thing but doesn't mention anything about peening the weld. hope it helps