cracked weld

[Rusty4242]

OK, I finish stick welding a Northern splitter blade to the base plate and a backing plate with 7018 rods.Preped it well, even chamfered the edges, then I noticed one entire weld bead split right down its whole 6 inches. I did tack everything before welding a whole seam. Did it split because I should have done much heavier tacking? I went over it and put down a couple of slow, heavy beads. Seems to have taken care of the problem. Thanks, Larry

 

[jimgerken]

Sounds like cooling shrinkage cracking to me. Sometimes if the stress has no where to go, it will crack the weld. If both parts had been hotter it might not have happened. Otherwise, Weld an inch, stop, let it cool somewhat, then go to the other side and weld an inch, pause for cooling, back to first side, skip an inch and weld an inch, let cool, back to other side, skip an inch weld an inch, etc.

 

[Rusty4242]

Thanks, Larry

 

[Egon]

Are you sure you are using the correct rod??

 

[RonL]

My recollection is that those blades are standard A36 steel plate that is one inch thick. Probably needed pre-heating. Are the electrodes fresh? Low hydrogen rods need to be kept in a rod storage oven once they are opened. I fact, the reason you use low hydrogen rod is to lay in multiple stringers on heavy fabrication. Hydrogen causes the steel to become brittle. 7018 should be the correct rod to use in this situation. I believe Northern recommends this for this application.

RonL

 

[Egon]

My source says maybe a 6011 or so rod would make a difference.

 

[RonL]

Just read your "6011 instead of 7018" thread.

Not to sound like a "Madreferee" post but you may want to do a search on one of the welding sites with this question. "Mad" was right on with this advice.

Miller, Lincoln, and Esab have tons of information in their knowledge bases.

There is much more to welding and metallurgy than simply melting two pieces of steel. Good Luck.

RonL

 

[CRAFTBENDER]

My recollection is that those blades are standard A36 steel plate that is one inch thick. Probably needed pre-heating. Are the electrodes fresh? Low hydrogen rods need to be kept in a rod storage oven once they are opened. I fact, the reason you use low hydrogen rod is to lay in multiple stringers on heavy fabrication. Hydrogen causes the steel to become brittle. 7018 should be the correct rod to use in this situation. I believe Northern recommends this for this application.

RonL

A36 is low carbon hot rolled steel. Maybe the cutting edge has a hardened edge welded on.

 

[Egon]

Well maybe a 6013 rod then seeing as it was cleaned up good!

In actuality welding is merely melting two pieces of metal.

Oh where oh where is Thingy in time of need?

 

[RonL]

Egon

You are absolutely right! Welding is merely the melting together of metal. Getting the desired results may be a little more complicated.
The Northern site has two listings for splitter wedges. One still lists it as being A36 steel and recommends using 7018. The other simply states that it is "1045 hardness".
I am by no means an expert, but I would think that welding a 1 inch thick piece of any type of steel to a beam would entail using pre-heat and some type of low hydrogen rod.
For the price that Northern charges, I think that the wedges are simply a solid chunk of steel. I don't think they could afford to weld on a piece a tool steel for that price.

RonL