Machining a 1” Plate Welding Coupon

Erik, do you know any ways to control shrinkage like that? I don't, but I'd like to. I just think about these welders here who make multi-pass stringed welds on ships and submarines that are made of a spec made steel alloy armor plate, typically 1" for the outer hulls, sometimes vastly thicker. On modern build, the plates line up perfectly. On WWII era stuff, the plates look puckered like a patchwork quilt. I sure would like to learn how to control that shrinkage.
 
pontiac428 said:
Erik, do you know any ways to control shrinkage like that? I don't, but I'd like to. I just think about these welders here who make multi-pass stringed welds on ships and submarines that are made of a spec made steel alloy armor plate, typically 1" for the outer hulls, sometimes vastly thicker. On modern build, the plates line up perfectly. On WWII era stuff, the plates look puckered like a patchwork quilt. I sure would like to learn how to control that shrinkage.
Click to expand...

You just have to clamp them down better. The clamps that I used had a spring in them. If you use a clamp like the one in the photo below, the plates will stay flat while you weld them.

F88B1D57-95AB-46B5-B535-8F1B50F9C2AA.jpeg

I have these. That is what I will use next time. The reason I didn’t use them this time is because one of my clamps has a bit of spatter on the copper threads, & it prevents it from rotating.
 
Oh, quickly, that's why the threads ARE copper. The spatter brushes/pops/scrapes right off. Find the offending spatter ballie and dig it out, that tool is not ruined at all!
 
pontiac428 said:
Oh, quickly, that's why the threads ARE copper. The spatter brushes/pops/scrapes right off. Find the offending spatter ballie and dig it out, that tool is not ruined at all!
Click to expand...

Good to know, although I already tried that & it is going to require a file to remove the stubborn booger.

I decided that I am going to drill holes in the plate welding coupon as well as the platter that it sits on while I weld it and run bolts through there. Let’s see it warp then!
 
That's a plan! Then you can practice plug welds too. They would look like damascus spots in your coupon-top welding table after you face it off.
 
Here is my best effort for the second one of these that I have ever done.

Feel free to point out the defects. I see that the the bead is probably higher than 1/8” above the plate surface.

I probably should have knocked off the slag & gone over it with a stainless brush before the pictures, but I didn’t.

8E89F17C-5339-458E-8EB3-89DA8BDC60F7.jpeg

E3A7C942-DC83-4078-AF8D-1276E2F3E14C.jpeg

I had planned for the backside to be a backing strap, but I failed to get fusion on the backing strap.

Right now I am off to the steelyard for something else, & I am going to ask them if they can cut this in half for me.
 
The steel yard charged me $22 to cut it in their bandsaw.

Their welder was there, & he told me that I would have failed x-ray (which is obvious):

58FF08A5-C1AC-498F-8EAD-B560367A8DAA.png
 
Here is a picture of the top showing the discontinuities (including porosity).

My weld bead was supposed to be less than 1/8” tall, and it was .255”.

09CE4369-9C9F-4B10-8647-833477B537E3.png
 
Are you going to make coupons? If so, is your capable of bending 1"?
 
You must log in or register to reply here.
Back
Top