1/8" ball bearing canister stuck but didn't weld?

L

Leon Husock

Joined
Jul 17, 2019
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I made a canister with 1/8" balls made out of 1085. It worked like it was solid for a while, but when I peeled the can off it broke in half and revealed a texture that looked like all the balls had basically sintered together. They were stuck at room temperature, but not welded into a solid mass. Is it possible that the balls were too small and I couldn't fit enough powdered steel between them to facilitate the weld? I was setting the welds by hand, first with a small hammer and then switching to a sledge to make sure the force was getting all the way to the center of the billet.
 
In a setup where you will create lots of tiny voids … like a canister filled with 1/8" balls … layer the things in and vibrate the heck out of it. If you don't have a vibrator, use a hammer drill with a 1/2" bolt chucked in it.

An oblong canister (open top) is the wisest choice, around 2X2X4". I would not use white out or other paint. Put down a 1/4" layer of powdered steel and cover with a single layer of balls, Tap them down into the powder with a block of wood and vibrate the canister, repeat as you fill the canister and settle the balls down. Finish with a good layer of powdered steel and vibrate well. Weld on the top while clamped hard. As with all canisters, when you think it is soaked hot enough for long enough, heat it a good 15 minutes longer. The powder does not transmit heat like solid steel does and it tales a LOT longer for the center to get to welding heat. In the subsequent heats as you compact the billet and weld it, also soak longer than you think is needed. Use "V" (squaring) dies. By the time it is reduced by 25% or so, to around 1.5X1.5", it should be a solid bar of steel. Don't be in a hurry to cut the canister off. The longer the skin is on the longer the core is protected from oxidation and the solider it gets. Draw the billet out with the canister on and when it is a 1/2" thick flat bar, grind what's left of the canister skin off starting with the sides. By now it will be pretty thin. If the top and bottom peels away easily with an air chisel, fine. If not, just grind it all off. Of course if you have a surface grinder there really isn't any reason/need to peel it off.
 
Thanks, Stacy! Alas, my setup is pretty rudimentary as far as machinery goes (no vibrator, no surface grinder, no hammer drill but that I can probably get pretty cheaply). I'll keep all that in mind on the next one. I want to try a canister with stainless steel tumbling media in assorted shapes, all of which are pretty small, so I wanted to make sure I figured out what went wrong on the 1/8" bearings before I try that one since I know air will absolutely kill a stainless weld.
 
Just be advised that the tumbling media in the canister may not weld with the powder, and the stainless will not harden in HT.
 
Yeah, it’s an iffy project. I’m going to put a piece of 1084 in the center to act as a cutting edge. We’ll see if it works.
 
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