Dynasty 300 Dx Help

[Lonny Doyle]

New test this morning.

Started with a scrap head.

I machined the head surface clean.

I welded the head with the old set up.
110 Freq.
75 Bal.
2% Ceria Tungsten

The moment the puddle forms you can see bubbles forming and opening to the surface. The bubbles do not seem to go away with time.

I went ahead and layed a bead. The bead looked clean from the outside with no visible signs of pitting.

I then switched regulators and line. It seemed to weld the same.

Next I removed all of our torch quick disconnects and installed a brand new torch with all new parts directly to the machine. I still see bubbles forming.

I then took a carbide burr and cut a trench 1/4 wide by 1/8 deep and removed some of the surrounding material. as soon as a puddle starts I see bubbles.

I set the balance to 50 and the frequency to 60. It welded slower but still bubbled.

I just went and remachined the deck surface to check the welds for pitting. All of the welds had about the same amount of pitting.

I have put the head back in the oven. Im going to raise the temp to 450 deg. to see if it affects the welds.

[dyn88]

Ive welded cyl heads before and it always seemed dirty till I acid washed the head and baked it at 600 degrees for two hours bolted to a torque plate. After it cooled completely I gouged area to be welded with a carbide burr and cleaned thoroughly with acetone then reheated to 400 and welded. After all that it seemed fine. Using 75% he 25% ar and some special rod that harris makes(dont remember the designation though). All this work was done while still bolted to the torque plate. All said and done it went back into the oven at 500 for 3 hours and ramped down to stress relieve. The machine shop said that the surfaces cleaned perfectly and the heads stayed flat within .003.

[Lonny Doyle]

Thanks

Thanks for the information. I tried heating the head 450 deg. and it help temendously. I use to heat the heads to 350 deg. with our Dial Arc and it worked fine. But I think the reason it worked was because it welded so slow that by the time it started to form a puddle it had the head considerably over 350 deg.

Now I just hope that taking these heads to 450 deg. does not compromise the heat treat of the head?

I guess we will see.

[dyn88]

absolutly not. as stated before you can go up to 600 but absolutely no more. remember your weld area will reach around 1700 at the arc and dwindle from there.