Pipe swage dies need help

[781]

I am trying to make a set of spring seage pipe dies.
I make them out of the bottom web of track rail top and bottom are each 6" long.
I made an 2 oblong 1/2 round cut out in both top and bottom. These were radiused so no sharp edges.
I heated a pice of 2" black iron pipe and began swaging.
The first cut out brought it down to about 1" or slightly larger.
When I switch to the small hole the pipe shears off.
I doesnt appear to be getting too thin just breaks off
When I look at the sheared end it loks like it has very large grain.

What am I doing wrong?
Not hot enough?
Dies not radiused enough?
Bad pipe?
too thin pipe?

[CurlyGeorge]

Got any pix? I'd like to see the swage that you made. Thanks.

[Don A]

I'd say you need to have a good heat going in, and don't work it too cold.

Also, are you rotating the pipe as you swage?

Try reversing the direction of the rotation each time you make a full 360 (360 clockwise, 360 counter clockwise, etc.).
It's possible you could be twisting the swaged area if you're only going in one direction (say, clockwise only). This would cause more stress in the necked portion.

Don