You said your pipe was not made in the USA. I have had a big problem welding some pipe marked "made in India". Even with premium pipe It should be plenty strong to thread it. That is how it was designed.
Good luck,
David
I have a Hobart 140 110v riding around on a UPS truck today. Should be here tomorrow. $474.00 with a free cart, from Northern tool. Free shipping and no tax.
I chose it over the Lincoln because the drive looked stronger. and it was cheaper. I have never heard any bad comments about either...