Since the 753 is heat treated, a hardness test away from the heat affected zone (the immediate area of the joints) would work.
Just cut a sample out of the center of your tube, flatten it and do the ol Rockwell hardness test.
For enquiring minds that really want to know.
Great Notch, NJ
> At 12:10 AM 4/5/2004 -0400, Philcycles@aol.com ushered forth:
> >In a message dated 4/4/04 7:56:43 PM, firstname.lastname@example.org writes:
> > >You could collect some shavings of the metal and have it analyzed to know
> > >what alloying materials are there and in what proportions. You'd probably
> > >need to do the same with a known sample of 753 and some other steels for
> > >comparison purposes. No doubt a frightfully expensive proposition unless
> > >you
> > >know of a graduate student in metallurgy with some time on their hands
> > >and
> > >ready access to some pretty fancy analytical equipment.
> >Wouldn't work. 753 is heat treated 531.
> Metallurgical analysis should still work, but you'd probably have to look
> at other properties besides material composition, such as grain structure.
> Dave "former computer geek in a metallurgical lab" Baseley