MBsims,
You wrote "If this is for pressure-retaining service, you can't manufacture tube or pipe from machining hot-rolled or cold-rolled bar. The end product will be susceptible to rupture due to the directionality of the grain structure and inclusions/stringers."
Now I must Question if this practice is acceptable..........
Doesn't this depend on the diameter? According to UG-14(b) it is permitted up to and including NPS 4 (DN 100) provided the other requirements of UG-14(b) are met.
From the code...
UG-14 Rods and bars (b)
Except for flanges of all types , hollow cylindrically shaped parts (up to and including NPS 4 (DN100) may be machined from ROLLED or forged bar , provided that the axial length of the part is approx parallel to the metal flow lines of the stock.
Correct me if im wrong ...... but isnt cold drawn out of the question?
The dia of the tube i have is 3.75 this is smaller than NPS 4 ............ correct?
UG-14 indicates to me that this practice is acceptable within its limits.
MDK