ASME SA312 covers seamless, straight-seam welded, and heavily cold
worked welded austenitic stainless steel pipe intended for high
temperature and general corrosive service.
Product Analysis
At the request of the buyer, the analysis of one billet or one
length of flat-rolled stock from each heat, or two pipes from each
lot shall be made by the manufacturer. A lot of pipe shall consist
of the following number of lengths of the same size and wall
thickness from any one heat of steel:
Grade 316 is an austenitic stainless steel that can operate from
450 degrees Celsius to 850 degrees Celsius roughly. The range
differs depending on the pressure of a system, the components
flowing inside the pipe and the environment outside it. Marine
environment is full of chloride ions and the wind and water are
salty.
The salty conditions catalyze all forms of corrosions because they
act as a medium for electron transfer for oxidation and reduction
chemical reactions. The 316L has a lower carbon content than the
316 which means, there is less intergranular precipitation and
local corrosion due to welding. Also, the material has molybdenum
in addition to chromium and nickel which is specifically resistant
to chloride ion stress corrosion.
These properties make the pipe resistant to crevice and pitting
corrosion under chloride ion. Since the marine environments is full
of chloride ions, the 316L material is resistant to chloride ion
corrosion, has an operating temperature range up to roughly 850
degrees Celsius (1550F to be exact), the combination makes the
pipes suitable for piping projects in the marine industry and
temperature up to 850 degrees Celsius.
Hydrostatic or Nondestructive Electric Test
Each pipe shall be subjected to the nondestructive electric test or
the hydrostatic test. The type of test to be used shall be at the
option of the manufacturer, unless otherwise specified in the
purchase order.
For pipe whose dimensions equal or exceed NPS 10, the purchaser,
with the agreement of the manufacturer, may waive the hydrostatic
test requirement when in lieu of such test the purchaser performs a
system test. Each length of pipe furnished without the completed
manufacturer’s hydrostatic test shall include with the mandatory
markings the letters “NH.”
Nondestructive Electric Test:
Nondestructive electric tests shall be in accordance with
Specification A 999/A 999M.
