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.