Specifications of ASTM A312 TP

Steel steel pipes are used in a wide variety of applications. From plumbing to ducts, stainless steel pipe is an integral part of the modern world.


Some stainless pipe applications, such as in the food industry, require a pipe that is resistant to corrosion. For this use, is an ideal choice, as it regulates multiple features of the pipe including the material and strength attributes.

ASTM A312 Standard

ASTM A312 Standard Specification for Seamless, Welded, and Heavily Cold Worked Austenitic Stainless Steel Pipes

ASTM A312 Gr.TP304-S NPS12 / SCH40

  • ASTM: American Society for Testing and Materials(美國材料試驗協會),Founded in 1898, the the nonprofit international standard-setting organization, is committed to meet the standardization needs of the global market, industry standard authority, the task is to develop the standard of materials, products, systems, and testing services; contains, including metals, oil, iron and steel, textiles, plastics, electronic products, medical equipment service, special chemicals and other related standards documents.
  • ASTM A312: Specification number
  • Gr.: Grade
  • TP: Tube pipe
  • 304: Steel grade
  • S: Seamless
  • NPS: Nominal Pipe Size
  • SCH: Pipe Schedule, SCH size

The exact chemical composition of ASTM A312 TP varies. However, 304 stainless steel is the most common steel used, which typically contains about 0.08 percent carbon, 0.75 percent silicon, 2 percent manganese, between 16 and 20 percent chromium, between 8 and 14 percent nickel, less than 0.03 percent sulfur and less than 0.04 percent phosphorous. The rest of the steel is composed of iron as a base element.

Pressure Ratings
One of the most important pipe specifications when considering a pipe for a particular application is the material’s pressure rating. This rating, measured in kilogram per square inch (ksi), is dependent on the temperature of the material. At 100 degrees Fahrenheit, A 312 TP has a pressure rating of 16.7 ksi. As the temperature increases the pressure rating decreases. At 500 degrees the temperature rating is 14.8 ksi, 13.5 at 700 degrees, 12.8 at 850 degrees, 7.8 at 1,000 degrees and only 4 ksi at 1,150 degrees.

Other Specifications
The steel most commonly used in A312 TP pipe—304 stainless steel—has a tensile strength of 525 newton per millimeter. The yield strength of the steel is typically rated at 205 N/mm. The elongation percentage, or the amount of stretch the steel can undergo without breaking, is 35 percent.

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