ASTM A376 Standard Specification

/ A376M – 12 Standard Specification for Seamless Austenitic Steel Pipe for High-Temperature Central-Station Service

ASTM A312 Standard

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

This specification covers seamless austenitic steel pipe intended for high-temperature central-station service. The grades covered are five H grades and two nitrogen grades. Pipe may be either hot finished or cold finished, with a suitable finishing treatment. All pipes shall be furnished in the heat-treated condition unless the order specifically states that no final heat treatment shall be applied. Tensile tests, hydrostatic test, nondestructive electric tests, ultrasonic tests, eddy-current tests, tension tests, and flattening tests shall be made to conform to the requirements specified.

This abstract is a brief summary of the referenced standard. It is informational only and not an official part of the standard; the full text of the standard itself must be referred to for its use and application. ASTM does not give any warranty express or implied or make any representation that the contents of this abstract are accurate, complete or up to date.


1.1 This specification covers seamless austenitic steel pipe intended for high-temperature central-station service. Among the grades covered are H grades and nitrogen grades that are specifically intended for high-temperature service.

1.2 Optional supplementary requirements (S1 through S10) are provided. These supplementary requirements specify additional tests that will be made only when stated in the order, together with the number of such tests required.

1.3 Grades TP321 and TP321H have lower strength requirements for nominal wall thicknesses greater than 3/8 in. [9.5 mm].

1.4 The values stated in either inch-pound units or SI units are to be regarded separately as standard. Within the text, the SI units are shown in brackets. The values stated in each system may not be exact equivalents; therefore, each system shall be used independently of the other. Combining values from the two systems may result in non-conformance with the standard. The inch-pound units shall apply unless the “M” designation of this specification is specified in the order.

Note 1—The dimensionless designators NPS (nominal pipe size) and DN (Diametre Nominel) have been substituted in this standard for such traditional terms as “nominal diameter,” “size,” and “nominal size.”

Austenitic stainless steel

Austenitic steels have austenite as their primary phase (face centered cubic crystal). These are alloys containing chromium and nickel (sometimes manganese and nitrogen), structured around the Type 302 composition of iron, 18% chromium, and 8% nickel. Austenitic steels are not hardenable by heat treatment. The most familiar stainless steel is probably Type 304, sometimes called T304 or simply 304. Type 304 surgical stainless steel is an austenitic steel containing 18-20% chromium and 8-10% nickel.
Austenitic stainless steel can be tested by Nondestructive testing using the Dye penetrant inspection method but not the Magnetic particle inspection method. Primary stainless steel used in aviation construction. Chemical and steel industry applicableGrades are 308,308L,316,316L , 316LN Nitrogen bearing, 312, 309L, 310L L denotes carbon percentage less than .03% mostly used for corrosion heat resistance has work hardening properties welding primarily done by TIG and MMAW process however GMAW, FCW, SAW process are also used. Another grade 312 is used for dissimilar steel welding , also known as universal alloy steel as unknown composition steels can be welded. For high temperature application >600*C ss309,310 grades are preffered.

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