ASTM A376 TP347H Heat-Resistant Stainless Steel Seamless Pipe

Stainless Steel Seamless Pipe ASTM A376 TP347/347H

ASTM A376 TP347H Stainless Steel Seamless Pipe is a high-performance material used in various industries for its excellent corrosion resistance, heat resistance, and mechanical strength. TP (Tribology Package) 347H refers to the specific grade of austenitic stainless steel, which is an alloy of iron, chromium, nickel, and molybdenum, with higher molybdenum content compared to standard 347.

Key features of ASTM A376 TP347H Seamless Pipe include:

When specifying or purchasing ASTM A376 TP347H Seamless Pipe, it's essential to consider factors like dimensions, wall thickness, tolerances, and any additional specifications required by the project's specifications or codes.

Chemical Analysis

Resistance to Corrosion of 347 Stainless Steel Pipes and Tubes
General Corrosion
Alloys 321 and 347 offer similar resistance to general, overall corrosion as the unstabilized chromium nickels Alloy 304. Heating for long periods of time in the chromium carbide precipitation range may affect the general resistance of Alloys 321 and 347 in severe corrosive media.
In most environments, both alloys will show similar corrosion resistance; however, Alloy 321 in the annealed condition is somewhat less resistant to general corrosion in strongly oxidizing environments than annealed Alloy 347. For this reason, Alloy 347 is preferable for aqueous and other low temperature environments. Exposure in the 800⁰F to 1500⁰F (427⁰C to 816⁰C) temperature range lowers the overall corrosion resistance of Alloy 321 to a much greater extent than Alloy 347. Alloy 347 is used primarily in high temperature applications where high resistance to sensitization is essential, thereby preventing intergranular corrosion at lower temperatures.

Physical Properties of 347 Stainless Steel Pipes and Tubes
The physical properties of Types 321 and 347 are quite similar and, for all practical purposes, may be considered to be the same. The values given in the table may be used to apply to both steels.
When properly annealed, the Alloys 321 and 347 stainless steels consist principally of austenite and carbides of titanium or columbium. Small amounts of ferrite may or may not be present in the microstructure. Small amounts of sigma phase may form during long time exposure in the 1000⁰F to 1500⁰F (593⁰C to 816⁰C) temperature range.
The stabilized Alloys 321 and 347 stainless steels are not hardenable by heat treatment.
The overall heat transfer coefficient of metals is determined by factors in addition to thermal conductivity of the metal. In most cases, film coefficients, scaling, and surface conditions are such that not more than 10 to 15% more surface area is required for stainless steels than for other metals having higher thermal conductivity. The ability of stainless steels to maintain clean surfaces often allows better heat transfer than other metals having higher thermal conductivity.

Mechanical Properties of 347 Stainless Steel Pipes and Tubes
Room Temperature Tensile Properties
Minimum mechanical properties of the stabilized Alloys 321 and 347 chromium-nickel grades in the annealed condition (2000⁰F [1093⁰C], air cooled) are shown in the table.
Elevated Temperature Tensile Properties
Typical elevated temperature mechanical properties for Alloys 321 and 347 sheet / strip are shown below. Strength of these stabilized alloys is distinctly higher than that of non-stabilized 304 alloys at temperatures of 1000⁰F (538⁰C) and above.
High carbon Alloys 321H and 347H (UNS32109 and S34700, respectively) have higher strength at temperatures above 1000⁰F (537⁰C). ASME maximum allowable design stress data for Alloy 347H reflects the higher strength of this grade in comparison to the lower carbon Alloy 347 grade. The Alloy 321H is not permitted for Section VIII applications and is limited to 800⁰F (427⁰C) use temperatures for Section III code applications.

Heat Treatment of 347 Stainless Steel Pipes and Tubes
The annealing temperature range for Alloys 321 and 347 is 1800 to 2000⁰F (928 to 1093⁰C). While the primary purpose of annealing is to obtain softness and high ductility, these steels may also be stress relief annealed within the carbide precipitation range 800 to 1500⁰F (427 to 816⁰C), without any danger of subsequent intergranular corrosion. Relieving strains by annealing for only a few hours in the 800 to 1500⁰F (427 to 816⁰C) range will not cause any noticeable lowering in the general corrosion resistance, although prolonged heating within this range does tend to lower the general corrosion resistance to some extent. As emphasized, however, annealing in the 800 to 1500⁰F (427 to 816⁰C) temperature range does not result in a susceptibility to intergranular attack.For maximum ductility, the higher annealing range of 1800 to 2000⁰F (928 to 1093⁰C) is recommended.