ASTM A312 TP347H Stainless Steel Seamless Pipe

ASTM A312, which covers seamless and welded austenitic stainless steel pipes for high-temperature and corrosive service. The "TP" designation stands for "Type," indicating a specific grade within the standard.

ASTM A312 TP347H seamless pipe is a premium choice for demanding environments requiring robust performance at high temperatures and resistance to corrosion, particularly in welded configurations. Its controlled composition and seamless manufacturing ensure reliability in critical industrial applications.

Material Grade (TP347H):
Grade 347H is a stabilized stainless steel with niobium (columbium) added to prevent chromium carbide precipitation during welding, enhancing resistance to intergranular corrosion.

The "H" suffix denotes high-temperature service, requiring a controlled carbon content (0.04–0.10%) for improved creep strength at elevated temperatures.

What is TP347H

TP347H is a specific grade of austenitic stainless steel designed for high temperature and corrosive service environments.

Alloy Stabilization: Contains niobium (Nb) to prevent the formation of chromium carbides during welding or high temperature exposure, reducing intergranular corrosion susceptibility.

High Temperature Strength: Maintains mechanical properties (e.g. creep resistance) up to 800°C (1472°F).

Corrosion Resistance: Resists oxidation, scaling and stress corrosion cracking in corrosive environments.

Higher Carbon Content: TP347H has a controlled carbon range (0.04–0.10%) compared to TP347 (up to 0.08%), which enhances creep resistance at elevated temperatures.

Optimized for Welding: Niobium stabilization minimizes the need for post-weld heat treatment, which reduces the risk of corrosion in welded joints.

Ideal for applications requiring long-term exposure to elevated temperatures (e.g., power plant boilers).

Outperforms non-stabilized grades (e.g., 304/316) in welded assemblies due to reduced risk of intergranular corrosion.

Balances cost and performance compared to alloys with higher nickel content such as Inconel.

ASTM A312 / A312M:Standard Specification for Seamless, Welded, and Heavily Cold Worked
Austenitic Stainless Steel Pipes

ASTM A269 / A269M:Standard Specification for Seamless and Welded Austenitic Stainless Steel Tubing
for General Service

ASTM A312 SS 347 stainless steel Pipe Mechanical Characteristics

ASTM A312 TP347 Composition Analysis

Equivalent of SA 312 TP 347 stainless steel Pipe