ASTM A312 / ASME SA312 TP304 TP304N TP304LN Stainless Steel Seamless Pipe

ASTM A312 TP304 / 1.4301 / 06Cr19Ni10 Stainless Steel Seamless Pipe Cold Drawn Pipe

Corrosion & Heat Resistance of ASTM A312 TP304, TP304N, TP304LN Stainless Steel Seamless Pipe

• General corrosion: All three are equivalent in most non-chloride environments (food, organics, oxidizing acids).

• Sensitization risk (weld heat affected zone):

  • TP304 – susceptible (carbide precipitation 425–870°C)

  • TP304N – same as 304

  • TP304LN – resistant (low carbon)

• Chloride pitting/crevice: All have same PREN ≈ 18-19 – not recommended for seawater or high-chloride hot water.

• Oxidation resistance: Good up to 870°C intermittent, 925°C continuous (same for all).

TP304 (standard)

• General chemical piping (low chloride)

• Food, dairy, brewery

• Heat exchangers (moderate temp)

• Sanitary tubing

TP304N

• High-pressure gas/liquid lines where higher strength allows thinner wall (cost saving)

• Pressure vessels (ASME Section VIII)

• Piping systems requiring reduced weight (offshore topside, platform piping)

• Where 304 strength is insufficient but 316 not needed

TP304LN

• Welded structures / heavy-wall pipe where post-weld heat treatment is impractical

• Nuclear secondary systems (low carbon + N gives good properties and weldability)

• Cryogenic service (austenite stable, good toughness)

• High-temperature service requiring long-term aging resistance