Why this matters
LNG is stored and handled at around -162 degC, with safety margin pushing test temperatures to -196 degC (the boiling point of liquid nitrogen). At these temperatures, ordinary carbon steel and even 3.5% nickel steel become brittle. The industry standard for cryogenic LNG piping, plate and fittings is the 9% nickel steel family, codified in ASTM A553 Type I (plate), ASTM A333 Grade 8 (pipe) and ASTM A420 WPL8 (fittings).
Key technical facts
ASTM A553 Type I (9% nickel steel plate) typical chemistry and mechanical envelope:
| Property | Value |
|---|---|
| Carbon (C) | 0.13 max |
| Manganese (Mn) | 0.90 max (heat) |
| Phosphorus (P) | 0.015 max |
