Knowledge

09MnNiDR low-temperature plate for -70°C service

Knowledge2026-09-05

Ethylene cold boxes, cryogenic tanks, deep-cold gas separation — once the medium falls below -45°C, ordinary vessel plate steps aside and nickel-bearing low-temperature steel takes the stage. 09MnNiDR is the volume leader in that band: -70°C impact guarantee, normalized delivery, and a friendlier price than high-nickel grades. Here is how it works and how to order it.

Why nickel: the source of cryogenic toughness

09MnNiDR follows GB/T3531 with carbon capped at 0.12% and nickel at 0.30–0.70%. Nickel lowers the ductile-brittle transition temperature; normalizing refines the grain. Together they keep impact energy up at -70°C. Read the grade: 09 is carbon in ten-thousandths, MnNi the main additions, D low temperature, R vessel.

The temperature ladder

GB/T3531 is a ladder of design temperatures: 16MnDR (-40°C) → 15MnNiDR (-45°C) → 15MnNiNbDR (-50°C) → 09MnNiDR (-70°C) → 08Ni3DR (-100°C, ~3.5% Ni) → 06Ni9DR (-165°C, ~9% Ni, Q+T). Design temperature picks the rung — stepping up wastes money; stepping down breaks the code.

09MnNiDR stencil: 10×2200×12000 mm, Xingeng, normalized + UT I — Side stencil: 10×2200×12000 mm, normalized, UT Class I

09MnNiDR face stencil with standard and UT class — Face stencil: standard and UT class at a glance

Ordering checklist

Impact test temperature per the minimum design temperature — state -70°C (or per drawing)
UT: plate by plate to Class II as a baseline, Class I for critical equipment
Z grade (Z15/Z25/Z35) for thick welded joints under through-thickness load
Condition: N or N+T, matched to the design property curves
Nickel steel is booking material — allow 4–6 weeks

Acceptance and storage

Beyond the usual checks, read the -70°C impact values heat by heat on the certificate — single and average values must both clear the standard. Store on dunnage, away from carbon-steel handling marks, and leave machining allowance on cut edges before the welding shop takes over.