P275NL2 and P355NL2 are European (EN 10028-3) fine-grain structural steels for pressure vessels, with 'P' for pressure, numbers for strength, and 'NL2' indicating normalization and low-temperature impact toughness down to -50°C, making P355NL2 a stronger variant for colder conditions than P275NL2, both prized for weldability in boilers, tanks, and piping.
Chemical Composition
|
P275NL2 Chemical Composition |
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|
Grade |
The Element Max (%) |
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|
C |
Si |
Mn |
P |
S |
Al(min) |
N |
|
|
P275NL2 |
0.16 |
0.40 |
0.5-1.40 |
0.025 |
0.015 |
|
0.02 |
|
Cr |
Cu |
Mo |
Nb |
Ni |
Ti |
V |
|
|
0.30 |
0.30 |
0.08 |
0.005 |
0.50 |
0.03 |
0.05 |
|
|
P355NL2 Chemical Composition |
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|
Grade |
The Element Max (%) |
||||||
|
C |
Si |
Mn |
P |
S |
Al(min) |
N |
|
|
P355NL2 |
0.18 |
0.50 |
0.9-1.70 |
0.025 |
0.015 |
|
0.02 |
|
Cr |
Cu |
Mo |
Nb |
Ni |
Ti |
V |
|
|
0.30 |
0.30 |
0.08 |
0.005 |
0.50 |
0.03 |
0.10 |
|
Mechanical Property
|
Grade |
|
P275NL2 Mechanical Property |
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|
Thickness |
Yield |
Tensilmie |
Elongation |
Impact Energy(KV J) min |
|||
|
P275NL2 |
mm |
Min Mpa |
Mpa |
Min % |
-20° |
0° |
+20° |
|
≤ 16 |
275 |
390-510 |
24 |
65 |
90 |
100 |
|
|
16> to ≤35 |
275 |
390-510 |
24 |
65 |
90 |
100 |
|
|
35> to ≤50 |
265 |
390-510 |
24 |
65 |
90 |
100 |
|
|
50> to ≤70 |
255 |
390-510 |
24 |
65 |
90 |
100 |
|
|
70> to ≤100 |
235 |
370-490 |
23 |
65 |
90 |
100 |
|
|
100> to ≤150 |
235 |
350-470 |
23 |
65 |
90 |
100 |
|
|
Grade |
|
P355NL2 Mechanical Property |
|||||
|
Thickness |
Yield |
Tensilmie |
Elongation |
Impact Energy(KV J) min |
|||
|
P355NL2 |
mm |
Min Mpa |
Mpa |
Min % |
-20° |
0° |
+20° |
|
≤ 16 |
355 |
490-630 |
22 |
65 |
90 |
100 |
|
|
16> to ≤35 |
355 |
490-630 |
22 |
65 |
90 |
100 |
|
|
35> to ≤50 |
345 |
490-630 |
22 |
65 |
90 |
100 |
|
|
50> to ≤70 |
325 |
490-630 |
22 |
65 |
90 |
100 |
|
|
70> to ≤100 |
315 |
470-610 |
21 |
65 |
90 |
100 |
|
|
100> to ≤150 |
295 |
450-590 |
21 |
65 |
90 |
100 |
|
Key Differences & Similarities
Standard: Both fall under EN 10028-3, the standard for weldable fine-grain steels for pressure equipment.
Strength: P355NL2 has a higher minimum yield strength (355 MPa) than P275NL2 (275 MPa), making it stronger and suitable for higher stress.
Toughness: The 'NL2' designation means both are tough at low temperatures, specifically impact tested to -50°C.
Applications: Used for pressure vessels, boilers, tanks, and pipelines, with P355NL2 favored for colder environments due to its higher toughness.
