P690QH and P355QH are European (EN 10028-6) normalized/quenched & tempered steel grades for pressure vessels, indicating strength levels (690 MPa vs. 355 MPa minimum yield) and quality, with 'Q' meaning quenched and 'H' meaning normalized/quenched, designed for high toughness, good weldability, and performance in demanding, often high-temperature, industrial environments, contrasting with lower-strength structural steels like S355.
Chemical Composition
|
P355QH Chemical Composition |
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|
Grade |
The Element Max (%) |
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|
C |
Si |
Mn |
P |
S |
N |
B |
|
|
P355QH |
0.16 |
0.4 |
1.5 |
0.025 |
0.015 |
0.015 |
0.005 |
|
Mo |
Cu |
Nb |
Ni |
Ti |
V |
Zr |
|
|
0.25 |
0.3 |
0.05 |
0.5 |
0.03 |
0.06 |
0.05 |
|
|
P690QH Chemical Composition |
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|
Grade |
The Element Max (%) |
||||||
|
C |
Si |
Mn |
P |
S |
N |
B |
|
|
P690QH |
0.20 |
0.80 |
1.70 |
0.025 |
0.015 |
0.015 |
0.005 |
|
Mo |
Cu |
Nb |
Ni |
Ti |
V |
Cr |
|
|
0.70 |
0.3 |
0.06 |
2.50 |
0.05 |
0.12 |
1.50 |
|
Mechanical Property
|
Grade |
P355QH Mechanical Property |
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|
Thickness |
Yield |
Tensile |
Elongation |
|
|
P355QH |
mm |
Min Mpa |
Mpa |
Min % |
|
6-50 |
355 |
490-630 |
22% |
|
|
50-100 |
335 |
490-630 |
22% |
|
|
100-150 |
315 |
450-590 |
22% |
|
|
Grade |
P690QH Mechanical Property |
|||
|
Thickness |
Yield |
Tensile |
Elongation |
|
|
P690QH |
mm |
Min Mpa |
Mpa |
Min % |
|
6-50 |
690 |
770-940 |
14% |
|
|
50-100 |
670 |
770-940 |
14% |
|
|
100-150 |
630 |
720-900 |
14% |
|
P355QH Steel Plate
Standard: EN 10028-6, EN 10222-2.
Type: High-strength, fine-grain, normalized/quenched steel.
Properties: Good weldability, high toughness, resistance to cracking, excellent creep/fatigue resistance at high temps.
Application: Pressure vessels, boilers, structural components needing toughness.
Strength: Minimum yield strength around 355 MPa (hence '355').
P690QH Steel Plate
Standard: EN 10028-6.
Type: High-strength, quenched & tempered (Q&T) steel.
Properties: Superior strength, designed for high performance, excellent impact toughness, good weldability.
Application: High-pressure vessels, heavy machinery, demanding structural uses.
Strength: Significantly higher, minimum yield strength around 690 MPa (hence '690').
Key Differences & Similarities
Strength: P690QH is a higher strength grade than P355QH.
Application: Both are for pressure equipment, but P690QH handles more extreme pressures and stresses.
Processing: Both use quenching and tempering for their properties, differing in temperature/procedure to achieve their specific strength.
