ASTM A335 P91 High Temperature and High Pressure Resistant Seamless Alloy Pipe
1. Product Description:
High-temperature and high-pressure seamless pipes are alloy steel (or stainless steel) seamless pipes designed specifically for extreme operating conditions. They are primarily used in critical piping systems that transport fluids under long-term conditions of high temperature (typically >450°C), high pressure, and sometimes corrosive media. Due to the stringent requirements for safety, stability, and longevity, their production standards and material properties are far superior to those of ordinary seamless steel pipes.
2. Key Features
① Excellent High-Temperature Strength:
l High Endurance and Creep Strength: Under high temperature and high pressure, materials slowly deform (creep). This type of steel pipe exhibits extremely high creep resistance, maintaining structural integrity and preventing rupture throughout its design life (typically over 100,000 hours).
l Excellent Microstructural Stability: Under long-term high-temperature conditions, its internal metallographic structure (such as bainite and martensite) remains stable, preventing performance degradation caused by pearlite spheroidization and graphitization.
② Excellent Corrosion and Oxidation Resistance:
l Oxidation Resistance: The pipes are exposed to high-temperature, high-pressure fluids (steam, process gas, oil) within the pipes, while the outside of the pipes may be exposed to high-temperature flue gases. Alloying elements (such as Cr and Si) form a dense protective chromium oxide film, preventing continued oxidation.
l Corrosion Resistance: Able to withstand corrosion from specific process media (such as H₂S, CO₂, hydrogen environments, and sulfides). For example, hydrogen pipelines require strong resistance to hydrogen corrosion and hydrogen embrittlement.
③ Excellent Thermal Processing and Processing Performance:
l Excellent Welding Performance: The optimized chemical composition facilitates high-quality on-site welding and assembly, with low post-weld crack susceptibility.
l Excellent Cold Bending Performance: It can be cold or hot bent to meet the requirements of complex piping layouts, with stable post-bending performance.
④ High Quality Consistency and Reliability:
l Strict Non-destructive Testing: 100% undergoes ultrasonic testing (UT) and eddy current testing (ET) to ensure the absence of internal and surface defects.
l Comprehensive Performance Testing: Each batch of material undergoes rigorous mechanical property (tensile, impact, hardness), metallographic structure, and high-temperature endurance testing.
l Precise Dimensional Control: Strict tolerances on outer diameter and wall thickness ensure pressure-bearing capacity and reliable system connections.
3. Main Applications
This type of piping is the "artery" of the energy, petrochemical, and heavy industries, and is used in the following key areas:
① Power plant boilers and power generation systems (core application):
l Four major pipelines: main steam pipe, hot reheat section pipe, cold reheat section pipe, and high-pressure feedwater pipe.
l Key components: superheater, reheater, water wall, header, steam guide pipe, etc.
l Applicable units: subcritical, supercritical, and ultra-supercritical thermal power generating units.
② Petrochemical Industry:
l Hydrogen Pipelines: Pipelines used to transport high-temperature, high-pressure hydrogen and oil mixtures in hydrocracking, hydrorefining, and residue hydrotreating units.
l Process Pipelines: Pipelines used to transport high-temperature oil, gas, process gas, and catalysts.
l Heat Exchange Equipment: Manufacturing tube bundles for high-pressure heat exchangers.
③ Nuclear Power Industry:
l Used in the conventional island portion of nuclear power plants, such as the high-pressure feedwater system and auxiliary steam system (non-nuclear grade).
④ Other Industrial Fields:
l High-temperature and high-pressure pipelines in coal chemical plants (such as coal-to-gas and coal-to-liquids), natural gas processing, and chemical fertilizer plants.
High-temperature, high-pressure seamless pipes are a key foundational material for high-end industrial equipment and represent the pinnacle of seamless steel pipe manufacturing technology. Their selection and application directly impact the safety, efficiency, energy consumption, and lifespan of entire industrial installations, and are a crucial reflection of a nation's energy and heavy industry strength.
Tolerances of carbon seamless steel pipe
|
Pipe types |
Pipe sizes(mm) |
Tolerances |
|
Hot rolled |
OD<50 |
±0.50mm |
|
|
OD≥50 |
±1% |
|
|
WT<4 |
±12.5% |
|
|
WT 4～20 |
+15%, -12.5% |
|
|
WT>20 |
±12.5% |
|
Cold drawn |
OD 6～10 |
±0.20mm |
|
|
OD 10～30 |
±0.40mm |
|
|
OD 30～50 |
±0.45 |
|
|
OD>50 |
±1% |
|
|
WT≤1 |
±0.15mm |
|
|
WT 1～3 |
+15%, -10% |
|
|
WT >3 |
+12.5%, -10% |
|
NOMINAL PIPE SIZE |
OD(mm) |
||||||||||||||
|
DN |
NB(inch) |
ASME |
SCH10 |
SCH20 |
SCH30 |
STD |
SCH40 |
SCH60 |
XS |
SCH80 |
SCH100 |
SCH120 |
SCH140 |
SCH160 |
XXS |
|
15 |
1/2" |
21.3 |
2.11 |
|
2.41 |
2.77 |
2.77 |
|
3.73 |
3.73 |
|
|
|
4.78 |
7.47 |
|
20 |
3/4" |
26.7 |
2.11 |
|
2.41 |
2.87 |
2.87 |
|
3.91 |
3.91 |
|
|
|
5.56 |
7.82 |
|
25 |
1" |
33.4 |
2.77 |
|
2.9 |
3.38 |
3.38 |
|
4.55 |
4.55 |
|
|
|
6.35 |
9.09 |
|
32 |
1.1/4" |
42.2 |
2.77 |
|
2.97 |
3.56 |
3.56 |
|
4.85 |
4.85 |
|
|
|
6.35 |
9.7 |
|
40 |
1.1/2" |
48.3 |
2.77 |
|
3.18 |
3.68 |
3.68 |
|
5.08 |
5.08 |
|
|
|
7.14 |
10.15 |
|
50 |
2" |
60.3 |
2.77 |
|
3.18 |
3.91 |
3.91 |
|
5.54 |
5.54 |
|
|
|
8.74 |
11.07 |
|
65 |
2.1/2" |
73 |
3.05 |
|
4.78 |
5.16 |
5.16 |
|
7.01 |
7.01 |
|
|
|
9.53 |
14.02 |
|
80 |
3" |
88.9 |
3.05 |
|
4.78 |
5.49 |
5.49 |
|
7.62 |
7.62 |
|
|
|
11.13 |
15.25 |
|
90 |
3.1/2" |
101.6 |
3.05 |
|
4.78 |
5.74 |
5.74 |
|
8.08 |
8.08 |
|
|
|
|
|
|
100 |
4" |
114.3 |
3.05 |
|
4.78 |
6.02 |
6.02 |
|
8.56 |
8.56 |
|
11.13 |
|
13.49 |
17.12 |
|
125 |
5" |
141.3 |
3.4 |
|
|
6.55 |
6.55 |
|
9.53 |
9.53 |
|
12.7 |
|
15.88 |
19.05 |
|
150 |
6" |
168.3 |
3.4 |
|
|
7.11 |
7.11 |
|
10.97 |
10.97 |
|
14.27 |
|
18.26 |
21.95 |
|
200 |
8" |
219.1 |
3.76 |
6.35 |
7.04 |
8.18 |
8.18 |
10.31 |
12.7 |
12.7 |
15.09 |
18.26 |
20.62 |
23.01 |
22.23 |
|
250 |
10" |
273 |
4.19 |
6.35 |
7.8 |
9.27 |
9.27 |
12.7 |
12.7 |
15.09 |
18.26 |
21.44 |
25.4 |
28.58 |
25.4 |
|
300 |
12" |
323.8 |
4.57 |
6.35 |
8.38 |
9.53 |
10.31 |
14.27 |
12.7 |
17.48 |
21.44 |
25.4 |
28.58 |
33.32 |
25.4 |
|
350 |
14" |
355.6 |
6.35 |
7.92 |
9.53 |
9.53 |
11.13 |
15.09 |
12.7 |
19.05 |
23.83 |
27.79 |
31.75 |
35.71 |
|
|
400 |
16" |
406.4 |
6.35 |
7.92 |
9.53 |
9.53 |
12.7 |
16.66 |
12.7 |
21.44 |
26.19 |
30.96 |
36.53 |
40.19 |
|
|
450 |
18" |
457.2 |
6.35 |
7.92 |
11.13 |
9.53 |
14.27 |
19.05 |
12.7 |
23.83 |
39.36 |
34.93 |
39.67 |
45.24 |
|
|
500 |
20" |
508 |
6.35 |
9.53 |
12.7 |
9.53 |
15.09 |
20.62 |
12.7 |
26.19 |
32.54 |
38.1 |
44.45 |
50.01 |
|
|
550 |
22" |
558.8 |
6.35 |
9.53 |
12.7 |
9.53 |
|
22.23 |
12.7 |
28.58 |
34.93 |
41.28 |
47.63 |
53.98 |
|
|
600 |
24" |
609.6 |
6.35 |
9.53 |
14.27 |
9.53 |
17.48 |
24.61 |
12.7 |
30.96 |
38.89 |
46.02 |
52.37 |
59.54 |
|
|
650 |
26" |
660.4 |
7.92 |
12.7 |
|
9.53 |
|
|
12.7 |
|
|
|
|
|
|
|
700 |
28" |
711.2 |
7.92 |
12.7 |
15.88 |
9.53 |
|
|
12.7 |
|
|
|
|
|
|
|
750 |
30" |
762 |
7.92 |
12.7 |
15.88 |
9.53 |
|
|
12.7 |
|
|
|
|
|
|
|
800 |
32" |
812.8 |
7.92 |
12.7 |
15.88 |
9.53 |
17.48 |
|
12.7 |
|
|
|
|
|
|
|
850 |
34" |
863.6 |
7.92 |
12.7 |
15.88 |
9.53 |
17.48 |
|
12.7 |
|
|
|
|
|
|
|
900 |
36" |
914.4 |
7.92 |
12.7 |
15.88 |
9.53 |
19.05 |
|
12.7 |
|
|
|
|
|
|
Chemical Composition and Mechanical Properties
|
Standard |
Grade |
Chemical Components (%) |
Mechanical Properties |
|||||
|
|
|
C |
Si |
Mn |
P |
S |
Tensile STrength(Mpa) |
Yield STrength(Mpa) |
|
ASTM A53 |
A |
≤0.25 |
- |
≤0.95 |
≤0.05 |
≤0.06 |
≥330 |
≥205 |
|
|
B |
≤0.30 |
- |
≤1.2 |
≤0.05 |
≤0.06 |
≥415 |
≥240 |
|
ASTM A106 |
A |
≤0.30 |
≥0.10 |
0.29-1.06 |
≤0.035 |
≤0.035 |
≥415 |
≥240 |
|
|
B |
≤0.35 |
≥0.10 |
0.29-1.06 |
≤0.035 |
≤0.035 |
≥485 |
≥275 |
|
ASTM A500 |
A |
≤0.26 |
- |
≤1.35 |
≤0.035 |
≤0.035 |
≥310 |
≥230 |
|
|
B |
≤0.30 |
- |
≤1.40 |
≤0.045 |
≤0.045 |
≥400 |
≥290 |
|
|
C |
≤0.23 |
- |
≤1.35 |
≤0.035 |
≤0.035 |
≥425 |
≥315 |
|
|
D |
≤0.27 |
- |
≤1.40 |
≤0.045 |
≤0.045 |
≥400 |
≥250 |
Katherine A. Fogg
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