Views: 8 Author: Site Editor Publish Time: 2025-08-01 Origin: Site
Alloy steel pipes are a type of steel pipe made by adding chromium (Cr), molybdenum (Mo), nickel (Ni), manganese (Mn), vanadium (V) and other alloy elements to carbon steel. It has excellent properties such as high strength, high temperature resistance, corrosion resistance, and impact resistance, and is widely used in key fields such as petroleum, chemical, power, mechanical manufacturing, aerospace, etc.
Alloy steel pipes are made by adding alloy elements such as Cr (chromium), Mo (molybdenum), Ni (nickel), V (vanadium), Mn (manganese), Si (silicon), etc. to carbon steel, giving it the following outstanding characteristics:
Alloy elements such as Cr, Mo, and V can refine grain size, improve tensile strength and yield strength, and are suitable for high-pressure and heavy-duty environments.
30%~50% higher strength and better impact resistance than ordinary carbon steel.
Alloy steel pipes can be used for a long time at high temperatures of 500 ℃~800 ℃, suitable for boilers, thermal pipelines, etc. A dense oxide film (Cr ₂ O3) is formed on the surface to prevent further oxidation and corrosion.
High hardness, good wear resistance, acid, alkali, salt corrosion resistance, suitable for chemical and marine environments, mining machinery, and transportation pipelines.
Some alloy steels undergo special heat treatment and maintain high strength even after welding, reducing the risk of cracking. It can be processed in various ways such as cold bending, hot rolling, forging, etc.
The common alloy steel pipes are divided into two material standards: American standard and European standard. American standard is steel pipes produced according to the American Society for Testing and Materials (ASTM) standards, with the common material standard being ASTM A335; European standard refer to steel pipes produced in accordance with the European Norm standard system, with the common European standard being EN10216-2.
ASTM A335 is a common material standard for American standard alloy steel seamless pipes, which are widely used in fields such as petroleum, chemical, power, and nuclear energy. Its material contains alloy elements such as Cr, Ni, Mo, etc., which can improve the high temperature and high pressure resistance, corrosion resistance, and mechanical properties of steel pipes, and can be widely used in complex pipeline environments with high temperature and high pressure. The ASTM A335 alloy seamless pipe quality standard includes standard requirements such as chemical composition, mechanical properties, heat treatment methods, and inspection standards, ensuring that the performance of alloy seamless pipes produced according to this standard can meet the requirements of pipeline systems and environments.
ASTM A335 standard include various types of alloy materials such as P5/P11/P12/P22/P91, and the chemical composition and mechanical properties required in the standard are also different. In practical pipeline engineering applications, suitable materials can be selected according to different design requirements and environmental characteristics.
Chemical Composition
| CHEMICAL | LIMITS | C | Mn | P | S | Si | Cr | Mo | V | N | Ni | Al | Cb | Ti | Zr |
| ASTM A335 P5 | MIN | 0.30 | 4.0 | 0.44 | |||||||||||
| MAX | 0.15 | 0.60 | 0.025 | 0.025 | 0.50 | 6.0 | 0.65 | ||||||||
| ASTM A335 P12 | MIN | 0.05 | 0.30 | 0.80 | 0.44 | ||||||||||
| MAX | 0.15 | 0.61 | 0.025 | 0.025 | 0.50 | 1.25 | 0.65 | ||||||||
| ASTM A335 P22 | MIN | 0.05 | 0.30 | 1.90 | 0.87 | ||||||||||
| MAX | 0.15 | 0.60 | 0.025 | 0.025 | 0.50 | 2.60 | 1.13 | ||||||||
| ASTM A335 P91 | MIN | 0.08 | 0.30 | 0.20 | 8.00 | 0.85 | 0.18 | 0.03 | 0.06 | ||||||
| MAX | 0.12 | 0.60 | 0.020 | 0.010 | 0.50 | 9.50 | 1.05 | 0.25 | 0.07 | 0.40 | 0.02 | 0.10 | 0.01 | 0.01 |
Mechanical Properties
MATERIAL | ASTM A335 P5 | ASTM A335 P12 | ASTM A335 P22 | ASTM A335 P91 |
T.S (MPA) | 415 min | 415 min | 415 min | 620 min |
Y.S (MPA) | 205 min | 205 min | 205 min | 415 min |
EL % | 30 min | 30 min | 30 min | 20 min |
EN 10216-2 is the European standard for the production of seamless steel pipes for pressure applications. EN 10216-2 alloy steel pipes include various types of alloy materials such as 13CrMo4-5, 10CrMo9-10, X11CrMo5, X10CrMoVNb9-1, etc. The standard specifies the chemical composition and mechanical properties of each material to ensure that the performance of alloy seamless pipes produced according to this standard can meet the requirements of pipeline systems and environments.
Chemical Composition
CHEMICAL | LIMITS | C | Si | Mn | P | S | Cr | Mo | Ni | Al | Cu | Nb | V | N |
13CrMo4-5 | MIN | 0.10 | 0.40 | 0.70 | 0.40 | |||||||||
MAX | 0.17 | 0.35 | 0.70 | 0.03 | 0.02 | 1.15 | 0.60 | 0.30 | 0.04 | 0.30 | ||||
10CrMo9-10 | MIN | 0.50 | 0.30 | 2.00 | 0.90 | |||||||||
MAX | 0.15 | 1.00 | 0.70 | 0.03 | 0.02 | 2.50 | 1.10 | 0.30 | 0.04 | 0.30 | ||||
X11CrMo5 | MIN | 0.08 | 0.15 | 0.30 | 4.00 | 0.45 | 0.00 | |||||||
MAX | 0.15 | 0.50 | 0.60 | 0.03 | 0.02 | 6.00 | 0.65 | 0.04 | 0.30 | |||||
X10CrMoVNb9-1 | MIN | 0.08 | 0.20 | 0.30 | 8.00 | 0.85 | 0.06 | 0.18 | 0.03 | |||||
MAX | 0.12 | 0.50 | 0.60 | 0.02 | 0.01 | 9.50 | 1.05 | 0.40 | 0.04 | 0.30 | 0.10 | 0.25 | 0.07 |
Mechanical Properties
MATERIAL | 13CrMo4-5 | 10CrMo9-10 | X11CrMo5 | X10CrMoVNb9-1 |
T.S (MPA) | 440-590 | 480-630 | 430-580 | 630-830 |
Y.S (MPA) | 290 min | 280 min | 175 min | 450 min |
EL % | 22 min | 22 min | 22 min | 19 min |
The outer diameter range of steel pipes is 1/8 inch to 48 inches, and they are commonly used in high temperature and high pressure environments in industrial applications. Therefore, thick walled pipes are commonly found in the market; The length of alloy steel pipes is divided into fixed length and loose length. The fixed length is generally 11.8 meters or 12 meters per unit length; The production standards must comply with the American standard ASME B36.10.
Outer diameter (OD) range
Small caliber: Φ 10mm~Φ 89mm (suitable for instrument pipes and hydraulic systems)
Medium caliber: Φ 89mm~Φ 325mm (commonly used in petroleum and chemical pipelines)
Large caliber: Φ 325mm~Φ 1000mm+(suitable for power plant boilers and large structural components)
Wall thickness (WT) range
Thin walled tube: 1mm~5mm (used for lightweight structures and heat exchangers)
Conventional wall thickness: 5mm~20mm (for oil and gas pipelines)
Thick Wall&Extra Thick Wall: 20mm~50mm+(High Pressure Boiler Tubes, Nuclear Power Equipment)
Nominal Size | OD | Nominal Wall Thickness T | |||||||||||||
DN | NPS | OD | Sch10 | Sch20 | Sch30 | STD | Sch40 | Sch60 | XS | Sch80 | Sch100 | Sch120 | Sch140 | Sch160 | XXS |
6 | 1/8 | 10.3 | 1.24 | 1.45 | 1.73 | 1.73 | 2.41 | 2.41 | |||||||
8 | 1/4 | 13.7 | 1.65 | 1.85 | 2024 | 2024 | 3.02 | 3.02 | |||||||
10 | 3/8 | 17.1 | 1.65 | 1.85 | 2.31 | 2.31 | 3.20 | 3.20 | |||||||
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 | 2.90 | 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 | 1015 | |||||
50 | 2 | 60.3 | 2.77 | 3.18 | 3.91 | 3.91 | 5.54 | 5054 | 8.74 | 11.07 | |||||
65 | 2 1/2 | 73.0 | 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 | 15.24 | |||||
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 | 3.40 | 6.55 | 6.55 | 9.53 | 9.53 | 12.70 | 15.88 | 19.05 | |||||
150 | 6 | 168.3 | 3.40 | 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 | 12.70 | 12.70 | 15.09 | 18.26 | 20.62 | 23.01 | 22.23 |
250 | 10 | 273.0 | 4.19 | 6.35 | 7.80 | 9.27 | 9.27 | 12.70 | 12.70 | 15.09 | 18.26 | 21.44 | 25.40 | 28.58 | 25.40 |
300 | 12 | 323.8 | 4.57 | 6.35 | 8.38 | 9.53 | 10.31 | 14.27 | 12.70 | 17.48 | 21.44 | 25.40 | 28.58 | 33.32 | 25.40 |
350 | 14 | 355.6 | 6.35 | 7.92 | 9.53 | 9.53 | 11.13 | 15.09 | 12.70 | 19.05 | 23.83 | 27.79 | 31.75 | 35.71 | |
400 | 16 | 406.4 | 6.35 | 7.92 | 9.53 | 9.53 | 12.70 | 16.66 | 12.70 | 21.44 | 26.19 | 30.56 | 36.53 | 40.49 | |
450 | 18 | 457.0 | 6.35 | 7.92 | 11.13 | 9.53 | 14.27 | 19.05 | 12.70 | 23.83 | 29.36 | 34.93 | 39.67 | 45.24 | |
500 | 20 | 508.0 | 6.35 | 9.53 | 12.70 | 9.53 | 15.09 | 20.62 | 12.70 | 26.19 | 32.54 | 38.10 | 44.45 | 50.01 | |
550 | 22 | 559.0 | 6.35 | 9.53 | 12.70 | 9.53 | 22.23 | 12.70 | 28.58 | 34.93 | 41.28 | 47.63 | 53.98 | ||
600 | 24 | 610.0 | 6.35 | 9.53 | 14.27 | 9.53 | 17.48 | 24.61 | 12.70 | 30.96 | 38.89 | 46.02 | 52.37 | 59.54 | |
Tolerance of Outer diameter size and wall thickness
Outside Diameter D mm | Tolerances on | Tolerances on T for a T/D ratio | |||
D | |||||
≤ 0,025 | > 0,025 | > 0,050 | > 0,10 | ||
≤ 0,050 | ≤ 0,10 | ||||
D ≤ 219,1 | ± 1% or ± 0.5mm | ± 12,5% or ± 0.4mm whichever is the greater | |||
D > 219,1 | whichever is the greater | ± 20% | ± 15% | ± 12,5% | ± 10% a |
a For outside diameters D ≥ 355,6 mm it is permitted to exceed the upper wall thickness locally by a further 5% of the wall thickness T | |||||
Tolerance of Inner diameter size and wall thickness
Tolerances on inside diameter | Tolerances on T for a T/d ratio | |||||
d | d min | ≤ 0,03 | > 0,03 | > 0,06 | > 0,12 | |
≤ 0,06 | ≤ 0,12 | |||||
± 1% or ± 2 mm whichever is the greater | (+ 2% ,0)or (+ 4 mm,0) | whichever is the greater | ± 20% | ± 15% | ± 12,5% | ± 10% a |
a For outside diameters D ≥ 355,6 mm it is permitted to exceed the upper wall thickness locally by a further 5% of the wall thickness T | ||||||
Tolerance of Alloy Steel Pipes Length
Length L | Tolerance on exact length |
L ≤ 6000 | 10 |
0 | |
6000 < L ≤ 12 000 | 15 |
0 | |
L > 12 000 | + by agreement |
0 |
Oil&Gas
Chemical industry
Electric energy
Mechanical manufacturing
Automotive&Aerospace
Alloy steel pipes have become the core material of modern industry due to their advantages of high strength, temperature resistance, corrosion resistance, and long service life. We offer steel pipes in various materials and sizes, and support customized production to meet the needs of different industries.
