Oil Field Piping
Oil field piping is an integral component of the oil and gas industry, serving to transport crude oil and natural gas from drilling sites to refineries and processing plants.
There are a variety of materials used in oil field piping, with each offering unique properties and features for different applications.
In this article, we will focus on the properties and features of some of the most commonly used materials in oil field piping: AISI 4130, AISI 4140, ASTM A106, P5, P9, P11, P22, P91, and P92 (Cr-Mo Heat-resistant Steels).
AISI 4130 Steel
AISI 4130 steel is a low-alloy steel commonly used in oil field piping applications due to its high strength, toughness, and ability to withstand high pressures and temperatures. It is also known for its good weldability and machinability.
AISI 4130 steel is commonly known as Chromoly steel due to its main alloying elements.
Related Reading: AISI 4130 Steel Properties, applications.
AISI 4140 Steel
AISI 4140 steel is a high-strength, low-alloy steel that is commonly used in applications where strength, toughness, and wear resistance are critical, such as in the manufacturing of machinery, automotive parts, and oil and gas drilling equipment.
It is known for its excellent hardenability, good weldability, good fatigue and impact resistance, and the ability to be easily heat-treated for increased strength and hardness.
Related Reading: Everything you need to know about 4140 Steel.
ASTM A106 Steel
ASTM A106/ASME SA106 sets the standard for seamless carbon steel pipes intended for high-temperature applications. ASTM A106 pipes are available in three grades A, B, and C.
are widely used across various industries for different purposes including pipelines for the transmission of oil and gas, water, and mineral slurry, as well as in boiler, construction, and structural applications.
A106 Grade B is the most commonly used grade due to its availability and cost-effectiveness.
The chemical and mechanical properties of ASTM A106 Grade B are similar to those of ASTM A53 Grade B and API 5L B.
This general-use carbon steel has a minimum yield strength of 240 MPa and a tensile strength of 415 MPa.
Chrome-Moly Steels (heat resistant Cr-Mo alloy steels)
Chrome-moly steels, also known as Cr-Mo steels, are a group of low-alloy steels that contain chromium and molybdenum as alloying elements.
They are commonly used for high-temperature applications where elevated temperatures and high pressures are a concern.
The addition of chromium and molybdenum to the steel enhances its strength, toughness, and resistance to oxidation and corrosion at high temperatures.
Chrome-moly steels have excellent creep and rupture strength and can withstand temperatures up to 600°C (1112°F).
They are commonly used in power plants, refineries, petrochemical plants, and other high-temperature applications.
The most commonly used chrome-moly steels are:
- 1.25Cr-0.5Mo,
- 2.25Cr-1Mo,
- 5Cr-0.5Mo,
- 7Cr-0.5Mo,
- 9Cr-1Mo,
- 9Cr-1Mo-V.
Heat resistant chromium-molybdenum alloy steels belong to a group of deliberate ferritic alloy steels that are purposely formulated with chromium and molybdenum alloying elements. These alloy steels typically have a composition ranging from 0.5%- 9% Cr and 0.5%- 1.0% Mo, which work together to enhance the alloy’s creep strength and corrosion resistance at elevated temperatures, hence its name “heat resistant”.
These alloys are often used in the manufacturing of pressure vessels, steam boilers, heat exchangers, and piping systems.
The selection of the appropriate chrome-moly steel will depend on the specific application, operating temperature, and pressure requirements.
1.25Cr-0.5Mo Steel (P11 Material Grade)
The 1.25Cr-0.5Mo steel belongs to the family of low alloy heat-resistant steels of the Cr-Mo steel group and is commonly used for elevated temperature applications. The terms “1.25” and “0.5” refer to the nominal chemical composition of the alloying elements chromium and molybdenum respectively.
1.25Cr-0.5Mo Steel (P11 Material Grade) material specifications are ASTM A217-WC6, ASTM A426 CP11, ASTM A182 F11, ASTM A213 T11, ASTM A335 P11 and ASTM A387 11.
This steel is commonly used in the manufacturing of high-temperature pressure vessels and piping systems where its high strength, excellent corrosion resistance, and ability to withstand elevated temperatures make it an ideal choice.
Chromium enhances the steel’s oxidation and corrosion resistance, while molybdenum improves its creep strength at high temperatures.
ASME Codes usually associate 1.25Cr-0.5Mo with castings, whereas various wrought 1.25Cr-0.5Mo steels are furnished with silicon element addition (0.5~1.0%) and called “1.25Cr-0.5Mo-Si,” which enhances the steel’s elevated-temperature strength and resistance to scaling of low-chromium steels in air at elevated temperatures. The steel can be annealed, normalized and tempered, or quenched and tempered.
1.25Cr-0.5Mo steel has a maximum operating temperature of 593°C (1100°F) and can be easily welded and fabricated.
It is also known for its good creep and rupture strength, making it a popular choice for high-temperature applications in the oil and gas, petrochemical, and power generation industries.
2.25Cr-1Mo Steel (P22 Material Grade)
2.25Cr-1Mo steel is a low-alloy steel that contains 2.25% chromium and 1% molybdenum as alloying elements.
This steel is commonly used in the manufacturing of high-temperature pressure vessels and piping systems where its high strength, excellent corrosion resistance, and ability to withstand elevated temperatures make it an ideal choice.
2.25Cr-1Mo steel has a maximum operating temperature of 650°C (1200°F) and is known for its good creep and rupture strength.
It is also highly resistant to hydrogen-induced cracking and sulfide stress corrosion cracking, making it a popular choice for use in sour gas applications.
Additionally, it has good weldability and can be easily fabricated, making it a versatile choice for a wide range of high-temperature applications in industries such as oil and gas, petrochemical, and power generation.
5Cr-0.5Mo Steel (P5 Material Grade)
5Cr-0.5Mo steel is a low-alloy steel that contains 5% chromium and 0.5% molybdenum as alloying elements. This steel is commonly used in the manufacturing of high-temperature pressure vessels and piping systems, particularly in the petrochemical industry.
15Cr-0.5Mo Steel (P5 Material Grade) material specifications are ASTM A217-C5, ASTM A426 CP5, ASTM A182 F5, ASTM A213 T5, ASTM A335 P5 and ASTM A387 Gr. 5.
The addition of chromium to this steel provides excellent corrosion resistance, while the molybdenum improves its high-temperature strength and creep resistance.
In addition to its excellent mechanical and corrosion-resistant properties, 5Cr-0.5Mo steel has good weldability and can be easily fabricated.
It is commonly used in the manufacturing of heat exchangers, reactors, and other high-temperature processing equipment.
Its unique combination of strength, toughness, and corrosion resistance make it an ideal choice for applications where high-temperature and corrosive environments are a concern.
7Cr-0.5Mo Steel (P7 Material Grade)
7Cr-0.5Mo steel is a low-alloy steel that is highly sought-after for its excellent high-temperature strength and corrosion resistance.
This steel contains 7% chromium and 0.5% molybdenum as alloying elements, providing superior resistance to oxidation and high-temperature creep.
7Cr-0.5Mo steel is commonly used in the manufacturing of high-temperature pressure vessels, heat exchangers, and piping systems in the petrochemical industry.
The addition of chromium to this steel provides exceptional corrosion resistance, making it highly resistant to the corrosive effects of many chemicals and gases.
9Cr-1Mo Steel (P9 Material Grade)
The 9Cr-1Mo steel is a low-alloy steel that is widely used in various high-temperature applications, particularly in the oil and gas industry.
Its excellent resistance to corrosion and oxidation at elevated temperatures is attributed to the presence of 9% chromium in its composition.
Related reading: Welding Guide for 9Cr-1Mo-V Steel (P91 Material Grade)
It is widely utilized in the production of high-temperature pressure vessels, heat exchangers, heat exchanger plugging, and boilers, among others.
9Cr-1Mo-V Steel (P91 Material Grade)
9Cr-1Mo-V steel is a low-alloy steel that contains 9% chromium, 1% molybdenum, and small amounts of vanadium as alloying elements.
This steel is commonly used in the manufacturing of high-temperature pressure vessels and piping systems in the oil and gas industry.
Related reading: P91 Welding Guidelines.
The addition of chromium to this steel provides excellent resistance to corrosion and oxidation at high temperatures.
The molybdenum in this steel provides good creep strength at elevated temperature.
