The oil and gas industry has strict requirements for materials that must operate in aggressive and extreme conditions. To ensure the necessary reliability and durability, special steels with specified physical and mechanical properties are required that can withstand high pressures, temperatures and aggressive environments. In this article, we will look at the basic requirements for materials, popular grades of steels and alloys, as well as their use in various types of equipment.
Basic material requirements
Equipment in the oil and gas industry is exposed to high temperatures (up to +600°C and above), aggressive chemical media, including acids, bases and salts, as well as significant mechanical loads. To operate reliably under such conditions, steels and alloys must have the following characteristics:
- Strength and wear resistance. Materials must withstand mechanical loads up to 300 MPa and above. For example, in deep-sea drilling, the pressure can reach several hundred atmospheres. The use of high-strength steels with a yield strength of more than 600 MPa helps to avoid equipment failures under high loads.
- Resistance to aggressive environments. Contact with hydrogen sulfide and carbon dioxide contained in the extracted oil and gas causes corrosion. Nickel and chromium-based alloys, such as Inconel 625 and analogues, are resistant to stress cracking, which is very important in hydrogen sulfide deposits.
- Heat resistance. Materials must maintain mechanical properties at temperatures above 500°C, for example, during catalyst regeneration or oil cracking processes. Iron and nickel-based alloys, such as Inconel 718 and analogues, remain strong at temperatures up to 700°C, which makes them irreplaceable in heat exchangers and turbines.
- Corrosion resistance. In corrosive environments, such as seawater or acidic solutions, materials with increased resistance to pitting and crevice corrosion are required. For example, austenitic steels 12X18H10T et 10X17N13M3T they have excellent resistance to various types of corrosion due to their high content of chromium (up to 18%) and molybdenum (up to 3%).
- Tightness. Equipment operating under high pressure requires reliable seals that are resistant to chemically active media. Modern metal and polymer gaskets based on fluoroplastics and graphite are widely used to seal joints.
- Environmental friendliness. Special materials must prevent the leakage of toxic substances and withstand the effects of aggressive oil and gas fractions. For example, when operating equipment in Arctic conditions not only corrosion resistance is important, but also the ability of materials to withstand prolonged exposure to low temperatures (up to -60°C) without losing their properties.
- Processability. The good weldability and machinability of steels are very important. High-alloy alloys (for example, those containing more than 18% chromium) require special welding modes to avoid cracking and reducing the corrosion resistance of welds. Modern laser and plasma welding technologies make it possible to minimize these risks.
For especially harsh operating conditions additional properties may be required, such as increased vibration resistance or resistance to ultra-low temperatures (up to -160°C). The latter is relevant for heat exchangers at liquefied natural gas plants and vessels for transporting LNG.
The main equipment used in the oil and gas industry
The production, transportation and refining of oil and gas require the use of various types of equipment, each of which must meet unique requirements. Let's look at the main types of equipment and materials used for their manufacture:
- Pump and compressor pipes — for lifting oil and gas from wells. They must withstand high pressures and temperatures, as well as be resistant to corrosion. For their manufacture, steels with a high content of chromium (13-15%) and nickel (9-12%) are mainly used, as well as internal coatings such as glass enamel or polymers that are resistant to chemical effects.
- Casing pipes — strengthen the walls of the well, preventing rock shedding. High-alloy steels with the addition of molybdenum (for example, 13HF) provide high strength and resistance to hydrogen sulfide cracking, which is especially important when developing deep wells.
- Fountain fittings — a set of devices for sealing the wellhead, resistant to high pressures and temperatures. Modern materials, such as inconel alloys, are used in fountain fittings to protect against high-temperature corrosion and premature wear.
- Pumping rods — transmit the movements of the pump to lift the liquid. Strength and wear resistance are particularly important characteristics for them.
- Tanks and tanks — for storing and transporting petroleum products. Materials must be resistant to chemical effects and temperature changes.
- Pipeline valves — for controlling the flow of liquids and gases. It must be airtight and resistant to aggressive environments.
- Heat exchangers — devices for transferring heat between media with different temperatures. Heat resistance and corrosion resistance are important. Nickel-based alloys (HN78T, X20N80) ensure stable operation at temperatures above 1000°C.
- Column equipment and reactors — for refining and separating oil into fractions. Materials must withstand chemical reactions and extreme temperatures. Austenitic steels with a high content of chromium and nickel (12X18H10T, 10X17H13M3T) provide resistance to intergranular corrosion and oxidation in corrosive media.
All these devices, as well as devices for carrying out chemical reactions (reactors) and furnaces for heating and heat treating raw materials, require the use of special steels to ensure durability and reliable operation in aggressive environments. The compliance of the materials used with their requirements directly affects the safety, efficiency and profitability of oil and gas enterprises.
Steels and alloys for oil and gas equipment manufactured by PZPS
Due to special operating conditions, materials for the oil and gas industry must combine resistance to extreme temperatures and various types of corrosion, as well as high strength characteristics. Here are a few grades of steels and alloys that meet industry requirements:
- Corrosion resistant steels. Brands like 12X18N9, 12X18N10T, 12X18N9SMR and 10X17H13M3T are highly resistant to pitting corrosion, which makes them suitable for pipes and equipment operating in sea water and aggressive chemical environments. The addition of molybdenum increases resistance to acid corrosion.
- Heat-resistant alloys. Inconels 625 and 718, whose analogues are produced by PZPS, as well as alloys 20X13, KhN78T and other chromium- and nickel-based alloys retain their strength characteristics at extremely high temperatures. They are used in oil and gas processing equipment, where high heat resistance and oxidation resistance are required.
- Heavy duty steels. For equipment operating under extreme loads, steels with a high content of vanadium and niobium are used, which provide a yield strength of up to 900 MPa. Such alloys are used for deep-water pipelines and high-load drilling equipment elements.
These materials are used for the manufacture of various elements of oil and gas equipment, such as:
- Pump and compressor housings — to prevent wear and corrosion.
- Pipes and pipelines — for transporting oil and gas under high pressure and at high or low temperatures.
- Reactor and furnace parts — to improve the durability of equipment operating at high temperatures and chemically active media.
- Seals and gaskets — to ensure tightness, protect against leaks, and increase the reliability and efficiency of equipment.
The use of special steels and alloys in the oil and gas industry is a key factor that ensures the reliable operation of equipment under extreme loads and corrosive environments. PZPS offers a wide range of products that meet the most stringent requirements, guaranteeing high quality materials and a long equipment life.
Not only PZPS produces and sells popular alloys for critical use, but also provides a complex production services. If you need to develop a technology for smelting an analogue of a foreign alloy or create innovative products for solving specific production problems, contact us at phone or leave application on the site. We will conduct all the necessary research and launch the production of products from pilot to industrial batches.
