Oil and gas industry equipment is often exposed to highly corrosive environments. Using traditional metal in manufacturing means frequent wear and structural damage. That’s why it’s suggested that you opt for stainless steel. It’s durable, machinable, and corrosion-resistant. Want to know which stainless steel structural shapes are used in the oil and gas industry and their benefits? Continue reading!
Which Stainless Steel is Used in the Oil and Gas Industry?
The typical options used in the oil and gas industry include duplex, austenitic, martensitic, and precipitation-hardened stainless steel. That’s why stainless steel demand is seeing immense growth and is expected to hit USD 308.49 billion by 2033.
Let’s get into the details of different types of stainless steel that you can use for many applications:
Duplex Stainless Steel
Duplex stainless steel is known for its high durability and incredible toughness. When we look at its structure, it has a dual microstructure. It combines the beneficial properties of both ferritic and austenitic stainless steel. Hence, it has double the strength of traditional ferritic and austenitic versions.
The first duplex stainless steel grade was developed in the 1930s. This discovery was made by Avesta Ironworks in Sweden, which later became Outokumpu. Initial grades were sold to people who wanted high-strength and corrosion-resistant steel.
However, duplex stainless steel became more commercially successful in the 1970s.
Engineers achieved the right balance of ferritic and austenitic stainless steels. The steel’s increased corrosion resistance was suitable for downhill components in the oil and gas industry. The corrosion resistance is due to the high chromium content, which ranges from 18% to 28%.
The least resistant duplex stainless steel exhibits greater protection against corrosion than typical 316 and 304 grades. Other than that, it features a very small quantity of nickel and molybdenum. This reduces price fluctuation. Duplex stainless steel is a reliable and cost-effective option in the oil and gas industry.
Martensitic Stainless Steel
Another type of stainless steel used in the oil and gas industry is martensitic stainless steel. Due to its chemical composition, it can be hardened through heat and aging treatments. It contains 11.5% to 18% chromium, along with other elements such as 1.2% carbon and nickel.
The presence of carbon enhances mechanical strength, ensuring it performs well in the oil and gas sector. Its inception goes all the way back to 1890. German microscopist Adolf Martens first noticed the body-centered tetragonal microstructure.
Nonetheless, the first viable martensitic stainless steel was made in the US. It was done by an inventor named Harry Brearley. He found martensitic steel while attempting to manufacture corrosion-resistant gun barrels.
Since then, this material has been used in manufacturing different components, including oil and gas ones. The reason is its incredible corrosion resistance in CO2 and H2S environments. It’s budget-friendly than other fancy alloys and provides excellent mechanical properties.
Austenitic Stainless Steel
The term austenitic stainless steel is used to describe face-centered cubic alloys. It has excellent strength and resists both heat and corrosion. It was given its name after Sir William Chandler Roberts-Austen. He was known for his studies on the physical properties of metals.
Austenitic stainless steel’s history began in the early 20th century. It was with Monnartz’s discovery of passivity in Fe-Cr alloys in 1908. Then, research in Germany by Strauss and Maurer led to the first patents for high-chromium-containing steel.
They named it “V2A” or toVersuchsschmelze 2 Austenit and “Experimental Melt 2 Austenite.” This material showed properties similar to those discovered by Brearley. It is commonly used in the oil and gas industry as it withstands extreme temperatures and pressures. In addition, it can easily withstand the corrosive nature of crude oil and natural gas.
Precipitation Hardened Steel
The next one is the precipitation-hardened steel, which is heat-treated to enhance its strength. It provides tensile strengths of 850MPa to 1700MPa and yields strengths of 520MPa to over 1500MPa. This is way higher than the austenitic steel grades 316 and 304.
Precipitation hardening is achieved by the addition of metals, either singly or in combination. Some common elements include copper, aluminum, molybdenum, and titanium. The process of precipitation hardening steel dates back to the early 20th century.
In 1929, an inventor from Luxembourg, William J. Kroll, discovered it. He found that adding titanium to stainless steel and then heat treating it makes the steel stronger.
The first generation of PH stainless steel, 17-4 PH, was developed in the 1940s. These days, it’s part of the oil and gas industry as it offers a combination of high strength and corrosion resistance.
Ferritic structural steel shapes are also used in the oil and gas industry. They have high chromium content and little to no iron. Their widespread usage is because they are magnetic and non-hardened by heat. In addition, they show excellent resistance to stress corrosion cracking. This is important in the high-pressure and corrosive environments of the oil industry.
What Metals Have to Face in the Oil and Gas Industry?
In the oil and gas industry, components have to face many corrosive elements, such as:
- Cyanides: Cyanides are found in refinery effluents. It’s primarily from the catalytic cracking unit (FCCU), leading to corrosion and hydrogen blistering. For instance, hydrogen cyanide can enter amine systems through H2S-containing gases. This results in quick corrosion of the manufacturing equipment and other tools.
- Chlorides: Chlorides are crude oil contaminants that cause major issues in the oil and gas industry. They accumulate in various refinery equipment, including heaters and crude distillation units. Corrosion, equipment damage, and other operational issues result from these.
- Hydrogen Chloride: Hydrogen chloride is often produced during the refining of chloride-containing oil. It’s a highly corrosive agent that, in the presence of water, can lead to leaks and catalyst deactivation. Pipelines, reactors, and other equipment get damaged by this.
- Carbon Dioxide: Carbon dioxide, or CO2, is present naturally in oil and gas reservoirs. Dry CO2 isn’t corrosive. However, when dissolved in water, it forms carbonic acid. Hence, there’s severe corrosion of equipment and pipelines, also known as “Sweet Corrosion.”
- Ammonia: Ammonia is present in crude refining and other industrial processes. In the presence of hydrogen chloride, it transforms into ammonium chloride. This leads to corrosion, fouling, and pressure drops in different processes.
- Sulphur: Like carbon dioxide, sulphur is present naturally in the crude oil. It changes into SO2 due to combustion in the equipment. As a result, catalyst inhibition and corrosion in equipment and pipelines.
- Hydrogen: Hydrogen is present in either gas or atomic form. The major concerns due to its presence are hydrogen embrittlement and high-temperature hydrogen attack (HTHA). It’s because these cause weakening of materials and eventually cracking or other failures.
- Sulphuric Acid: Sulfuric acid acts as a catalyst, converting olefins into higher octane gasoline. However, it’s also highly corrosive and leads to the weakening of different metal structures.
- Phenols: Phenols are found in refinery operations and as fuel contamination. It can cause damage to seals and rubbers, as well as cause corrosion. All this impacts the stability and filtration of fuels in the oil and gas industry.
- Oxygen: Oxygen is present in the oil and gas industry in drilling fluids, gas streams, and pipelines. It can result in corrosion, especially if there’s hydrogen sulfide or moisture in the environment. You’ll see equipment damage as well as potential safety concerns.
- Polythionic Acid: Polythionic acid isn’t initially present in the oil and gas industry. However, it forms in the equipment due to exposure to sulfides, oxygen, and water. It occurs in FCC regenerators and leads to corrosion and cracking.
Applications of Stainless Steel in the Oil and Gas Industry
The applications of this steel in the oil and gas industry are diverse. Here are some common ones:
Hydrocracking
Hydrocracking is a refining process that breaks down large hydrocarbons into smaller, valuable ones. These include diesel and jet fuel, using hydrogen and a catalyst under high pressure.
This process has some concerns, like embrittlement and Polythionic stress-corrosion cracking. Therefore, many stainless steel grades, such as 304, 321, 347, 410, and 430, are used in hydrocracking equipment.
The goal is to prevent damage from corrosion and cracking. Common examples include heat exchangers, feed heaters, feed piping, and air coolers.
Delayed Coking
Delayed coking is a batch refinery process. It involves the conversion of low-value heavy oils into higher-value products using high temperatures.
Ammonia, cyanide, and hydrogen sulfide are all present during coking. That’s why coke drum pumps, fractionators, and recycled heat exchangers are made using stainless steel.
For high-temperature applications, grades 304 and 316 are used. On the other hand, for low-temperature processes, grades 410 and 405 are common.
Fluid Catalytic Cracking
Fluid catalytic cracking is the breakdown of hydrocarbons for gasoline production. It uses a sand-like catalyst and involves concerns such as high-temperature carburization of steel.
In addition, there are other challenges like oxidation and sulphonation. Austenitic stainless steel is therefore used for FCC equipment.
For instance, grades 304, 321, 347, 405, and 410 are employed in cyclone, air distribution, and injection systems. Some other applications include risers and reactor liners.
Crude Distillation
Crude distillation separates crude oil into different fractions based on their boiling points. It’s quite helpful in converting crude oil into useful products like gasoline, kerosene, and diesel.
While it’s a useful process, it brings challenges, including increased temperature sulphidation. Naphthenic acid Corrosion is another risk.
However, crude distillation equipment, including trays, draw lines, and preheat lines, now uses stainless steel. They become resistant to corrosion and other structural damage.
Gas Plants
Gas plants are actually natural gas processing facilities. They clean and prepare raw natural gas for transportation via pipelines. In addition, raw materials like natural gas undergo complex processes to produce valuable products.
However, the environment in these plants has chlorides, ammonia, and sulfides.
To avoid damage from these elements, stainless steel grades 304, 304L, 316, 316L, 329, 405, 410, and 26-1 are used in gas plants. Thus, equipment, including de-ethanizers and compressors, inter- and after-cooling tubes and shells, is protected.
Other applications include sulphuric acid alkylation, amine plants, and hydrogen plants.
Benefits of Using Stainless Steel in the Oil and Gas Industry
Stainless steel is becoming popular in the oil and gas industry for all the right reasons. Let’s explore a few of those:
- Corrosion Resistance: One of the primary benefits of stainless steel in the oil and gas industry is corrosion resistance. It can easily withstand harsh chemicals and environmental conditions. This significantly extends the lifespan of the equipment and makes maintenance an easy task.
- Cost-Effective: Some stainless steel grades are really inexpensive compared to other fancy materials. On top of this, they are very durable, lasting for years. The best part is that the maintenance costs are also very low. All this saves you money in the long run since you don’t have to spend much on replacement and maintenance. Just mild cleaning with soap and warm water is enough to restore its shine.
- Versatility: The versatility of stainless steel in the oil and gas industry is also top-notch. Some grades are very machinable. They can be transformed into different shapes, including pipes and trays. Hence, you can use them in various applications, from gas plants to alkylation.
- Sustainability: Stainless steel is 100% recyclable, which contributes to overall sustainability. The discarded steel can be used to make new products without losing quality.
How to Pick the Right Stainless Steel Grade for the Oil and Gas Industry?
There are many things you need to pay attention to when choosing the right stainless steel grade. These include strength, corrosion resistance, operating conditions, cost, and other applications. For general purposes, grade 304 is good. However, for complex environments, grade 316 or duplex stainless steel is the ideal option. They are more corrosion-resistant and can withstand changing temperatures and pressure.
Conclusion
Stainless steel is a must in the oil and gas industry if you want to make your processes efficient. If you struggle to find the right stainless steel for your needs, Jianglin is the right solution. We offer high-quality stainless steel products that perform well even in highly corrosive environments. Our steel is also competitively priced and durable, so you enjoy an incredible return on investment. Contact us now to get a great deal.
