What is fusion bond epoxy /FBE coating for steel pipes?

Fusion Bonded Epoxy (FBE) Coated Line Pipe

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Anti-corrosive steel pipe refers to a steel pipe that is processed by anti-corrosive technology and can effectively prevent or slow down the corrosion phenomenon caused by chemical or electrochemical reactions in the process of transportation and use.
Anti-corrosion steel pipe is mainly used in domestic petroleum, chemical, natural gas, heat, sewage treatment, water sources, bridges, steel structures, and other pipeline engineering fields. Commonly used anti-corrosion coatings include 3PE coating, 3PP coating, FBE coating, polyurethane foam insulation coating, liquid epoxy coating, epoxy coal tar coating, etc.

What is fusion bonded epoxy (FBE) powder anti-corrosive coating?

Fusion-bonded epoxy (FBE) powder is a kind of solid material that is transported and dispersed by air as a carrier and applied on the surface of preheated steel products. Melting, leveling and curing form a uniform anti-corrosion coating, which is formed under high temperatures. The coating has the advantages of easy operation, no pollution, good impact, bending resistance, and high-temperature resistance. Epoxy powder is a thermosetting, non-toxic coating, which forms a high molecular weight cross-linked structure coating after curing. It has excellent chemical anti-corrosion properties and high mechanical properties, especially the best wear resistance and adhesion. It is a high-quality anti-corrosion coating for underground steel pipelines.

Classification of fused epoxy powder coatings:

1) according to the use method, it can be divided into: FBE coating inside the pipe, FBE coating outside the pipe, and FBE coating inside and outside the pipe. The outer FBE coating is divided into single-layer FBE coating and double-layer FBE coating(DPS coating).
2)According to the usage, it can be divided into: FBE coating for oil and natural gas pipelines, FBE coating for drinking water pipelines, FBE coating for fire fighting pipelines, coating for anti-static ventilation pipelines in coal mines, FBE coating for chemical pipelines, FBE coating for oil drill pipes, FBE coating for pipe fittings, etc.
3) according to curing conditions, it can be divided into two types: fast curing and ordinary curing. The curing condition of fast curing powder is generally 230℃/0.5~2min, which is mainly used for external spraying or three-layer anti-corrosion structure. Due to the short curing time and high production efficiency, it is suitable for assembly line operation. The curing condition of ordinary curing powder is generally more than 230℃/5min. Due to the long curing time and the good leveling of the coating, it is suitable for in-pipe spraying.

Thickness of FBE coating

300-500um

Thickness of DPS(double layer FBE) coating

450-1000um

standard of coating

SY/T0315,CAN/CSA Z245.20,

AWWA C213,Q/CNPC38,etc

Use

Land and underwater pipeline anticorrosion

Advantages

Excellent adhesive strength

High insulation resistance

Anti-aging

Anti-cathode stripping

Anti high temperature

Resistance to bacteria

Small cathode protection current (only1-5uA/m2)

 

Appearance

 Performance index Test method
Thermal characteristics Surface smooth, color uniform, no bubbles, cracks and holidays                                                       Visual inspection

24h or 48h cathodic disbondment (mm)

 ≤6.5

SY/T0315-2005

Thermal characteristics(rating of)

1-4

Cross-section porosity (rating of)

 1-4
3 degree centigrade flexibility(Order specified minimum temperature+3 degree centigrade

No track

1.5J impact resistance(-30 degree centigrade)

 No holiday
24h Adhesion(rating of)

1-3

Breakdown voltage(MV/m)

 ≥30
Mass resistivity(Ωm)

≥1*1013

Anti-corrosion method of fusion bonded epoxy powder:

The main methods are electrostatic spraying, thermal spraying, suction, fluidized bed, rolling coating, etc. Generally, friction electrostatic spraying method, suction method, or thermal spraying method are used for coating in the pipeline. These several coating methods have a common characteristic, that is needed before spraying the workpiece preheated to a certain temperature, melt powder a contact namely, heat should be able to make the film continue to flow, further flow flat covers the whole surface of the steel tube, especially in the cavity on the surface of the steel tube, and on both sides of weld molten coating into the bridge, combined closely with the coating and the steel tube, minimize pores, and curing within the prescribed time, the last water cooling solidification process termination.

API 5CT standard petroleum borewell seamless steel casing pipe for oil drilling

API 5CT Casing Pipe for Drilling Service

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In oil and gas exploration, ensuring the structural integrity of a wellbore is one of the most critical tasks. API 5CT casing pipes play a central role in this process, providing structural support and preventing the collapse of the wellbore, isolating different layers of underground formations, and protecting the well from external contamination. These pipes are designed and manufactured to meet the stringent requirements of drilling service, where harsh environments and extreme pressures are common.

This blog post provides a comprehensive guide on API 5CT casing pipes, covering their design, benefits, applications, grades, and key considerations for selecting the right casing pipe for drilling services. It will be particularly valuable for oil and gas professionals seeking to understand the role of casing pipes in well integrity and performance.

What is API 5CT Casing Pipe?

API 5CT is a specification created by the American Petroleum Institute (API) that defines the standard for casing and tubing used in oil and gas wells. API 5CT casing pipes are steel pipes placed into a wellbore during drilling operations. They serve several essential purposes, including:

  • Supporting the wellbore: Casing pipes prevent the wellbore from collapsing, especially in soft formations or high-pressure zones.
  • Isolating different geological layers: These pipes seal off the well from water-bearing formations, preventing contamination of freshwater aquifers.
  • Protecting the well from external pressure: Casing pipes protect the wellbore from the extreme pressures encountered during drilling, production, and injection operations.
  • Providing a path for production tubing: Once the well is drilled, casing pipes serve as a guide for production tubing, which is used to extract oil and gas from the reservoir.

The API 5CT specification defines various grades, material properties, testing methods, and dimensions to ensure that casing pipes meet the demanding requirements of drilling service.

Key Features and Benefits of API 5CT Casing Pipes

1. High Strength and Durability

API 5CT casing pipes are made from high-strength steel alloys designed to withstand extreme pressures and challenging downhole conditions. This strength ensures that the pipes can handle the weight of the overlying formations while maintaining well integrity.

2. Corrosion Resistance

Casing pipes are often exposed to corrosive fluids, such as drilling muds, formation waters, and hydrocarbons. To protect the pipes from corrosion, many grades of API 5CT casing are manufactured with corrosion-resistant coatings or materials, such as H2S-resistant steels for sour gas wells. This resistance helps extend the life of the well and reduces the risk of casing failure due to corrosion.

3. Versatility Across Different Well Conditions

API 5CT casing pipes come in various grades and thicknesses, making them suitable for different well depths, pressures, and environmental conditions. Whether for a shallow land well or a deep offshore well, there is an API 5CT casing pipe designed to handle the specific challenges of the application.

4. Enhanced Safety and Well Integrity

Casing pipes play a critical role in ensuring well integrity by providing a secure barrier between the wellbore and surrounding formations. Properly installed casing helps prevent blowouts, wellbore collapse, and fluid contamination, ensuring the safety of drilling personnel and the environment.

5. Meeting Stringent Industry Standards

The API 5CT specification ensures that casing pipes meet strict industry standards for mechanical properties, chemical composition, and dimensional tolerances. These pipes undergo rigorous testing, including tensile tests, hydrostatic pressure tests, and non-destructive evaluations, to ensure they meet the high standards required for oil and gas drilling.

API 5CT Grades and Their Applications

The API 5CT specification includes several grades of casing pipe, each designed for different drilling environments and well conditions. Some of the most commonly used grades include:

1. J55

  • Application: J55 casing pipes are commonly used in shallow wells where pressures and temperatures are relatively low. They are often used in oil, gas, and water wells.
  • Key Features: J55 is cost-effective and provides sufficient strength for shallow applications. However, it is not suitable for highly corrosive environments or deeper wells with high pressure.

2. K55

  • Application: K55 is similar to J55 but with slightly higher strength, making it suitable for similar applications but offering improved performance under higher pressures.
  • Key Features: This grade is often used in wells with moderate depths and pressures, particularly in onshore drilling operations.

3. N80

  • Application: N80 casing pipes are used in deeper wells with moderate to high pressures and temperatures. They are commonly deployed in oil and gas wells that require enhanced strength.
  • Key Features: N80 provides excellent tensile strength and is more resistant to collapse than lower grades, making it ideal for more challenging drilling conditions.

4. L80

  • Application: L80 is a sour service grade used in wells that produce hydrogen sulfide (H2S), a corrosive and toxic gas. This grade is designed to withstand sour gas environments without suffering from sulfide stress cracking.
  • Key Features: L80 is corrosion-resistant and has a high yield strength, making it suitable for deep wells and sour gas environments.

5. P110

  • Application: P110 casing pipes are used in deep, high-pressure wells where strength is critical. This grade is often employed in offshore and deep onshore wells.
  • Key Features: P110 provides high tensile strength and resistance to high-pressure environments, making it suitable for extreme drilling conditions.

Each grade has specific properties designed to meet the unique challenges of different well conditions. Choosing the right grade is crucial to ensuring well integrity and operational success.

API 5CT standard petroleum borewell seamless steel casing pipe for oil drilling

Key Considerations When Selecting API 5CT Casing Pipes

1. Well Depth and Pressure

One of the most critical factors when selecting a casing pipe is the depth of the well and the pressures encountered at that depth. Deeper wells require higher-strength casing materials, such as N80 or P110, to withstand the increased pressure and weight of the overlying formations.

2. Corrosion Potential

If the well is expected to produce sour gas or other corrosive fluids, it is essential to select a casing pipe grade that is resistant to hydrogen sulfide (H2S) and other corrosive elements. L80 is commonly used for sour gas wells, while J55 and K55 are suitable for wells with lower corrosion risk.

3. Temperature and Environmental Conditions

Wells drilled in high-temperature environments, such as geothermal wells or deep oil and gas wells, require casing pipes that can withstand extreme heat. High-strength grades like P110 are often used in these situations to provide resistance to thermal expansion and material fatigue.

4. Cost and Availability

The selection of casing pipes also depends on cost considerations. Lower grades like J55 and K55 are more cost-effective and suitable for shallow wells, while higher grades like P110 are more expensive but necessary for deeper, high-pressure wells. Balancing cost and performance is critical in casing pipe selection.

5. Joint Connections

API 5CT casing pipes can be fitted with various types of threaded connections, such as Buttress Threaded and Coupled (BTC) and Premium Threads. The choice of connection depends on the specific well design and operational requirements. High-performance connections are often required in wells with high torque or bending loads.

The Role of API 5CT Casing in Drilling Operations

1. Surface Casing

The surface casing is the first casing string set in the well after drilling begins. Its primary purpose is to protect freshwater aquifers from contamination by isolating them from the wellbore. J55 and K55 are commonly used for surface casing in shallow wells.

2. Intermediate Casing

Intermediate casing is used in wells with deeper formations to provide additional support and protection. This casing string isolates problem zones, such as high-pressure gas zones or unstable formations. N80 or L80 grades may be used for intermediate casing in wells with higher pressure and corrosive conditions.

3. Production Casing

The production casing is the final casing string set in the well, and it is through this casing that hydrocarbons are produced. Production casing must be strong enough to withstand the pressure and mechanical stresses encountered during production. P110 is commonly used in deep, high-pressure wells for production casing.

Testing and Quality Control for API 5CT Casing Pipes

To ensure the integrity and reliability of API 5CT casing pipes, manufacturers subject the pipes to stringent quality control measures and testing. These include:

  • Tensile Testing: Verifying the pipe’s ability to withstand axial forces without failure.
  • Hydrostatic Pressure Testing: Ensuring the pipe can withstand the internal pressures encountered during drilling and production.
  • Non-Destructive Testing (NDT): Methods like ultrasonic or magnetic particle testing are used to detect any flaws, cracks, or defects in the pipe material.

These tests help ensure that API 5CT casing pipes meet the mechanical and chemical properties required by the API standard and the demanding conditions of drilling operations.

Conclusion

API 5CT casing pipes are a crucial component in the oil and gas drilling process, providing the structural integrity needed to keep the wellbore stable, safe, and functional. Their strength, corrosion resistance, and versatility make them indispensable for various well environments, from shallow land wells to deep offshore operations.

By selecting the appropriate grade and type of API 5CT casing pipe based on well conditions, professionals in the oil and gas industry can ensure safe, efficient, and long-lasting well operations. Proper selection, installation, and maintenance of casing pipes are essential to avoid costly failures, protect the environment, and maximize the productivity of the well.

A brief guide to different types of carbon steel pipes

Classifications of Carbon Steel Pipes

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The manufacturing process of pipe is determined by the material, diameter, wall thickness, and quality for a specific service. Carbon steel piping is classified according to the manufacturing methods as follows:

  • Seamless
  • Electric resistance weld (ERW)
  • Spiral-submerged arc weld (SAW)
  • Double submerged arc weld (DSAW)
  • Furnace weld, butt-welded, or continuous weld

Seamless Steel Pipe

Seamless pipe is formed by piercing a solid, near-molten, steel rod, called a billet, with a mandrel to produce a pipe that has no seams or joints. The figure below depicts the manufacturing process of seamless pipe.

ERW Steel Pipe

ERW pipe is made from coils that are cupped longitudinally by forming rolls and a thin-pass section of rolls that brings the ends of the coil together to form a cylinder.

The ends pass through a high-frequency welder that heats the steel to 2600 °F and squeezes the ends together to form a fusion weld. The weld is then heat-treated to remove welding stresses and the pipe is cooled, sized to the proper OD, and straightened.

ERW pipe is produced either in individual lengths or in continuous lengths that are then cut into individual lengths. ERW is supplied according to ASTM A53 and A135 and API Specification 5L.

ERW is the most common type of manufacturing process due to its low initial investment for manufacturing equipment and the process’ adaptability in welding different wall thicknesses.

The pipe is not fully normalized after welding, thus producing a heat-affected zone on each side of the weld that results in non-uniformity of hardness and grain structure, thus making the pipe more susceptible to corrosion.

Therefore, ERW pipe is not as desirable as SMLS pipe for handling corrosive fluids. However, it is used in oil and gas production facilities and transmission lines, after normalized or cold expanded, for 26″ (660.4 mm) OD and larger lines.

SSAW Steel Pipe

The spiral-welded pipe is formed by twisting strips of metal into a spiral shape, similar to a barber’s pole, then welding where the edges join one another to form a seam. This type of pipe is restricted to piping systems using low pressures due to its thin walls.

SAW or DSAW pipe?

SAW and DSAW pipes are produced from plate (skelp’s), which are either formed into a “U” and then an “O” and then welded along the straight seam (SS) or twisted into a helix and then welded along the spiral seam (SW). DSAW longitudinal butt joint uses two or more passes (one inside) shielded by granular fusible materials where pressure is not used.

DSAW is used for pipe greater than 406.4 mm nominal. SAW and DSAW are mechanically or hydraulically cold expanded and are supplied according to ASTN Specifications A53 and A135 and API Specification 5L. It is supplied in sizes 16″ (406.4 mm) OD to 60″ (1524.0 mm) OD.

LSAW Steel Pipe

LSAW (LSAW) in leaflets plate as raw material, the steel plate in the mold or molding machine pressure (volume) into using double-sided submerged arc welding and flaring from production.

A wide range of finished product specifications, weld toughness, ductility, uniformity, and density, with a large diameter, wall thickness, high-pressure resistance, low-temperature corrosion resistance, etc.. Required steel pipe in the construction of high-strength, high toughness, high-quality long-distance oil and gas pipelines, mostly large diameter thick wall LSAW.

API standard provisions, in the large-scale oil and gas pipelines, when 1, Class 2 areas through the alpine zone, the bottom of the sea, the city densely populated area, LSAW only applied specifically casts.

The difference between hot rolled and cold rolled steel pipe

Hot-rolled Steel Pipe vs Cold-rolled Steel Pipe

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The difference between hot-rolled and cold-rolled steel pipe

The difference between hot-rolled and cold-rolled steel pipes mainly depends on the temperature of the rolling process. If it is over the recrystallization temperature, this process is called hot rolled; while if it is below the recrystallization temperature, this process is called cold rolled.

Process flow:

Hot rolled (extruded) seamless steel tube: round solid billet → heating → perforation → three-high cross rolling, continuous rolling or extrusion → tube stripping → sizing (or reducing) → cooling →billet tube→ straightening → hydraulic test (or flaw detection) → marking → storage.

Cold rolled (drawn) seamless steel tube: round solid billet → heating → perforation → heading → annealing → pickling → oiling (copper plating) → multi-pass cold drawn (cold rolled) → billet tube→ heat treatment → straightening → hydrostatic test (flaw detection) → marking → storage.

Products under different processes have different characteristics.

Hot Rolled Seamless Steel Pipe 

Advantages: it can destroy the casting structure of the ingot, refine the grain of steel, and eliminate the defects of microstructure so that the steel structure is compact and mechanical properties are improved. This improvement is mainly reflected in the rolling direction so that the steel is no longer isotropic to some extent; Bubbles, cracks, and porosity formed during pouring can also be welded together under high temperature and pressure.

Disadvantages: After hot rolling, the non-metallic inclusions (mainly sulfide, oxide, as well as silicate) inside the steel are pressed into thin sheets, resulting in lamination (interlayer). Lamination greatly degrades the tensile properties of the steel along the thickness direction and may lead to interlayer tearing during weld shrinkage. The local strain induced by weld shrinkage often reaches several times the yield point strain, which is much larger than the strain induced by the load. Residual stress caused by uneven cooling is the internal self-phase equilibrium stress under the action of no external force. The hot-rolled steel section of all sections has this kind of residual stress, the larger the section size of the general section, the larger the residual stress. Although the residual stress is self-phase equilibrium, it has a certain effect on the performance of steel members under the action of external forces. For example, it may produce adverse effects on deformation, stability, anti-fatigue, and other aspects. For hot-rolled steel products, it is difficult to control the thickness and side width. We are familiar with thermal expansion and cold contraction. Even if the length and thickness of the hot rolling reach the standard at the beginning, there will still be a certain negative difference after cooling. The wider the negative difference is, the thicker the thickness will be. So for large steel, it can not be too accurate in steel side width, thickness, length, angle, and edge line.

Cold Rolled Seamless Steel Pipe 

Advantages: Fast molding speed, high yield, and no damage to the coating. It can be made into a variety of cross section forms, to meet the needs of the usage conditions. Cold rolling can produce great plastic deformation of steel, thus raising the yield point of steel.

Disadvantages: Although there is no thermal plastic compression during the forming process, residual stress still exists in the section, which will inevitably affect the overall and local buckling characteristics of the steel. Cold rolled steel section is generally open section so that the section of the free torsional stiffness is low. Torsion is easy to occur in bending, bending and torsional buckling is easy to occur in compression, and the torsional resistance is poor. The cold rolled section steel wall thickness is smaller, and there is no thickening at the corner of the plate connection, so the ability to bear local concentrated load is weak.

Other aspects

  1. Dimension accuracy: cold rolled steel pipe has high accuracy in dimension;
  2. Appearance: The surface of cold-rolled steel pipe is bright, while the surface of hot-rolled steel tube has obvious oxidation skin or red rust;
  3. Diameter: The diameter of cold-rolled steel pipe is smaller than that of hot-rolled steel pipe (The diameter of hot-rolled steel pipe is larger than 32mm, and wall thickness is between 2.5-75mm; while the diameter of cold-rolled steel pipe can be 5mm, and wall thickness can be less than 0.25mm);
  4. Price: cold rolled steel tube is 1000-2000 more expensive than hot rolled steel pipe per ton;
  5. Use: Hot rolled steel pipe is used in the field in which dimensions are not so precise, such as fluid transport and mechanical structure; while cold rolled steel pipe is used in precision instruments, such as hydraulic systems, pneumatic…

If you have any needs or questions about hot rolled seamless steel pipe for various applications, welcome to consult and contact us!

Introduction of 3LPE Coated Line Pipe

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Brief introduction:

The base material of 3PE anti-corrosive coating steel pipe includes seamless steel pipe, spiral welded steel pipe and straight seam welded steel pipe. Three-layer polyethylene (3PE) anti-corrosive coating has been widely used in the oil pipeline industry for its good corrosion resistance, water vapor permeability resistance and mechanical properties. 3PE anti-corrosion coating is very important for the service life of buried pipelines. Some pipelines of the same material are buried in the ground for decades without corrosion, and some are leaked in a few years. The reason is that they use different coatings.

Anti-corrosion structure:

3PE anti-corrosion coating is generally composed of three layers of structure: the first layer is epoxy powder (FBE) > 100um, the second layer is adhesive (AD) 170 ~ 250um, the third layer is polyethylene (PE) 1.8-3.7mm. In the actual operation, the three materials are mixed and integrated, which are processed to be firmly combined with the steel pipe to form an excellent anti-corrosive coating. The processing method is generally divided into two types: winding type and circular mold covering type.

3PE anti-corrosive steel pipe coating (three-layer polyethylene anti-corrosive coating) is a new anti-corrosive steel pipe coating produced by an ingenious combination of 2PE anti-corrosive coating in Europe and FBE coating widely used in North America. It has been recognized and used for more than ten years in the world.

The first layer of 3PE anti-corrosive steel pipe is epoxy powder anti-corrosive coating, and the middle layer is copolymerized adhesive with a branch structure functional group. The surface layer is high-density polyethylene anti-corrosive coating.

3LPE anti-corrosive coating combines the high impermeability and mechanical properties of epoxy resin and polyethylene. Up to now, it has been recognized as the best anti-corrosive coating with the best effect and performance in the world, which has been applied in many projects.

Advantages:

The common steel pipe will be severely corroded in the bad use environment, which will reduce the service life of the steel pipe. The service life of the anti-corrosion and heat preservation steel pipe is also relatively long. Generally, it can be used for about 30-50 years, and the correct installation and use can also reduce the maintenance cost of the pipe network. The anti-corrosion and heat preservation steel pipe can also be equipped with an alarm system, Automatic detection of pipe network leakage fault, accurate knowledge of fault location, and also automatic alarm.

3PE anti-corrosion and heat preservation steel pipes have good heat preservation performance, and the heat loss is only 25% of that of traditional pipes. Long-term operation can save a lot of resources, significantly reduce energy costs, and still have strong water-proof and corrosion-resistant ability. Moreover, it can be directly buried underground or in the water without an additional pipe trench, which is also simple, rapid, and comprehensive in construction. The cost is also relatively low, and it has good corrosion resistance and impact resistance under low-temperature conditions, and it can also be directly buried in frozen soil.

Application:

For 3PE anti-corrosion steel pipe, many people only know one thing and don’t know the other. Its function is really wide coverage. It is suitable for underground water supply and drainage, underground shotcreting, positive and negative pressure ventilation, gas drainage, fire sprinklers and other pipe networks. Waste residue and return water transmission pipeline for process water of thermal power plant. It has excellent applicability for the water supply pipeline of anti-spray and sprinkler systems. Power, communication, highway and other cable protection sleeve. It is suitable for high-rise building water supply, heat supply networks, waterworks, gas transmission, buried water transmission and other pipelines. Petroleum pipeline, chemical and pharmaceutical industry, printing and dyeing industry, etc. Sewage treatment discharge pipe, sewage pipe and biological pool anti-corrosion engineering. It can be said that 3PE anti-corrosion steel pipe is indispensable in the current construction of agricultural irrigation pipes, deep well pipes, drainage pipes and other network applications, and it is believed that through the extension of science and technology, it will still have more brilliant achievements in the future.

If you need any kind of anti-corrosion coating steel pipes such as 3PE coating steel pipes, FBE coating steel pipes and 3PP coating steel pipes, etc. Please contact us!