API 5L and API 5CT seamless steel pipe
We supply high-performance API 5L and API 5CT seamless steel pipes at competitive prices directly from our manufacturing network. Catering to the foundational needs of the oil and gas industry, our portfolio includes API 5L Grade B line pipe for surface gathering and transmission, and API 5CT grades such as J55, K55, N80, and P110 casing for wellbore integrity. These pipes, manufactured through advanced seamless processes, provide the essential strength, pressure integrity, and environmental resistance required for drilling, completion, and production operations. As direct suppliers, we bridge the gap between mill production and project execution, offering cost-effective solutions without compromising on the stringent quality mandates of API (American Petroleum Institute) standards. Our pipes are engineered to withstand high internal pressures, external loads, and corrosive downhole environments, serving as reliable conduits for hydrocarbon extraction and transport.
Product parameters
| Product name | seamless pipes, ERW pipe, DSAW pipes. |
| Standard | ASME B36.10M, API 5L, ASTM A312, ASTM A213. ASTM A269, etc |
| Material | Carbon steel: A106 GR B, A53 GR B,ASTM A333 GR 6 etc. |
| Cr-Mo alloy: A335 P11, A335 P22, A335 P12, A335 P5, A335 P9, A335 P91,etc | |
| Pipeline steel: API 5L GR B, API 5L X42, API 5L X46, API 5L X56, API 5L X60, API 5L X65, API 5L X70,etc | |
| OD | 3/8" -100" , customized |
| Wall thickness | SCH5S SCH10S, SCH10, SCH20,SCH30, SCH40S, STD, SCH40, SCH80S, SCH80,
XS, SCH60,SCH100, SCH120,SCH140,SCH160,XXS, customized , etc |
| Length | 5.8m, 6m, 11.8m, 12m, or as required |
| Surface | Black painting, 3PE coating, other special coating, etc |
| Application | Stainless steel pipe widely used in petroleum,chemical industry,electric power, boiler,high temperature resistant,
low temperature resistant, corrosion resistant., sour service, etc. |
| The size of the pipes can be made according to clients requirements. | |
| Contacts | If you have any questions, please feel free to contact me.we are sure your inquiry or requirements will get prompt attention. |
Material & API Compliance:
Pipes are produced from fine-grained, fully killed carbon or carbon-manganese steel, precisely formulated to meet the chemical and mechanical requirements of API Specification 5L (Line Pipe) and API Specification 5CT (Casing and Tubing). Each grade is defined:
API 5L Gr B: General service line pipe with minimum yield strength of 35,000 psi (241 MPa).
API 5CT J55/K55: Economical casing grades with minimum yield of 55,000 psi (379 MPa). K55 has stricter phosphorus/sulfur limits.
API 5CT N80: High-strength casing available in Types (e.g., N80-1 for quenched & tempered), with a 80,000 psi (552 MPa) minimum yield.
API 5CT P110: Premium high-strength casing with 110,000 psi (758 MPa) minimum yield, often used in deep wells.
API 5L X46-X70: High-strength line pipe grades for high-pressure transmission.
Seamless Manufacturing Process:
Pipes are manufactured using rotary piercing (Mannesmann process) or mandrel mill technology from solid round steel billets. This creates a pipe with uniform wall thickness, superior concentricity, and no longitudinal weld seam—a critical advantage for high-pressure and sour service applications. The process includes hot forming, sizing, and controlled cooling, followed by heat treatment (normalizing or quenching & tempering for higher grades like N80 and P110) to achieve specified mechanical properties.
Precision & Quality Features:
Dimensional Accuracy: Strict control over OD, wall thickness, and ovality per API tolerances.
End Preparation: Precision-cut and beveled for welding (line pipe) or threaded to API 5B specifications (casing) using CNC threading machines.
Internal/External Surface: Smooth bore to minimize friction loss; external surface free of harmful defects per API visual inspection standards.
Marking: Each pipe is stenciled or stamped per API requirements with grade, size, wall, heat number, manufacturer, and API monogram (where licensed).
Detailed photos
1. Varnished, black painting, 3 LPE coating etc.
2. End can be bevel end or plain end
3. length can be on request, customized.
Inspection
1. PMI, UT ,RT, X-ray test.
2. Dimension test.
3. Supply MTC, inspection certificate, EN10204 3.1/3.2.
4. NACE certificate, sour service
Marking
Printed or Curved marking on request. OEM is accepted.
Packaging & Shipping
Pipes are bundled according to size and weight for safe handling. Threaded and coupled casing receives thread protectors (steel or composite) on both pin and box ends. Plain end line pipe bundles are secured with heavy-duty steel straps. For long-distance sea transit, bundles are placed on steel or wooden skids and often wrapped in waterproof, reinforced packaging to prevent seawater corrosion.
Bundles are tagged with weather-resistant labels detailing grade, size, quantity, heat number, and PO number. Shipping documentation is comprehensive:
Commercial Invoice & Packing List
Mill Test Certificates (originals or certified copies)
Certificate of Origin
Weight Certificate
Third-Party Inspection Report (if requested)
Product description
We provide API Monogrammed products from licensed mills. Each shipment includes a Mill Test Certificate (MTC) compliant with API requirements, listing heat chemistry, mechanical test results, hydrostatic test pressure, and NDE summary. Full traceability from billet to finished pipe is maintained.
Product Application
Oil & Gas Well Construction:
API 5CT J55, K55, N80, P110 casing strings for surface, intermediate, and production casing to isolate formations and maintain wellbore integrity.
Pipeline Infrastructure:
API 5L Gr B and X-grade line pipe for gathering lines from wellheads, transmission pipelines for crude oil/natural gas, and distribution networks.
Downhole Tools & Surface Equipment:
Used for manufacturing pup joints, mandrels, and other oilfield equipment components.
Sour Service Fields:
Specially tested and certified pipes for environments containing hydrogen sulfide (H₂S).
FAQ
1. What is ASTM A312?
ASTM A312 is a specification for seamless, welded, and heavy cold worked austenitic stainless steel pipe for use in high temperature and generally corrosive environments.
2. What is black steel pipe?
Black steel pipe is a non-galvanized steel pipe with a dark iron oxide coating. The coating enhances corrosion resistance and gives the pipe its characteristic black appearance.
3. What are the benefits of using hot-rolled pipes?
Hot-rolled tubes offer several benefits, including improved formability, superior surface finish, improved dimensional accuracy and enhanced mechanical properties. They are typically used in applications that require strong, durable, and precision-engineered pipes.
4. Why are carbon steel pipes favored in various industries?
Carbon steel pipes are popular in various industries because of their strength, affordability, and versatility. It is widely used in oil and gas exploration, chemical processing, power generation, automobiles, construction and many other fields.
5. How is the manufacturing process of black steel pipe different from other pipes?
The manufacture of black steel pipes involves specific heating and cooling processes. The steel is heated to high temperatures, rolled into tubes, and then rapidly cooled to form a stable layer of iron oxide that gives the tube its black color.
6. What are the applications of ASTM A312 black steel pipe?
ASTM A312 black steel pipe is used in a variety of industries, including oil and gas, petrochemicals, water treatment, piping, HVAC systems, structural supports, and general manufacturing. It is commonly used to transport fluids and gases under high pressure and high temperature conditions.
7. Can black steel pipes be used outdoors?
Yes, black steel pipe is available for outdoor applications. The iron oxide coating provides excellent protection against corrosion, making it suitable for a wide range of environmental conditions. However, additional protective coatings may be required in extremely corrosive environments.
8. Are hot rolled tubes suitable for precision engineering applications?
Yes, hot rolled pipes are widely used in precision engineering applications. Its improved dimensional accuracy and superior surface finish make it ideal for manufacturing high-precision components, machinery and structures requiring tight tolerances.
9. What are the advantages of carbon steel pipes compared with other materials?
Carbon steel pipes offer several advantages, including high tensile strength, excellent wear resistance, good machinability and ease of welding. It is also cost-effective and available in a variety of sizes and specifications.
10. Is ASTM A312 black steel pipe suitable for high temperature applications?
Yes, ASTM A312 black steel pipe is specifically designed for high temperature applications. They have excellent heat resistance and are suitable for conveying steam, hot water and other high temperature fluids.
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