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API Casing

Application:Oil well casing serves as well sidewall Pipe Standard:API SPEC 5CT Size:OD: 114.3-508mm,WT: 5.21-16.13mm Process Type: Seamless (SMLS), Electric Resistance Welded (ERW) Grade: J55, K55, N80-1, N80-Q, L80-1, L80-9Cr, L80-13Cr,C95, P110. Thread types:STC, LTC, BTC etc



Casing is used for lining the complete borehole which has been dug into the ground to procure oil. Similar to the drill pipe, the oil well casing pipe is also subjected to axial tension, therefore they are required to be made from high-quality strong steel material. OCTG casing is large diameter pipe which are held in place in the borehole using cement.

The diameters of OCTG casing pipe range from 4.5″ to 36″. The well-cemented pipe acts as the structural component of the well and offer hole integrity. They prevent the well from collapsing when the drilling process is on. Good quality, well cemented casing can stay in place for the whole life of the well.

The oil well casing pipe are further divided into:

Conductor Casing – Conductor casing is the first boundary between the surface and the subsurface. It helps prevention of well collapse; it keeps away the groundwater and most importantly provides structural support. Conductor casing is installed in the ground by either drilling it or hammering it down. They are available in sizes ranging from 18″ to 36″.

Surface Casing – The purpose of Surface casing is primarily environmental and to ensure safety. It helps in separating the freshwater zones, offering protection from blowout and supporting the wellhead and blow out prevention equipment. Therefore surface casings are required to maintain very high safety standards. They are responsible for supporting the next casing in line.  They may vary in size depending on their purpose, but the most common size of surface casing is 13 3/8”.

Intermediate Casing: Intermediate casing is not always required in all types of oil and gas production. If used, they are placed between the surface and the production casing. They are available in sizes ranging from 13 3/8” to 16”.

Production Casing – Production casing help provide structural integrity and pressure control of the hydrocarbon-bearing sections mainly during the production of oil.

Production Liner – Production liners can be suspended from the production casing or one of the previous casings. They help in reducing the cost significantly as the liner is not required to run through the full depth of the well. Liners can be pre-perforated to help save time and cost.


More casing pipes and their colors


API 5CT Well Casing Length:


API 5CT Casing

Range 1

Range 2

Range 3





Labels OD(mm) WT(mm) J55/K55 N80 L80 C90/T95 P110 Q125
4 1/2 9.5 114.3 5.21 PS - - - - -
10.5 114.3 5.69 PSB -        


Packing and shipping

 Now the main business scope of our company covers various kinds of Stainless steel and carbon steel materials , such as hot rolled / cold rolled stainless steel coils / sheet , Seamless / welded stainless steel pipe ( tube ).






Warehouse Storage

As a steel supplier in Shandong Province, Zhongyilian Steel (Shandong) Co., Ltd. has its own factory.


Customer conversation

We have advanced technology and equipment, and we have a highly qualified management team with energy and service consciousness. So far, we have more than 1000 regular customers and we have ISO,CE certification.


Application field

We promise to provide the right products at the right time. The products are exported to Southeast Asia, the Middle East, North America, South America, Europe, Africa, Australia and other regions, forming a global marketing network.




Q: Do you accept the third party inspection?

A: Yes absolutely we accept.

Q: Do you provide the samples? Free or Extra?

A: The cost of the samples is according to the value.The cost of the freight is necessary.

Q: About the complaint,quality problem,etc after-sales service,how do you handle it?

A: We will have certain colleague to follow our order accordingly for each order with professional after-sales service. If any claim happen, we will take our responsibility and compensate as per contract. For better serve our client, we'll keep tracing feedback of our products from clients and that's what make us different from other suppliers. We're customer care enterprise and our mission is to add honor to Made in China.

Q: How can you ensure the quality of your product?

A: All products have to go through three checks in the whole manufacturing process,it includes production and Random Testing in warehouse and Before Shipping.

Q: What is your delivery time and the supply ability?

A:The delivery time normally within 15~28working days,we can supply about 10,000tons every month.

Q: Do you have large amount of steel products in stock?

A: Yes , we have a large-scale indoor warehouse with perennial spot stocks totally above 5000 tons.

Q: How to order?

A: Buyer sends the enquery --> Buyer gets the quotation --> Order confirmation --> Buyer send the deposit --> Seller prepares goods --> Seller makes the strict inspection --> Buyer Arranges Balance Payment --> packing and delivery

Q: Can I get your best price?

A: Price is different based on steel grade, size and quantity. Our goal is to provide you the best price with great quality assured in a long run. Please leave your contact information for the best quotations, we will get back to you with the best solutions as soon as we can. Please give those info. for price checking. If the required is sheet metal fabrication, please send drawing.