The Casing And Tubing Pipe Grades

The API 5CT standard covers seamless and welded casing and tubing pipes for oil and gas transportation. Casing pipes are available in the following materials: H-40, J-55, K-55, N-80, L-80, C-90,T-95 ,P-110, Q-125.

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Depending on the different condition and depth of the well, we use the different steel grades. The casing is required anti-corrosion under the corrosive environment. In the case of complex geological conditions, the casing has to be resistant to collapse. Most casing steel grades have the same chemical composition. What makes grade different is the heat treatment applied. Casing grades mainly differ in their yield strength, tensile strength, and hardness.

According to API 5CT, there are four groups of products to API SPEC 5CT is applicable include the following grades of pipe:

Group 1: Grades H, J, K,M, N and R;

Group 2: Grades C, L and T;

Group 3: Grade P;

Group 4: Grade Q.

Additional tests required by API 5CT for certain groups of casing make sure that each casing grade is suitable for its intended application.

Common Application Casing (H40, J55, K55, M65, N80, R95)

Due to their lower price compared to other steel grades, casing pipes of grades J55, K55, and N80 are a popular choice for wells without stringent anti-corrosion or strength requirements.

M65, and R95 are newer grades, each with their own field of application. These casing grades mainly differ in their yield strength and tensile strength.

Corrosion-Resistant Casing (L80，C90，T95, C110)

API 5CT steel grades L80-1, C90, T95, and C110 show a higher resistance to sulfide stress cracking in H2S environments due to lower limits of sulfur and phosphorous as well as the addition of the following mandatory tests:

Casing grades L80-9Cr and L80-13Cr are suitable for application in CO2 environments, mainly because of their higher chromium content.

Deep Well Casing (P110, Q125)

With the highest yield strengths among all API 5CT casing grades, P110 and Q125 are ideally suited for high pressure formations in deep wells. However, as steel becomes more susceptible to sulfide stress cracking the higher the yield strength, both grades should not be used in H2S environments.

The commonly used types including: API 5CT H40, J55, C75, N80, P110. Bestar Steel Pipe stock extensive range of oil casing pipe and OCTG pipe according API 5CT.

Price List for Steel Pipe and Tube2018.5.9

Price List for Steel pipe and tube from Bestar Steel Pipe, all the prices are subject to our final confirmation.​

If you have purchasing plan, we will try to apply a discount from our manager. Any other inquiries please send to: sales@bestartubes.com

The Difference between Hot Rolled and Cold Rolled Steel

Steel is a super alloy that has found fundamental resonance with the construction and engineering activities of entire diversity. The invention as steel (as opposed to the iron) re-defined the building tasks because of its noted attributes like sturdiness, high tensile strength and corrosion resistance among others. Dedicated metallurgical interventions were done to develop differentiated matrix of steels. Hot rolled and cold rolled steel types relate to the rolling processes that are employed when forming base products like stainless steel bars, sheets, steel round bars and slabs which are then used for other products of direct utility. While hot and cold rolled steels are not distinguished through different grades (which are more function of alloy composition), the techniques involved in both processes do generate specific distinctions in the two types.

Hot rolled and cold rolled steels

The difference is exemplified in the name – hot and cold rolled. The steel that is rolled at a temperature of 1700 degree Fahrenheit which is the re-crystallization temperature of steel is called as the hot rolled type. The one which is rolled below this re-crystallization temperature is called as cold rolled steel. The significance emanates from this temperature itself. As said, this is the re-crystallization temperature, the steel gets reformed and the atoms are realigned during the hot rolling process. The steel is pressed very hot between the rollers that generate the desired dimensional characteristics through rolling process. However, there is a twist in this process and the hot steel when cools off to room temperature slowly loose the shape and size attributes slightly of course! This means that the finished hot rolled steel displays minor imperfections like scales and other texture imperfections which are superficial only. This makes hot rolled stainless steel bars or other products less suitable for making the components in which very high dimensional precision and surface perfection are required. However, the rolling at a temperature above re-crystallization (hot rolling) also has an inherent advantage because the steel is reformed and the internal stresses that are generally accumulated during mechanical cold rolling are not present.

The cold rolled steels exhibit better finish!

Cold rolling is not a separate process but which is done post hot rolling. The hot rolled steel when cools down is again pressed in the rollers but this time the temperature is near to room temperature as opposed to the re-crystallization temperature of 1700 degrees Fahrenheit in the hot rolling process. The steel is thus not re-formed in cold rolling and stresses may develop to a varying extent due to the same factor. However, the advantage is that cold rolled steel exhibits much smoother finish and texture characteristics. This also means that lesser processing and finishing is required when making components with cold rolled steel. This makes cold rolled steel round bars and sheets suitable for use in high precision applications. Cold rolled steel however also has higher tensile strength and the shape and dimensional features are not lost post rolling. The additional time and process involved in cold rolling make the process expensive as compared to the hot rolled steel manufacture.

Manufacture/Inspection and Advantages of ERW Line Pipe

Electric resistance welding (ERW) pipes are manufactured by continuously roll-forming hot coil material into a pipe shape, and butt-welding the weld seam after heating/melting the coil edges using the Joule heat generated by passing a high frequency current through the edges. At the seam of the ERW butt weld (hereinafter, seam), the welding beads on the pipe inside and outside surfaces are removed by online, full-length grinding, followed by seam heat treatment to improve the weld microstructure.

After ERW linepipes are cut to the specified length, product pass through the quality assurance process, which includes hydrostatic testing, ultrasonic testing of the seam and pipe body, inspections of external appearance and dimensions, etc.

In general, ERW pipes have the following advantages.

(1) Because hot coils are used as the starting material, thin wall thickness pipe can be manufactured, and its thickness accuracy is good and the pipe has a smooth surface which is free of roughness, pits, etc.

(2) The pipemaking process is characterized by high productivity and high dimensional accuracy. As a result, lower costs can be expected in the pipe-laying process due to reduction of the work load in girth welding to join pipes, etc.