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API 5CT ​OCTG seamless steel casing pipe

OCTG casing and tubing is a kind of popular steel pipe in the steel industry, but there occurs decarburization phenomenon for the OCTG tubing and casing. Then what do we take the measures to avoid decarburization for them?

Generally, there are two ways to avoid decarburization for OCTG casing and tubing. One is the common and simple way: make full use of nitrogen protective to sustain the pressure inside the furnace. According to proportion, workers can join or inject into the neutral nitrogen to the furnace, which will not only prevent the outside air decomposing into oxygen and water vapor into the debris but also disperse the gas existing oxidation in furnace effectively. Without reaction medium with the surface of carbon, decarburization would not happen and the area of the decarburization also can be reduced generally.

Another way is to make the balance to control furnace carbon dioxide levels according to the OCTG tubing and casing workpiece. Expert research if the balance in the furnace is higher than the content of carbon dioxide and other gases, there will be no decarburization and oxidation phenomenon; If carbon dioxide is equal to balance, there will show the results of the neutral without decarburization and oxidation; the final result is the main cause of decarburization, that is the oxidation furnace gas content is higher than balance. So if you want to avoid the decarburization phenomenon, you must calculate the balance point according to the internal temperature and carbon content of workpiece; then control the content of oxidizing gases in the furnace.

steel casing pipe is used in different types of horizontal underground boring, where the pipe is jacked into an augered hole in segments and then connected together by welding or by threaded and coupled ends, or other proprietary pipe connectors such as the interference-fit Permalok interlocking push-on joint. The steel casing pipe can also be set up and welded into a “ribbon” and then directionally pulled through a previously drilled hole under highways, railroads, lakes and rivers.

Standard: API Standard: API 5CT Grade: API J55-API P110 Grade: API P110 Thickness: 5.21 – 16.13 mm Section Shape: Round Outer Diameter: 114.3 – 508 mm Place of Origin: China (Mainland) Application: Oil Pipe Technique: Hot Rolled Certification: API Surface Treatment: Painted Special Pipe: API Pipe Alloy Or Not: Is Alloy .Packaging & Delivery



1. Provide API 5CT OCTG casing pipe

2. Hydrostatic/UT tested; heat treatment applied


4-1/2”, 5”, 5-1/2”, 6-5/8”, 7”, 7-5/8”, 7-3/4”, 8-5/8”,

9-5/8”, 10-3/4”, 11-3/4”, 13-3/8”, 16”, 18-5/8”, 20”


(mm) 114.3-508 * 5.21-16.13

Grade: J55, K55, M65, N80-1, N80-Q, L80-1, L80-9Cr, L80-13Cr, C90, C95, T95, P110, Q125

Standard: API 5CT or Agreement

Type of End: 1. PE, STC, LTC, BTC




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