Views: 2 Author: Site Editor Publish Time: 2022-03-30 Origin: Site
According to American Petroleum Institute standard APISPEC5CT1988 1st edition, petroleum casing steel grades H-40, J-55, K-55, N-80, C-75, L-80, C-90, C-95, P -110, Q-125 a total of 10 kinds. Oil casing shall be supplied with threads and couplings, or in any of the following pipe end forms: plain end, round thread without coupling or with coupling, buttress thread with coupling or without coupling, straight Connecting thread, special end processing, sealing ring structure.
(1) The main importing countries of petroleum casing are Germany, Japan, Romania, the Czech Republic, Italy, the United Kingdom, Austria, Switzerland, the United States, Argentina, and Singapore. Import standards mostly refer to American Petroleum Institute standards API5A, 5AX, 5AC. The steel grades are H-40, J-55, N-80, P-110, C-75, C-95, etc. The specifications are mainly 139.77.72R-2, 177.89.19R-2, 244.58.94R-2, 244.510.03R-2, 244.511.05R-2, etc.
(2) There are three types of lengths specified by API: R-1 is 4.88~7.62m, R-2 is 7.62~10.36m, and R-3 is 10.36m or longer.
(3) Some imported goods are marked with the word LTC, that is, long threaded sleeve.
(4) In addition to API standards imported from Japan, there are a small number of Japanese manufacturers' standards (such as Nippon Steel, Sumitomo, Kawasaki, etc.), steel grades are NC-55E, NC-80E, NC-L80, NC-80HE, etc.
(5) In the claim case, there have been appearance defects such as black buckle and thread damage, folding of the pipe body, broken buckle and thread tightness distance, coupling J value being out of tolerance, etc., as well as brittle cracking of oil casing, low yield strength, etc. Internal quality issues.
According to the provisions of SY/T6194-96, domestic oil casing should be bundled with steel wire or a steel belt. A protection ring shall be screwed on the exposed portion of each casing and coupling thread to protect the thread.