According to the first edition of American Petroleum Institute standard APISPEC5CT1988, casing steel grades are H-40, J-55, K-55, N-80, C-75, L-80, C-90, C-95, P- 110, Q-125, a total of 10 types.
Oil casing shall be supplied with threads and couplings, or with one of the following pipe ends: plain end, round thread without or with coupling, butcher thread with or without coupling, direct connection Type thread, special end processing, and sealing ring structure.
Origin:
(1) The main importing countries of oil 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, and 5AC. 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) API specifies three lengths: 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 words LTC, that is, long threaded sleeves.
(4) In addition to adopting API standards for casings imported from Japan, there are also a small number of Japanese factory standards (such as Nippon Steel, Sumitomo, Kawasaki, etc.), and the steel grades are NC-55E, NC-80E, NC-L80, NC-80HE, etc.
(5) In the claim cases, there have been appearance defects such as black buckle and threaded buckle damage, pipe body folding, broken buckle and thread close distance, coupling J value out of tolerance, etc., as well as internal casing brittle cracks and low yield strength. quality problem.
Package:
According to the regulations of SY/T6194-96, the domestic casing should be bound with steel wire or steel belt. The exposed portion of each casing and coupling thread shall be screwed with a protective ring to protect the thread.
