API oil gauge gem buckle long round thread gauge CSG4.5

Petroleum Equipment Co., Ltd. Shanghai Jing Wang 15800691952 regulation oil oil drilling project in the casing is high, a large amount of deep machining products. Threaded will become a single casing and tubing connections can withstand up to several kilometers long column of hundreds of atmospheres - tubular pressure vessel. 1924 API developed the first standard OCTG, oil spigot thread is 10 teeth per inch and 8 teeth per inch V-thread, but was later replaced API8 and partial ladder round thread for thread, and still in use. API SPEC 5B standard common thread round thread casing (abbreviated CSG) and buttress thread (abbreviated BCSG).