The advantages of API standard threads are:
1) Easy to process, general precision, easy to process and connect the related sub on the field, low cost.2) The connection under general operating conditions is easy to repair and handle on site.
3) When used with high quality sealing grease, the fluid sealing condition can reach 69MPa and 1490 C.4) Can be used repeatedly on the buckle.
Its disadvantages are:
1) High pressure and gas cannot meet the sealing requirements.
2) The connection strength of API thread is only 80% of the tensile strength of pipe body.
3) In the environment with corrosive fluid, because the “interference value” of API collar is too large, excessive circumferential stress is easy to produce hydrogen embrittleness stress failure or strain crack of API collar