API steel pipe is a kind of low carbon steel pipe, because of its easy processing, is widely used in structural pipes and fluid pipes. However, the common problem of API steel pipe is that there are pits and pitting on the surface, or it is easy to crack in the later bending, flattening and other processing, which affects the product quality of customers. These problems are also not solved by many seamless steel pipe manufacturers at present, but the steel pipe can be solved, mainly due to the following reasons: API-free steel pipe contains a certain amount of silicon and manganese for deoxidation, it does not contain other alloying elements (except for residual elements), so it is particularly easy to cause surface pits during perforation.

API steel pipe is a line pipe that belongs to the American Petroleum Standard. Line pipe is to transport oil, steam and water extracted from the ground to oil and gas industry enterprises through line pipe. The line pipe includes seamless pipe and welded steel pipe, and its pipe end has flat end, threaded end and socket end; its connection mode is end welding, coupling connection, socket connection, etc.

The quality inspection of API steel pipes is particularly important. Generally, the ultrasonic inspection of API steel pipes is divided into on-line and manual inspection. The on-line API steel pipe ultrasonic inspection wave is installed in the production line to carry out on-line inspection of continuously produced steel pipes. As the on-line ultrasonic inspection equipment is automatic, omission and misstatement will occur in the inspection process, therefore, after each batch of API steel pipes are offline, manual ultrasonic testing shall be carried out.

API steel pipe due to its special production process, the use of high-frequency welding, so the general welding defect is not fusion, and because the current and voltage are controlled by the machine, so a quantity of api steel pipe appears not fusion phenomenon is usually a long one, so API steel pipe ultrasonic testing judgment is easier. However, it is necessary to require the testing personnel to detect fast, slow speed will affect the efficiency of production, but also easy to cause the increase in the amount of steel pipe waste.