Bending test is a test to determine the mechanical properties of seamless pipes and welded pipes under bending load, and it is one of the basic methods for testing the mechanical properties of seamless pipe machines and welded pipes. Bend tests can also be used to check the surface quality of materials. The bending test is carried out on a universal material machine, and there are two loading methods: three-point bending and four-point bending. The cross-section of the sample is circular or rectangular, and the span during the test is generally 10 times the diameter.

Straightening is an important process in the production of LSAW steel pipes. Especially for oil casing and oil and gas pipes of API standard with high quality requirements, special pipes for machinery and equipment,These kinds of steel pipes not only have strict requirements on the steel grade and weld quality, but also have high requirements on the straightness of the steel pipes.

The anti-corrosion coating of seamless steel pipe refers to the use of paint to uniformly and densely coat the surface of the rust-removed steel pipe to isolate it from various corrosive media. It is one of the most basic methods for anti-corrosion of seamless pipes. There are many kinds of anti-corrosion coatings, and their properties and uses are different. Among them, the coating technology is to form a continuous covering layer of insulating material on the metal surface to insulate the metal and the electrolyte in direct contact with it.That is to set a high resistance so that the electrochemical reaction cannot occur normally.

High pressure seamless tube is a kind of boiler tube, which has strict requirements on the steel used to manufacture steel tubes. High pressure seamless pipes are often used in high temperature and high pressure conditions, and the pipes will be oxidized and corroded under the action of high temperature flue gas and water vapor. The steel pipe is required to have high lasting strength, high oxidation corrosion resistance, and good organizational stability. High-pressure boiler tubes are mainly used to manufacture superheater tubes, reheater tubes, gas guide tubes, main steam tubes, etc. of high-pressure and ultra-high-pressure boilers.

API 5L line pipe is a pipeline that transports the oil, gas or water extracted from the ground to the oil and gas industry enterprises through the line pipe. API 5L line pipe includes two kinds of seamless and welded pipe, and its pipe ends include flat end, threaded end and socket end; its connection methods are end welding, coupling connection, socket connection, etc.

Different from the seamless steel pipe, which is directly perforated by round steel, the welded pipe is a steel pipe made of steel plate or strip steel after crimping and welding.It is easily affected during the welding process, resulting in cracks, pores and other defects in the steel pipe (especially the weld part)