Physical Test Methods of Structural Steel Pipe

There are many kinds of steel pipe quality physical test methods of steel structural steel pipe, including physical method which is the most commonly used inspection method, physical test some physical phenomena is used for measurement or test methods. Internal defects of materials or the workpiece inspection, are generally adopt the method of nondestructive flaw detection. Current NDT magnetic testing, ultrasonic testing, X-ray flaw detection, penetration testing, etc.

First is the magnetic testing can only be found in magnetic metal surface and near surface defects, and can only do quantitative analysis of defects, for the nature of the defect and depth can only estimate according to the experience. Magnetic inspection is magnetized ferromagnetic metal parts of the magnetic fields generated by the magnetic flux leakage to find defects. According to the different method of measurement of magnetic flux leakage, the magnetic particles can be divided into method, induction method and magnetic recording, of which the most widely used method of magnetic powder.

Followed by some liquid penetrant inspection is to use the physical properties such as permeability to find and display defects, including two fluorescent dye penetrant inspection and testing, can be used to check the ferromagnetic and the defects on the surface of the ferromagnetic materials.

Followed by X-ray detector is to use the rays can penetrate and attenuation in the material properties to found a flaw detection method. According to the detection of radiation is different, can be divided into X ray flaw detection and gamma ray flaw detection and high-energy X-ray detector. Due to the different methods display the defect, each ray flaw detection and ionization method, screen method of observation, photography and industrial television method. Ray test is mainly used to test the inside of the weld crack, lack of penetration, porosity, slag inclusion and other defects.

Followed by ultrasonic wave in the metal and other homogeneous medium propagation, due to the different medium interface will produce reflection, thus can be used for internal defect inspection. Ultrasound can test any welding materials, any part of the defects, and is more sensitive to find defect position, but the nature of defects, shape and size are difficult to determine. So ultrasonic testing is often used with X-ray inspection for carbon steel pipe.