Different Kinds Of Oil Casing Test

Oil casing pipe is a high end product of steel pipe production. There are many kinds of casing, the diameter of the casing is in the range of 15 kinds of specifications and the external diameter of casing is 114.3-508mm. Steel grade is divided into J55, K55, N80, L-80, P-110, C-90, C-95, T-95 and so on; There are different kinds of type and requirements of the casing pipe end button type, the processing button type has STC, LC, BC, VAM and so on. There are many tests in the production and installation of the oil casing, including the following aspects:

Ultrasonic Testing

When the ultrasonic propagates in the detected material, acoustic characteristics of materials and internal organizational changes have a certain effect on ultrasonic propagation. By detecting the extent of ultrasonic affected, to understand the changes in the performance and structure of the material.Radiographic Testing

The amount of radiation from the normal part and the defect is different, according to this, ray detectors can cause differences in the blackness of the negative.

Penetrant Testing

Take advantage of capillary action, penetrant testing will penetrate liquid into the opening on the surface of solid materials, and then imaging agent suction the liquid to reveal surface defects. From the penetration operation to the defect display is relatively short, generally about half an hour, you can test surface fatigue, stress corrosion and welding crack, the size of the crack also can be directly measured.

Magnetic Particle Testing

The magnetic flux leakage of the casing tube defects can adsorb the magnetic particle forming the magnetic mark, so as to provide the defect display. Magnetic particle testing can test the surface and subsurface defects, the defect is easy to identify. Paint and plating surface does not affect the detection sensitivity.

Eddy Current Testing

Take advantage of eddy currents induced by ferromagnetic coil in the workpiece, the quality of the internal workpiece is analyzed. Eddy current testing can test the surface defects of various conductive materials, and can indirectly measure the length of the defect, but it is difficult to control the parameters, and the results are difficult to interpret. What’s more, the object to be detected must be conductive crack.

Magnetic Flux Leakage Testing

The magnetic flux leakage detection is based on the characteristics of high permeability of ferromagnetic materials. Measuring permeability changes due to defects in ferromagnetic materials to test the quality of in-service oil casing.

Magnetic Memory Test

Magnetic memory testing is the relationship between the physical nature of the magnetic phenomenon and the process of dislocation, which has high efficiency, low cost, no need to be polished and so on. It has important and wide application prospects in industry.

Development of magnetic memory testing technology

As we all know, ferromagnetic metal materials as a force structure can withstand fatigue loads in different degrees, so as to cause fatigue crack.

Due to fatigue crack mostly sprouted in the stress concentration region caused by surface defects, adding the stress concentration in the component can cause the material to produce the early damage such as stress corrosion, therefore, it is very important to effectively carry out the test of the surface stress of the component. Because some of the components must be loaded and some of the equipment is complex in the conventional stress testing methods, most of them are not adapted to the non-destructive testing of industrial field.

In 1990s, Russian scholars first proposed that the stress concentration zone of the component surface can be detected by magnetic memory. The magnetic memory testing technology is expected to accurately test the dangerous parts that are characterized by stress concentration. This is a new nondestructive testing method for the early diagnosis of metal components, thus the theory has been paid attention by all the countries in the world.

It is anticipated that, as a new in-service diagnostic methods, magnetic memory testing technology will be further developed through non-destructive testing industry colleagues tireless efforts, for the benefit of human society.

Conclusion

In these tests, there is no specific standard for the magnetic memory testing, yet to be developed. The remaining six kinds have their own testing standards and more mature.