Casing is a high-end product for steel pipe production. There are many types of casing, and there are 15 kinds of casing diameter specifications. External diameter range is 114.3-508mm; steel types are J55, K55, N80, L-80, P-110, C-90, C-95, T-95, etc. 11 kinds; casing end buckle type and various types of requirements, Machinable button STC, LC, BC, VAM equation. Casing production and installation process involves a large number of tests, mainly the following:


1. Ultrasound detection
When the ultrasonic wave propagates in the material to be tested, the changes of the acoustic characteristics and internal structure of the material have an effect on the propagation of the ultrasonic wave. Through the degree and condition of ultrasonic testing, we can understand the change of material properties and structure.


2. Radiographic Detection
Radiographic examination of the difference in the amount of radiation transmitted between the normal and defective parts results in the difference in blackness on the substrate.


3. Penetration test
Penetration testing is to use the capillary effect of liquid to penetrate the penetrant into the open defects on the surface of solid materials, and then to attract the penetrant to the surface through the developer to show the existence of defects.


Permeation test is suitable for all kinds of metal and ceramic workpieces. The time from penetration operation to defect display is relatively short, generally about half an hour. Surface fatigue, stress corrosion and welding cracks can be detected, and crack size can be measured directly.


4. Magnetic Particle Detection
Magnetic particle detection uses flux leakage at defect sites to absorb magnetic particles and form magnetic traces to provide defect indication. It can detect surface and subsurface defects. The nature of defects is easy to identify. Coatings and electroplated surfaces do not affect detection sensitivity.


5. Eddy Current Detection
Eddy current detection mainly uses the eddy current induced by ferromagnetic coils on the workpiece to analyze the internal quality of the workpiece. It can detect surface and near surface defects of various conductive materials. Usually, parameter control is difficult, test results are difficult to interpret, and test objects are needed. It must be a conductive crack and indirectly measure the length of the defect.


6. Magnetic flux leakage detection
The magnetic leakage detection of casing is based on the high permeability of ferromagnetic materials. The quality of casing in use can be measured by measuring the permeability change caused by defects in ferromagnetic materials.


7. Magnetic Memory Detection
Magnetic memory testing is the relationship between the physical properties of magnetic phenomena and the missed distance of metal potential. It has many advantages such as high efficiency, low cost, no need of grinding and so on. It has important and wide application prospects in industry.


Among several testing methods, there are no specific standards for magnetic memory testing of products, which need to be developed. The other six types have their own testing standards and are relatively mature.