The casing is a high-end product produced by steel pipes. There are many types of bushings and there are 15 bushing diameter specifications. The outer diameter range is 114.3-508mm; the steel grade is divided into J55, K55, N80, L-80, P-110, C-90, C-95, T-95, etc.; the casing end buckle type and various requirements, Button type STC, LC, BC, VAM, etc. can be processed. The casing production and installation process involves a large number of tests, mainly in the following aspects:


1, ultrasonic testing
When ultrasonic waves propagate in the material to be tested, changes in the acoustic properties and internal structure of the material have an effect on the propagation of the ultrasonic waves. Detect by the degree and condition of the ultrasonic waves to understand changes in material properties and structure.


2. Radiation detection
Radiographic inspection uses the difference in the amount of radiation transmitted between the normal position and the defect location, resulting in a difference in substrate blackness.


3. Penetration test
Penetration testing utilizes the capillary action of a liquid to penetrate the permeate into open defects on the surface of the solid material and then pull the permeate through the developer onto the surface to reveal the presence of defects.


Penetration testing is applicable to a wide variety of metal and ceramic workpieces. The time from osmotic operation to defect display is relatively short, typically about half an hour, to detect surface fatigue, stress corrosion and weld cracks, and to directly measure crack size.


4, magnetic particle testing
Magnetic particle inspection uses magnetic flux leakage from the defect to absorb magnetic powder and form magnetic marks to provide defects. Surface and subsurface defects can be detected. The nature of the defect is easily identifiable. Paint and plating surfaces do not affect detection sensitivity.


5, eddy current testing
Eddy current testing mainly uses the eddy current induced by the ferromagnetic coil inside the workpiece to analyze the internal quality of the workpiece. Surface and near surface defects of various conductive materials can be detected. 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
Casing magnetic flux leakage detection is based on the high magnetic permeability properties of ferromagnetic materials. The quality of the in-service casing can be detected by measuring the change in permeability caused by defects in the ferromagnetic material.


7, magnetic memory detection
Magnetic memory detection is the relationship between the physical properties of magnetic phenomena and metal dislocation processes. It has the advantages of high efficiency, low cost and no need for grinding. It has an important and broad application prospect in the industry.


Among several detection methods, there is no specific standard for magnetic memory testing of products, which has yet to be developed. The remaining six types have their own test criteria and are relatively mature.