1. Observe carefully with tools
During the inspection, it can be carefully observed with the naked eye. Inspect the appearance and standard dimensions of steel pipes. During the inspection, it is necessary to observe the appearance, wall thickness, end and other aspects of the defects of the seamless steel pipe mentioned above, so as to judge by experience. In order to the qualified rate of seamless steel pipe, supervision and inspection can also be carried out before installation. Formulate a regular inspection mechanism to conduct regular inspection on deformation, expansion, diameter, size and bending of seamless steel pipe.
2. Pay attention to the thickness of inner wall and hydrogen corrosion
During the use of seamless steel pipe, the whole pipe will burst when it operates under high temperature and high pressure for a long time. The reason for the burst accident is that there is a deviation in the wall thickness of a part of the inner wall of the pipe. When the load cannot be met, these deviation parts become a weak point, which is very easy to cause the burst accident. Therefore, before inspection, it is necessary to inspect the surface of the inspected pipeline to observe whether there is rust, oxidation, oil stain and other phenomena. If so, it needs to be treated before inspection. During the inspection, the wall thickness inspection shall be carried out for the parts.
3. Improve the ultrasonic testing accuracy with the help of multiple auxiliary tools
When inspecting inner wall defects, ultrasonic testing is required. This inspection technology can inspect the wall thickness direction of the whole steel pipe. Especially for the defects of seamless steel pipe. Due to the simple shape of seamless steel pipe, simple automatic water immersion method is basically used for ultrasonic inspection in the manufacturing process, but if the steel pipe in use cannot adopt this inspection form. The direct contact method and shear wave test method should be used.
4. Use magnetic particle and penetrant testing to judge the qualification rate of elbow
Due to the manufacturing process of seamless steel pipe
, the reserved cutting allowance at both ends is relatively small. In addition to the limitations of the current inspection equipment, the inspection at the elbow cannot be. However, this part is one of the parts where cracks often occur. Especially during installation, the crack problem is not inspected in time, and the crack will expand during welding. Therefore, for welded elbows, magnetic particle testing and penetrant testing can be used as inspection objects.