The inspection of mechanical steel pipe generally includes: inspection of geometric dimension and surface quality; inspection of chemical composition, mechanical properties, technological properties, high and low magnification structure; non-destructive inspection; inspection of some special properties and length measurement and weighing, etc.
1.Geometric Dimension Inspection of mechanical steel pipe
External diameter, wall thickness, curvature and length of mechanical steel pipe can be inspected on the inspection table with external calipers, micrometers, curvature gauges and length tapes. External diameter, wall thickness and length can also be continuously measured by automatic size detection device (such as automatic diameter measurement, thickness measurement, length measurement device). For OCTG steel pipe, thread parameters need to be checked.
2.Inspection of inner and outer surface of mechanical steel pipe
In general, visual inspection is used to inspect the inner and outer surfaces, and besides visual inspection, the inner surfaces can also be inspected by reflecting prisms. Some special purpose mechanical steel pipes also require non-destructive testing, including eddy current, magnetic flux leakage, ultrasonic, magnetic particle testing and other inspection of the internal and external surface quality of mechanical steel pipes.
3.Inspection of mechanical and technological properties
In order to verify that the mechanical properties of mechanical steel pipe meets the requirements of the standards, it is necessary to test the mechanical properties of mechanical steel pipe by sampling.
The test of mechanical properties mainly includes tensile strength, yield strength, elongation, impact work and so on. The process performance test mainly includes flattening test, expanding test, hydraulic test, edge rolling test, cold bending test, perforation test, etc. These inspection items are selected according to different standards and different uses of mechanical steel pipes.
Non-destructive testing refers to the direct inspection of internal and surface defects of mechanical steel pipes without damaging them. At present, magnetic flux leakage testing, ultrasonic testing, eddy current and fluorescent magnetic particle testing have been widely used in mechanical steel pipe enterprises. In recent years, non-destructive testing has made great progress. Recently, new technologies such as acoustic emission holography, ultrasonic spectrum analysis, ultrasonic imaging and high temperature ultrasonic testing have emerged.