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Inspection of Steel Tubes
- Jul 31, 2018 -

Steel tube Inspection generally includes: geometrical size, surface quality inspection, chemical composition, mechanical properties, process performance, high and low times the organization of inspection, nondestructive testing, some special properties of the inspection and length weighing and so on.

(1) Inspection of the geometrical dimensions of steel tubes

The diameter, thickness and curvature of the steel pipe can be inspected on the inspection table by means of external calipers, micrometer and bending degree and length measuring tape. The external diameter, wall thickness and length can also be detected by automatic size detection device (such as automatic diameter measurement, thickness measurement, length measuring device) for continuous detection. In the late the 1980s, the pipe production plant generally has on-line automatic diameter measurement, thickness measuring device, in the finishing area with long weighing equipment.

For OCTG steel pipe also need to check the thread parameters. (2) The internal and external surface inspection of steel pipe is generally used to inspect internal and external surfaces, and the inner surface can be inspected by reflection prism in addition to visual inspection. 

Some special-purpose steel tubes also require nondestructive testing, including Eddy current, magnetic flux leakage, ultrasonic, magnetic particle flaw detection, and other internal and external surface quality inspection.

(3) Mechanical properties and process performance check in order to verify the mechanical properties of steel pipe meet the requirements of the standard, it is necessary to test the mechanical properties of steel tube sampling. The mechanical properties test mainly include tensile strength, yield intensity, elongation, impact work and so on. The process performance test mainly includes flattening test, expansion test, water pressure test, roll edge test, cold bending test, perforation test, etc.

These inspection items are selected according to the difference between the standards and the use of steel tubes.

(4) Nondestructive Testing Nondestructive testing refers to the internal and surface defect inspection directly without damaging the steel pipe. At present, magnetic flux leakage flaw detection, ultrasonic flaw detection, eddy current and fluorescence magnetic particle flaw detection have been widely used in steel pipe enterprises.

In recent years, there has been a great development in nondestructive testing, and recently there have been new technologies such as acoustic emission holography, ultrasonic spectrum analysis, ultrasonic imaging flaw detection and ultrasonic high temperature flaw detection. 

(5) Chemical composition test according to the standard requirements, according to the furnace batch number of the main components of the steel tube retest. (6) High and low test it includes the steel tube of the macro-structure, non-metallic inclusions, the actual grain size, metallographic microstructure, decarburization layer, such as testing and determination. 

It needs to be done according to the standard requirements. 

(7) Weight testing for the steel pipe with a single weight, but also by weighing devices to check whether the weight meets the contract or standard requirements.