Hollow bar micropiles are made of seamless steel tube.
The product quality of seamless steel pipe must be in accordance with product standards and technical specifications for a comprehensive inspection. Specific inspection, including chemical composition analysis of steel pipe, geometric size inspection, surface quality inspection, physical and chemical performance testing, process performance testing, metallographic analysis and thread inspection, measurement and so on. The aim is to ensure the quality of the pipe can meet the requirements of the corresponding standard or technical conditions.
1,The chemical composition analysis of steel pipe
Analysis of the chemical composition of steel pipe can be used chemical analysis, which can also be used instrumental analysis. The so-called chemical analysis method is based on the chemical reaction of the material. And instrumental analysis is based on the physical or physical and chemical properties of the material. Commonly used chemical composition analysis of the instrument are: infrared carbon sulfur instrument, direct reading spectrometer, X-ray fluorescence spectrometer.
2, The size and shape inspection of steel pipe
The contents of the steel pipe inspection include: the wall thickness, the outer diameter, the length, the curvature, the ellipticity, the end groove and the blunt angle.
3, The surface quality inspection of steel pipe
The surface quality inspection of steel pipe mainly includes artificial naked eye inspection and nondestructive testing. In the artificial eye inspection, which should have full lighting conditions, according to the standards and the experience of the inspectors, the discovery of various defects in the steel pipe with a special symbol on the body to identify the inspection ,slow rolling on the surface of steel pipe during the process. Many methods of non-destructive testing are mainly used in the surface quality inspection of seamless steel pipes, including ultrasonic testing, eddy current testing, magnetic particle testing, magnetic flux leakage testing, electromagnetic ultrasonic testing and penetration testing.
4, The physical and chemical properties of steel pipe inspection
The physical and chemical properties of seamless steel pipes include mechanical tests (tensile tests, toughness tests, hardness tests), hydraulic tests and corrosion tests (intergranular corrosion tests, anti-hydrogen cracking tests – HIC, anti-sulfide stress cracking test-SSCC) and so on.
5, The performance test of steel pipe
According to the different specifications and use of steel pipe, the product standard requirements of the process performance test, including steel pipe flattening test, ring test, flaring test, curling test and bending test.
6, The metallographic analysis of steel pipe
Metallographic analysis includes high power test and low magnification test. The high power test refers to a method of assessing the internal structure and defects of the material by microscopy. Seamless steel pipe often carried out high-power test items are: steel non-metallic inclusions micro-assessment; average grain size determination; decarburization layer depth determination; microstructure test. Low magnification test, also known as macroscopic analysis, refers to the artificial eye or 10 times the magnifying glass to observe the evaluation of material defects in a low-level method.