Quality control and assurance is an integral part of the manufacturing process. The verification of the mechanical properties of any steel pipes would require conformance to several standards. Hence, the preparation of the specimen to undergo analysis must be with utmost care.
We use the latest equipment to perform examinations such as non-destructive that is magnetic flux leakage along with eddy current test and an ultrasonic test. Other process performance-based experiments include the flattening and flaring type for seamless pipes. Generally, examinations such as hardness and tensile are also deemed necessary across several industries.
Hardness and tensile strength
A sample of the carbon steel pipe can determine several mechanical properties. Usually, properties like tensile and yield strength, percentage elongation, and section shrinkage are collectible from this sample with the use of a tensile analysis. A tensile test is possibly the only method to gauge its mechanical properties, in those instances where it is difficult to get values for a hardness inspection.
A mechanical analysis that is the easiest and fastest is the performance of a hardness inspection. The hardness inspection is a hard indenter designated conditions gradually compressed into the surface of the sample. After which the depth or size of the indentation will ascertain the measurement of the material hardness. Although a non-destructive examination, it approximates the exchange relationship between both the hardness and tensile strength values. The hardness value has great practical significance, as the transformation of the material could be within the readings of the tensile strength. This mechanical examination accounts for the performance as well as the quality of steel, in terms of its deformation. This data also takes into consideration the raw materials & process used to produce, cut, and stamp the pipes.
NDT or as also known as a Non-destructive Test - is one of the most extensively utilized methods for steel pipes. The characteristics and quality of the steel pipe are achievable by conducting experiments, inspections, or evaluations, without causing damage or by affecting the work in a system. The different techniques involved in the NDT include visual, ultrasonic, radiographic, and hydrostatic experiment.
The use of an ultrasonic test is to discover any flaws present on the pipes. In this method, high-frequency ultrasound measures the dimensions. The frequency adopted by the instrument is at a pitch ranging as high as 500 kHz to 20 MHz, more dominant than human hearing. A non-destructive experiment, the sample is not cut or sectioned or even exposed to various corrosive chemicals. Automated tests offer highly accurate data, and the preference is much more than a manual type.
A way to test components of a pressure system is by performing a hydrostatic test. This experiment intends to update the examiner for the presence of any leaks while receiving data for its strength. This method exhibits durability while maintaining safety standards. The performance of a hydrostatic analysis on a newly produced specimen is initially qualifying, followed by qualifying at regular intervals with the use of a proof pressure test. And is known as a modified hydrostatic examination. It is a particularly important step for products used in the transportation or storage of gases in the natural gas industry. Flammable gases could cause a blast in the piping system due to the high pressure. Typically a pipe is filled with an approximately incompressible fluid. This fluid could be either - water or oil, that is pressurized to test load, following which an examination checks for any sign of leaks or the occurrence of a permanent change in shape.
Eddy-current testing, or as known in short as ECT, is a non-destructive test that uses electromagnetic induction. Electromagnetic induction is the generation of voltage or an electromotive force transverse to an electrical conductor in a dynamic magnetic area. Therefore, it is useful in the characterization and detection of flaws on the surface or sub-surface of a conductive material. In this case, the conductive material is a seamless steel pipe.
A Flattening experiment exhibits the compression strength of the metallic pipe. The result is what helps to determine the pipes pliancy when it has become flat. The specimen is a portion of a tube, cut to resemble a ring. The ring is then subject to stress or load, where it forms a parallel plateau. The severity of this examination is under observation by gauging the interval between the platens. Under a specific weight, the interlude between the two platens must not exceed the prerequisites. The result will inform the examiner whether the pipe could fracture once it is flat.
This test makes use of a tapered mandrel. The examiner inserts the tapered mandrel into the specimen, which causes it to expand at an angle of 60°. Usually, specification ASTM A370-10 is used to administer this test. Hence, the adjacent expanse of the edge, the inside and outside diameter must follow the fore-mentioned specification. The resultant value must not be lesser than the specified requirements, and the specimen must not have any visible cracks.