subject: A brief about Materials Testing Techniques [print this page] A brief about Materials Testing Techniques
Any defects or shortcomings in the composition of a material may result in disaster amounting to loss of valuable times, or worse lives and property. This can be easily avoided using the support of materials testing. Whether you are manufacturing a paper clip or a nuclear reactor, you must ensure the use of quality material for your product and that this quality is maintained throughout the manufacturing process. Only a stringent quality control can ensure product reliability, durability, efficiency and above all safety. There are a number of materials testing techniques available. These include non-destructive tests (NDT) and magnetic testing procedures.
Mechanical testing
For testing mechanical properties, microscopic and subsurface flaws, material composition, corrosion susceptibility etc. different methods of material analysis such as mechanical testing and chemical analysis are used. So while microscopic defect such as a gas bubble, a hole, a cavity can be a possible reason behind quality non-adherence. A prior test can help in avoiding huge loss. A material is often found to be defective due to the presence of incomplete fusion, lack of bond, lamination, surface flaws, incomplete penetration, inconsistent thickness, etc. These defects may cause poor tensile strength, poor resistance, poor ductility, susceptibility to leakages, corrosion, breakage etc.
Magnetic testing:
In order to determine the quality and other characteristics of a material, a number of tests are available, such as, magnetic testing, Charpy Impact Testing, Visual testing, Bend Testing, Liquid penetrant testing, Tensile Testing, Radiographic testing, Hardness Testing, Positive material identification, Salt Spray Testing, magnetic particle testing and ultrasonic testing.
Magnetic testing methods are preferred to detect corrosion and pitting in steel structures as they require no direct contact with the material to be tested. The material to be tested is magnetized and then the absence of flux lines, indicate corrosion. The In-line Inspection Tool or ILI is another popular magnetic testing technique in which the ILI is inserted inside a pipeline and then it detects corrosion and pitting using magnetic fields.
NDT
In Non-Destructive Testing, the properties of the material are evaluated using various analysis techniques. Since NDT doesn't alter the material or article that's being inspected, the testing technique is both time saving and economical.
