Materials Testing And Analysis ? An Overview

The wheels of the industry must keep rolling. The only way to ensure this is by carrying out routine inspection of sections that are prone to failures before expiry of their life cycle. This is true irrespective of whether the industry is that of Aerospace, Nuclear, Power, Petrochemicals, Pharmaceuticals or Pipeline and Paper. Such routine inspections are generally carried out using Non Destructive Testing methods in an industry that is functioning. However, there are cases when destructive testing is carried out.

One such case is when manufacturing a specimen component, a machine or any piece of equipment for an industry. The engineering requirement is to ensure that the material does not fail while in service. This is to obviate breakdowns that could be extremely costly for the industry. The basic requirement is therefore for the engineers to define the working envelope of the materials. This envelope could be high temperature creep in a turbine blade or fatigue in the undercarriage of an aircraft that is subject to repeated cyclic loads. Corrosion or stress corrosion could be the cause of failure in a chemical industry. Once the desirable properties of the relevant materials are identified and specified the materials are subjected to materials testing. Such testing would involve properties such as UTS, hardness, impact strength and the likes.

Secondly, materials testing could also be called for in order to define the reason for a failure. Thus, the turbine blade that cracks while in service would be subjected to various analytical tests using equipment such as electron microscope and gas chromatography among others. These are basically techniques for conducting materials analysis that could be carried out using metallography technique that can reveal the internal grain structure as well. Modern laboratories now employ sophisticated equipment that can analyze both ferrous and non-ferrous metals and their alloys besides glass, ceramics and refractory materials. Wet chemistry, inductively coupled plasma spectrometry, optical emission spectroscopy and tests for corrosion and stress corrosion are some of the materials analysis methods being used. Materials used in the industries are tested either before production, during service or in case of failure.