Laboratory for Materials Testing and Materials Analysis

Industries cannot run efficiently and safely unless there is a constant improvement in technology and materials. These improvements are essential for the modernization process that ushers in higher quality of output while increasing cost effectiveness. This is true for the Power Production and Paper & Pulp industries as much as it is for Nuclear or Aerospace industries. Quite frequently improvements in technology need an improvement in material specification as well. This is borne out in the manufacture of higher performance fighter aircraft, nuclear submarines and power turbines among others. The introduction of newer materials accentuates the requirement of materials testing laboratories that need to be fully equipped with test equipment for the testing of the wide range of properties of materials. Such tests could be for physical properties as in stress, fatigue, creep, impact and hardness or chemical properties as in the composition, alloying and microstructure. A modern laboratory that is equipped to conduct materials analysis best establishes chemical properties as well as tests for corrosion and the effects of heat treatment.

Materials testing laboratories are equipped with modern machines to perform tests to establish tensile strength, compressive strength, flexural strength and tear or peel strength. However, materials analysis laboratories could be used as a tool for failure analysis besides the identification of materials, their structural analysis, characterization or the level of contamination. The health and the well being of the industry is dependant on its monitoring or diagnostic laboratory of which the testing and analysis of materials are key ingredients.

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An Introduction to Failure Analysis

When we discuss industries such as the Petrochemical or Power and Automotive or Nuclear and Paper or Pharmaceutical failures are not acceptable but still they do occur. A turbine blade could fail in an aircraft engine due to thermal fatigue or creep. An important pipeline in the Chemical industry could fail due to corrosion. These failures need to be investigated in order to establish the actual cause. This investigation is necessary in order to prevent a recurrence and initiate changes in design or material as warranted. Thus it’s a disciplined failure analysis carried out in a modern laboratory that will confirm whether the failure has occurred due to fatigue, creep or stress corrosion cracking, operator’s error or a faulty design.

Failure analysis is a painstaking scientific process more akin to forensic science. It could involve metallography or chemical analysis and destructive or non-destructive testing techniques. In complex cases where, for example, aircraft debris may have to be sifted for clues accident reconstruction involving computer modeling and simulation techniques could be necessary. In the simpler cases a good metallography laboratory will establish whether the heat treatment had been adequate or not. To establish tensile strength and capacity to withstand impact loads, there are facilities for testing for tensile strength at 1000 c and impact testing using the notched bar at temperatures as low as –196 c. Hardness values can be checked using various standards such as Brinell, Rockwell and Vickers.

A combination of failure analysis techniques such as metallography, fracture mechanics, mechanical testing, SEM analysis etc. can be used to determine the cause of failure of components in industries spanning pulp and paper, pipeline, civil industries, and petrochemical.

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Important Information about Ultrasonic Testing

The health of any industry can be ascertained by routine inspection and testing. The industry could be Nuclear, Power, Paper or Petrochemical. Every industry has to be maintained periodically in order to prevent costly breakdowns that could spell financial disaster. Nondestructive testing or NDT is the predominant method of conducting such maintenance work or inspection. NDT prevents the degradation of the article under inspection and is carried out by various types of equipment such as Eddy Current, Magnetic, Radiographic and Ultrasonic Testing.

With the help of this testing you can not only evaluate flaws, cracks and areas under corrosion but can also measure sample thickness. This form of NDT is routinely used in the examination of welded areas in vessels, plates and piping. Therefore, in the aerospace industry use is made of services such as the Automated Ultrasonic Testing or AUT and the Electromagnetic Acoustic Transmission or EMAT besides Shear Wave and Time of Flight Diffraction or TOFD.

The EMAT generates an ultrasonic wave within the sample. The reflected wave creates a small electrical pulse that is analyzed by software to form a picture of the sample’s internal structure. The EMAT can detect flaws and cracks and calculate their dimensions. It can also be used for calculating the sample thickness.

The TOFD utilizes probes that are placed on a buggy that runs along the weld to be examined. The software makes accurate assessment of the dimensions of the crack. The accuracy of ultrasonic testing makes it a handy tool for engineers engaged in NDT.