Eddy Current Testing

Non Destructive Hardness Testing


How can anyone define hardness, by means of its resistance & durability? The hardness is not just a term but a practical implementation of “Sustaining power that can never get worn-out, no matter how the thing is been put to the test.” While doing a hardness test, the mechanism of the hardness tester device, applies a fixed amount of load, along with the needed depth of insertion that can be measured, by means of various units & techniques. A set of fixed force or weight is given to the object that shows the result of any scratch or dents that might happen when the product or object is put on work before getting it on use in the industry or when it’s going to be used for its actual purpose.
The implemented hardness – value can be obtained by measuring the depth or the area, of how…? and in what manner…? the applied force shows the result of the products’ hard resistance power when its being put on nearly various different methods of testing’s one after another stages of tests that are conducted.

Why is hardness test needed?
 Hardness testing helps to check the sustenance of any material, before putting it up for its actual use.
 The tester machine implies a swift force within a time lap of 0 to 30 seconds of tremendous impact and power on the object.
 Keeping this line of test, if the product sustains without breaking, means it has completed the first stage of its test.
 These tests are mostly less expensive.
 Moreover, any type of objects can be tested before introducing them into the market and assured stamp of [OK TESTED] is marked on the products when the entire procedure is completed.
 This is done by the QC – Quality Check device, when the product is put to the test & after the entire tests are completed.

Tests conducted to check hardness of any given object are described through these given techniques.

1. The Eddy-current Testing’s: It’s technically called as ECT which is one of a kind, electro-magnetic testing methods implemented for non-destructive forms of objects that are conducted by means of using electromagnetic tests, that help to detect base region & defected points in any conductive (conductive – means object that are good respondent to electric current) materials.

2. Ultrasonic Testing’s: Termly known as UT is another form of a non-destructive form of testing that helps to spread sounds that are highly unbearable to the human ear’s. The transmission of these high-end ultra sound frequency waves are tested by evaluated forms of reflected waves on a time measured oscilloscope – a device used for displaying and analysment’s of waveform from electronic signals. In addition, it helps for detecting sub-surfaced uneven platforms, helps in measuring dimensional thickness and other analysing materials. The reflected wave is transformed to an electrical signal by a device that helps to convert these waves into the oscilloscope.

3. Rebound Testing’s of hammer: Just like other non-destructive forms of hardness tests that are conducted, the rebound procedure of hammer test on concrete surfaces check upon, as per how well the steel has its hardness which must be least of 5000 tensile strength which is calculated in (n/mm2) units. Tensile strength is a technical word, used to calculate the mass strength applied on any object that needs to be unbreakable or undamaged as per the amount of strength applied on it. On a general term, the rebound number increases as per the strength and also gets affected by various other factors like, the type of cement, surface conditions, the type of concrete used, and many other such factors. Usually the internal cracks occurring across the cross section are usually not indicated to be counted as rebound numbers.

4. Ultra-sonic Impedance or Acoustic Impedance: As we all know sound travels at a faster rate through materials under any applied sound pressure. Ultra-sonic sound transmits an impact to the boundaries of any 2 materials that have different sound impedances. Such an impact creates a difference in the physical point of change in the pressure of any given object. Thus, the applied design of US-ultra sonic impedance can be used to calculate resistance of any material, as long as the density & speed are known. The device or apparatus can also show the changes of any sound that varies from its start, till the end of the over all amount of energy that is used for transmitting the sound energy.

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