Introduction to NDT (Non Destructive Testing)
NDT means Non Destructive Testing, It is a technique used to find defects present inside any material. QA/QC testing process could be classified into Destructive testing and nondestructive testing. Destructive testing process results in damaging the test specimen. Non Destructive testing: Testing process is conducted without physically damaging the test specimen NDT is of four types 1. Ultrasonic testing [UT] 2. Liquid Penetrant testing [LTP] 3. Magnetic particle testing [MPT] 4. Radiographic testing [RT] 1. Ultrasonic Testing : UT UT is performed using sound waves/ Ultrasonic waves. Sound waves can be classified into three based on frequency: a. Infrasonic waves (with frequency less than 20 Hz, these waves are produced by the vibration of huge bodies like earth) b. Audible/Sonic waves(with frequency range extends from 20 Hz to 20 KHz, only these waves are audible to human ears) c. Ultrasonic waves(with frequency more than 20 KHz, these waves proved very useful to mankind Eg . communication , testing , Agriculture etc .. In UT, ultrasonic waves when forced to propagate through the test material gets reflected back either from the defective region (cracks) or from the backside of the test material. The reflected waves is received using transducers processed to analyzed and understand about the defects in the material. 2. Liquid Penetrant testing [LTP] Liquid penetrant testing is used to find defects on the open surfaces (0-3 mm) of the test materials 3. Magnetic particle testing [MPT] MPT is used to find defects on the open surfaces of test material to a depth of (0-6 mm)/ subsurface level .Only ferromagnetic metals(iron, cobalt, nickel….) can be inspected using MPT. 4. Radiographic testing [RT] RT is performed by transiting light rays/ electromagnetic rays (X-ray , alpha , beta , gama ...). The resultant ray that emerges out of the test material is copied to a photographic film and analyzed to understand details(size , shape , depth..) about the defects
NDT(Non Destructive Testing) LAB - Introduction 01
Techshore Inspection Services giving you a quick introduction on (NDT)Non Destructive Testing. NDT means Non Destructive Testing. Normally we may use two different types of testing methods such as destructive testing as well as non destructive testing for a test material. Destructive testing means we must destroy that particular test material and detect whether some defect is there or not. In this case we cannot use that material afterwards. So we are going for NDT. Here we are not doing any harm to the test material so that we may reuse it. NDT mainly follows two different standards. • American Standards (ASNT) • British Standards.
Non Destructive Testing (NDT) Probe Caliberation
Techshore Inspection Services explaining how to do the probe calibration for performing a Non Destructive Testing(NDT). Calibration means standardization. If you are getting a test material means you cannot directly go for its testing. Before that you should check whether your probe is working properly or not. That is called as probe calibration. We are using different types of probes for different testing such as normal probe, angle probe..etc. the actual result will be known for us and by calibrating these probes we are checking whether we are getting those values or not. If you are not getting that values means you must mark the percentage of error or else we should go for maintenance of the particular probe. Methods used are 1. horizontal linearity 2. Vertical linearity 3. Sensitivity 4. Resolution Techshore Inspection services provide courses like QA/QC in electrical, mechanical and other branches. And they also provide good laboratory training to the students. Its the best institution for taking any diploma courses based in South India.
Material Inspection & Identification
Material inspection and identification Whenever supplier supplies the steel to the project field they will also issue a test certificate , it contains heat number, the diameter of raw material, the tensile strength of raw materials, toughness of raw materials etc.Thus our duty is to take a sample from the raw materials and have to make a sample test in our laboratory to compare the test certificate value .for chemical composition testing PMA machine or spectrometer has been used and for tensile UTM machine will be used. After getting a result from the testing , have to cross check with the test certificate , thus both the result are matching then only the proceed the material for further.
NDT - UltraSonicTesting : Session 1 - www.techshore.in
1. Ultrasonic Testing : UT UT is performed using sound waves/ Ultrasonic waves. Sound waves can be classified into three based on frequency: a. Infrasonic waves (with frequency less than 20 Hz, these waves are produced by the vibration of huge bodies like earth) b. Audible/Sonic waves(with frequency range extends from 20 Hz to 20 KHz, only these waves are audible to human ears) c. Ultrasonic waves(with frequency more than 20 KHz, these waves proved very useful to mankind Eg . communication , testing , Agriculture etc .. In UT, ultrasonic waves when forced to propagate through the test material gets reflected back either from the defective region (cracks) or from the backside of the test material. The reflected waves is received using transducers processed to analyzed and understand about the defects in the material.
NDT - UltraSonic Testing (Beam Explained) Session 02
An Ultrasonic Beam produced by piezo electric crystal. Electricity is used to excite the crystal hence forth making it vibrate , the vibrational(mechanical) energy is converted to waves which are used in the testing process. An ultrasound beam consist of three zones 1. Dead Zone Its is referred distance traveled by wave during as crystal ringing time / crystal vibration time. Every probe has independent crystal ringing time . No defects will be captured during this time. 2. Near Zone Near zone is adjacent to Dead zone. In Near Zone the intensity of sound is varying and does not have any consistence. Hence the defects detected in this zone is either magnified or diminished once when compared with the actual defect due to varying sound intensity 3. Far Zone Far zone is the ideal zone for observing the defects. Here the intensity of sound decreases gradually / periodically, which means there exist a consistency for sound waves in the Far Zone.
QA/QC : NDT RT
Radiographic Testing is the most important method used in NDT. NDT is the abbreviated form of Non Destructive Testing. Without destructing our specimen we are able to check all the defects. There are mostly 14 methods in NDT. Radiographic Testing is most commonly used for finding out the subsurface as well as internal discontinuities present in a specimen. Major working principle regarding this one is shadow projection. Radiographic testing mainly consists of a Radiographic source such as a X- Ray source or else a Gamma ray source, Specimen to be tested and also a Radiographic Film. The specimen should be placed in between the Radiographic source and the radiographic film. An image will be recorded in the film and by interpreting this film we are able to identify the defect. A Radiographic machine consists of mainly three parts. They are Camera, guide tube and control unit.
NDT : Liquid Penetrant Testing
Procedure of conducting NDT examination in order to identify surface related defects which could be proceed due to processing manufacturing and service related issues this method is the most economic cost effective and user friendly testing methods when compared with other NDT methods but cleaning actually is a challengeable thing to be supervised by a NDT engineer