 Hello, I am Melkar Jagle working as assistant professor in Department of Mechanical Engineering, Vulturen Institute of Technology, Solapur. Today we are going to learn about destructive testing methods. What are destructive testing methods for the material? Let's see. Learning outcome. At the end of this session, student will be able to select various material destructive testing methods and its significance. Learning outcome. At the end of this session, student will be able to select various destructive testing methods and its significance. So this is the content, so testing of materials, destructive testing methods. As we have already seen in the previous video, this is the reason why the testing of material is required. So it has n number of factors for which the material is needed to test. For example, to assess the mechanical properties, to determine the data, to determine the surface and subsurface defects, to check chemical composition, to determine suitability of material for the particular application. So before moving forward, I would like to ask a question. So can you tell me or can you state what are different types of destructive testing methods? So you need to state few methods used for destructive testing. So the methods for destructive testing are tensile test, hardness test, fatigue test, creep test. So these are the few tests which are destructive testing. Destructive test that is, in this test the component or the specimen either breaks or remains no longer for further use. So these are the tests, tensile testing, hardness testing, impact test, creep test and fatigue test. So destructive testing methods. So in this method, the first test is tensile test which is performed on UTM that is universal testing machine. The tensile specimen is prepared and the test is conducted on UTM. The specimen is fixed between the two jaws and hardness test gives the information about wear resistance of the material. So depending upon the service conditions, fatigue and creep test are specified in some cases. So these are the destructive testing methods. In impact test there are two types of tests that is Charpy test and Izot test. Charpy test is used in United States whereas Izot test is used in United Kingdom. Difference between the Charpy test and the Izot test is the specimen. So you see the specimen for the Charpy test is square prism with 10 by 10 by 52 mm V notch in the center. So this is V notch in the center with 45 degree and 0.2 mm radius whereas for Izot test the specimen is square prism with 10 by 10 by 75 V notch shown as in the figure. So it is at 28 mm from one side of the specimen whereas here it is in center the notch in the Charpy test is in center and in Izot test it is not in the center it is 28 mm from the one side of specimen. So this is the pendulum impact machine. So you see this is the specimen placed over here on the anvil. This is the hammer. This is the starting position of the hammer before impacting on the specimen. This is the reader scale pointer. This is the end of the swing. The swing starts from this location. It hits the specimen either Charpy or Izot and then it goes and it swings back. So let's see. So this is the setup of Charpy test and Izot test. So this is Charpy test whereas this is Izot test. This is the top view and this is the side view. Charpy test. For Charpy test pendulum is released from an angle at 140 degree that is drop height is 1.457 meter and weight is 20.932 kg. The impact velocity is root 2 gh that is root 2 into height into gravitational force. So the impact velocity for the Charpy test is 5.346 meter per second that is impact velocity is root 2 into mg that root 2 the impact velocity is root 2 of gh that is height into gravitational force. And for Izot test the weight of the pendulum is 21.70 kg and it is released from 85 degree and the drop height is 0.758 meter. So the impact velocity for Izot test is 3.856 meter per second. So these readings the pointer is provided on the semicircular dial which indicates the position of pendulum. So this is the Charpy and Izot test. The in Charpy test the specimen is arranged as a simply supported beam with a span of 40mm and notch is on the tension side. And in Izot the specimen is clamped to act as a virtual cantilever with notch on same side of striking end. The results of this test indicate differences in condition of metal or an alloy that are not indicated by other tests such as hardness or tensile. This test when carried out on a specimen at low temperature proved useful in indicating whether or not adequate toughness is maintained at those temperature. So the results these results cannot be explained in terms of design criteria. So the next test is creep test. So what is creep? Creep is nothing but slow and progressive plastic deformation of a material with time under constant stress and temperature above the melting point of a metal or an alloy. This test is carried out at high temperature that is above recrystallization temperature. So the creep test the usual method of creep testing consist of subjecting the specimen at a constant tensile stress at a constant temperature and measuring the strain with time. So this test is a test in which the specimen is subjected to the high temperature and under tensile load. The test requires considerable laboratory equipment care and precision in performance. The time for test may be in hours or weeks, days or a months. So this is the setup for the creep test. So this is the specimen, this is the furnace, the load, this is the weight or the load. So as after the test is there we observe the creep in the specimen. The graph is plot strain versus time. This is OA that is elongation due to application of load. The region from A to B is known as primary creep where strain rate increases with time and the region B to C is known as secondary creep. In this you observe strain is practically minimum and whereas C to D is tertiary creep. In this the strain rate increases non-uniform and the plastic deformation and necking results in failure. So this failure is tensile in nature. So this is the effect of temperature on the creep it is SN curve at room temperature you find this curve at 100 degree 200 and 300. The field is referred from the book Dr. Kodkire and VK Agarwal. Thank you.