Presentation on theme: "IMPACT TEST EXPERIMENT # 7 Instructor: M.Yaqub. IMPACT LOAD Shock load or sudden load is referred as impact load. In order to select a material to."— Presentation transcript:
IMPACT TEST EXPERIMENT # 7 Instructor: M.Yaqub
IMPACT LOAD Shock load or sudden load is referred as impact load. In order to select a material to withstand sudden intense below, we must measure a material’s resistance to failure in an impact test. The ability to withstand an impact below is referred as toughness of the material.
IMPACT TEST CURVE
RESULT OF IMPACT TEST From the curve, it is clear at high temperature, a higher amount of energy is required for the fracture. Here fracture is ductile, means a lot of deformation before the fracture. At low temperature, a small amount of energy is required for the fracture. Here fracture is brittle, means a very small (practically no) deformation before the fracture.
DUCTILE TO BRITTLE TRANSITION TEMPERAURE The fracture mechanism changes from ductile to brittle over a narrow range of temperature. This temperature is called DUCTILE TO BRITTLE TRANSITION TEMPERATURE (DBTT). DBTT can be read from the impact test curve as the median temperature of the curve.
MORE ABOUT DBTT DBTT should be below the working environment temperature for a metal subjected to impact loading condition. Not all materials have a distinct DBTT. Usually BBC metals have DBTT while FCC metals don’t.