INTRODUCTION• Many parts are formed into various shape by applying external forces to the workpiece.• Material Testing is a test done to determine the properties of a substance in comparison with a standard or specification.
PURPOSE• To determine quality of material• To determine mechanical properties such as strength, hardness, ductility, toughness, etc.• To trace defects/ flaws in the materials.• To evaluate materials potential in certain use.
DEFINITION The strength of the material and of its Ductility resistance to scratching and to wear. The ability of a material to have plasticPlasticity deformation after applying a tensile load before fracture. Tendency of a material to fracture or fail uponToughness the application of force, impact, or shock. The ability of a material to return to itsBrittleness original shape after load is removed. The ability of a material to withstand tensileHardness force without fractured. The ability of a material to withstand impact Strength force without fractured. The ability of a material to deformedElasticity permanently and will not return to its original shape after the load is removed.
DEFINITION• Tests are carried out to the specimens failure, in order to understand a specimens structural performance or material behaviour under different loads.
TYPES OF DESTRUCTIVE TEST Destructive Test Hardness Test Toughness TestBrinell Test Brinell Test Charpy Test Izod Test Vickers Test Shore Test
BRINELL TEST• Test procedure : Giving a force to a steel ball against a test surface.
• Principe to measure hardness by Brinell test; i) Thickness of the specimen should be at least 7 times the depth of penetration of the indenter. ii) The location of penetration of the indenter should be at least 3 diameters of the indenter from the edge of the specimen. iii) The test should not exceed 500HB due to the indenter can undergoes elastic deformation.
D = steel ball diameter(mm)d = indent diameter (mm)P/F = force (kg)
VICKERS TEST• Test procedure : Indenting the test surface with a pyramid diamond indenter.
ROCKWELL TEST• Test procedure : Press indenter onto the material surface, first with a minor load and then with major load. i) A minor load is applied and a zero reference position is established ii) The major load is applied for a specified time period. iii) The major load is released leaving the minor load applied.
E = a constant dependingon form of indenter HR = ( E – e )e = increase in depth ofpenetration (mm)
SHORE TEST• Test procedure : Drop a diamond tipped hammer onto the specimen from a certain height.• The hardness is related to the rebound of the indenter ( the higher the rebound, the harder the material).