LEC 28 CH07 Hardness(ppt) KFUPM Open CoursewareLEC 28 ch07度PPT KFUPM開放課件

1、dr. a. aziz bazoune chapter 7: fatigue failure resulting from variable loadingme 307 machine design i dr. a. aziz bazounech-07 lec 27 slide 1dr. a. aziz bazoune chapter 7: fatigue failure resulting from variable loadingme 307 machine design i ch-07 lec 27 slide 2dr. a. aziz bazoune chapter 7: fatigu

2、e failure resulting from variable loadingme 307 machine design i ch-07 lec 27 slide 3hardness the resistance of a material metal to penetration by a pointed tool is called hardness. it is the property of a metal, which gives it the ability to resist being permanently, deformed (bent, broken, or have

3、 its shape changed), when a load is applied. the greater the hardness of the metal, the greater resistance it has to deformation. dr. a. aziz bazoune chapter 7: fatigue failure resulting from variable loadingme 307 machine design i ch-07 lec 27 slide 4hardness measurement methods qrockwell hardness

4、test qbrinell hardness qvickersqknoop hardness qshoredr. a. aziz bazoune chapter 7: fatigue failure resulting from variable loadingme 307 machine design i ch-07 lec 27 slide 5rockwell hardness test the rockwell hardness test is a hardness measurement based on the net increase in depth of impression

5、as a load is applied. hardness numbers have no units and are commonly given in the r, l, m, e and k scales. the higher the number in each of the scales means the harder the material.dr. a. aziz bazoune chapter 7: fatigue failure resulting from variable loadingme 307 machine design i ch-07 lec 27 sli

6、de 6dr. a. aziz bazoune chapter 7: fatigue failure resulting from variable loadingme 307 machine design i ch-07 lec 27 slide 7brinell hardness test brinell hardness is determined by forcing a hard steel or carbide sphere of a specified diameter under a specified load into the surface of a material a

7、nd measuring the diameter of the indentation left after the test. the brinell hardness number, or simply the brinell number, is obtained by dividing the load used, in kilograms, by the actual surface area of the indentation, in square millimeters. the result is a pressure measurement, but the units

8、are rarely stated. dr. a. aziz bazoune chapter 7: fatigue failure resulting from variable loadingme 307 machine design i ch-07 lec 27 slide 8dr. a. aziz bazoune chapter 7: fatigue failure resulting from variable loadingme 307 machine design i ch-07 lec 27 slide 9for steelsthe relationship between th

9、e minimum ultimate strength and the brinell harness number for is0.4953.41bubhkpsishmpa200450bhcast ironthe minimum strength, as defined by the astm, is found to be0.23812.51.5886bubhkpsishmpadr. a. aziz bazoune chapter 7: fatigue failure resulting from variable loadingme 307 machine design i ch-07

10、lec 27 slide 10dr. a. aziz bazoune chapter 7: fatigue failure resulting from variable loadingme 307 machine design i ch-07 lec 27 slide 11dr. a. aziz bazoune chapter 7: fatigue failure resulting from variable loadingme 307 machine design i ch-07 lec 27 slide 12dr. a. aziz bazoune chapter 7: fatigue failure resulting from variable loadingme 307 machine design i ch-07 lec 27 slide 13dr. a. aziz bazoune chapter 7: fatigue failure resulting from variable loadingme 307 mac