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![1.) Brinell Test Method1.) Brinell Test Method
a.) Press a 10mm (3/8") diameter ball into
material with a known amount of load.
b.) Measure diameter of the indentation.
c.) BHN = Load = 2L
Surface Area D[D-(D2
-d2
)1/2
]](https://image.slidesharecdn.com/determinationofhardnessofmetals-190317153211/75/Determination-of-hardness-of-metals-6-2048.jpg)
Uploaded byDarshil Vekaria
Determination of hardness of metals
The document discusses various hardness testing methods for metals, including the Brinell, Rockwell, and Vickers tests, highlighting their procedures, advantages, disadvantages, and limitations. It outlines the principles of hardness, which indicates a material's resistance to deformation but not necessarily its strength, along with details on the correlation of hardness measurements to tensile strength. Each hardness test has specific requirements and applications, with varied accuracy, cost, and portability considerations.
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Determination of hardness of metals
- 1. VishwakarmaVishwakarma GovernmentGovernment Engineering College,Engineering College, ChandkhedaChandkheda NameName-Vekaria Darshil(150170106061)Vekaria Darshil(150170106061) BranchBranch -Civil EngineeringCivil Engineering TopicTopic –Determination Of Hardness OfDetermination Of Hardness Of Metals:Brinell/ Vicker /Rockwell Hardness TestMetals:Brinell/ Vicker /Rockwell Hardness Test
- 2. HardnessHardness is theresistance ofis the resistance of a material to abrasion ora material to abrasion or localized plastic deformation.localized plastic deformation.
- 3. Hardness is notnecessarily anHardness is not necessarily an indication of strength ,indication of strength , although for some materialsalthough for some materials such as steel, a harder steel issuch as steel, a harder steel is a stronger steel.a stronger steel.
- 4. Hardness TestingHardness Testing BrinellHardness TestBrinell Hardness Test:: 10mm diameter10mm diameter ball with a load of 500, 1000 or 3000kgball with a load of 500, 1000 or 3000kg Rockwell Hardness TestRockwell Hardness Test:: A cone shapeA cone shape indenter; the depth of penetration isindenter; the depth of penetration is measured.measured. Vickers Hardness TestVickers Hardness Test:: Pyramid shapePyramid shape indenterindenter
- 5. A.) Brinell HardnessTestA.) Brinell Hardness Test (BHN)(BHN)
- 6. 1.) Brinell TestMethod1.) Brinell Test Method a.) Press a 10mm (3/8") diameter ball into material with a known amount of load. b.) Measure diameter of the indentation. c.) BHN = Load = 2L Surface Area D[D-(D2 -d2 )1/2 ]
- 7. L = Loadplaced on ball, usually 3000 kg , but 1500 kg, and 500 kg can also be used. D = Diameter of steel ball ( = 10 mm) d = diameter of dent, measured by looking thru a Brinell microscope.
- 8. Hardness (HB) TensileStrength(MPa) Correlations between the Brinellhardness number (BHN) and tensile strength of carbon steels. Tensile Strength = 3.4 BHN
- 9. BHN PROS &CONSBHN PROS & CONS Widely used and wellWidely used and well acceptedaccepted Large ball gives goodLarge ball gives good average reading with aaverage reading with a single test.single test. AccurateAccurate Easy to learn and useEasy to learn and use Non-portableNon-portable DestructiveDestructive High initial cost ($5,000)High initial cost ($5,000) Error due to operatorError due to operator reading Brinellreading Brinell Microscope (10% max)Microscope (10% max)
- 10. 2.) Limitations ofthe Brinell2.) Limitations of the Brinell Hardness TestHardness Test a.) Sample must be ten times thicker than the indentation depth (sample usually should be at least 3/8" thick). b.) Test is most accurate if the indentation depth is 2.5 - 5.0 mm. Adjust load to achieve this. c.) Test is no good if BHN > 650
- 11. 3.) Advantages ofthe Brinell Test3.) Advantages of the Brinell Test a.) Widely used and well accepteda.) Widely used and well accepted b.) Large ball gives good average readingb.) Large ball gives good average reading with a single test.with a single test. c.) Accuratec.) Accurate d.) Easy to learn and used.) Easy to learn and use
- 12. 4.) Disadvantages ofthe Brinell Test4.) Disadvantages of the Brinell Test a.) Destructivea.) Destructive b.) Non-portableb.) Non-portable c.) High initial cost ($5,000)c.) High initial cost ($5,000) Error due to operator reading BrinellError due to operator reading Brinell Microscope (10%max)Microscope (10%max)
- 13. Rockwell Hardness TestRockwellHardness Test (Hrb,HRc,etc.)(Hrb,HRc,etc.)
- 14. 1.) Method a.) SelectScale - load and indentor depending on the scale b.) Press a point into material - Diamond Point (Brale) - 1/16" ball - 1/8" ball - ¼” ball
- 15. 1.) Method Machine measuresdepth of penetration and computes hardness.
- 16. 2.) Limitations ofthe.) Limitations of the Rockwell TestRockwell Test a.) Sample must be ten times thicker than the indentation depth (sample usually should be at least 1/8" thick). b.) Test is most accurate if the Rockwell Hardness is between 0 and 100. Adjust scale to achieve this. For Steel: If Hra > 60, use Hrc scale If Hra < 60, use Hrb scale
- 17. 3.) Advantages ofthe.) Advantages of the Rockwell TestRockwell Test a.) Widely used and well accepteda.) Widely used and well accepted b.) Little operator subjectivityb.) Little operator subjectivity c.) Accuratec.) Accurate d.) Fastd.) Fast e.) Large range of hardnesses (plastics to steels)e.) Large range of hardnesses (plastics to steels)
- 18. 44.) Disadvantages ofthe.) Disadvantages of the Rockwell TestRockwell Test a.) Destructivea.) Destructive b.) Non-Portableb.) Non-Portable c.) Initial cost ($5,000)c.) Initial cost ($5,000)
- 19. Rockwell Test LimitationsRockwellTest Limitations Sample must be ten times thicker than theSample must be ten times thicker than the indentation depth (sample usually should be atindentation depth (sample usually should be at least 1/8" thick).least 1/8" thick). Need 3 tests (minimum) to avoid inaccuracies dueNeed 3 tests (minimum) to avoid inaccuracies due to impurities, hard spots.to impurities, hard spots. Test is most accurate if the Rockwell HardnessTest is most accurate if the Rockwell Hardness is between 0 and 100. Adjust scale to achieveis between 0 and 100. Adjust scale to achieve this.this. For Steel:For Steel: If HRa > 60, use HRc scaleIf HRa > 60, use HRc scale If HRa < 60, use HRb scaleIf HRa < 60, use HRb scale
- 20. PROS & CONS(RHT)PROS & CONS (RHT) Widely used and wellWidely used and well acceptedaccepted Little operatorLittle operator subjectivitysubjectivity AccurateAccurate FastFast DestructiveDestructive Non-PortableNon-Portable Initial cost ($5,000)Initial cost ($5,000)
- 21. Rockwell Readings toBrinellRockwell Readings to Brinell 1)1) If -20 < HRc < 40If -20 < HRc < 40 BHN =BHN = 1,420,0001,420,000 (100 – HRc)(100 – HRc)22 2)2) If 40 < HRc < 100If 40 < HRc < 100 BHN =BHN = 25,000__25,000__ (100 - HRc)(100 - HRc) 3)3) If 35 < HRb < 100If 35 < HRb < 100 BHN =BHN = 7,300____7,300____ (130 - HRb)(130 - HRb)
- 22. Vickers Hardness =F/A = 3σ A P 2 1.854P HV L = P: applied load in kg, 5-120 kg L: average diagonal length, mm (typically from a few µm to 1 mm) θ: angle between opposite faces of indenter; ≡ 136° Range: 5 (extremely soft metals) - 1500 (extremely hard materials) θ DPH/VHN/VPH/VH = 2PSin(θ/2)/L2 L
- 23. Vickers hardness testVickershardness test Vickers Hardness is an alternative to the BrinellVickers Hardness is an alternative to the Brinell method to measure the hardness of materials.method to measure the hardness of materials. The Vickers test is often easier to use than otherThe Vickers test is often easier to use than other hardness tests since the required calculations arehardness tests since the required calculations are independent of the size of the indenter, and theindependent of the size of the indenter, and the indenter can be used for all materials irrespective ofindenter can be used for all materials irrespective of hardnesshardness.
- 24. Vickers Hardness TestingVickersHardness Testing Continuous hardness from soft (5 DPH) to hardContinuous hardness from soft (5 DPH) to hard materials (1500 DPH)materials (1500 DPH) DPH independent on load value unlike BHNDPH independent on load value unlike BHN Careful surface preparation requiredCareful surface preparation required Slow due to careful measurementSlow due to careful measurement Small indentation compared to BHNSmall indentation compared to BHN Pin cushion and Barrel indentations possiblePin cushion and Barrel indentations possible
- 25.