Question

5- What are differences in Brinell, Rockwell and Vicker hardness measurements? Write your answer in a tabular form based upon type of indenter(s) used, range of applied typical loads and type of material substrates where test is typically applicable and one example per material of application where test could be used.

Text Book- The Science and Engineering of Materials, Askeland et al. (seven edition)

Home Work- # 6 for Chapter 6

please yype your answer in the computer

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Answer 1

Sr. No.	Brinell Hardness test	Rockwell Hardness test	Vicker’s Hardness test
1	Indentation is done with 10 mm diameter steel ball.	Two types of indenters – 120° diamond cone called Brale indenter and 1.6 and 3.2 mm diameter steel balls -Combination of indenter and major load gives rise to different hardness scales.	Vickers test uses a square-base diamond pyramid indenter having an angle of 136° between the opposite faces.
2	A load of 3000 kg (500 kg for softer materials) is applied for 10 – 30 s.	C - Scale – Brale indenter + 150 kg load, designated as RC. Range is RC 20 – RC 70. Used for hard materials like hardened steels.	The hardness, called DPH or VHN (Diamond pyramid hardness no. or Vickers Hardness no.), is obtained by dividing the load (1 – 120 kg) with the surface area of the indentation.
3	Diameter of the indentation is measured to obtain the hardness (Brinell Hardness No.) from the relationship:- BHN= P/ (π*D*t)          = P/[π*D/2*(D-(D2 – d2)]0.5 P = Applied load D = Diameter of ball d = Diameter of indentation t = Depth of impression	B-Scale – Steel ball indenter + 100 kg load, written as RB. Range is RB 0 to RB 100. Minor loads in RC and RB scales are 10 kg and 3 kg respectively.	The surface area is calculated from the diagonals length of the impression. VHN= 1.854 *P/L2 P = Applied Load L = Diagonal length of indentation

BRINELL HARDNESS TEST

ROCKWELL HARDNESS TEST

VICKER HARDNESS TEST