Mitutoyo HR-530 Series - Hardness Test Methods; Rockwell;Rockwell Superficial Hardness Test; About the Rockwell;Rockwell Superficial Hardness Test

No. 99MBG518A
A-9
PART A : 4 Hardness Test Methods
4
Hardness Test Methods
4.1
Rockwell/RockwellSupercialHardnessTest
4.1.1 AbouttheRockwell/RockwellSupercialHardnessTest
TheRockwellhardnesstestandRockwellsupercialhardnesstestobtainthehardnessusingadia-
mond indenter or a ball indenter (a steel ball or a carbide ball).
Thesetestmethodsobtainthehardnessfromthedi󰀨erenceindepthoftheindentsthattheindenter
formsbyrstapplyingapreliminarytestforce,thenapplyingthetotaltestforce,andthenreapplyingthe
preliminary test force.
Thehardnesstestsdi󰀨erinthepreliminarytestforceusedfortheRockwellhardnessandtheRockwell
supercialhardness.
y Rockwell hardness: The preliminary test force is 98.07 N.
y Rockwellsupercialhardness:Thepreliminarytestforceis29.42N.
Also,scalesarerepresentedbyaspecicsymbolassignedtothecombinationoftheindenterandthe
test force.
Symbol Description Unit
F
0
Preliminary test force N
F
1
Additional test force (total test force minus preliminary test force) N
F Total test force F = F
0
+ F
1
N
S
A constant for hardness conversion corresponding to scale-spe-
cic1HR
mm
N Aconstantspecictothescale
h
Depth of permanent indent when returning to the preliminary test
force after eliminating the additional test force
mm
HRA, HRC, HRD Rockwell hardness
HRB, HRE, HRF
HRG, HRH, HRK
Rockwell hardness
HRN, HRT Rockwellsupercialhardness