Tutorial:Engineering metrology Topic: Hardness measuring Prepared by: Ing. Pavel Rožek Projekt...
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Anglicky v odborných předmětech "Support of teaching technical subjects in English“ Tutorial: Engineering metrology Topic: Hardness measuring Prepared by: Ing. Pavel Rožek Projekt Anglicky v odborných předmětech, CZ.1.07/1.3.09/04.0002 je spolufinancován Evropským sociálním fondem a státním rozpočtem České republiky.
Tutorial:Engineering metrology Topic: Hardness measuring Prepared by: Ing. Pavel Rožek Projekt Anglicky v odborných předmětech, CZ.1.07/1.3.09/04.0002
Tutorial:Engineering metrology Topic: Hardness measuring
Prepared by: Ing. Pavel Roek Projekt Anglicky v odbornch pedmtech,
CZ.1.07/1.3.09/04.0002 je spolufinancovn Evropskm socilnm fondem a
sttnm rozpotem esk republiky.
Slide 3
Hardness measuring
Slide 4
Material hardness is mechanical quality defined as resistance
which is put up by material against foreign element penetration.
Main point of methods hardness measuring is based on pressing a
small body (indenter) into tested material surface by specific
force in defined conditions. Trace size is hardness criterion which
results by suitably shaped body pressing (small ball, cone,
pyramid) of hard enough material (quenched steel, sintered carbide,
diamond).
Slide 5
Hardness tests divide into: scratch penetrating reflective Up
to loading force: Static Dynamic
Slide 6
They are the most common and the most famous. Indentation is
made by slow pressing of penetrating body continuously with
increasing force vertically to tested surface. Basic tests are:
Brinell Rockwell Vickers
Slide 7
Made by SN EN ISO 6506 standard. Measuring made on Brinell
durometer. Steel quenched ball with diameter D is pressed into
tested material by force F. Indentation diameter is measured in 2
perpendicular directions. Brinell tests are suitable only for
hardness testing of medium hard and light materials.
Slide 8
Marking Hardness up to Brinell is marked by measured value and
by H letters at standard force and ball size H. Third letter marks
ball material, HBS marks Brinell test with steel ball and HBW with
tungsten ball. 228 HBW 2,5/187,5/30 228 -Hardness value HBW
-Brinell and ball material 2,5ball diameter in mm 187,5force in kp
187,5 x 9,81 = 1839 N 30exposure time in seconds
Slide 9
Made up to SN EN ISO 6507 standard. Measuring made on Vickers
durometer. Regular diamond four-walled pyramid is pressed with apex
angle 136. Hardness is determined after measuring of mean length of
both diagonal indentation. Vickers hardness tests are used for soft
and hard materials of the same tested body.
Slide 10
Marking Hardness up to Vickers is marked by numeral hardness
value, abbreviation HV, by testing force ratio value and force 9,81
N and by exposure force time in seconds. 210 HV/50/30 210 hardness
value HV tests up to Vickers 50 testing force F = 50 x 9,81 N =
490,3 N 30 exposure force time in seconds
Slide 11
Made up to SN EN ISO 6508 standard. Made on Rockwell durometer.
Penetrating body is diamond cone with apex angle 120 or quenched
steel ball with 1/16 or 1/8 diameter. Indentation depth reached by
penetrating body pressing is measured in defined conditions.
Slide 12
Marking Hardness up to Rockwell is marked by measured value, by
letters HR and by measuring scale letter. Diamond cone with apex
angle 120 is used to hardness measuring of hard materials (e.g. At
HRB and HRA process). Quenched steel ball with 1,59 mm or 3,175 mm
diameter is used to measuring soft materials (e.g. at HRB and HRF
process). 58 HRC 56 hardness value HRC Rockwell test C
Slide 13
Used to hardness testing of big components or difficult to
reach components spaces. Manual durometer is pressed to material
and it is switched on by button. Measured hardness value is
displayed. Ultrasound durometer evaluates reflected ultrasound
signal and it determines material hardness by sound decay (hard
material absorbs little energy). Reflective durometer evaluates
reflected steel ball speed (hard material absorbs little
energy).
Slide 14
What materials are appropriate to be measured by Brinell or
Vickers methods? Question Question 2: Explain the example of
Vickers hardness designation: 220HV/50/30
Slide 15
BUMBLEK, Leo. Kontrola a men. 1. Praha: Informatorium, 2009.
205 s. ISBN 978-80-7333-072-9 Modern strojrenstv pro kolu i praxi.
55. Praha: EUROPA - SOBOTLES cz., 2007. ISBN 978-80-86706-19-1.
Translation: www.seznam.cz www.seznam.cz www.slovnik.cz
www.slovnik.cz JANATA, Petr. Handy slovnk technick anglicko-esk a
esko-anglick. Plze: Nakladatelstv Fraus, 2000. ISBN 80-7238-075-3
Lingea LEXIKON 5, Technick slovnk anglicko-esk a esko-anglick.
2010.