1 / 14

Anglicky v odborných předmětech "Support of teaching technical subjects in English “

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

kasi
Download Presentation

Anglicky v odborných předmětech "Support of teaching technical subjects in English “

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Anglicky v odborných předmětech"Support ofteachingtechnicalsubjects in English“ Tutorial: Engineeringmetrology Topic:Hardnessmeasuring Preparedby: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.

  2. Hardness measuring

  3. Hardness measuring • Material hardness is mechanical quality defined as resistance which is put up by material against foreign element penetration. • Main point of method’s 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).

  4. Hardness measuring Hardness tests divide into: • scratch • penetrating • reflective Up to loading force: • Static • Dynamic

  5. Static penetrating hardness tests • 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

  6. Hardness tests up to Brinell • Made by ČSN EN ISO 6506 standard. • Measuring made on Brinelldurometer. • 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.

  7. Hardness tests up to Brinell 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 • 2,5 ball diameter in mm • 187,5 force in kp 187,5 x 9,81 = 1839 N • 30 exposure time in seconds

  8. Hardness tests up to Vickers • Made up to ČSN 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.

  9. Hardness tests up to Vickers 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

  10. Rockwell hardness tests • Made up to ČSN 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.

  11. Rockwell hardness tests 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

  12. Mobile durometers • 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 durometerevaluates reflected ultrasound signal and it determines material hardness by sound decay (hard material absorbs little energy). • Reflective durometerevaluates reflected steel ball speed (hard material absorbs little energy).

  13. Question 1: What materials are appropriate to be measured by Brinell or Vickers methods? Question 2: Explain the example of Vickers hardness designation: 220HV/50/30

  14. Literature • BUMBÁLEK, Leoš. Kontrola a měření. 1. Praha: Informatorium, 2009. 205 s. ISBN 978-80-7333-072-9 • Moderní strojírenství pro školu i praxi. 55. Praha: EUROPA - SOBOTÁLES cz., 2007. ISBN 978-80-86706-19-1. Translation: • www.seznam.cz • www.slovnik.cz • JANATA, Petr. Handy slovník technický anglicko-český a česko-anglický. Plzeň: Nakladatelství Fraus, 2000. ISBN 80-7238-075-3 • Lingea LEXIKON 5, Technický slovník anglicko-český a česko-anglický. 2010.

More Related