ISO 4545:1993

Metallic materials -- Hardness test -- Knoop test

Specifies the method of Knoop hardness test covering test forces up to and including 9,807 N. The principle of the method is forcing a diamond indenter, in the form of a rhombic-based pyramid with specified angles between opposite faces at the vertex, into the surface of a test piece and measuring the long diagonal of the indentation left in the surface after removal of the test force. The Knoop hardness is proportional to the quotient obtained by dividing the test force by the projected area of the indentation.


General information

  • Status :  Withdrawn
    Publication date : 1993-03
  • Edition : 1
  • :
    ISO/TC 164/SC 3
    Hardness testing
  • 77.040.10
    Mechanical testing of metals

Got a question?

Check out our FAQs

Customer care
+41 22 749 08 88

Opening hours:
Monday to Friday - 09:00-12:00, 14:00-17:00 (UTC+1)

Keep up to date with ISO

Sign up to our newsletter for the latest news, views and product information

Subscribe