DIN EN ISO 4498:2010-11

This document (EN ISO 4498:2010) has been prepared by Technical Committee ISO/TC 119 "Powder metallurgy"), the secretariat of which is held by SIS (Sweden), in cooperation with Technical Committee CEN/TC SS M11 "Powder metallurgy", the secretariat of which is held by CCMC. The responsible German Committee is Working Committee NA 145-01-03 AA "Probenahme und Prüfverfahren für Sintermetalle (ausgenommen Hartmetalle") ("Sampling and testing methods for sintered metal materials (excluding hardmetals)") at the Technology of Materials Standards Committee (NWT). Sintered metal materials generally have a porous structure. Therefore, they can be understood as composite metal/pore materials. That is why this International Standard describes two procedures to determine their hardness: - Procedure 1 for the macrohardness (this is the apparent hardness); - Procedure 2 for the microhardness (this is the hardness of the metallic phase only). Tests in Procedure 1 determine Vickers, Brinell and/or Rockwell macrohardnesses - their acronyms are: HV, HBW and HR. These tests determine the apparent hardness (macrohardness) of the materials because indentations generally include both the solid phase and a number of pores. The usual test forces applied to an indenter are from 10 N to 2 000 N. The apparent hardness value is often used as an expression of the mechanical strength of the material as a whole. It is usually lower than that of a solid material of the same composition and metallurgical condition. This does not imply that the functional characteristics (for example, wear resistance) are necessarily inferior to those of an equivalent full-density material. The apparent hardness is a macrostructural property. It characterizes the material taken as a whole. Tests in Procedure 2 determine the Vickers and/or Knoop microhardnesses of the material - their acronyms are: HVa and HKa. The usual test forces applied to an indenter are from 0,147 N to 1,960 N for Vickers, and 0,981 N for Knoop. The microhardness is a microstructural property used to control chemical composition, heat treatment or surface treatment. For these purposes, it is necessary to ensure that hardness test indentations are small enough not to include any visible pores, but only the solid phase. This International Standard specifies methods for testing hardness of metallic sintered materials, excluding hard metals. With respect to DIN EN ISO 4498:2007-05, the dates for the normative references provided have been removed from clause 2, a suggestion for preparation of nickel-alloyed sintered steels has been added to 4.3, testing conditions in Table A.1 regarding the use of steel balls (HBS) has been changed to the use of hardmetal balls (HBW) according to the current edition of ISO 6506-1 and the standard has been editorially revised.