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Line 22: − − {| class="wikitable" border="1" − |+ Various Rockwell scales − |- − ! Scale !! Abbreviation !! Load !! Indenter !! Use − !N − !s − |- − | A || HRA || 60 [[Kilogram-force|kgf]] || 120° diamond spheroconical<sup>†</sup> || [[Tungsten carbide]] − |100 − |0.002mm − |- − | B || HRB || 100 kgf || {{convert|1/16|in|mm|adj=mid|-diameter|3}} steel sphere || Aluminium, brass, and soft steels − |130 − |0.002mm − |- − | C || HRC || 150 kgf || 120° diamond spheroconical || Harder steels >B100 − |100 − |0.002mm − |- − | D || HRD || 100 kgf || 120° diamond spheroconical − | − |100 − |0.002mm − |- − | E || HRE || 100 kgf || {{convert|1/8|in|mm|adj=mid|-diameter|3}} steel sphere − | − |130 − |0.002mm − |- − | F || HRF || 60 kgf || {{convert|1/16|in|mm|adj=mid|-diameter|3}} steel sphere − | − |130 − |0.002mm − |- − | G || HRG || 150 kgf || {{convert|1/16|in|mm|adj=mid|-diameter|3}} steel sphere − | − |130 − |0.002mm − |- − | colspan=5 | <sup>†</sup>Also called a ''brale indenter'' − | − | − |} − − * Except for testing thin materials in accordance with A623, the steel indenter balls have been replaced by tungsten carbide balls of the varying diameters. When a ball indenter is used, the letter "W" is used to indicate a tungsten carbide ball was used, and the letter "S" indicates the use of a steel ball. E.g.: 70 HRBW indicates the reading was 70 in the Rockwell B scale using a tungsten carbide indenter.<ref>E18-08b Section 5.1.2.1 & 5.2.3</ref> − − The ''superficial'' Rockwell scales use lower loads and shallower impressions on brittle and very thin materials. The 45N scale employs a 45-kgf load on a diamond cone-shaped Brale indenter, and can be used on dense [[ceramic]]s. The 15T scale employs a 15-kgf load on a {{convert|1/16|in|mm|adj=mid|-diameter|3}} hardened steel ball, and can be used on [[sheet metal]]. − − The B and C scales overlap, such that readings below HRC 20 and those above HRB 100, generally considered unreliable, need not be taken or specified.
Rockwell Hardness Tester (view source)
Revision as of 23:01, 18 January 2018
, 23:01, 18 January 2018→Scales and values
==Scales and values==
==Scales and values==
There are several alternative scales, the most commonly used being the "B" and "C" scales. Both express hardness as an arbitrary [[dimensionless number]].
There are several alternative scales, the most commonly used being the "B" and "C" scales. Both express hardness as an arbitrary [[dimensionless number]].
===Typical values===
===Typical values===