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Standard Test Method for Rubber Property´International Hardness
Přeložit název
NORMA vydána dne 1.6.2018
Označení normy: ASTM D1415-18
Datum vydání normy: 1.6.2018
Kód zboží: NS-897712
Počet stran: 7
Přibližná hmotnost: 21 g (0.05 liber)
Země: Americká technická norma
Kategorie: Technické normy ASTM
Keywords:
ICS Number Code 83.060 (Rubber)
Significance and Use | |||||||||||||||||
4.1 The International Hardness test is based on measurement of the penetration of a rigid ball into the rubber specimen under specified conditions. The measured penetration is converted into IRHD, the scale of degrees being so chosen that 0 represents a material having an elastic modulus of zero, and 100 represents a material of infinite elastic modulus. 4.1.1 The scale also fulfills the following conditions over most of the normal range of hardness: one IRHD range represents approximately the same proportionate difference in Young's modulus, and for rubber vulcanizates in the usual range of resilience, readings in IRHD are comparable with those given by a Type A durometer (Test Method D2240) when testing standard specimens. 4.1.1.1 The term “usual range of resilience” is used to exclude those compounds that have unusually high rates of stress relaxation or deformational hysteresis. For such compounds, differences in the dwell time in the two hardness tests (Test Methods D2240 and D1415) result in differences in hardness values. Readings may not be comparable when testing curved or irregularly shaped test specimens. 4.1.2 For substantially elastic isotropic materials like well-vulcanized natural rubbers, the hardness in IRHD bears a known relation to Young's modulus, although for markedly plastic or anisotropic rubbers the relationship will be less precisely known. 4.1.3 The relation between the difference of penetration and the hardness expressed in IRHD is based on the following: 4.1.3.1 The relation4
between penetration and Young's modulus for a perfectly elastic
isotropic material:
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