ASTM D2240-99 用硬度计测定橡胶硬度的试验方法

ASTM

Designation: D 2240– 97e1 AMERICAN SOCIETY FOR TESTING AND MATERIALS 100 Barr Harbor Dr., West Conshohocken, PA 19428 Reprinted from the Annual Book of ASTM Standards. Copyright ASTM

Standard Test Method for

Rubber Property—Durometer Hardness1 This standard is issued under the xed designation D 2240; the number immediately following the designation indicates the year of original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A superscript epsilon (e) indicates an editorial change since the last revision or reapproval.

e1 NOTE—A footnote was removed from Note 5 in February 1999.

1. Scope 1.1 This test method covers seven types of durometers A, B, C, D, DO, O and OO, and the procedure for determining indentation hardness of substances classied as rubber, cellular materials, elastomeric materials, thermoplastic elastomers and some hard plastics. 1.2 This test method is not applicable to the testing of fabrics. 1.3 The values stated in SI units are to be regarded as standard. The values given in parentheses are for information only. 1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. 2. Referenced Documents 2.1 ASTM Standards: D 618 Practice for Conditioning Plastics for Testing2 D 785 Test Method for Rockwell Hardness of Plastics and Electrical Insulating Materials2 D 1349 Practice for Rubber—Standard Temperatures For Testing3 D 4483 Practice for Determining Precision for Test Method Standards in the Rubber and Carbon Black Industries3 3. Summary of Test Method 3.1 This test method permits hardness measurements based on either initial indentation or indentation after a specied period of time, or both. NOTE 1—Durometers with maximum reading pointers used to determine initial hardness values may yield lower hardness when the maximum pointer is used.

type of indentor when forced into the material under specied conditions. The indentation hardness is inversely related to the penetration and is dependent on the elastic modulus and viscoelastic behavior of the material. The shape of the indentor and the applied force inuence the results obtained so there may be no simple relationship between the results obtained with one type of durometer and those obtained with another type of durometer or other instruments for measuring hardness. This test method is an empirical test intended primarily for control purposes. No simple relationship is known to exist between indentation hardness determined by this test method and any fundamental property of the material tested. For specication purposes it is recommended that Test Method D 785 be used for hard material. NOTE 2—Durometer scale comparison chart only. This is not and cannot be used a

s a conversion reference.

4. Signicance and Use 4.1 This test method is based on the penetration of a specic 1 This test method is under the jurisdiction of ASTM Committee D-11 on Rubber and is the direct responsibility of Subcommittee D11.10 on Physical Testing. Current edition approved Feb. 10, 1997. Published March 1997. Originally published as D 2240– 64 T. Last previous edition D 2240– 95. 2 Annual Book of ASTM Standards, Vol 08.01. 3 Annual Book of ASTM Standards, Vol 09.01.

5. Apparatus 5.1 Hardness measuring apparatus or durometer consisting of the following components: 5.1.1 Presser Foot, with a hole having a diameter as specied in Fig. 1(a), (b), or (c) with its center at least 6 mm (0.25 in.) from any edge of the foot. 5.1.2 Indentor, formed from hardened steel rod and shaped in accordance with Fig. 1(a), (b), or (c) with full extension adjustable between 2.46 to 2.54 mm (0.97 to 0.100 in.). 5.1.3 Indentor Extension Indicating Device (analog or electronic), having a scale reading from 0 to 100 with equal divisions throughout the range. The scale reading is an inverse function of the indentor extension. The device shall have a pointer that moves on the scale at a rate of one hardness point for each 0.025 mm (0.001 in.) of indentor movement. NOTE 3—Type A Shore Durometers serial numbers 1 through 16 300 and 16 351 through 16 900 and Type A-2 Shore Durometers numbers 1 through 8077 do not meet the requirement of 2.46 to 2.54 mm (0.097 to 0.100 in.) extension of the indentor at zero reading. These durometers will give readings which are low by amounts ranging from 3 units at 30