ASTM D785-03

Standard Test Method for Rockwell Hardness of Plastics and Electrical Insulating Materials

SCOPE
1.1 This test method covers two procedures for testing the indention hardness of plastics and related plastic electrical insulating materials by means of the Rockwell hardness tester.
1.2 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only.
1.3 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.
Note 1—This test method and ISO 2039-2 are equivalent.

General Information

• Status: Historical
• Publication Date: 31-Oct-2003
• ICS: 29.035.20 - Plastics and rubber insulating materials
• Technical Committee: D20 - Plastics
• Drafting Committee: D20.10 - Mechanical Properties

Relations

• Replaces: ASTM D785-98e1 - Standard Test Method for Rockwell Hardness of Plastics and Electrical Insulating Materials
• Effective Date: 01-Nov-2003
• Referred By: ASTM D6943-15(2019) - Standard Practice for Immersion Testing of Industrial Protective Coatings and Linings
• Effective Date: 01-Nov-2003
• Referred By: ASTM F1957-99(2017) - Standard Test Method for Composite Foam Hardness-Durometer Hardness
• Effective Date: 01-Nov-2003
• Referred By: ASTM D4101-17e1 - Standard Classification System and Basis for Specification for Polypropylene Injection and Extrusion Materials
• Effective Date: 01-Nov-2003
• Referred By: ASTM F2783-20 - Standard Practice for Design, Manufacture, Operation, Maintenance, and Inspection of Amusement Rides and Devices, in Canada
• Effective Date: 01-Nov-2003
• Referred By: ASTM D3753-20 - Standard Specification for Fiberglass (Glass-Fiber-Reinforced Thermosetting-Resin) Manholes and Wetwells
• Effective Date: 01-Nov-2003
• Referred By: ASTM D1404/D1404M-99(2019) - Standard Test Method for Estimation of Deleterious Particles in Lubricating Grease
• Effective Date: 01-Nov-2003
• Referred By: ASTM D787-18 - Standard Specification for Ethyl Cellulose Molding and Extrusion Compounds
• Effective Date: 01-Nov-2003
• Referred By: ASTM D619-21 - Standard Test Methods for Vulcanized Fibre Used for Electrical Insulation
• Effective Date: 01-Nov-2003
• Referred By: ASTM D1039-16(2022) - Standard Test Methods for Glass-Bonded Mica Used as Electrical Insulation
• Effective Date: 01-Nov-2003
• Referred By: ASTM F790-23 - Standard Guide for Testing Materials for Aerospace Plastic Transparent Enclosures
• Effective Date: 01-Nov-2003
• Referred By: ASTM D229-19e1 - Standard Test Methods for Rigid Sheet and Plate Materials Used for Electrical Insulation
• Effective Date: 01-Nov-2003
• Referred By: ASTM G21-15(2021)e1 - Standard Practice for Determining Resistance of Synthetic Polymeric Materials to Fungi
• Effective Date: 01-Nov-2003
• Referred By: ASTM D4000-23 - Standard Classification System for Specifying Plastic Materials
• Effective Date: 01-Nov-2003
• Referred By: ASTM F561-19 - Standard Practice for Retrieval and Analysis of Medical Devices, and Associated Tissues and Fluids
• Effective Date: 01-Nov-2003

Standards Content (Sample)

NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Contact ASTM International (www.astm.org) for the latest information
Designation:D785–03
Standard Test Method for
Rockwell Hardness of Plastics and Electrical Insulating
1
Materials
This standard is issued under the fixed designation D 785; 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.
This standard has been approved for use by agencies of the Department of Defense.
1. Scope* ISO 2039-2 Plastics—Determination of Hardness—Part 2:
Rockwell Hardness
1.1 This test method covers two procedures for testing the
indention hardness of plastics and related plastic electrical
3. Terminology
insulating materials by means of the Rockwell hardness tester.
3.1 Definitions used in this test method are in accordance
1.2 The values stated in SI units are to be regarded as the
with Terminology D 883.
standard.Thevaluesgiveninbracketsareforinformationonly.
1.3 This standard does not purport to address all of the
4. Significance and Use
safety concerns, if any, associated with its use. It is the
4.1 A Rockwell hardness number is a number derived from
responsibility of the user of this standard to establish appro-
the net increase in depth impression as the load on an indenter
priate safety and health practices and determine the applica-
is increased from a fixed minor load to a major load and then
bility of regulatory limitations prior to use.
returned to a minor load (Procedure A). A Rockwell alpha (a)
NOTE 1—This test method and ISO 2039-2 are equivalent. ProcedureA
hardness number represents the maximum possible remaining
of this test method is equivalent to the test method in the main body of
travel of a short-stroke machine from the net depth of impres-
ISO 2039-2. Procedure B of this test method is equivalent to the test
sion,astheloadontheindenterisincreasedfromafixedminor
method in the integral annex part of ISO 2039-2.
load to a major load (Procedure B). Indenters are round steel
2. Referenced Documents balls of specific diameters. Rockwell hardness numbers are
2 always quoted with a scale symbol representing the indenter
2.1 ASTM Standards:
size,load,anddialscaleused.ThistestmethodisbasedonTest
D 618 Practice for Conditioning Plastics for Testing
MethodsE18. ProcedureA(Section 11) yields the indentation
D 883 Terminology Relating to Plastics
of the specimen remaining 15 s after a given major load is
D 2240 Test Method for Rubber Property—Durometer
released to a standard 10-kg minor load. Procedure B (Section
Hardness
12) yields the indentation of the indenter into the specimen
D 4000 Classification System for Specifying Plastic Mate-
after a 15-s application of the major load while the load is still
rials
applied. Each Rockwell scale division represents 0.002-mm
E18 Test Methods for Rockwell Hardness and Rockwell
[0.00008-in.] vertical movement of the indenter. In practice,
Superficial Hardness of Metallic Materials
the Rockwell hardness number is derived from the following
E 691 Practice for Conducting an Interlaboratory Study to
relationship:
Determine the Precision of a Test Method
3
HR 5 130 2 e (1)
2.2 ISO Standards
where:
1
This method is under the jurisdiction ofASTM Committee D20 on Plastics and
HR = the Rockwell hardness number, and
is the direct responsibility of Subcommittee D20.10 on Mechanical Properties.
e = the depth of impression after removal of the major
Current edition approved Nov. 1, 2003. Published January 2004. Originally
load, in units of 0.002 mm. This relation only holds
e1
approved in 1944. Last previous edition approved in 1998 as D 785 - 98 .
2
for the E, M, L, R, and K scales.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
4.2 A Rockwell hardness number is directly related to the
Standards volume information, refer to the standard’s Document Summary page on
indentation hardness of a plastic material, with the higher the
the ASTM website.
3 reading the harder the material.An a hardness number is equal
Available from American National Standards Institute (ANSI), 25 W. 43rd St.,
4th Floor, New York, NY 10036. to 150 minus the instrument reading. Due to a short overlap of
*A Summary of Changes section appears at the end of this standard.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
1

---------------------- Page: 1 ----------------------
D785–03
Rockwell hardness scales by Procedure A, two different dial ings to 115 are permissible. For comparison purposes, it may
readings on different scales may be obtained on the same bedesirabletotakereadingshigherthan115orlowerthanzero
material, b
...