ASTM E448-82(1997)e1

Standard Practice for Scleroscope Hardness Testing of Metallic Materials

SCOPE
1.1 This practice covers the determination of the Scleroscope hardness of metallic materials (Part A), the verification of Scleroscope hardness instruments (Part B), and the calibration of standardized hardness test blocks (Part C).
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 problems, 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.

General Information

• Status: Historical
• Publication Date: 29-Jul-1982
• Technical Committee: E28 - Mechanical Testing
• Drafting Committee: E28.06 - Indentation Hardness Testing

Relations

• Replaced By: ASTM E448-82(1997)e2 - Standard Practice for Scleroscope Hardness Testing of Metallic Materials
• Effective Date: 30-Jul-1982
• Referred By: ASTM F3122-14(2022) - Standard Guide for Evaluating Mechanical Properties of Metal Materials Made via Additive Manufacturing Processes
• Effective Date: 30-Jul-1982
• Referred By: ASTM C886-21 - Standard Test Method for Scleroscope Hardness Testing of Carbon and Graphite Materials
• Effective Date: 30-Jul-1982

Standards Content (Sample)

NOTICE: This standard has either been superseded and replaced by a new version or discontinued.
Contact ASTM International (www.astm.org) for the latest information.
An American National Standard
e1
Designation: E 448 – 82 (Reapproved 1997)
Standard Practice for
Scleroscope Hardness Testing of Metallic Materials
This standard is issued under the fixed designation E 448; 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.
e NOTE—Note 1 was editorially revised in December 2001.
1. Scope average rebound of a hammer from a forged steel roll of
accepted maximum hardness.
1.1 This practice covers the determination of the Sclero-
scope hardness of metallic materials (Part A), the verification
NOTE 1—The flat striking surface of the hammer in the forged roll
of Scleroscope hardness instruments (Part B), and the calibra-
Scleroscope is slightly larger than the corresponding surface in the
Scleroscope described in 3.1.3 (see Fig. 1). Hence the forged roll
tion of standardized hardness test blocks (Part C).
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 problems, if any, associated with its use. It is the
responsibility of the user of this standard to establish appro-
priate safety and health practices and determine the applica-
bility of regulatory limitations prior to use.
2. Referenced Documents
2.1 ASTM Standards:
A 427 Specification for Wrought Alloy Steel Rolls for Cold
and Hot Reduction
E 140 Hardness Conversion Tables for Metals (Relationship
Among Brinell Hardness, Vickers Hardness, Rockwell
Hardness, Rockwell Superficial Hardness, and Knoop
Hardness, and Scleroscope Hardness)
3. Terminology
3.1 Definitions:
3.1.1 calibration—determination of the values of the sig-
nificant parameters by comparison with values indicated by a
reference instrument or by a set of reference standards. FIG. 1 Profile of Scleroscope Diamond Showing Range of
Diameters of Flat Tip
3.1.2 forged roll Scleroscope hardness number (HFRSc or
HFRSd) —a number related to the height of rebound of a
Scleroscope yields correspondingly higher hardness numbers.
diamond-tipped hammer dropped on a forged steel roll. It is
measured on a scale determined by dividing into 100 units the 3.1.3 Scleroscope hardness number (HSc or HSd)—a num-
ber related to the height of rebound of a diamond-tipped
hammer dropped on the material being tested. It is measured on
a scale determined by dividing into 100 units the average
This practice is under the jurisdiction of ASTM Committee E-28 on Mechanical
Testing and is the direct responsibility of E28.06 on Indentation Hardness Testing.
rebound of the hammer from a quenched (to maximum
Current edition approved July 30, 1982. Published December 1982. Originally
hardness) and untempered high carbon water-hardening tool
published as E 448– 72. Last previous edition E 448 – 72 (1977).
steel test block of AISI W-5.
Registered trademark of the Shore Instrument & Mfg. Co., Inc.
3.1.4 Scleroscope hardness test—a dynamic indentation
Annual Book of ASTM Standards, Vol 01.05.
Annual Book of ASTM Standards, Vol 03.01.
hardness test using a calibrated instrument that drops a
The conversion from Forged Roll “C” Scleroscope hardness to Vickers
diamond-tipped hammer (Note 2) from a fixed height onto the
hardness contained in Specification A 427 and to Rockwell C hardness contained in
surface of the material under test. The height of rebound of the
Standard E 140 are presently the only Scleroscope hardness conversions in ASTM
standards. hammer is a measure of the hardness of the material.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
E 448
NOTE 2—An all-steel “Magnifier Hammer” that yielded a greater
3.1.5 verification—checking or testing the instrument to
spread in hardness readings on soft nonferrous metals has been available.
assure conformance with the specification.
This hammer has become obsolete and, hence, is not considered in this
practice.
GENERAL DESCRIPTION OF INSTRUMENTS AND TEST PROCEDURE FOR SCLEROSCOPE
HARDNESS TEST
4. Apparatus known hardness. In the forged roll Scleroscope the diamond tip
is specifically dimensioned to produce a correct reading on a
4.1 The instrument used for determining Scleroscope hard-
forged-steel roll of known hardness. In profile, the diamond is
ness numbers is supplied in two models designated Model C
convex, having an approximate radius terminated by a flat
and Model D.
striking surface, as shown in Fig. 1. The flat striking surface is
4.2 Scleroscope Model C—This model consists of a verti-
approximately circular and from 0.004 to 0.016 in. (0.1 to 0.4
cally disposed barrel containing a precision bore glass tube. A
mm) in diameter, depending on the type of instrument and the
scale, graduated from 0 to 140, is set behind and is visible
hardness and other physical characteristics of the diamond.
through the glass tube. A pneumatic actuating head, affixed to
4.5 Supporting Devices—The three supporting devices used
the top of the barrel, is manually operated by a rubber bulb and
most frequently with the Scleroscope are (a) the clamping
tube. A hammer drops from a specified height and rebounds
stand, (b) the swing arm and post, and (c) the roll-testing stand.
within the glass tube.
4.3 Scleroscope Model D—This model is known as the Dial
5. Test Specimens
Recording Scleroscope. It consists of a vertically disposed
5.1 Form—Specimens used in Scleroscope testing vary
barrel containing a clutch to arrest the hammer at maximum
greatly with respect to size and shape. Smaller specimens may
height of rebound. This is made possible by using a hammer
be tested in the clamping stand which has a jaw capacity of 3
which is longer and heavier than the hammer in the Model C
in. (76 mm) high by 2 ⁄2 in. (64 mm) deep. Large specimens,
Scleroscope, and which develops the same striking energy in
beyond the jaw capacity of the clamping stand, may be tested
dropping through a shorter distance. A number of supporting
with the instrument mounted on the swing arm and post or the
devices are available with this instrument and it is recom-
roll-testing stand. The swing arm and post has a height and
mended that one of these be used (see section 4.5).
reach capacity of 9 in. (230 mm) and 14 in. (360 mm),
4.4 Diamond-Tipped Hammers:
respectively. The roll-testing stand may be used for mounting
4.4.1 There are two sizes of diamond-tipped hammers
the instrument on cylindrical specimens with a diameter of 2 ⁄2
commonly used in the Scleroscope hardness instruments.
in. (64 mm) and upward without limit. The roll-testing stand
These are the small hammer used in the Model C instrument
may also be used for mounting the instrument on flat, horizon-
and the larger hammer used in the Model D instrument.
tal surfaces with a minimum perimetric dimension of 3 by 5 in.
4.4.2 The following dimensions are applicable to the
(76 by 130 mm). The Model C Scleroscope may be used free
diamond-tipped hammers:
hand for testing specimens with a minimum mass of 5 lb (2.3
Model C
kg). It is not recommended that the Model D Scleroscope be
Diameter 0.234 in. (5.94 mm)
used free hand.
Mass 2.300 6 0.500 g
Over-all length 0.815 to 0.840 in. (20.7 to 21.3 mm)
5.2 Thickness—Thin strips or sheets may be tested, with
Distance hammer 9.890 + 0.005, −0.015 in. (251.2 + 0.1,
some limitations, but only when the Scleroscope is mounted in
falls −0.4 mm)
the clamping stand. Ideally, the sheet should be flat and without
Model D
undulation. If the sheet material is bowed, the concave side
Diameter 0.3125 in. (7.94 mm)
should be up to preclude any possibility of erroneous readings
Mass 36.0 6 2.0 g
due to spring effect. The minimum thicknesses of sheet in
Over-all length 3.990 to 4.010 in. (101.33 to 104.10 mm)
Distance hammer 0.704 + 0.017, −0.021 in. (17.9 + 0.4, −0.5 various categories that may be tested are as follows:
falls mm)
Thickness
Material in. mm
4.4.3 The geometry of the diamond tip is of significance
Hard steel 0.005 to 0.006 0.13 to 0.15
only at its ultimate extremity because of the limited penetration
Half-hard brass strip 0.010 0.25
of the diamond into the material being tested. Such penetration Cold-rolled steel 0.010 0.25
Annealed-brass sheet 0.015 0.38
is about 0.001 in. (0.025 mm) on mild steel and about 0.0005
in. (0.013 mm) on hardened tool steel. Further, the variation in
5.3 Finish—The degree of test-surface finish is important.
hardness of commercially available industrial diamonds has a
An excessively coarse finish will yield low and erratic read-
significant effect on the readings of a rebound-type hardness
ings. Hence, when necessary, the surface shall be filed,
instrument. Consequently, the geometry of the diamond must
machined, ground, or polished to permit accurate, consistent
be shaped to produce a correct reading on reference bars of
readings to be obtained. Care should be taken to avoid
overheating or excessively cold working the surface. The
6 surface finish required to obtain reproducible results varies
Model C and D Scleroscopes are manufactured by the Shore Instrument and
Manufacturing Co., Inc., Jamaica, NY. with the hardness of the test specimen. In proceeding from soft
E 448
metals to hardened steel the required surface finish ranged from the same spot. Flat specimens with parallel surfaces may be
a minimum finish as produced by a No. 2 file to a finely ground tested within ⁄4
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