ASTM B389-81(1998)

Standard Test Method for Thermal Deflection Rate of Spiral and Helical Coils of Thermostat Metal

SCOPE
1.1 This test method covers the determination of the thermal deflection rate of spiral and helical coils of thermostat metal.  
1.2 The values stated in inch-pound units are to be regarded as the standard. The metric equivalents of inch-pound units may be approximate.  
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: 09-Oct-1998
• ICS: 21.160 - Springs
• Technical Committee: B02 - Nonferrous Metals and Alloys
• Drafting Committee: B02.10 - Thermostat Metals and Electrical Resistance Heating Materials

Relations

• Replaced By: ASTM B389-81(2004) - Standard Test Method for Thermal Deflection Rate of Spiral and Helical Coils of Thermostat Metal
• Effective Date: 01-May-2004
• Referred By: ASTM B388-06(2018) - Standard Specification for Thermostat Metal Sheet and Strip
• Effective Date: 10-Oct-1998
• Referred By: ASTM B106-08(2019) - Standard Test Methods for Flexivity of Thermostat Metals
• Effective Date: 10-Oct-1998

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NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.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: B 389 – 81 (Reapproved 1998)
Standard Test Method for
Thermal Deflection Rate of Spiral and Helical Coils of
Thermostat Metal
This standard is issued under the fixed designation B 389; 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.
1. Scope
1.1 This test method covers the determination of the thermal
deflection rate of spiral and helical coils of thermostat metal.
1.2 The values stated in inch-pound units are to be regarded
as the standard. The metric equivalents of inch-pound units
may be approximate.
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:
E 77 Test Method for Inspection and Verification of Ther-
mometers
3. Terminology
3.1 thermostat metal—a composite material, usually in the
form of sheet or strip, comprising two or more materials of any
appropriate nature, metallic or otherwise, that, by virtue of
differing expansivities of the components, tends to alter its
curvature when its temperature is changed.
3.2 thermal deflection rate—the ratio of angular rotation to
temperature change. It is a measure of the coil’s thermal
activity. It may have the units of angular degrees per degree
Fahrenheit, or Celsius, and is expressed by the equation D
=(A −A )/(T −T ) where A and A are angular positions at
2 1 2 1 2 1
temperature T and T respectively.
2 1
3.3 spiral coil—a part made by winding strip on itself. Fig. FIG. 1 Spiral Coil
1andFig.2showtypicalspiralcoils,whichcanbewoundwith
the low-expansive side inside or outside, mounted on the
specimen holder.
axial length. Fig. 3 shows a typical helical coil, which can be
3.4 helical coil—a part made by winding strip in a form
wound with the low-expansive side inside or outside, and
wherein the plane of the width of the strip is parallel to the
right-hand or left-hand, mounted on the specimen holder.
4. Summary of Test Method
This test method is under the jurisdiction of ASTM Committee B-2 on
4.1 The test for thermal deflection rate of spiral and helical
Nonferrous Metals and Alloys and is the direct responsibility of Subcommittee
coils consists of measuring the angular rotation that a coil
B02.10 on Thermostat Metals.
Current edition approved June 26, 1981. Published August 1981. Originally
undergoes in response to a known temperature change.
published as B 389 – 62 T. Last previous edition B 389 – 65 (1975).
Annual Book of ASTM Standards, Vol 14.03.
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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.
B 389
FIG. 2 Spiral Coil
5. Significance and Use 6.2 Protractor—The angular position at each test tempera-
tureshallbemeasuredbyaprotractorwithaminimumdivision
5.1 This test method simulates, to a practical degree, the
of 0.5°.
operation of the thermostat metal coil.
6.3 Temperature-Measuring Apparatus—The apparatus for
5.2 The thermal deflection properties of a coil may vary
making temperature measurements shall be of such accuracy
from lot-to-lot of thermostat metal material. This method is
that the individual temperatures shall be known to be within
useful for determining the optimum thickness and length of the
60.5°F (60.3°C).
material for a given deflection specification.
6.4 Specimen Holder—The preferred methods of holding
5.3 This method is useful as a quality test to determine
spiral and helical coils are as follows:
acceptance or rejection of a lot of thermostat metal coils.
6.4.1 Spiral Coils—The specimen holder for spiral coils
6. Apparatus
shall provide means for securely holding the coil. Although
6.1 Temperature Bath—A stirred liquid bath or uniformly other means of support are possible, the holder or mounting
heated enclosure in which the specimen and mounting fixture arbor shall be preferably circular cross section whose diameter
can be placed shall be used. An adjustable heating source is shall be as large as possible without touching the inner turn of
desirable for maintaining the specimen at the desired tempera- the coil under any conditions of test temperatures. The arbor
tures with a variation in temperature throughout the specimen shall be slotted across its diameter and to a depth greater than
not to exceed 0.5°F (0.3°C). the width of the specimen. The width of the slot shall be
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.
B 389
FIG. 3 Helical Coil
slightly narrower than the thickness of the specimen so that the 6.5.1 Spiral Coils To the outer end of the spiral coil shall be
inner tab will be a push or snug fit in the slot. The edges of the attached a pointer that will transmit the rotation of the coil so
slot shall be sharp where it intersects the circumference of the that it can be read on the protractor. The pointer shall be of
arbor.The slot shall be so positioned in the arbor that the center lightweight construction and attached to the coil by suitable
of rotation of the coil and the center of the arbor coincide. means so that the movement of these portions of the coil that
6.4.2 Helical Coils—The specimen holder for helical coils do not normally contribute to the movement of the coil with a
shall provide means for securely holding the coil. Although temperature change shall not influence the rotation of the
other means of support are possible, the coil shall be held with pointer. The pointer, when using the fixture shown in Fig. 1,
its axis in a vertical position, the bottom end of the co
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