ASTM B388-06(2012)
(Specification)Standard Specification for Thermostat Metal Sheet and Strip
Standard Specification for Thermostat Metal Sheet and Strip
ABSTRACT
This specification covers the standard for thermostat metals in the form of sheet or strip proposed for use as temperature-sensitive elements of devices for controlling, compensating, or indicating temperature. Metals shall adhere to physical requirements such as maximum sensitivity range, maximum recommended temperature, flexibility, electrical resistivity, modulus of elasticity, specific heat, density, and hardness.
SCOPE
1.1 This specification covers thermostat metals in the form of sheet or strip that are used for the temperature-sensitive elements of devices for controlling, compensating, or indicating temperature and is intended to supply acceptance requirements to purchasers ordering this material by type designation.
1.2 The values stated in inch-pound units are to be regarded as standard. The values given in parentheses are mathematical conversions to SI units that are provided for information only and are not considered standard.
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 become familiar with all hazards including those identified in the appropriate Material Safety Data Sheet (MSDS) for this product/material as provided by the manufacturer, to establish appropriate safety and health practices, and determine the applicability of regulatory limitations prior to use.
General Information
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Standards Content (Sample)
NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
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Designation:B388 −06(Reapproved 2012)
Standard Specification for
Thermostat Metal Sheet and Strip
This standard is issued under the fixed designation B388; 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 (´) indicates an editorial change since the last revision or reapproval.
1. Scope Insulation (Withdrawn 2008)
E92 Test Method forVickers Hardness of Metallic Materials
1.1 This specification covers thermostat metals in the form
(Withdrawn 2010)
of sheet or strip that are used for the temperature-sensitive
E384 Test Method for Knoop and Vickers Hardness of
elements of devices for controlling, compensating, or indicat-
Materials
ing temperature and is intended to supply acceptance require-
ments to purchasers ordering this material by type designation.
3. Terminology
1.2 The values stated in inch-pound units are to be regarded
3.1 Definitions:
as standard. The values given in parentheses are mathematical
3.1.1 thermostat metal, n—a composite material comprising
conversions to SI units that are provided for information only
two or more metallic layers of differing coefficients of thermal
and are not considered standard.
expansion such that the radius of curvature of the composite
changes with temperature change.
1.3 This standard does not purport to address all of the
safety concerns, if any, associated with its use. It is the
4. Ordering Information
responsibility of the user of this standard to become familiar
4.1 Orders for material under this specification shall include
with all hazards including those identified in the appropriate
the following information:
Material Safety Data Sheet (MSDS) for this product/material
4.1.1 Type designation (Table 1 and Table 2),
as provided by the manufacturer, to establish appropriate
4.1.2 Thickness (see 9.1),
safety and health practices, and determine the applicability of
4.1.3 Width (see 9.2),
regulatory limitations prior to use.
4.1.4 Temper (designated as percent cold reduction as
needed),
2. Referenced Documents
2 4.1.5 Marking to identify vendor, type, high-expansion side
2.1 ASTM Standards:
or low-expansion side,
B63 Test Method for Resistivity of Metallically Conducting
4.1.6 Weight.
Resistance and Contact Materials
B106 Test Methods for Flexivity of Thermostat Metals
5. Material Segregation
B223 Test Method for Modulus of Elasticity of Thermostat
5.1 The thermostat metal shall be supplied segregated into
Metals (Cantilever Beam Method)
two groups after slitting: (1) the burr on the low-expansive
B362 Test Method for Mechanical Torque Rate of Spiral
component, and (2) the burr on the high-expansive component.
Coils of Thermostat Metal
These two groups shall be identified and packaged separately
B389 TestMethodforThermalDeflectionRateofSpiraland
or together as mutually agreed upon between the producer and
Helical Coils of Thermostat Metal
the user.
B478 TestMethodforCrossCurvatureofThermostatMetals
B753 Specification for Thermostat Component Alloys 6. Chemical Composition
C351 Test Method for Mean Specific Heat of Thermal
6.1 The nominal composition of component materials is
given in Table 1.
6.1.1 The component alloys shall be as specified in Speci-
This specification is under the jurisdiction of ASTM Committee B02 on
fication B753.
Nonferrous Metals and Alloys and is the direct responsibility of Subcommittee
B02.10 on Thermostat Metals and Electrical Resistance Heating Materials.
7. Component Ratio
Current edition approved May 1, 2012. Published May 2012. Originally
approved in 1962. Last previous edition approved in 2006 as B388 – 06. DOI:
7.1 Thetypicalthicknessratioofthecomponentmaterialsis
10.1520/B0388-06R12.
given in Table 1. The component thickness ratios are given for
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
Standards volume information, refer to the standard’s Document Summary page on The last approved version of this historical standard is referenced on
the ASTM website. www.astm.org.
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B388−06(2012)
TABLE 1 Composition
NOTE 1—TM6 and TM7 are no longer manufactured due to availability, difficulty to produce, commercial interest, or combinations thereof.
ASTM Type
Element TM1 TM2 TM3 TM4 TM5 TM8 TM9
Nominal chemical high-expansive nickel 22 10 25 25 25 10 22
composition, component chromium 3 . 8.5 8.5 8.5 . 3
weight,% manganese . 72 . . . 72 .
copper . 18 . . . 18 .
iron 75 . 66.5 66.5 66.5 . 75
aluminum . . . . . . .
carbon . . . . . . .
intermediate nickel . . . . . . 100
component manganese . . . . . . .
low-expansive nickel 36 36 42 45 50 36 36
component iron 64 64 58 55 50 64 64
cobalt . . . . . . .
Component ratio, high-expansive 50 53 50 50 50 80 27
thickness, % component
intermediate . . . . . . 46
component
low-expansive 50 47 50 50 50 20 27
component
ASTM Type
Element TM10 TM11 TM12 TM13 TM14 TM15 TM16
Nominal chemical high-expansive nickel 22 22 22 22 22 22 22
composition, component chromium 3 3 3 3 3 3 3
weight,% manganese . . . . . . .
copper . . . . . . .
iron 7575 7575 757575
aluminum . . . . . . .
carbon . . . . . . .
intermediate nickel 100 100 100 100 100 100 100
component manganese . . . . . . .
low-expansive nickel 36 36 36 36 36 36 36
component iron 64 64 64 64 64 64 64
cobalt . . . . . . .
Component ratio, high-expansive 34 36 40 42 44 47 48
thickness, % component
intermediate 32 28 20 16 12 6 4
component
low-expansive 34 36 40 42 44 47 48
component
ASTM Type
Element
TM17 TM18 TM19 TM20 TM21 TM22 TM23
Nominal chemical high-expansive nickel 22 19.4 19.4 18 18 100 10
composition, component chromium 3 2.25 2.25 11.5 11.5 . .
weight,% manganese . . . . . . 72
copper . . . . . . 18
iron 75 78.3 78.3 70.5 70.5 . .
aluminum . . . . . . .
carbon . 0.5 0.5 . . . .
intermediate nickel 100 . . . . . .
component manganese . . . . . . .
low-expansive nickel 36 42 39 36 42 36 42
component iron 64 58 61 64 58 64 58
cobalt . . . . . . .
Component ratio, high-expansive 49 50 50 50 50 50 54
thickness,% component
intermediate 2 . . . . . .
component
low-expansive 49 50 50 50 50 50 46
component
ASTM Type
Element TM24 TM25 TM26 TM27 TM28 TM29 TM30
Nominal chemical high-expansive nickel 22 22 22 22 22 20 22
composition, component chromium 3 3 3 3 3 . 3
weight, % manganese . . . . . 6.5 .
copper . . . . . . .
iron 75 75 75 75 75 73.5 75
aluminum . . . . . . .
carbon . . . . . . .
B388−06(2012)
TABLE1 Continued
ASTM Type
Element TM24 TM25 TM26 TM27 TM28 TM29 TM30
intermediate copper 100 100 100 100 100 . .
component manganese . . . . . . .
low-expansive nickel 36 36 36 36 36 36 42
component iron 64 64 64 64 64 64 58
cobalt . . . . . . .
ASTM Type
TM24 TM25 TM26 TM27 TM28 TM29 TM30
resistivity ohm cir 20 30 50 70 90 477 415
mil/ft
Component ratio, high-expansive 10 20 31 38 42 50 50
thickness, % component
intermediate 53 35 20 14 10 . .
component
low-expansive 37 45 49 48 48 50 50
component
ASTM Type
Element TM31 TM32 TM33 TM34 TM35 TM36
Nominal chemical high-expansive nickel 10 10 10 10 19 25
composition, component chromium . . . . 2 8
weight, % manganese 72 72 72 72 . .
copper 18 18 18 18 . .
iron . . . . 79 67
aluminum . . . . . .
carbon . . . . . .
intermediate copper 100 100 100 100 . .
component manganese . . . . . .
low-expansive nickel 36 36 36 36 36 36
component iron 64 64 64 64 64 64
cobalt . . . . . .
ASTM Type
TM31 TM32 TM33 TM34 TM35 TM36
resistivity ohm cir 30 150 50 70 482 500
mil/ft
Component ratio, high-expansive 26 50 42 45 50 50
thickness, % component
intermediate 38 6 21 15 . .
component
low-expansive 36 44 37 40 50 50
component
reference as they are lot-to-lot variable to produce required 8.3.2 Residual stress loading can affect flexivity test results.
flexivity and resistivity. Barrier(s) layer(s) for stability of Specimensshallbestabilizedpriortotestingbystressrelieffor
resistivity is (are) allowable. Flexivity may vary.
1 h at 500°F (260°C). Suitable stress relief conditions must be
determined for individual end use applications. Initial condi-
8. Physical Requirements
tion recommendations are given in Table 2.
8.1 Maximum Sensitivity Range—Thetemperaturerangesof
8.4 Electrical Resistivity—The electrical resistivity shall
maximum thermal response of designated types of thermostat
conformtothevaluesgiveninTable2andTable3.Component
metals are given in Table 2 and Table 3. These are nominal
materials designated in Specification B753 shall, in thermostat
values presented only to aid users in designing devices.
metal combinations, yield product in conformance with the
8.2 Maximum Recommended Temperature—The maximum
values designated in Table 2 and Table 3.
recommended temperatures of use of designated types of
8.4.1 Electrical resistivity shall be determined by Test
thermostat metals are given in Table 2 and Table 3. These
Method B63 at 75°F (24°C).
values are presented to aid users in designing devices.
8.5 Modulus of Elasticity—The nominal moduli of elasticity
8.3 Flexivity—The flexivity of a designated thermostat
of designated thermostat metals at a temperature of 75°F
metal shall conform to the values in Table 2 and Table 3.
(24°C) are given in Table 2 and Table 3. These are nominal
Component materials designated in Specification B753 shall,
values presented to aid users in designing devices and shall not
in thermostat metal combinations, yield product in confor-
be used for rejection or acceptance purposes.
mance with the values designated in Table 2 and Table 3.
8.5.1 Modulus of elasticity shall be determined by Test
8.3.1 Flexivity shall be determined by Test Methods B106,
Method A. Method B223.
B388−06(2012)
TABLE 2 Properties of Thermostat Metals (Inch-Pound Units)
NOTE 1—TM6 and TM7 are no longer manufactured due to availability, difficulty to produce, commercial interest, or combinations thereof.
ASTM Type
Properties Units
TM1 TM2 TM3 TM4 TM5 TM8 TM9
Maximum sensitivity °F 0 to 300 0 to 400 200 to 600 250 to 700 300 to 850 0 to 400 0 to 300
temperature range
Maximum recommended °F 1000 500 1000 1000 1000 500 900
temperature
−6
Flexivity × 10 50 to 200°F 15.0 ± 5 % 21.7 ± 5 % 10.4 ± 6 % 8.6 ± 6 % 6.4 ± 6 % 15.6 ± 8 % 11.5 ± 10 %
100 to 300°F 14.6 ± 5 % 21.1 ± 5 % 10.6 ± 6 % 9.0 ± 6 % 6.6 ± 6 % 15.6 ± 8 % 11.2 ± 10 %
Heat treatment °F 700 500 700 700 700 500 700
Electrical resistivity at Ω·cmil/ft 475 ± 4 % 675 ± 5 % 435 ± 4 % 400 ± 4 % 345 ± 5 % 850 ± 5 % 100 ± 5.5 %
75°F Ω·mil /ft 373±4% 530±5% 342±4% 314±4% 271±5% 668±5% 78±5.5%
Modulus of elasticity psi × 10 25 20 25 25 25.5 19.5 26
Density lb/in. 0.29 0.28 0.29 0.29 0.29 0.27 0.31
TM10 TM11 TM12 TM13 TM14 TM15 TM16
Maximum sensitivity °F 0 to 300 0 to 300 0 to 300 0 to 300 0 to 300 0 to 300 0 to 300
temperature range
Maximum recommended °F 900 900 900 900 900 900 900
temperature
−6
Flexivity × 10 50 to 200°F 13.1 ± 6 % 13.2 ± 6 % 13.7± 5.5 % 14.0 ± 5.5 % 14.7 ± 5.5 % 14.8 ± 5.5 % 14.9 ± 5.5 %
100 to 300°F 12.7 ± 6 % 13.3 ± 6 % 13.7 ± 5.5 % 14.0 ± 5.5 % 14.3 ± 5.5 % 14.4 ± 5.5 % 14.6 ± 5.5 %
Heat treatment °F 700 700 700 700 700 700 700
Electrical resistivity at Ω·cmil/ft 125 ± 5.5 % 150 ± 5.5 % 175 ± 5.5 % 200 ± 5.5 % 250 ± 5.5 % 300 ± 5.5 % 350 ± 5.5 %
75°F Ω·mil /ft 98 ± 5.5 % 118 ± 5.5 % 137 ± 5.5 % 157 ± 5.5 % 196 ± 5.5 % 236 ± 5.5 % 275± 5.5 %
Modulus of elasticity psi × 10 26 26 25.5 25.5 25.5 25 25
Density lb/in. 0.30 0.30 0.30 0.30 0.30 0.30 0.29
TM17 TM18 TM19 TM20 TM21 TM22 TM23
Maximum sensitivity °F 0 to 300 200 to 600 150 to 450 0 to 300 200 to 600 0 to 300 200 to 600
temperature range
Maximum recommended °F 900 900 900 900 900 900 500
temperature
−6
Flexivity × 10 50 to 200°F 15.0 ± 5.5 % 11.9 ± 7 % 14.4 ± 7 % 13.8 ± 5 % 10.7 ± 7 % 10.2 ± 5 % 18.3 ± 5 %
100 to 300°F 14.6 ± 5.5 % 11.9 ± 7 % 14.1 ± 7 % 13.5 ± 5 % 10.9 ± 7 % 10.2 ± 5 % 18.6± 5 %
Heat treatment °F 700 700 700 700 700 700 500
Electrical resistivity at Ω·cmil/ft 400 ± 5.5 % 420 ± 4 % 456 ± 5 % 479 ± 4 % 418 ± 4 % 92 ± 6 % 565 ± 4 %
75°F Ω·mil /ft 314±5.5% 330±4% 358±5% 376±4% 328±4% 72±6% 444±4%
Modulus of elasticity psi × 10 25 25 25 25 25 26 20
Density lb/in. 0.29 0.29 0.29 0.29 0.29 0.31 0.28
TM24 TM25 TM26 TM27 TM28 TM29 TM30
Maximum sensitivity °F 0 to 300 0 to 300 0 to 300 0 to 300 0 to 300 0 to 300 200 to 600
temperature range
Maximum recommended °F 500 500 500 500 500 1000 1000
temperature
−6
Flexivity × 10 50 to 200°F 13.1 ± 5 % 14.0 ± 5 % 14.7 ± 5 % 14.7 ± 5 % 14.8 ± 5 % 15.8 ± 6 % 11.8 ± 6 %
100 to 300°F 12.9 ± 5 % 13.6 ± 5 % 14.2 ± 5 % 14. 4± 5 % 14.6 ± 5 % 15.6 ± 6 % 12.2 ± 6 %
Heat treatment °F 500 500 500 500 500 700 700
Electrical resistivity at Ω·cmil/ft 20 ± 10 % 30 ± 7.5 % 50 ± 7.5 % 70 ± 7.5 % 90 ± 5 % 477 ± 4 % 415 ± 4 %
75°F Ω·mil /ft 15.7 ± 10 % 23.6 ± 7.5 % 39.3 ± 7.5 % 55± 7.5 % 70.6 ± 5 % 375 ± 4 % 326 ± 4 %
Modulus of elasticity psi × 10 24 24 23 23 22 25 25
Density lb/in. 0.29 0.29 0.29 0.29 0.29 0.29 0.29
TM31 TM32 TM33 TM34 TM35 TM36
Maximum sensitivity °F 0 to 300 0 to 300 0 to 300 0 to 300 0 to 300 0 to 300
temperature range
Maximum recommended °F 500 500 500 500 900 900
temperature
−6
Flexivity × 10 50 to 200°F 18.9 ± 5 % 21.7 ± 5 % 20.8 ± 5 % 21.4 ± 5 % 15.2 ± 7 % 13.7 ± 5 %
100 to 300°F 18.7 ± 5 % 20.8 ± 5 % 20.1 ± 5 % 20.3 ± 5 % 14.9 ± 7 % 13.3 ± 5 %
Heat treatment °F 500 500 500 500 700 700
Electrical resistivity at Ω·cmil/ft 30 ± 10 % 150 ± 5 % 50 ± 10 % 70 ± 8 % 482 ± 4 % 500 ± 4 %
75°F Ω·mil /ft 23.6 ± 10 % 117.8 ± 5 % 39.3 ± 10 % 55 378.6 ± 4 % 392.7 ± 4 %
Modulus of elasticity psi × 10 19 19 19 19 25 24
Density lb/in. 0.30 0.30 0.29 0.29 0.29 0.29
8.6 Specific Heat—The nominal specific heat of the desig- values presented to aid users in designing devices and shall not
nated thermostat metals is 0.12 BTU/lb°F (500 J/kg°K). This be used for rejection or acceptance purposes.
nominal value is presented to aid users in designing devices
8.8 Hardness—The hardness of the components of a desig-
and shall not be used for rejection or acceptance purposes.
n
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