ASTM A125-96(2013)e1
(Specification)Standard Specification for Steel Springs, Helical, Heat-Treated
Standard Specification for Steel Springs, Helical, Heat-Treated
ABSTRACT
This specification covers the standard for hot-coiled, heat-treated helical compression springs with tapered, closed, squared and ground ends made of hot-wrought round steel bars. Cross sections for hot-wrought round, square, and round-cornered square bars of steel of the bar diameter shall be taken into consideration when designing and calculating the solid height, spring rate, solid stress, and solid capacity. The spring shall undergo quenching and tempering to have sufficiently high hardness and withstand the stresses developed in testing. Springs with specific indentation diameter shall not exceed the specified Brinell hardness numbers. The spring shall meet the metallurgical requirement, end construction, physical requirements such as measurements, solid height, free height, loaded height, permanent set, uniformity of pitch, outside diameter and calculations of solid capacity and uncorrected solid stress.
SCOPE
1.1 This specification covers hot-coiled, heat-treated helical compression springs with tapered, closed, squared and ground ends made of hot-wrought round steel bars 3/8 in. (9.5 mm) and larger in diameter.
1.2 This specification also serves to inform the user of practical manufacturing limits, mechanical tests, and inspection requirements applicable to the type of spring described in 1.1.
1.3 Supplementary Requirements S1 to S8 inclusive of an optional nature are provided. They shall apply only when specified by the purchaser. Details of these supplementary requirements shall be agreed upon by the manufacturer and purchaser.
1.4 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.
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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NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.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:A125 −96 (Reapproved 2013)
Standard Specification for
Steel Springs, Helical, Heat-Treated
This standard is issued under the fixed designation A125; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision.Anumber in parentheses indicates the year of last reapproval.A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
This standard has been approved for use by agencies of the Department of Defense.
ε NOTE—Table references were editorially corrected in November 2013.
1. Scope 3. Ordering Information
3.1 Orders for springs under this specification shall include
1.1 This specification covers hot-coiled, heat-treated helical
compression springs with tapered, closed, squared and ground the following information:
endsmadeofhot-wroughtroundsteelbars ⁄8 in.(9.5mm)and
3.1.1 Quantity,
larger in diameter.
3.1.2 Name of material,
3.1.3 A drawing or list showing required dimensions and
1.2 This specification also serves to inform the user of
loads, and part number,
practical manufacturing limits, mechanical tests, and inspec-
tion requirements applicable to the type of spring described in
3.1.4 Packaging, marking and loading, and
1.1.
3.1.5 End use.
1.3 Supplementary Requirements S1 to S8 inclusive of an
NOTE 1—A typical ordering description is: 500 springs Drawing 3303
optional nature are provided. They shall apply only when
Rev. A. to ASTM A125, 1095 steel, for cyclical machine operation.
Palletize, maximum weight 4000 lb.
specified by the purchaser. Details of these supplementary
requirements shall be agreed upon by the manufacturer and
4. Materials and Manufacture
purchaser.
4.1 Material:
1.4 Thevaluesstatedininch-poundunitsaretoberegarded
as standard. The values given in parentheses are mathematical
4.1.1 Unless otherwise specified, the springs shall be made
conversions to SI units that are provided for information only of carbon steel bars conforming to the requirements of Speci-
and are not considered standard. fication A689. Due to hardenability limitations of carbon steel,
it is suggested that the bar diameter be limited to 1 ⁄8 in. (41.8
2. Referenced Documents mm) max in order to withstand the maximum test stress
requirements of this specification.
2.1 ASTM Standards:
4.1.2 If alloy steel is specified, the springs shall be made
A29/A29MSpecification for Steel Bars, Carbon and Alloy,
fromalloysteelbarsconformingtoSpecificationA689.Anyof
Hot-Wrought, General Requirements for
the alloy steel grades referred to may be used at the option of
A689Specification for Carbon and Alloy Steel Bars for
the spring manufacturer, providing that a minimum as-
Springs
quenched hardness of Rockwell HRC-50 will be achieved at
E10Test Method for Brinell Hardness of Metallic Materials
the center of the bar section representing the spring when
E112Test Methods for Determining Average Grain Size
quenched in the same media and manner as the spring.
E709Guide for Magnetic Particle Testing
4.1.3 Springs Made from Bars Over 2 in. (50.8 mm)—Note
that the bias tolerance (reference Specification A29/A29M,
TableA1.1 on Permissible Variations in Cross Section for
This specification is under the jurisdiction ofASTM Committee A01 on Steel,
Hot-Wrought Round, Square, and Round-Cornered Square
Stainless Steel and RelatedAlloysand is the direct responsibility of Subcommittee
Bars of Steel) of the bar diameter shall be taken into consid-
A01.15 on Bars.
Current edition approved Oct. 1, 2013. Published November 2013. Originally eration when designing and calculating the solid height, spring
approved in 1929. Last previous edition approved in 2007 as A125–96 (2007).
rate, solid stress, and solid capacity.
DOI: 10.1520/A0125-96R13E01.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
4.2 Hardness:
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
4.2.1 The springs must be quenched and tempered to a
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website. sufficiently high hardness (strength) to withstand the stresses
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
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A125−96 (2013)
developed in testing the finished spring. The maximum hard- deviate from the perpendicular more than the number of
ness shall not exceed 477 Brinell numbers (2.80 mm indenta- degrees prescribed in Table 3, as determined by standing the
tion diameter). spring on its end and measuring the angular deviation of a
4.2.2 When hardness limits are specified, the total range or straightedge along the outer helix from a perpendicular to the
spread may not be less than 0.15 mm difference in indentation plate on which the spring is standing.
diameters. The specified or indicated minimum hardness must
4.4.3 Theendsofspringsshallbeparallelwithinatolerance
be sufficient to develop the required strength to withstand the
oftwicethatspecifiedforthesquarenessofendsasdetermined
solid stresses of the spring design involved.
by standing the spring on its end and measuring the maximum
4.2.3 Hardness shall be read on a prepared flat surface in an
angular deviation of the other end from a plane parallel to the
area not detrimental to the life of the spring at a full section
plate on which the spring is standing.
after removal of the decarburized layer. A tungsten-carbide
10-mm ball shall be applied under a 3000-kg load and the
5. Physical Requirements
indentation diameter converted to Brinell numbers by using
5.1 Measurements:
Table 1. The values for Table 1 have been taken from
5.1.1 Solid Height—The solid height is the perpendicular
Specification E10.
distance between the plates of the testing machine when the
4.3 Metallurgical Requirements:
spring is compressed solid with the load specified in 7.3. The
4.3.1 The total depth of decarburization, partial plus com-
solid height thus measured may be less, but shall not exceed
plete as measured on the finished spring in the quenched and
thespecifiednominalsolidheightbymorethanthelimitsgiven
tempered condition, shall not exceed 0.006 in. (0.15 mm) plus
in Table 4.
1%ofthebardiameter.Thedecarburizationshallbeexamined
5.1.2 Free Height—The free height is the height of the
at 100× on a test specimen suitably etched and cut from a full
spring after the load specified in 7.3 has been released, and is
cross section of the test spring showing at least one lineal inch
determined by placing a straightedge across the top of the
of original bar circumference.
springandmeasuringtheperpendiculardistancefromtheplate
4.3.2 The structure of the finished spring shall have an
on which the spring stands to the bottom of the straightedge at
averageASTM Grain Size No. 5 or finer as determined by the
the approximate center of the spring. Tolerances are shown in
latest revision of Test Methods E112.
Table 5.
4.4 End Construction:
5.1.3 Loaded Height—The loaded height is the perpendicu-
4.4.1 EndConstruction-TaperedSquaredandGround—The
lardistancebetweentheplatesofthetestingmachinewhenthe
end bearing surfaces of the spring shall be ground to produce
specified working load has been applied in compression.
afirmbearing.Theendbearingsurfacesshallhaveaminimum
Tolerances are shown in Table 5.
bearing surface of two thirds of the mean coil circumference
5.1.4 Permanent Set—After determining the free height as
and a minimum width of two thirds of the hot-tapered surface
specified in 5.1.2, the permanent set is the difference between
of the bar. The tip ends of the bar shall be in approximate
this free height and the height after the spring has been
contact with the adjacent coil, and shall not protrude beyond
compressed solid three additional times under the test load
the maximum permissible outside diameters of the spring as
specified in 7.3, measured at the same point and in the same
established by Table 2.
manner. Tolerances are shown in Table 5.
4.4.1.1 End Construction Coil Blunt Squared and Ground
5.1.5 Uniformity of Pitch—The pitch of the coils shall be
(Optional)—The end bearing surfaces of the spring shall be
sufficiently uniform so that when the spring is compressed
ground to produce a firm bearing. The end bearing surfaces
without lateral support to a height representing a deflection of
shall have a minimum ground bearing surface of two thirds of
85% of the nominal total travel, none of the coils shall be in
the mean coil circumference and a minimum width of two
contact with one another, excluding the inactive end coils.
thirds of the bar diameter. The tip ends of the bar shall be in
Under85%deflection,themaximumspacingbetweenanytwo
approximate contact with the adjacent coil and shall not
adjacent active coils shall not exceed 40% of the nominal free
protrude beyond the maximum permissible outside diameters
coil spacing.The nominal free coil spacing is equivalent to the
of the spring as established by Table 2.
specified total travel divided by the number of active turns.
4.4.2 Springs with ground ends having a free height-to-
When the design is such that it cannot be compressed to solid
mean diameter ratio of not less than 1 or more than 5 shall not
heightwithoutlateralsupport,theserequirementsdonotapply.
5.1.6 Outside Diameter—The outside diameter shall be
TABLE 1 Brinell Hardness
measured on a spring in the free condition and across any full
Indentation Diameter, mm Brinell Hardness Numbers
turn excluding the end turns and must be taken approximately
2.75 495
perpendicular to the helix axis. The tolerances are shown in
2.80 477
Table 2.
2.85 461
2.90 444
5.1.7 Calculations for Testing Loads and Stresses:
2.95 429
5.1.7.1 Solid Capacity—Calculate the solid capacity of the
3.00 415
3.05 401
spring as follows:
3.10 388
4 3
P 5 Gd F/8 ND (1)
3.15 375
where:
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A125−96 (2013)
TABLE 2 Permissible Variations in Outside Diameter of Helix
(For springs with D/d ratio not exceeding 8)
NOTE 1—(For design information). These permissible variations, exclusives of manufacturing taper, should be used as a guide in the design of
concentrically-nested helical-spring units for free assembly. The diametrical clearance desired is ⁄16 in. (1.59 mm) less than the sum of the applicable
tolerances of the nested spring units, but in no case should it be less than ⁄8 in. (3.17 mm).
NOTE 2—In cases where radical clearance on existing concentrically-nested helical-spring units will not accommodate these tolerances, the nominal
insidediametersshallbeadheredtoascloselyaspracticable,withplusvariationontheouterspringsandminusvariationontheinnerspringstoguarantee
free assembly. Drawings must show reference to the complete nested spring units.
NOTE 3—(For springs with D/d ratio not exceeding 8). For D/d ratio greater than 8, increase tolerance 50%.
Nominal Outside Diameter, in. Nominal Free Height or Length of Spring, in. (mm)
(mm)
Up to 10 (254) Over 10 to 18 Over 18 to 26 Over 26 to 34 Over 34 to 42 Over 42 to 60
incl, ± (254 to 457), (457 to 661), (661 to 874), (874 to 1067), (1067 to 1524),
incl, ± incl, ± incl, ± incl, ± incl, ±
1 3 1 5 3
Up to 6 (152), incl ⁄16 (1.59) ⁄32 (2.38) ⁄8 (3.17) ⁄32 (3.97) ⁄16 (4.76) . . .
3 1 3 1 1
Over 6 to 8 (152 to 203), incl ⁄32 (2.38) ⁄8 (3.17) ⁄16 (4.76) ⁄4 (6.35) ⁄4 (6.35) . . .
1 3 1 1 1
Over 8 to 12 (203 to 305), incl ⁄8 (3.17) ⁄16 (4.76) ⁄4 (6.35) ⁄4 (6.35) ⁄4 (6.35) . . .
1 1 1 1 5
Over 12 to 16 (305 to 406), incl . . . ⁄4 (6.35) ⁄4 (6.35) ⁄4 (6.35) ⁄4 (6.35) ⁄16 (7.94)
5 5 5 3
Over 16 to 20 (406 to 508), incl . . . . . . ⁄16 (7.94) ⁄16 (7.94) ⁄16 (7.94) ⁄8 (9.53)
3 3 3 7
Over 20 to 24 (508 to 610), incl . . . . . . ⁄8 (9.53) ⁄8 (9.53) ⁄8 (9.53) ⁄16 (11.00)
7 7 7 1
Over 24 to 28 (610 to 701), incl . . . . . . ⁄16 ⁄16 ⁄16 ⁄2
1 1 1 1
Over 28 (701), incl . . . . . . ⁄2 ⁄2 ⁄2 ⁄2
TABLE 3 Permissible Out-of-Squareness, Springs with Ground Ends
Total Travel, in. (mm) Mean Diameter, in. (mm)
2 (51) Over 2 Over 4 Over 6 Over 8 Over 10 Over 12 Over 14 Over 16 Over 18
and to 4 to 6 to 8 to 10 to 12 to 14 to 16 to 18 to 20
under (51 to (102 to (152 to (203 to (254 to (305 to (356 to (406 to (457 to
102), incl 152), incl 203), incl 254), incl 305), incl 356), incl 406), incl 457), incl 508), incl
Degree
1 1
2 (51) and under 1 ⁄4 1 ⁄4 1111 . . . .
3 1 1 1
Over 2 to 4 (51 to 102), incl 1 ⁄4 1 ⁄2 1 ⁄4 1 ⁄4 1 1 1 . . .
1 3 1 1 1
Over 4 to 6 (102 to 152), incl 2 ⁄4 1 ⁄4 1 ⁄2 1 ⁄4 1 ⁄4 1 1 . . .
1 1 3 1 1 1
Over 6 to 8 (152 to 203), incl 2 ⁄2 2 ⁄4 1 ⁄4 1 ⁄2 1 ⁄4 1 ⁄4 1 1 . .
3 1 1 1 1 1
Over 8 to 10 (203 to 254), incl 2 ⁄4 2 ⁄2 21 ⁄2 1 ⁄2 1 ⁄4 1 ⁄4 1 . .
3 1 3 1 1 1 1
Over 10 to 12 (254 to 305), incl 3 2 ⁄4 2 ⁄4 1 ⁄4 1 ⁄2 1 ⁄2 1 ⁄4 1 ⁄4 1 .
1 3 3 1 1 1 1
Over 12 to 14 (305 to 356), incl . . . 3 2 ⁄2 21 ⁄4 1 ⁄4 1 ⁄2 1 ⁄2 1 ⁄4 1 ⁄4
3 1 3 3 1 1
Over 14 to 16 (356 to 406), incl . . . . . . 2 ⁄4 2 ⁄4 22 1 ⁄4 1 ⁄4 1 ⁄2 1 ⁄2
1 1 3 3 1
Over 16 to 18 (406 to 457), incl . . . . . . 3 2 ⁄2 2 ⁄4 22 1 ⁄4 1 ⁄4 1 ⁄2
3 1 1 1 3
Over 18 to 20 (457 to 508), incl . . . . . . 3 2 ⁄4 2 ⁄2 2 ⁄4 2 ⁄4 22 1 ⁄4
3 1 1 3
Over 20 to 22 (508 to 559), incl . . . . . . . . . 3 2 ⁄4 2 ⁄4 2 ⁄4 22 1 ⁄4
1 1 3
Over 22 to 24 (559 to 610), incl . . . . . . . . . . . . 3 2 ⁄4 2 ⁄4 22 1 ⁄4
1 1 1 1
Over 24 to 26 (610 to 660), incl . . . . . . . . . . . . . . . 2 ⁄2 2 ⁄2 2 ⁄4 2 ⁄4 2
1 1 1 1
Over 26 to 28 (660 to 701), incl . . . . . . . . . . . . . . . 2 ⁄2 2 ⁄2 2 ⁄4 2 ⁄4 2
3 1 1 1
Over 28 to 30 (702 to 762), incl . . . . . . . . . . . . . . . 2 ⁄4 2 ⁄2 2 ⁄4 2 ⁄4 2
3 3 1 1
Over 30 to 32 (762 to 813), incl . . . . . . . . . . . . . . . 2 ⁄4 2 ⁄4 2 ⁄2 2 ⁄2 .
3 3 1 1
Over 32 to 34 (813 to 864), incl . . . . . . . . . . . . . . . 2 ⁄4 2 ⁄4 2 ⁄2 2 ⁄2 .
3 3 3
Over 34 to 38 (864 to 914), incl . . . . . . . . . . . . . . . 3 2 ⁄4 2 ⁄4 2 ⁄4 .
3 3
Over 36 to 38 (914 to 965), incl . . . . . . . . . . . . . . . . . . 3 2 ⁄4 2 ⁄4 .
Over 38 to 42 (965 to 1016), incl . . . . . . . . . . . . . . . . . . . . . 3 3 . . .
TABLE 4 Permissible Variations in Solid Height
G = 11×10 psi = effective torsional modulus of elasticity,
d = nominal bar diameter, in.,
Nominal Solid Height, in. (mm) Deviation Above Nominal Solid
A
Height, max, in. (mm)
D = mean coil or helix diameter, in.,
F = spring deflection = free to solid, in., Up to 7 (178), incl ⁄16 (1.59)
Over 7 to 10 (178 to 254), incl ⁄32 (2.38)
N = active turns = (solid height)/bar diameter) − 1.5, and
Over 10 to 13 (254 to 330), incl ⁄8 (3.17)
P = solid capacity, lb.
Over 13 to 16 (330 to 406), incl ⁄32 (3.97)
Over 16 to 19 (406 to 483), incl ⁄16 (4.76)
5.1.7.2 UncorrectedSolidStress—Calculatetheuncorrected
Over 19 to 22 (483 to 559), incl ⁄32 (5.56)
solid stress as follows: (Warning—Bar nom
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