ASTM A125-96

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Designation: A 125 – 96 An American National Standard
Standard Specification for
Steel Springs, Helical, Heat-Treated
This standard is issued under the fixed designation A 125; 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—Paragraph 4.4.1 was added and the year date changed in January 1996.
1. Scope 3.1.3 A drawing or list showing required dimensions and
loads, and part number,
1.1 This specification covers hot-coiled, heat-treated helical
3.1.4 Packaging, marking and loading, and
compression springs with tapered, closed, squared and ground
3.1.5 End use.
ends made of hot-wrought round steel bars ⁄8 in. (9.5 mm) and
larger in diameter.
NOTE 1—A typical ordering description is: 500 springs Drawing 3303
1.2 This specification also serves to inform the user of
Rev. A. to ASTM A 125, 1095 steel, for cyclical machine operation.
Palletize, maximum weight 4000 lb.
practical manufacturing limits, mechanical tests, and inspec-
tion requirements applicable to the type of spring described in
4. Materials and Manufacture
1.1.
4.1 Material:
1.3 Supplementary Requirements S1 to S8 inclusive of an
4.1.1 Unless otherwise specified, the springs shall be made
optional nature are provided. They shall apply only when
of carbon steel bars conforming to the requirements of Speci-
specified by the purchaser. Details of these supplementary
fication A 689. Due to hardenability limitations of carbon steel,
requirements shall be agreed upon by the manufacturer and
it is suggested that the bar diameter be limited to 1 ⁄8 in. (41.8
purchaser.
mm) max in order to withstand the maximum test stress
1.4 The values stated in inch-pound units are to be regarded
requirements of this specification.
as the standard. The values given in parentheses are for
4.1.2 If alloy steel is specified, the springs shall be made
information only).
from alloy steel bars conforming to Specification A 689. Any
2. Referenced Documents
of the alloy steel grades referred to may be used at the option
of the spring manufacturer, providing that a minimum as-
2.1 ASTM Standards:
quenched hardness of Rockwell HRC-50 will be achieved at
A 29/A 29M Specification for Steel Bars, Carbon and Alloy,
the center of the bar section representing the spring when
Hot-Wrought and Cold-Finished, General Requirements
quenched in the same media and manner as the spring.
for
4.1.3 Springs Made from Bars Over 2 in. (50.8 mm)—Note
A 689 Specification for Carbon and Alloy Steel Bars for
that the bias tolerance (reference A29/A 29M, Table A1.1 on
Springs
Permissible Variations in Cross Section for Hot-Wrought
E 10 Test Method for Brinell Hardness of Metallic Materi-
Round, Square, and Round-Cornered Square Bars of Steel) of
als
the bar diameter shall be taken into consideration when
E 112 Test Methods for Determining Average Grain Size
designing and calculating the solid height, spring rate, solid
E 709 Guide for Magnetic Particle Examination
stress, and solid capacity.
3. Ordering Information
4.2 Hardness:
4.2.1 The springs must be quenched and tempered to a
3.1 Orders for springs under this specification shall include
sufficiently high hardness (strength) to withstand the stresses
the following information:
developed in testing the finished spring. The maximum hard-
3.1.1 Quantity,
ness shall not exceed 477 Brinell numbers (2.80 mm indenta-
3.1.2 Name of material,
tion diameter).
4.2.2 When hardness limits are specified, the total range or
1 spread may not be less than 0.15 mm difference in indentation
This specification is under the jurisdiction of ASTM Committee A-1 on Steel,
Stainless Steel and Related Alloysand is the direct responsibility of Subcommittee diameters. The specified or indicated minimum hardness must
A01.15on Bars.
be sufficient to develop the required strength to withstand the
Current edition approved Jan. 25, 1996. Published February 1996. Originally
solid stresses of the spring design involved.
published as A 125 – 29 T. Last previous edition A 125 – 95.
4.2.3 Hardness shall be read on a prepared flat surface in an
Annual Book of ASTM Standards, Vol 01.05.
Annual Book of ASTM Standards, Vol 03.01.
area not detrimental to the life of the spring at a full section
Annual Book of ASTM Standards, Vol 03.03.
Copyright © ASTM, 100 Barr Harbor Drive, West Conshohocken, PA 19428-2959, United States.
A 125
TABLE 2 Brinell Hardness
after removal of the decarburized layer. A tungsten-carbide
10-mm ball shall be applied under a 3000-kg load and the
Indentation Diameter, mm Brinell Hardness Numbers
indentation diameter converted to Brinell numbers by using
2.75 495
Table 1. The values for Table 1 have been taken from
2.80 477
Specification E 10.
2.85 461
4.3 Metallurgical Requirements:
2.90 444
2.95 429
4.3.1 The total depth of decarburization, partial plus com-
3.00 415
plete as measured on the finished spring in the quenched and
3.05 401
tempered condition, shall not exceed 0.006 in. (0.15 mm) plus
3.10 388
3.15 375
1 % of the bar diameter. The decarburization shall be examined
at 1003 on a test specimen suitably etched and cut from a full
cross section of the test spring showing at least one lineal inch
of original bar circumference. 4.4.2 Springs with ground ends having a free height-to-
mean diameter ratio of not less than 1 or more than 5 shall not
4.3.2 The structure of the finished spring shall have an
average ASTM Grain Size No. 5 or finer as determined by the deviate from the perpendicular more than the number of
degrees prescribed in Table 3, as determined by standing the
latest revision of Test Methods E 112.
4.4 End Construction: spring on its end and measuring the angular deviation of a
straightedge along the outer helix from a perpendicular to the
4.4.1 End Construction-Tapered Squared and Ground—
The end bearing surfaces of the spring shall be ground to plate on which the spring is standing.
produce a firm bearing. The end bearing surfaces shall have a 4.4.3 The ends of springs shall be parallel within a tolerance
of twice that specified for the squareness of ends as determined
minimum bearing surface of two thirds of the mean coil
circumference and a minimum width of two thirds of the by standing the spring on its end and measuring the maximum
angular deviation of the other end from a plane parellel to the
hot-tapered surface of the bar. The tip ends of the bar shall be
in approximate contact with the adjacent coil, and shall not plate on which the spring is standing.
protrude beyond the maximum permissible outside diameters
5. Physical Requirements
of the spring as established by Table 2.
4.4.1.1 End Construction Coil Blunt Squared and Ground 5.1 Measurements:
(Optional)—The end bearing surfaces of the spring shall be 5.1.1 Solid Height—The solid height is the perpendicular
ground to produce a firm bearing. The end bearing surfaces distance between the plates of the testing machine when the
shall have a minimum ground bearing surface of two thirds of spring is compressed solid with the load specified in 7.3. The
the mean coil circumference and a minimum width of two solid height thus measured may be less, but shall not exceed
thirds of the bar diameter. The tip ends of the bar shall be in the specified nominal solid height by more than the limits given
approximate contact with the adjacent coil and shall not in Table 4.
protrude beyond the maximum permissible outside diameters 5.1.2 Free Height—The free height is the height of the
of the spring as established by Table 2. spring after the load specified in 7.3 has been released, and is
TABLE 1 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 . . .
A 125
TABLE 3 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 shoulds 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
inside diameters shall be adhered to as closely as practicable, with plus variation on the outer springs and minus variation on the inner springs to guarantee
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, 6 (254 to 457), (457 to 661), (661 to 874), (874 to 1067), (1067 to 1524),
incl, 6 incl, 6 incl, 6 incl, 6 incl, 6
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 4 Permissible Variations in Solid Height TABLE 5 Permissible Variations in Free Height, Loaded Height
and Permanent Set
Nominal Solid Height, in. (mm) Deviation Above Nominal Solid
A
Height, max, in. (mm)
Nominal Total Deviation Deviation Permanent
Deflection, in. (mm) From From Set, max,
Up to 7 (178), incl ⁄16 (1.59)
Nominal Free Nominal in. (mm)
Over 7 to 10 (178 to 254), incl ⁄32 (2.38)
Height, max, Loaded
Over 10 to 13 (254 to 330), incl ⁄8 (3.17)
A
in. (mm), 6 Height,
Over 13 to 16 (330 to 406), incl ⁄32 (3.97)
max,
Over 16 to 19 (406 to 483), incl ⁄16 (4.76)
in. (mm), 6
Over 19 to 22 (483 to 559), incl ⁄32 (5.56)
5 4 3
Over 22 to 25 (559 to 635), incl ⁄4 (6.35)
Up to 3 (76.2), incl ⁄32 (3.97) ⁄32 (3.17) ⁄64 (1.19)
9 8 5 4
Over 25 to 28 (635 to 711), incl ⁄32 (7.14) Over 3 to 4 (76.2 to 102), incl ⁄32 (6.35) ⁄32 (3.97) ⁄64 (1.59)
8 6 4
Over 28 to 31 (711 to 787), incl ⁄16 (7.94)
Over 4 to 5 (102 to 127), incl ⁄32 (6.35) ⁄32 (4.76) ⁄64 (1.59)
11 7 5
Over 5 to 6 (127 to 152), incl ⁄32 (8.73) ⁄32 (5.56) ⁄64 (1.99)
A
For additional 3-in. (76-mm) increase in solid height, the deviation shown
11 8 5
Over 6 to 7 (152 to 179), incl ⁄32 (8.73) ⁄32 (6.35) ⁄64 (1.99)
should be increased by ⁄32 in. (0.79 mm).
14 9 6
Over 7 to 8 (179 to 203), incl ⁄32 (11.0) ⁄32 (7.14) ⁄64 (2.38)
14 10 6
Over 8 to 9 (203 to 228), incl ⁄32 (11.0) ⁄32 (7.94) ⁄64 (2.38)
17 11 7
Over 9 to 10 (228 to 254), incl ⁄32 (13.49) ⁄32 (8.73) ⁄64 (2.78)
17 12 7
Over 10 to 11 (254 to 279), incl ⁄32 (13.49) ⁄32 (9.53) ⁄64 (2.78)
20 13 8
Over 11 to 12 (279 to 305), incl ⁄32 (15.87) ⁄32 (10.32) ⁄64 (3.17)
determined by placing a straightedge across the top of the
20 14 8
Over 12 to 13 (305 to 330), incl ⁄32 (15.87) ⁄32 (11.00) ⁄64 (3.17)
spring and measuring the perpendicular distance from the plate
23 15 8
Over 13 to 14 (330 to 356), incl ⁄32 (18.25) ⁄32 (11.91) ⁄64 (3.17)
23 16 9
on which the spring stands to the bottom of the straightedge at Over 14 to 15 (356 to 381), incl ⁄32 (18.25) ⁄32 (12.70) ⁄64 (3.57)
26 17 9
Over 15 to 16 (381 to 406), incl ⁄32 (20.64) ⁄32 (13.49) ⁄64 (3.57)
the approximate center of the spring. Tolerances are shown in
26 18 10
Over 16 to 17 (406 to 431), incl ⁄32 (20.64) ⁄32 (14.28) ⁄36 (3.97)
Table 5.
29 19 10
Over 17 to 18 (431 to 457), incl ⁄32 (23.01) ⁄32 (15.08) ⁄64 (3.97)
29 20 11
5.1.3 Loaded Height—The loaded height is the perpendicu- Over 18 to 19 (457 to 483), incl ⁄32 (23.01) ⁄32 (15.87) ⁄64 (4.37)
21 11
Over 19 to 20 (483 to 508), incl 1 (25.40) ⁄32 (16.67) ⁄64 (4.37)
lar distance between the plates of the testing machine when the
22 12
Over 20 to 21 (508 to 533), incl 1 (25.40) ⁄32 (17.46) ⁄64 (4.76)
specified working load has been applied in compression. 3 23 12
Over 21 to 22 (533 to 559), incl 1 ⁄32 (27.78) ⁄32 (18.25) ⁄64
...