ASTM A255-20a

This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the
Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
Designation: A255 − 20a
Standard Test Methods for
Determining Hardenability of Steel
This standard is issued under the fixed designation A255; 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 U.S. Department of Defense.
1. Scope* responsibility of the user of this standard to establish appro-
priate safety, health, and environmental practices and deter-
1.1 These test methods cover the identification and descrip-
mine the applicability of regulatory limitations prior to use.
tionoftestmethodsfordeterminingthehardenabilityofsteels.
1.7 This international standard was developed in accor-
The two test methods include the quantitative end-quench or
dance with internationally recognized principles on standard-
Jominy Test and a method for calculating the hardenability of
ization established in the Decision on Principles for the
steelfromthechemicalcompositionbasedontheoriginalwork
Development of International Standards, Guides and Recom-
by M. A. Grossman.
mendations issued by the World Trade Organization Technical
1.2 The selection of the test method to be used for deter-
Barriers to Trade (TBT) Committee.
mining the hardenability of a given steel shall be agreed upon
between the supplier and user. The Certified Material Test 2. Referenced Documents
Report shall state the method of hardenability determination. 2
2.1 ASTM Standards:
1.3 The calculation method described in these test methods E18Test Methods for Rockwell Hardness of Metallic Ma-
is applicable only to the range of chemical compositions that terials
follow: E112Test Methods for Determining Average Grain Size
Element Range, %
END-QUENCH OR JOMINY TEST
Carbon 0.10–0.70
Manganese 0.50–1.65
Silicon 0.15–0.60
3. Description
Nickel 1.50 max
Chromium 1.35 max 3.1 This test method covers the procedure for determining
Molybdenum 0.55 max
thehardenabilityofsteelbytheend-quenchorJominytest.The
Copper 0.35 max
test consists of water quenching one end of a cylindrical test
Vanadium 0.20 max
specimen 1.0 in. in diameter and measuring the hardening
1.4 Hardenability is a measure of the depth to which steel
response as a function of the distance from the quenched end.
will harden when quenched from its austenitizing temperature
(Table 1). It is measured quantitatively, usually by noting the
4. Apparatus
extentordepthofhardeningofastandardsizeandshapeoftest
4.1 Support for Test Specimen—Afixture for supporting the
specimen in a standardized quench. In the end-quench test the
test specimen vertically so that the lower end of the specimen
depthofhardeningisthedistancealongthespecimenfromthe
is a distance of 0.5 in. (12.7 mm) above the orifice of the
quenched end which correlates to a given hardness level.
water-quenching device.Asatisfactory type of support for the
1.5 Thevaluesstatedininch-poundunitsaretoberegarded
standard 1.0 in. (25.4 mm) specimen is shown in Fig. 1.
as standard. The values given in parentheses are mathematical
NOTE 1—Asuitable support for other sizes and shapes of specimens is
conversions to SI units that are provided for information only
shown in Fig. X1.1.
and are not considered standard.
4.2 Water-QuenchingDevice—Awater-quenchingdeviceof
1.6 This standard does not purport to address all of the
suitable capacity to provide a vertical stream of water that can
safety concerns, if any, associated with its use. It is the
be controlled to a height of 2.5 in. (63.5 mm) when passing
through an orifice 0.5 in. (12.7 mm) in diameter. A tank of
These test methods are under the jurisdiction of ASTM Committee A01 on
Steel, Stainless Steel and Related Alloys and are the direct responsibility of
Subcommittee A01.15 on Bars. For referenced ASTM standards, visit the ASTM website, www.astm.org, or
Current edition approved Nov. 1, 2020. Published November 2020. Originally contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
approved in 1942. Last previous edition approved in 2020 as A255–20. DOI: Standards volume information, refer to the standard’s Document Summary page on
10.1520/A0255-20A. the ASTM website.
*A Summary of Changes section appears at the end of this standard
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
A255 − 20a
A
TABLE 1 Normalizing and Austenitizing Temperatures NOTE 2—Other sizes and shapes of test specimens are described in
Appendix X1.
Normalizing Austenitizing
Steel Series Ordered Carbon Temperature, Temperature,
6. Procedure
Content, max, % °F (°C) °F (°C)
1000, 1300, 1500, 0.25 and under 1700 (925) 1700 (925)
6.1 Normalizing—The wrought product from which the
3100, 4000, 4100
specimenistobepreparedshallbenormalizedtoensureproper
hardening characteristics. The sample shall be held at the
4300, 4400, 4500, 0.26 to 0.36, incl 1650 (900) 1600 (870)
4600, 4700, 5000,
temperature listed in Table 1 for 1 h and cooled in air.
B
5100, 6100, 8100,
Tempering of the normalized sample to improve machinability
8600, 8700, 8800,
0.37 and over 1600 (870) 1550 (845)
9400, 9700, 9800
is permitted.
6.2 Heating—Place the specimen in a furnace that is at the
0.25 and under 1700 (925) 1550 (845)
2300, 2500, 3300,
specified austenitizing temperature (Table 1) and hold at this
0.26 to 0.36, incl 1650 (900) 1500 (815)
4800, 9300
temperature for 30 min. In production testing slightly longer
0.37 and over 1600 (870) 1475 (800)
times up to 35 min may be used without appreciably affecting
results. It is important to heat the specimen in such an
9200 0.50 and over 1650 (900) 1600 (870)
atmosphere that practically no scaling and a minimum of
A
A variation of ±10 °F (6 °C) from the temperatures in this table is permissible.
decarburization takes place. This may be accomplished by
B
Normalizing and austenitizing temperatures are 50 °F (30 °C) higher for the 6100
heating the specimen in a vertical position in a container with
series.
an easily removable cover containing a layer of cast-iron chips
with the bottom face of the specimen resting on the chips.
6.2.1 Other methods consist of placing the specimen in an
appropriately sized hole in a graphite block or placing the
sufficient capacity to maintain the water temperature require-
ments of 6.3 with a small pump and control valves will be specimen in an upright tube attached to a flat base, both of a
heat-resistant metal, with the collar projecting for a tong hold.
foundsatisfactory.Thewater-supplylineshallalsobeprovided
with a quick opening valve. Place a disk of graphite or carbon, or a layer of carbonaceous
material such as charcoal, in the bottom of the tube to prevent
5. Test Specimens
scaling.
6.2.2 Foraparticularfixtureandfurnace,determinethetime
5.1 Wrought Specimens—End-quench specimens shall be
required to heat the specimen to the austenitizing temperature
preparedfromrolledorforgedstockandshallrepresentthefull
byinsertingathermocoupleintoaholedrilledaxiallyinthetop
crosssectionoftheproduct.Ifnegotiatedbetweenthesupplier
of the specimen. Repeat this procedure periodically, for ex-
and the user, the end-quench specimen may be prepared from
ample once a month, for each combination of fixture and
a given location in a forged or rolled product or from a
furnace.
continuous cast billet. The test specimen shall be 1.0 in. (25.4
mm) in diameter by 4.0 in. (101.6 mm) in length, with means 6.3 Quenching—Adjust the water-quenching device so that
for hanging it in a vertical position for end quenching.
the stream of water rises to a free height of 2.5 in. (63.5 mm)
Dimensions of the preferred specimen and of an optional
above the 0.5 in. (12.7 mm) orifice, without the specimen in
specimen (Note 2) are given in Figs. 2 and 3. The specimen
position. The support for the specimen shall be dry at the
shall be machined from a bar previously normalized in
beginning of each test. Then place the heated specimen in the
accordance with 6.1 and of such size as to permit the removal
support so that its bottom face is 0.5 in. above the orifice, and
ofalldecarburizationinmachiningto1.0in.round.Theendof
turn on the water by means of the quick-opening valve. The
the specimen to be water cooled shall have a reasonably
time between removal of the specimen from the furnace and
smooth finish, preferably produced by grinding. Normalizing
thebeginningofthequenchshouldnotbemorethan5s.Direct
may be waived by agreement between the supplier and the
the stream of water, at a temperature of 40°F to 85°F (5°C to
user.The previous thermal history of the specimen tested shall
30°C), against the bottom face of the specimen for not less
always be recorded.
than 10 min. Maintain a condition of still air around the
specimen during cooling. If the specimen is not cold when
5.2 Cast Specimens—A separately cast end-quench speci-
removed from the fixture, immediately quench it in water.
men may be used for non-boron steels. Cast specimens are not
suitable for boron steel grades due to erratic results.Agraphite 6.4 Hardness Measurement—Two flats 180° apart shall be
ormetalmoldmaybeusedtoformanoverlengthspecimen1.0 ground to a minimum depth of 0.015 in. (0.38 mm) along the
in. (25.4 mm) in diameter which shall be cut to the standard entire length of the bar and Rockwell C hardness measure-
specimen size. The mold may also be used to form a 1.25 in. ments made along the length of the bar. Shallower ground
(31.8 mm) diameter specimen which shall be machined to the depthscanaffectreproducibilityofresults,andcorrelationwith
final specimen size. Cast tests need not be normalized. cooling rates in quenched bars.
A255 − 20a
FIG. 1 Test Specimen in Support for Water Quenching
FIG. 2 Preferred Test Specimen
FIG. 3 Optional Test Specimen
6.4.1 The preparation of the two flats must be carried out cooling and a coarse, soft-grinding wheel are recommended to
with considerable care. They should be mutually parallel and avoidheatingthespecimen.Inordertodetecttemperingdueto
the grinding done in such a manner that no change of the grinding, the flat may be etched with one of the following
quenched structure takes place. Very light cuts with water etchant solutions:
A255 − 20a
NOTE 3—5% nitric acid (concentrated) and 95% water by volume.
6.4.4.2 For reporting purposes, hardness readings should be
NOTE 4—50% hydrochloric acid (concentrated) and 50% water by
recorded to the nearest integer, with 0.5 HRC values rounded
volume.
to the next higher integer.
Wash the sample in hot water. Etch in solution No. 1 until
7. Plotting Test Results
black.Washinhotwater.ImmerseinsolutionNo.2for3sand
wash in hot water. Dry in air blast. 7.1 Test results should be plotted on a standard hardenabil-
ity chart prepared for this purpose, in which the ordinates
6.4.1.1 Thepresenceoflighterordarkerareasindicatesthat
represent HRC values and the abscissae represent the distance
hardness and structure have been altered in grinding. If such
from the quenched end of the specimen at which the hardness
changes caused by grinding are indicated, new flats may be
determinations were made. When hardness readings are taken
prepared.
on two or more flats, the values at the same distance should be
6.4.2 When hardness tests are made, the test specimen rests
averaged and that value used for plotting. A facsimile of the
on one of its flats on an anvil firmly attached to the hardness
standard ASTM hardenability chart on which typical harden-
machine. It is important that no vertical movement be allowed
ability curves have been plotted is shown in Fig. 4.
when the major load is applied. The anvil must be constructed
to move the test specimen past the penetrator in accurate steps
8. Index of Hardenability
of ⁄16 in. (1.5 mm). Resting the specimen in a V-block is not
8.1 The hardenability of a steel can be designated by a
permitted.
specific HRC hardness value or HRC hardness value range at
6.4.2.1 The Rockwell tester should periodically be checked
a given Jominy (“J”) distance. Examples of this method are
againststandardtestblocks.Itisrecommendedthatatestblock
4 7
J ⁄16 in. (6.4 mm) = 47 HRC min, J ⁄16 in. (11.1 mm) = 50
be interposed between the specimen and the indenter to check
HRC max, and J ⁄16 in. (7.9 mm) = 38–49 HRC.
the seating of the indenter and the specimen simultaneously.
For general statements regarding the use of test blocks and
9. Report
surface conditions, reference should be made to 4.7 and 5.2,
9.1 Report the following information that may be recorded
respectively, of Test Methods E18.
on the ASTM hardenability chart:
6.4.3 Exercisecareinregisteringthepointoftheindenterin
9.1.1 Previous thermal history of the specimen tested, in-
relationship to the quenched end of the specimen as well as
cluding the temperature of normalizing and austenitizing,
providing for accurate spacing between indentations. A low-
9.1.2 Chemical Composition,
powermeasuringmicroscopeissuitableforuseindetermining
9.1.3 ASTM grain size (McQuaid-Ehn) as determined by
the distance from the quenched end to the center of the first
Test Methods E112, unless otherwise indicated, and
impression and in checking the distance from center to center
9.1.4 A prominent notation on the standard hardenability
of the succeeding impressions. It has been found that with
chart if any of the test specimens listed in Appendix X1 are
reasonableoperatingcareandawell-builtfixture,itispractical
used.
to locate the center of the first impression 0.0625 in. 6 0.004
in. (1.5 mm 6 0.10 mm) from the quenched end. The
CALCULATION OF HARDENABILITY
variations between spacings should be even smaller.
10. Introduction
Obviously, it is more important to position the indenter
accurately when testing low-hardenability steels than when
10.1 This method of Jominy Hardenability calculation from
testing high-hardenability steels. The positioning of the in-
the chemical ideal diameter (DI) on a steel is based on the
denter should be checked with sufficient frequency to provide
original work of M. A. Grossman and provides increased
assurancethataccuracyrequirementsarebeingmet.Incasesof
accuracy by refinement of the carbon multiplying factors and
lack of reproducibility or of differences between laboratories,
the correlation of a boron factor (B.F.) with carbon and alloy
indenter spacing should be measured immediately.
content. These refinements were based on analysis of thou-
6.4.4 Readingsshallbetakeninstepsof ⁄16in.(1.6mm)for sands of heats of boron and non-boron 1500, 4100, 5000, and
the first 16 sixteenths (25.4 mm), then 18, 20, 22, 24, 28, and 8600 series steels encompassing a range of compositions as
32 sixteenths of an inch. Values below 20 HRC are not follows and a range of DI as contained in Tables 2-5. The
recorded because such values are not accurate. When a flat on accuracyofthistestmethodandthetechniquesusedtodevelop
which readings have been made is used as a base, the burrs ithavebeendocumented.Forcomparisonofthistestmethodto
around the indentation shall be removed by grinding unless a others, or for steel compositions outside the mentioned grades,
fixture is used which has been relieved to accommodate the the user should refer to other articles concerned with calculat-
irregularities due to the indentations. ing hardenability.
6.4.4.1 Hardness readings should preferably be made on Element Range, %
two flats 180° apart. Testing on two flats will assist in the
Carbon 0.10–0.70
detection of errors in specimen preparation and hardness
Manganese 0.50–1.65
measurement. If the two probes on opposite sides differ by Silicon 0.15–0.60
Nickel 1.50 max
morethan4HRCpointsatanyoneposition,thetestshouldbe
Chromium 1.35 max
repeated on new flats, 90° from the first two flats. If the retest
Molybdenum 0.55 max
also has greater than 4 HRC points spread, a new specimen Copper 0.35 max
Vanadium 0.20 max
should be tested.
A255 − 20a
FIG. 4 Facsimile of Standard ASTM Hardenability Chart, Showing Typical Hardenability Curves
[Chart Size: 8 ⁄2 in. by 11 in. (216 mm by 279 mm)]
differs from the procedure as shown in 6.4.4.
10.1.1 Calculated DI and Jominy hardenability curves are
valid only within the chemical ranges stated above. However,
10.3 DICalculationforNon-BoronSteels—Thiscalculation
to facilitate melting process control for higher alloy steels,
relies on a series of hardenability factors (Table 6) for each
Hardenability Multiplying Factors have been included for
alloying element in the composition which, when multiplied
calculating the DI within the following chemical composition
together, gives a DI value. (For simplicity, only multiplying
ranges:
factors for DI in inch-pound units are given. For DI in
Element Range, % millimetres, use the metric value table.) The effects of phos-
phorousandsulfurarenotconsideredsincetheytendtocancel
Carbon 0.01–0.90
oneanother.ANo.7austeniticgrainsizeisassumedsincemost
Manganese 0.01–1.95
steels with hardenability control are melted to a fine-grain
Silicon 0.01–2.00
Nickel 0.01–3.50
practice where experience has demonstrated that a high per-
Chromium 0.01–2.50
centage of heats conform to this grain size. An example DI
Molybdenum 0.01–0.55
Copper 0.01–0.55 calculationisgivenasfollowsforanSAE4118modifiedsteel:
Vanadium 0.01–0.20
Element % Multiplying Factor
Zirconium 0.01–0.25
Carbon 0.22 0.119
10.2 Tables 2-18 are to be used to calculate hardenability
Manganese 0.80 3.667
fromthechemicalidealdiameterforthegradesshownin10.1.
Silicon 0.18 1.126
Hardenabilityresultsaretobereportedforthefirst10sixteenth
Nickel 0.10 1.036
Chromium 0.43 1.929
(16mm),the12,14,16,18,20,24,28,and32sixteenthsofan
Molybdenum 0.25 1.75
inch.
Copper 0.10 1.04
Vanadium 0.05 1.09
NOTE 5—The reporting of hardenability using the calculated method
A255 − 20a
where: 10.4.5.3 Determine the boron multiplying factor fromTable
10.Forthisexamplewith0.29%carbonandanalloyfactorof
DI =0.119×3.667×1.126×1.036×1.929×1.75×1.04×1.09=1.95in.
8.6, the boron multiplying factor is 2.31 (interpolation re-
10.4 DI Calculation for Boron Steels—With an effective
quired).
steel making process, the boron factor (signifying the contri-
10.4.6 Calculate the DI with boron as follows:
bution for boron to increased hardenability) is an inverse
where:
functionofthecarbonandalloycontent.Thehigherthecarbon
or alloy content, or both, the lower the boron factor. DI = DI (without boron) × boron factor
B
DI = 1.35 in. × 2.31
B
10.4.1 Theactualboronfactorisexpressedbythefollowing
DI = 3.12 in.
B
relationship:
10.5 Hardenability Curves from Composition—With a pre-
measuredDI ~fromJominydataandcarboncontent!
B.F. 5 (1) determined DI (DI for boron steel), the end-quench harden-
B
calculatedDI ~fromcompositionexcludingboron!
ability curve can be computed by the following procedure:
10.5.1 The initial hardness (IH) at the J = ⁄16 in. position is
10.4.2 An example of actual boron factor determination is
a function of carbon content and independent of hardenability
given as follows for an SAE 15B30 modified steel:
and is selected from Table 7. For the example non-boron SAE
Calculated
DI 4118 modified heat containing 0.22% carbon, the initial
Composition, (boron
hardness is 45 HRC.
% C Mn Si Ni Cr Mo Cu B excluded)
10.5.2 Thehardnessatotherpositionsalongtheend-quench
0.29 1.25 0.20 0.13 0.07 0.03 0.24 0.0015 1.35
in.
specimen(termeddistancehardness)isdeterminedbydividing
End-Quench Test Results, in.
the initial hardness by the appropriate factor from Table 2 (in.)
“J” Position ( ⁄8in.) 1234567
or Table 3 (mm) for non-boron steels or from Table 4 (in.) or
Hardness, HRC 50 50 49 48 47 45 41
1 Table 5 (mm) for boron steels.
“J” Position ( ⁄8in.) 8 9 10121416
Hardness, HRC 38 33 28 25 22 20
10.6 For the example non-boron heat with an IH = 45 HRC
10.4.3 Using Table 7, determine the nearest location on the and a calculated DI of 1.95 in., the hardness at the respective
end-quench positions can be calculated by dividing 45 by the
end-quench curve where hardness corresponding to 50%
appropriatedividingfactorlistedinTable2(in.)fornon-boron
martensite occurs for the actual carbon content. For the
steels. (For simplicity, the DI should be rounded to the nearest
example heat with 0.29 carbon, this hardness is 37 HRC
0.1 in.).
occurring at a “J” distance of ⁄16in. from the quenched end
(interpolation required).
10.7 Distance Dividing Hardness Factors in Tables 2-5 are
10.4.4 FromTable8(in.),a“J”distanceof ⁄16in.equatesto calculated from the equations in Tables 15-18. Multiplying
Factors in Table 6 are calculated from the equations in Table
a measured DI of 2.97 in. (interpolation required).
11.JominyDistancefor50%MartensiteversusDIinTables8
2.97in.
BoronFactor 5 52.2boronfactor (2) and 9 are calculated from the equations in Table 13. Boron
1.35in.
Factor versus % Carbon and Alloy Factor in Table 10 are
calculatedfromtheequationsinTable14.Equationsrepresent-
10.4.5 Calculation of DI with Boron (DI ):
B
ingaleastsquarespolynomialfitofthedatacontainedinTable
10.4.5.1 CalculatetheDIwithoutboron.Fortheexamplein
7islistedinTable12.Theuseoftheseequationstoplotcurves
10.4.4, this DI is 1.35 in.
mayresultinrandominflectionpointsduetothecharacteristics
10.4.5.2 Calculate the alloy factor (the product of all the
of polynomial equations. These inflections will be minor,
multiplying factors from Table 6 excluding carbon). For the
however, and should be disregarded.
example in 10.4.4:
11. Keywords
CalculatedDI ~withoutboron! 1.35in.
AlloyFactor 5 5 58.6 (3)
Carbonmultiplyingfactor 0.157in. 11.1 end-quench hardenability; hardenability
A255 − 20a
TABLE 2 Distance Hardness Dividing Factors for Non-Boron Steels, in.
Ideal 1
Jominy End-Quench Distance ( ⁄16 in.)
Diameter
23456789 10 12 14 16 18 20 24 28 32
(DI), in.
1 1.15 1.50 2.14 2.46 2.72 2.81 2.92 3.07 3.22 3.49
1.1 1.12 1.42 1.99 2.32 2.60 2.70 2.80 2.94 3.07 3.34
1.2 1.10 1.35 1.85 2.20 2.48 2.59 2.69 2.81 2.94 3.20 3.32 3.44
1.3 1.08 1.29 1.74 2.09 2.38 2.48 2.58 2.69 2.81 3.07 3.19 3.30 3.53
1.4 1.07 1.24 1.64 1.99 2.27 2.38 2.47 2.58 2.69 2.95 3.06 3.17 3.37 3.50 3.79
1.5 1.05 1.19 1.56 1.89 2.18 2.28 2.37 2.47 2.58 2.83 2.94 3.05 3.22 3.35 3.61
1.6 1.04 1.16 1.49 1.81 2.09 2.19 2.28 2.37 2.47 2.73 2.83 2.94 3.09 3.21 3.45 3.67 3.77
1.7 1.03 1.13 1.43 1.73 2.00 2.10 2.19 2.28 2.38 2.62 2.73 2.83 2.96 3.07 3.30 3.51 3.63
1.8 1.02 1.11 1.37 1.66 1.92 2.02 2.11 2.19 2.29 2.53 2.63 2.73 2.85 2.95 3.17 3.37 3.49
1.9 1.02 1.09 1.33 1.60 1.85 1.94 2.03 2.11 2.20 2.44 2.54 2.64 2.74 2.84 3.04 3.24 3.36
2 1.01 1.08 1.29 1.54 1.78 1.87 1.95 2.03 2.12 2.35 2.45 2.55 2.65 2.74 2.93 3.12 3.24
2.1 1.01 1.07 1.26 1.48 1.72 1.80 1.89 1.96 2.05 2.27 2.37 2.47 2.56 2.65 2.83 3.00 3.13
2.2 1.00 1.07 1.23 1.44 1.65 1.74 1.82 1.90 1.98 2.20 2.30 2.39 2.47 2.56 2.74 2.90 3.03
2.3 1.00 1.06 1.21 1.39 1.60 1.68 1.76 1.83 1.91 2.13 2.22 2.32 2.40 2.48 2.65 2.81 2.93
2.4 1.00 1.06 1.18 1.35 1.55 1.62 1.70 1.77 1.85 2.06 2.16 2.25 2.32 2.41 2.57 2.72 2.84
2.5 1.00 1.05 1.17 1.32 1.50 1.57 1.65 1.72 1.80 2.00 2.09 2.19 2.26 2.34 2.50 2.64 2.76
2.6 1.00 1.05 1.15 1.29 1.45 1.52 1.60 1.67 1.74 1.94 2.03 2.13 2.19 2.27 2.43 2.57 2.68
2.7 1.00 1.04 1.13 1.26 1.41 1.48 1.56 1.62 1.69 1.88 1.97 2.07 2.14 2.21 2.37 2.50 2.61
2.8 1.00 1.04 1.12 1.23 1.37 1.44 1.52 1.58 1.65 1.83 1.92 2.02 2.08 2.16 2.31 2.43 2.54
2.9 1.00 1.03 1.11 1.21 1.34 1.40 1.48 1.54 1.61 1.78 1.87 1.97 2.03 2.10 2.25 2.37 2.48
3 1.00 1.02 1.10 1.19 1.31 1.37 1.44 1.50 1.56 1.73 1.82 1.92 1.98 2.05 2.20 2.31 2.41
3.1 1.00 1.01 1.09 1.17 1.28 1.34 1.41 1.47 1.53 1.68 1.77 1.87 1.94 2.01 2.15 2.26 2.36
3.2 1.00 1.00 1.08 1.15 1.25 1.31 1.38 1.43 1.49 1.64 1.73 1.83 1.89 1.96 2.10 2.21 2.30
3.3 1.00 1.00 1.07 1.13 1.23 1.28 1.35 1.40 1.46 1.60 1.69 1.79 1.85 1.92 2.05 2.16 2.25
3.4 1.00 1.00 1.06 1.12 1.20 1.26 1.32 1.37 1.43 1.56 1.65 1.75 1.81 1.87 2.01 2.11 2.20
3.5 1.00 1.00 1.05 1.10 1.18 1.24 1.30 1.35 1.40 1.53 1.61 1.71 1.77 1.83 1.96 2.07 2.15
3.6 1.00 1.00 1.05 1.09 1.17 1.22 1.28 1.32 1.37 1.49 1.58 1.68 1.73 1.79 1.92 2.02 2.10
3.7 1.00 1.00 1.04 1.08 1.15 1.20 1.26 1.30 1.35 1.46 1.54 1.64 1.70 1.76 1.87 1.98 2.06
3.8 1.00 1.00 1.04 1.07 1.14 1.18 1.24 1.28 1.32 1.43 1.51 1.61 1.66 1.72 1.83 1.94 2.01
3.9 1.00 1.00 1.03 1.06 1.12 1.17 1.22 1.25 1.30 1.40 1.48 1.58 1.63 1.68 1.79 1.90 1.97
4 1.00 1.00 1.02 1.05 1.11 1.15 1.20 1.24 1.28 1.37 1.45 1.55 1.60 1.65 1.75 1.86 1.93
4.1 1.00 1.00 1.01 1.04 1.10 1.14 1.18 1.22 1.26 1.35 1.42 1.52 1.57 1.62 1.71 1.82 1.89
4.2 1.00 1.00 1.00 1.03 1.09 1.13 1.17 1.20 1.24 1.32 1.39 1.49 1.54 1.58 1.68 1.78 1.85
4.3 1.00 1.00 1.00 1.02 1.08 1.12 1.15 1.18 1.22 1.30 1.37 1.46 1.51 1.55 1.64 1.75 1.82
4.4 1.00 1.00 1.00 1.01 1.07 1.10 1.14 1.17 1.21 1.28 1.35 1.44 1.48 1.52 1.60 1.71 1.78
4.5 1.00 1.00 1.00 1.00 1.06 1.09 1.13 1.15 1.19 1.26 1.32 1.41 1.45 1.49 1.57 1.67 1.75
4.6 1.00 1.00 1.00 1.00 1.05 1.08 1.11 1.14 1.18 1.24 1.30 1.39 1.42 1.46 1.54 1.64 1.71
4.7 1.00 1.00 1.00 1.00 1.04 1.07 1.10 1.13 1.16 1.22 1.28 1.36 1.40 1.43 1.50 1.60 1.68
4.8 1.00 1.00 1.00 1.00 1.03 1.06 1.09 1.11 1.15 1.21 1.26 1.34 1.37 1.40 1.47 1.57 1.65
4.9 1.00 1.00 1.00 1.00 1.02 1.05 1.08 1.10 1.13 1.19 1.24 1.32 1.35 1.37 1.44 1.54 1.62
5 1.00 1.00 1.00 1.00 1.01 1.04 1.07 1.09 1.12 1.18 1.23 1.30 1.32 1.35 1.41 1.51 1.59
5.1 1.00 1.00 1.00 1.00 1.00 1.03 1.06 1.08 1.11 1.17 1.21 1.28 1.30 1.32 1.39 1.48 1.56
5.2 1.00 1.00 1.00 1.00 1.00 1.02 1.05 1.07 1.10 1.15 1.20 1.26 1.28 1.30 1.36 1.45 1.53
5.3 1.00 1.00 1.00 1.00 1.00 1.01 1.04 1.06 1.09 1.14 1.18 1.24 1.26 1.28 1.34 1.42 1.50
5.4 1.00 1.00 1.00 1.00 1.00 1.00 1.03 1.05 1.08 1.13 1.17 1.22 1.24 1.25 1.32 1.39 1.48
5.5 1.00 1.00 1.00 1.00 1.00 1.00 1.02 1.04 1.07 1.12 1.16 1.21 1.22 1.23 1.30 1.37 1.45
5.6 1.00 1.00 1.00 1.00 1.00 1.00 1.01 1.03 1.06 1.11 1.15 1.19 1.20 1.22 1.28 1.34 1.43
5.7 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.02 1.05 1.10 1.14 1.18 1.19 1.20 1.26 1.32 1.41
5.8 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.01 1.04 1.09 1.13 1.16 1.17 1.18 1.25 1.30 1.38
5.9 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.03 1.08 1.12 1.15 1.16 1.17 1.23 1.28 1.36
6 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.02 1.07 1.11 1.13 1.14 1.15 1.22 1.26 1.34
6.1 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.01 1.06 1.10 1.12 1.13 1.14 1.21 1.24 1.32
6.2 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.05 1.09 1.11 1.12 1.13 1.20 1.22 1.30
6.3 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.04 1.08 1.10 1.11 1.12 1.19 1.21 1.28
6.4 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.03 1.07 1.09 1.10 1.11 1.18 1.20 1.26
6.5 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.02 1.06 1.08 1.09 1.10 1.17 1.18 1.25
6.6 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.05 1.07 1.08 1.09 1.15 1.17 1.23
6.7 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.04 1.06 1.07 1.08 1.14 1.16 1.21
6.8 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.03 1.05 1.06 1.07 1.12 1.15 1.19
6.9 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.02 1.04 1.05 1.06 1.11 1.14 1.17
7 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.03 1.04 1.05 1.08 1.13 1.15
A255 − 20a
TABLE 3 Distance Hardness Dividing Factors for Non-Boron Steels, mm
Ideal
Jominy End-Quench Distance (mm)
Diameter
3579 11 13 15 20 25 30 35 40 45 50
(DI), mm
25 1.13 1.62 2.11 2.62 2.82 2.96 3.15 3.52
27.5 1.11 1.54 1.99 2.50 2.70 2.84 3.01 3.37
30 1.09 1.47 1.88 2.38 2.58 2.72 2.89 3.24 3.48
32.5 1.07 1.41 1.78 2.27 2.48 2.61 2.76 3.11 3.34 3.58
35 1.06 1.35 1.69 2.17 2.37 2.51 2.65 2.99 3.20 3.43
37.5 1.05 1.30 1.61 2.07 2.28 2.41 2.54 2.88 3.08 3.28 3.52
40 1.04 1.26 1.54 1.99 2.19 2.31 2.44 2.77 2.96 3.15 3.37 3.56
42.5 1.03 1.22 1.48 1.91 2.10 2.22 2.35 2.67 2.85 3.03 3.23 3.41 3.55
45 1.02 1.19 1.42 1.83 2.02 2.14 2.26 2.57 2.75 2.92 3.10 3.27 3.41 3.54
47.5 1.02 1.16 1.37 1.76 1.95 2.06 2.17 2.48 2.66 2.81 2.98 3.14 3.28 3.41
50 1.01 1.13 1.33 1.70 1.87 1.99 2.10 2.40 2.57 2.71 2.87 3.03 3.16 3.29
52.5 1.01 1.11 1.29 1.64 1.81 1.92 2.02 2.32 2.48 2.62 2.77 2.92 3.05 3.18
55 1.00 1.10 1.26 1.58 1.75 1.85 1.95 2.24 2.40 2.54 2.68 2.82 2.95 3.07
57.5 1.00 1.08 1.23 1.53 1.69 1.79 1.89 2.17 2.33 2.46 2.60 2.73 2.85 2.97
60 1.00 1.07 1.21 1.48 1.63 1.74 1.83 2.10 2.26 2.39 2.52 2.65 2.76 2.88
62.5 1.00 1.06 1.18 1.44 1.58 1.68 1.77 2.04 2.19 2.32 2.45 2.57 2.68 2.79
65 1.00 1.05 1.16 1.40 1.54 1.63 1.72 1.98 2.13 2.26 2.38 2.50 2.60 2.70
67.5 1.00 1.04 1.15 1.36 1.49 1.59 1.67 1.92 2.08 2.20 2.32 2.43 2.53 2.62
70 1.00 1.04 1.13 1.33 1.45 1.54 1.63 1.87 2.02 2.14 2.26 2.37 2.46 2.55
72.5 1.00 1.03 1.12 1.30 1.41 1.50 1.58 1.82 1.97 2.09 2.20 2.31 2.40 2.48
75 1.00 1.03 1.11 1.27 1.38 1.46 1.54 1.77 1.92 2.04 2.15 2.25 2.34 2.41
77.5 1.00 1.03 1.10 1.24 1.35 1.43 1.51 1.72 1.87 1.99 2.10 2.20 2.28 2.35
80 1.00 1.02 1.09 1.22 1.32 1.40 1.47 1.68 1.83 1.95 2.06 2.15 2.22 2.29
82.5 1.00 1.02 1.08 1.20 1.29 1.37 1.44 1.64 1.79 1.90 2.01 2.10 2.17 2.23
85 1.00 1.02 1.07 1.18 1.26 1.34 1.41 1.60 1.75 1.86 1.97 2.05 2.12 2.17
87.5 1.00 1.02 1.07 1.16 1.24 1.31 1.38 1.57 1.71 1.82 1.92 2.01 2.07 2.12
90 1.00 1.02 1.06 1.14 1.22 1.29 1.35 1.53 1.67 1.78 1.88 1.96 2.03 2.07
92.5 1.00 1.01 1.05 1.13 1.20 1.27 1.33 1.50 1.64 1.75 1.84 1.92 1.98 2.02
95 1.00 1.01 1.05 1.11 1.18 1.24 1.31 1.47 1.60 1.71 1.81 1.88 1.94 1.98
97.5 1.00 1.01 1.04 1.10 1.16 1.22 1.28 1.44 1.57 1.67 1.77 1.84 1.90 1.93
100 1.00 1.01 1.04 1.09 1.15 1.21 1.26 1.41 1.54 1.64 1.73 1.80 1.86 1.89
102.5 1.00 1.01 1.03 1.08 1.13 1.19 1.24 1.39 1.51 1.61 1.70 1.76 1.82 1.85
105 1.00 1.01 1.03 1.07 1.12 1.17 1.23 1.36 1.48 1.58 1.66 1.73 1.78 1.81
107.5 1.00 1.00 1.02 1.06 1.11 1.16 1.21 1.34 1.46 1.55 1.63 1.69 1.74 1.77
110 1.00 1.00 1.02 1.05 1.10 1.15 1.19 1.32 1.43 1.51 1.59 1.65 1.71 1.73
112.5 1.00 1.00 1.02 1.04 1.08 1.13 1.18 1.29 1.41 1.49 1.56 1.62 1.67 1.70
115 1.00 1.00 1.01 1.04 1.07 1.12 1.16 1.27 1.38 1.46 1.53 1.59 1.64 1.67
117.5 1.00 1.00 1.01 1.03 1.07 1.11 1.15 1.26 1.36 1.43 1.50 1.55 1.61 1.63
120 1.00 1.00 1.01 1.03 1.06 1.10 1.14 1.24 1.34 1.40 1.47 1.52 1.58 1.60
122.5 1.00 1.00 1.01 1.02 1.05 1.09 1.12 1.22 1.31 1.38 1.44 1.49 1.55 1.57
125 1.00 1.00 1.00 1.02 1.04 1.08 1.11 1.21 1.29 1.35 1.41 1.46 1.52 1.54
127.5 1.00 1.00 1.00 1.01 1.04 1.07 1.10 1.19 1.27 1.33 1.39 1.43 1.49 1.52
130 1.00 1.00 1.00 1.01 1.03 1.06 1.09 1.18 1.25 1.31 1.36 1.41 1.46 1.49
132.5 1.00 1.00 1.00 1.01 1.02 1.05 1.08 1.16 1.24 1.28 1.34 1.38 1.44 1.47
135 1.00 1.00 1.00 1.01 1.02 1.04 1.07 1.15 1.22 1.26 1.32 1.36 1.42 1.44
137.5 1.00 1.00 1.00 1.00 1.01 1.04 1.06 1.14 1.20 1.24 1.30 1.34 1.39 1.42
140 1.00 1.00 1.00 1.00 1.01 1.03 1.05 1.13 1.19 1.22 1.28 1.32 1.37 1.40
142.5 1.00 1.00 1.00 1.00 1.00 1.02 1.04 1.12 1.17 1.21 1.26 1.30 1.35 1.38
145 1.00 1.00 1.00 1.00 1.00 1.02 1.03 1.11 1.16 1.19 1.24 1.28 1.33 1.36
147.5 1.00 1.00 1.00 1.00 1.00 1.01 1.03 1.10 1.14 1.17 1.23 1.26 1.32 1.34
150 1.00 1.00 1.00 1.00 1.00 1.00 1.02 1.09 1.13 1.16 1.21 1.25 1.30 1.33
152.5 1.00 1.00 1.00 1.00 1.00 1.00 1.01 1.08 1.12 1.15 1.20 1.23 1.29 1.31
155 1.00 1.00 1.00 1.00 1.00 1.00 1.01 1.07 1.10 1.13 1.19 1.22 1.27 1.30
157.5 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.06 1.09 1.12 1.18 1.21 1.26 1.28
160 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.05 1.08 1.11 1.17 1.20 1.24 1.27
162.5 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.05 1.07 1.10 1.16 1.19 1.23 1.26
165 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.04 1.06 1.09 1.15 1.17 1.22 1.25
167.5 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.03 1.05 1.08 1.14 1.16 1.21 1.24
170 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.02 1.04 1.07 1.13 1.15 1.20 1.23
172.5 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.01 1.03 1.06 1.12 1.14 1.18 1.22
175 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.02 1.05 1.11 1.12 1.17 1.21
177.5 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.01 1.04 1.10 1.10 1.15 1.20
A255 − 20a
TABLE 4 Distance Hardness Dividing Factors for Boron Steels, in.
Ideal 1
Jominy End-Quench Distance ( ⁄16 in.)
Diameter
23456789 10 12 14 16 18 20 24 28 32
(DI), in.
1.5 1.10 1.14 1.88 2.52 2.91 3.23
1.6 1.08 1.12 1.65 2.20 2.70 3.02
1.7 1.07 1.10 1.47 1.95 2.50 2.82 2.99
1.8 1.06 1.09 1.34 1.74 2.31 2.63 2.83 3.00
1.9 1.05 1.08 1.25 1.58 2.13 2.45 2.67 2.84 3.08
2 1.04 1.07 1.19 1.46 1.97 2.28 2.51 2.68 2.88 3.33
2.1 1.03 1.06 1.14 1.36 1.83 2.12 2.36 2.53 2.70 3.15 3.69
2.2 1.02 1.05 1.11 1.29 1.70 1.98 2.21 2.38 2.53 2.98 3.48 3.86
2.3 1.02 1.04 1.09 1.24 1.58 1.84 2.08 2.24 2.38 2.82 3.29 3.65
2.4 1.02 1.04 1.08 1.20 1.48 1.72 1.95 2.11 2.24 2.67 3.11 3.45 3.63
2.5 1.01 1.03 1.07 1.17 1.40 1.61 1.83 1.99 2.12 2.54 2.95 3.27 3.45 3.62 4.05
2.6 1.00 1.03 1.06 1.15 1.32 1.52 1.72 1.87 2.00 2.41 2.79 3.09 3.28 3.46 3.86 4.23
2.7 1.00 1.03 1.05 1.14 1.26 1.43 1.62 1.77 1.90 2.29 2.65 2.93 3.12 3.30 3.67 4.00
2.8 1.00 1.02 1.05 1.13 1.21 1.36 1.53 1.67 1.80 2.18 2.52 2.78 2.97 3.15 3.50 3.78 4.27
2.9 1.00 1.01 1.04 1.12 1.17 1.30 1.44 1.59 1.72 2.08 2.40 2.65 2.83 3.01 3.34 3.59 4.01
3 1.00 1.00 1.04 1.11 1.13 1.25 1.37 1.51 1.64 1.99 2.29 2.52 2.70 2.88 3.19 3.41 3.78
3.1 1.00 1.00 1.03 1.10 1.11 1.20 1.31 1.44 1.57 1.90 2.19 2.40 2.57 2.75 3.04 3.25 3.57
3.2 1.00 1.00 1.03 1.09 1.09 1.17 1.26 1.38 1.50 1.82 2.09 2.29 2.46 2.63 2.91 3.10 3.39
3.3 1.00 1.00 1.02 1.08 1.08 1.14 1.21 1.33 1.45 1.75 2.01 2.19 2.35 2.51 2.78 2.97 3.22
3.4 1.00 1.00 1.02 1.07 1.07 1.11 1.17 1.28 1.40 1.68 1.93 2.10 2.25 2.40 2.66 2.84 3.07
3.5 1.00 1.00 1.01 1.06 1.06 1.10 1.14 1.24 1.35 1.62 1.85 2.01 2.16 2.30 2.55 2.73 2.94
3.6 1.00 1.00 1.00 1.05 1.06 1.08 1.12 1.21 1.31 1.56 1.78 1.93 2.07 2.21 2.45 2.63 2.82
3.7 1.00 1.00 1.00 1.04 1.06 1.08 1.10 1.18 1.27 1.51 1.72 1.86 1.99 2.12 2.35 2.53 2.71
3.8 1.00 1.00 1.00 1.04 1.06 1.07 1.09 1.16 1.24 1.46 1.66 1.80 1.92 2.04 2.26 2.44 2.61
3.9 1.00 1.00 1.00 1.03 1.05 1.06 1.08 1.14 1.21 1.42 1.60 1.74 1.85 1.96 2.18 2.36 2.52
4 1.00 1.00 1.00 1.02 1.05 1.06 1.07 1.13 1.19 1.38 1.55 1.68 1.79 1.89 2.11 2.29 2.44
4.1 1.00 1.00 1.00 1.02 1.05 1.06 1.07 1.12 1.17 1.35 1.50 1.63 1.73 1.82 2.03 2.22 2.37
4.2 1.00 1.00 1.00 1.01 1.04 1.06 1.06 1.11 1.15 1.31 1.46 1.58 1.68 1.76 1.97 2.15 2.30
4.3 1.00 1.00 1.00 1.01 1.03 1.05 1.06 1.10 1.13 1.28 1.42 1.54 1.63 1.71 1.91 2.09 2.23
4.4 1.00 1.00 1.00 1.01 1.03 1.05 1.06 1.09 1.11 1.25 1.38 1.50 1.58 1.66 1.85 2.03 2.17
4.5 1.00 1.00 1.00 1.00 1.02 1.04 1.06 1.09 1.10 1.23 1.35 1.47 1.54 1.61 1.80 1.98 2.11
4.6 1.00 1.00 1.00 1.00 1.01 1.04 1.06 1.08 1.09 1.21 1.32 1.43 1.51 1.57 1.75 1.93 2.06
4.7 1.00 1.00 1.00 1.00 1.01 1.03 1.05 1.08 1.08 1.19 1.29 1.40 1.47 1.53 1.71 1.88 2.01
4.8 1.00 1.00 1.00 1.00 1.01 1.03 1.05 1.07 1.07 1.17 1.26 1.37 1.44 1.50 1.67 1.83 1.96
4.9 1.00 1.00 1.00 1.00 1.02 1.02 1.04 1.06 1.06 1.15 1.24 1.35 1.41 1.47 1.63 1.79 1.91
5 1.00 1.00 1.00 1.00 1.00 1.02 1.04 1.06 1.06 1.14 1.21 1.32 1.38 1.44 1.59 1.75 1.87
5.1 1.00 1.00 1.00 1.00 1.00 1.02 1.03 1.05 1.05 1.12 1.19 1.30 1.36 1.41 1.56 1.71 1.82
5.2 1.00 1.00 1.00 1.00 1.00 1.02 1.02 1.04 1.05 1.11 1.17 1.28 1.33 1.39 1.52 1.67 1.78
5.3 1.00 1.00 1.00 1.00 1.00 1.00 1.02 1.03 1.04 1.10 1.16 1.26 1.31 1.36 1.49 1.64 1.74
5.4 1.00 1.00 1.00 1.00 1.00 1.00 1.01 1.03 1.04 1.09 1.14 1.24 1.29 1.34 1.46 1.60 1.70
5.5 1.00 1.00 1.00 1.00 1.00 1.00 1.01 1.02 1.04 1.08 1.13 1.22 1.27 1.32 1.44 1.57 1.67
5.6 1.00 1.00 1.00 1.00 1.00 1.00 1.01 1.02 1.03 1.07 1.12 1.20 1.25 1.30 1.41 1.54 1.63
5.7 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.02 1.03 1.06 1.11 1.19 1.23 1.28 1.38 1.51 1.60
5.8 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.02 1.02 1.05 1.10 1.17 1.22 1.26 1.36 1.48 1.56
5.9 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.02 1.04 1.09 1.16 1.20 1.24 1.33 1.46 1.53
6 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.01 1.04 1.08 1.14 1.18 1.23 1.31 1.43 1.50
6.1 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.01 1.03 1.07 1.13 1.17 1.21 1.28 1.41 1.47
6.2 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.02 1.07 1.12 1.15 1.19 1.26 1.38 1.44
6.3 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.02 1.06 1.10 1.14 1.17 1.23 1.35 1.41
6.4 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.01 1.05 1.09 1.12 1.15 1.21 1.33 1.38
6.5 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.01 1.04 1.08 1.11 1.13 1.18 1.30 1.35
6.6 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.03 1.07 1.09 1.12 1.16 1.27 1.32
6.7 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.02 1.06 1.08 1.10 1.14 1.25 1.29
6.8 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.01 1.05 1.07 1.08 1.11 1.21 1.25
6.9 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.05 1.06 1.07 1.09 1.18 1.21
7 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.04 1.05 1.05 1.07 1.14 1.17
A255 − 20a
TABLE 5 Distance Hardness Dividing Factors for Boron Steels, mm
Ideal
Jominy End-Quench Distance (mm)
Diameter
3579 11 13 15 20 25 30 35 40 45 50
(DI), mm
40 1.07 1.25 1.92 2.56
42.5 1.06 1.21 1.73 2.34
45 1.05 1.18 1.57 2.14 2.64
47.5 1.04 1.14 1.45 1.97 2.44
50 1.03 1.12 1.35 1.83 2.26 2.57
52.5 1.03 1.09 1.28 1.70 2.10 2.40
55 1.03 1.08 1.22 1.59 1.96 2.24 2.52
57.5 1.02 1.06 1.17 1.49 1.83 2.10 2.37
60 1.02 1.05 1.14 1.41 1.71 1.97 2.23
62.5 1.01 1.04 1.11 1.35 1.61 1.86 2.10
65 1.01 1.03 1.09 1.29 1.53 1.75 1.99 2.56
67.5 1.00 1.03 1.08 1.24 1.45 1.66 1.88 2.43
70 1.00 1.02 1.07 1.20 1.38 1.57 1.78 2.32
72.5 1.00 1.02 1.06 1.17 1.32 1.50 1.70 2.21
75 1.00 1.01 1.06 1.14 1.27 1.43 1.62 2.11 2.53
77.5 1.00 1.01 1.05 1.12 1.23 1.37 1.55 2.01 2.42 2.71
80 1.00 1.00 1.05 1.11 1.19 1.32 1.48 1.93 2.31 2.59 2.82
82.5 1.00 1.00 1.05 1.10 1.16 1.27 1.43 1.85 2.21 2.47 2.70 2.89 3.06 3.26
85 1.00 1.00 1.04 1.09 1.13 1.23 1.38 1.78 2.11 2.37 2.59 2.77 2.92 3.11
87.5 1.00 1.00 1.04 1.08 1.11 1.20 1.33 1.71 2.03 2.27 2.48 2.66 2.80 2.98
90 1.00 1.00 1.03 1.07 1.09 1.17 1.29 1.65 1.95 2.18 2.38 2.55 2.69 2.86
92.5 1.00 1.00 1.03 1.07 1.08 1.15 1.26 1.59 1.87 2.09 2.29 2.46 2.59 2.75
95 1.00 1.00 1.02 1.06 1.07 1.13 1.23 1.54 1.81 2.01 2.20 2.37 2.50 2.65
97.5 1.00 1.00 1.01 1.06 1.06 1.11 1.20 1.49 1.74 1.94 2.12 2.28 2.42 2.56
100 1.00 1.00 1.00 1.06 1.05 1.09 1.18 1.45 1.69 1.87 2.05 2.21 2.34 2.48
102.5 1.00 1.00 1.00 1.05 1.04 1.08 1.16 1.41 1.63 1.81 1.98 2.13 2.27 2.41
105 1.00 1.00 1.00 1.05 1.04 1.07 1.14 1.37 1.58 1.75 1.91 2.07 2.21 2.34
107.5 1.00 1.00 1.00 1.05 1.04 1.06 1.13 1.34 1.54 1.70 1.86 2.01 2.15 2.27
110 1.00 1.00 1.00 1.04 1.03 1.06 1.12 1.31 1.50 1.65 1.80 1.95 2.09 2.21
112.5 1.00 1.00 1.00 1.04 1.03 1.05 1.11 1.28 1.46 1.61 1.75 1.89 2.03 2.16
115 1.00 1.00 1.00 1.03 1.03 1.05 1.10 1.25 1.43 1.56 1.70 1.84 1.98 2.10
117.5 1.00 1.00 1.00 1.03 1.03 1.05 1.09 1.23 1.39 1.53 1.66 1.80 1.93 2.05
120 1.00 1.00 1.00 1.03 1.03 1.04 1.08 1.21 1.36 1.49 1.62 1.75 1.88 2.01
122.5 1.00 1.00 1.00 1.02 1.02 1.04 1.08 1.19 1.34 1.46 1.58 1.71 1.84 1.96
125 1.00 1.00 1.00 1.02 1.02 1.04 1.07 1.17 1.31 1.43 1.55 1.67 1.80 1.91
127.5 1.00 1.00 1.00 1.01 1.02 1.04 1.07 1.15 1.29 1.40 1.52 1.64 1.75 1.87
130 1.00 1.00 1.00 1.01 1.02 1.03 1.06 1.14 1.27 1.38 1.49 1.60 1.72 1.83
132.5 1.00 1.00 1.00 1.00 1.02 1.03 1.05 1.13 1.25 1.35 1.46 1.57 1.68 1.79
135 1.00 1.00 1.00 1.00 1.02 1.03 1.05 1.11 1.23 1.33 1.44 1.54 1.64 1.75
137.5 1.00 1.00 1.00 1.00 1.01 1.02 1.04 1.10 1.21 1.31 1.41 1.51 1.61 1.72
140 1.00 1.00 1.00 1.00 1.01 1.02 1.04 1.09 1.19 1.29 1.39 1.48 1.58 1.68
142.5 1.00 1.00 1.00 1.00 1.01 1.02 1.03 1.08 1.18 1.27 1.37 1.45 1.55 1.65
145 1.00 1.00 1.00 1.00 1.01 1.01 1.03 1.07 1.16 1.25 1.34 1.43 1.52 1.62
147.5 1.00 1.00 1.00 1.00 1.00 1.01 1.02 1.06 1.15 1.24 1.32 1.41 1.49 1.59
150 1.00 1.00 1.00 1.00 1.00 1.01 1.02 1.05 1.14 1.22 1.30 1.38 1.47 1.56
152.5 1.00 1.00 1.00 1.00 1.00 1.00 1.02 1.05 1.12 1.20 1.28 1.36 1.44 1.53
155 1.00 1.00 1.00 1.00 1.00 1.00 1.01 1.04 1.11 1.18 1.26 1.34 1.42 1.51
157.5 1.00 1.00 1.00 1.00 1.00 1.00 1.01 1.03 1.10 1.17 1.24 1.31 1.40 1.48
160 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.03 1.09 1.15 1.22 1.29 1.37 1.45
162.5 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.02 1.07 1.13 1.20 1.27 1.35 1.43
165 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.02 1.06 1.12 1.18 1.25 1.33 1.40
167.5 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.01 1.05 1.10 1.16 1.22 1.30 1.37
170 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.04 1.08 1.14 1.20 1.27 1.33
172.5 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.03 1.07 1.12 1.17 1.23 1.29
175 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.02 1.05 1.10 1.14 1.19 1.25
177.5 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.01 1.04 1.08 1.11 1.14 1.20
A255 − 20a
TABLE 6 Multiplying Factors, in.
Carbon-
%
Grain Mn Si Ni Cr Mo Cu V Zr
Alloy
Size 7
0.01 0.005 1.033 1.007 1.004 1.022 1.03 1.00 1.02 1.02
0.02 0.011 1.067 1.014 1.007 1.043 1.06 1.01 1.03 1.05
0.03 0.016 1.100 1.021 1.011 1.065 1.09 1.01 1.05 1.07
0.04 0.022 1.133 1.028 1.015 1.086 1.12 1.01 1.07 1.10
0.05 0.027 1.167 1.035 1.018 1.108 1.15 1.02 1.09 1.12
0.06 0.032 1.200 1.042 1.022 1.130 1.18 1.02 1.10 1.15
0.07 0.038 1.233 1.049 1.025 1.151 1.21 1.03 1.12 1.17
0.08 0.043 1.267 1.056 1.029 1.173 1.24 1.03 1.14 1.20
0.09 0.049 1.300 1.063 1.033 1.194 1.27 1.03 1.16 1.22
0.10 0.054 1.333 1.070 1.036 1.216 1.30 1.04 1.17 1.25
0.11 0.059 1.367 1.077 1.040 1.238 1.33 1.04 1.19 1.27
0.12 0.065 1.400 1.084 1.044 1.259 1.36 1.04 1.21 1.30
0.13 0.070 1.433 1.091 1.047 1.281 1.39 1.05 1.22 1.32
0.14 0.076 1.467 1.098 1.051 1.302 1.42 1.05 1.24 1.35
0.15 0.081 1.500 1.105 1.054 1.324 1.45 1.05 1.26 1.37
0.16 0.086 1.533 1.112 1.058 1.346 1.48 1.06 1.28 1.40
0.17 0.092 1.567 1.119 1.062 1.367 1.51 1.06 1.29 1.42
0.18 0.097 1.600 1.126 1.065 1.389 1.54 1.07 1.31 1.45
0.19 0.103 1.633 1.133 1.069 1.410 1.57 1.07 1.33 1.47
0.20 0.108 1.667 1.140 1.073 1.432 1.60 1.07 1.35 1.50
0.21 0.113 1.700 1.147 1.076 1.454 1.63 1.08 . . . 1.52
0.22 0.119 1.733 1.154 1.080 1.475 1.66 1.08 . . . 1.55
0.23 0.124 1.767 1.161 1.083 1.497 1.69 1.08 . . . 1.57
0.24 0.130 1.800 1.168 1.087 1.518 1.72 1.09 . . . 1.60
0.25 0.135 1.833 1.175 1.091 1.540 1.75 1.09 . . . 1.62
0.26 0.140 1.867 1.182 1.094 1.562 1.78 1.09 . . .
0.27 0.146 1.900 1.189 1.098 1.583 1.81 1.10 . . . . . .
0.28 0.151 1.933 1.196 1.102 1.605 1.84 1.10 . . . . . .
0.29 0.157 1.967 1.203 1.105 1.626 1.87 1.11 . . . . . .
0.30 0.162 2.000 1.210 1.109 1.648 1.90 1.11 . . . . . .
0.31 0.167 2.033 1.217 1.113 1.670 1.93 1.11 . . . . . .
0.32 0.173 2.067 1.224 1.117 1.691 1.96 1.12 . . . . . .
0.33 0.178 2.100 1.231 1.120 1.713 1.99 1.12 . . . . . .
0.34 0.184 2.133 1.238 1.123 1.734 2.02 1.12 . . . . . .
0.35 0.189 2.167 1.245 1.127 1.756 2.05 1.13 . . . . . .
0.36 0.194 2.200 1.252 1.131 1.778 2.08 1.13 . . . . . .
0.37 0.200 2.233 1.259 1.134 1.799 2.11 1.14 . . . . . .
0.38 0.205 2.267 1.266 1.138 1.821 2.14 1.14 . . . . . .
0.39 0.211 2.300 1.273 1.142 1.842 2.17 1.14 . . . . . .
0.40 0.214 2.333 1.280 1.145 1.864 2.20 1.15 . . . . . .
0.41 0.216 2.367 1.287 1.149 1.886 2.23 1.15 . . . . . .
0.42 0.218 2.400 1.294 1.152 1.907 2.26 1.15 . . . . . .
0.43 0.220 2.433 1.301 1.156 1.929 2.29 1.16 . . . . . .
0.44 0.223 2.467 1.308 1.160 1.950 2.32 1.16 . . . . . .
0.45 0.225 2.500 1.315 1.163 1.972 2.35 1.16 . . . . . .
0.46 0.228 2.533 1.322 1.167 1.994 2.38 1.17 . . . . . .
0.47 0.230 2.567 1.329 1.171 2.015 2.41 1.17 . . . . . .
0.48 0.233 2.600 1.336 1.174 2.037 2.44 1.18 . . . . . .
0.49 0.235 2.633 1.343 1.178 2.058 2.47 1.18 . . . . . .
0.50 0.238 2.667 1.350 1.182 2.080 2.50 1.18 . . . . . .
0.51 0.240 2.700 1.357 1.185 2.102 2.53 1.19 . . . . . .
0.52 0.243 2.733 1.364 1.189 2.123 2.56 1.19 . . . . . .
0.53 0.246 2.767 1.371 1.192 2.145 2.59 1.19 . . . . . .
0.54 0.249 2.800 1.378 1.196 2.166 2.62 1.20 . . . . . .
0.55 0.252 2.833 1.385 1.200 2.188 2.65 1.20 . . . . . .
0.56 0.253 2.867 1.392 1.203 2.210 . . . . . . . . . . . .
0.57 0.255 2.900 1.399 1.207 2.231 . . . . . . . . . . . .
0.58 0.258 2.933 1.406 1.211 2.253 . . . . . . . . . . . .
0.59 0.260 2.967 1.413 1.214 2.274 . . . . . . . . . . . .
0.60 0.262 3.000 1.420 1.218 2.296 . . . . . . . . . . . .
0.61 0.264 3.033 1.427 1.221 2.318 . . . . . . . . . . . .
0.62 0.267 3.067 1.434 1.225 2.339 . . . . . . . . . . . .
A255 − 20a
TABLE 6 Continued
Carbon-
%
Grain Mn Si Ni Cr Mo Cu V Zr
Alloy
Size 7
0.63 0.269 3.100 1.441 1.229 2.361 . . . . . . . . .
...