Transactions of Materials and Heat Treatment, Vol. 25, No. 5, 2004, pp486-493.

1

14th Congress of International Federation for Heat Treatment and Surface Engineering, October 26-28, 2004, Shanghai, China.

Preliminary Study to Identify Criterion for Quench Crack Prevention
by Computer Simulation
Kyozo Arimoto1, Fumiaki Ikuta2, Takashi Horino2, Shigeyuki Tamura3,
Michiharu Narazaki4, Yoshio Mikita5
1. Arimotech Ltd., Osaka, Japan
2. Neturen Co. Ltd., Kanagawa, Japan
3. CRC Solutions Corp., Tokyo, Japan
4. Utsunomiya University, Utsunomiya, Japan
5. MIKITA Professional Engineer Office, Tokushima, Japan
Abstract: A criterion for preventing quench cracks has not been established although much research has been conducted inthis field. A few predictions of cracking have been recently reported using simulated results of heat treatment processes.
However, these results were insufficient to predict crack generation clearly because the mechanism relates not only to stress
distributions in the parts but also to material characteristics. Systematic studies by the combination of experiment andsimulation are therefore required to reliably identify a criterion for crack prevention by computer simulation. As apreliminary work before starting the full-scale research, a review of quench cracking research was conducted and existing
test methods were classified. Several test results for cylindrical specimens were simulated for considering a cause of thecrack generation. Lastly a tentative plan was made for the future research.
Key words: Quench Cracking, Heat Treatment Simulation

A CRITERION for preventing quench cracks has notbeen established although many investigations havebeen conducted for this purpose. Some studies on thequench cracking were reviewed in the texts [1, 2].
Some researchers have indicated that tensile stresses
may contribute to quench crack generation. Recently
heat treatment simulation [3, 4] has showed evidence of
this contribution. However, these results wereinsufficient to predict crack generation clearly because
the complex mechanism relates not only to stress
distribution in the parts but also to material
characteristics.
Systematic studies combining experiment andsimulation are therefore required to explain themechanism of crack generation and to provide a strict
criterion of crack prevention by computer simulation.
This full-scale research will take a long period of time
because of many comparisons for different shaped
specimens, steels, heat treatment conditions, etc. A
preliminary work is therefore appropriate to identify
the course of the full-scale research.
A review of research on quench cracking was
conducted and existing test methods were classified inthis work. Several experimental results from literature
were simulated for considering the causes of crack
generation. Lastly a tentative plan was made for future
research.

1. Review of Research on Quench Cracking
The research on the quench cracking has beenreviewed in various texts [1, 2]. However, additional
searching of the literature may be necessary. Selectedmajor research works on quench cracking have been
identified and outlined in chronological order. The
study by Scott [5] in 1925 will be introduced first,
because this would be the first investigation of cracking
by experimental and theoretical techniques.
Scott examined the influences of different diametersand quenchants on quench cracking using cylindrical
tool steel specimens, 4 in. (102 mm) length. He
reported that cracks occurred on oil-quenchedspecimens between 3/4 in. (19 mm) and 1.5 in. (38mm) diameter, and on water quenched specimens
between 1/4 in. (6.4 mm) and 1/2 in. (12.7 mm).
Distributions of axial residual stress were measured by
the Heyn method [6] and calculated by an analyticaltechnique. From these results, Scott concluded thatcracks in steel are due to tensile stresses produced on
the surface.
Buhler and Scheil [7] noted quench cracking related
to their stress measurement of the quenched Ni steel
cylinder, 50 mm diameter and 350 mm length. A
longitudinal crack was observed on the specimen thatwas cooled initially in a furnace until the temperature
decreased to 360°C and then quenched in ice water.
They measured the circumferential stress distribution
by the Sachs method [8] and identified a tensile stressregion below the surface of the specimen quenchedunder the same condition as the above but without
cracking.
Nishikiori and Iwaki [9] reported experimental
results of quench cracking on tungsten steel cylinders,
13 mm diameter and 100 mm long, in 1936. In the steel,containing 0.84% C, 0.3% Cr, 2.28% W and 0.28% V,
cracks occurred after quenching in water and oil,2

except for the 10% brine quenching. Tests usingtungsten steel specimens with different chemicalcompositions showed that the quenching by oil andbrine affects crack generation depending on the steel
alloy.
Udy and Barnett [10] performed quench cracking
experiments using cylinders, 1 in. (25.4 mm) diameterand 2 in. (50.8 mm) length for testing 120 steels in
1947. Notches, 1/16 in. (1.6 mm) wide, were sawed on
both end-faces of a cylinder. The depth of notch varied
from 1/8 in. (3.2 mm) to 7/8 in. (22.2 mm), in
increments 1/8 in. (3.2 mm). The quench cracking
index, I’=8-n, was proposed, where n denotes theminimum notch depth, in 1/8 in. unit, of the specimen
to generate cracks due to flowing water quenching. The
tendency was found out that steels with lower Ms havehigher crack susceptibility.
Wells et al [11] reported quench cracking tests using
notched hollow disks in 1950. The steel specimens
were approximately the same as 4335 steel. The
dimension was 6.5 in. (165 mm) outside diameter, 2.75
in. (70 mm) inside diameter and 0.5 in. (13 mm) thick.
The notch located close to the inner curved surface ofthe disk and its depth varied from 1/16 in. (1.6 mm) to
8/16 in. (12.7 mm) in increments 1/16 in. (1.6 mm).
The measured minimum notch depth to crack by water
spray quenching in 1/16 in. unit was specified as the“crack susceptibility index”. Using the same
experimental equipment and specimens as in the
research by Wells et al., Spretnak and Busby [12]investigated the effect of the pre-bore quench to quench
crack generation. The bore lead times of 10 to 20 s
suppressed to generate cracks at both the inside andouter surface.
Chapman and Jominy [13] devised the disk specimen
with an eccentric hole to evaluate the cracksusceptibility of steels in oil or salt bath quenching.
V-notches were provided on both the inside and outersurface at the thinnest section of the hole for easy
generation of cracks. From the results of their tests, theeffects of the austenitizing temperature, Ms, the amountof carbon and the ideal critical diameter were reported.
Isomura and Sato [14] quenched tool steel specimens,
18 mm diameter and 100 mm long, by water, andreported that the higher generation rate of quench
cracking was exhibited in steels with higher
austenitizing temperature and carbon content in 1961. It
was reported that quenching cracks occurred on bearing
steel cylinders, 18 mm diameter, with water quenchingafter 1 hr heating at 1000°C, while they were not foundin oil quenching after 1 hr heating at 1100°C on thesame specimens. In addition, although cracks on thesame bearing steel specimens were not observed inwater quenching after 1hr heating at 900°C, theyoccurred by water quenching after oil quenching for 5
to 20 s.
Isomura and Sato [14] considered the origin ofquench cracks to be the maximum point of tensilestress in their specimen, because the circumferential
stress distributions measured by the Sachs method [8]depicted higher compression stress on the surface and atensile stress peak below the surface.
Melloy [15] proposed a quench cracking test using
the end-quench test specimen in his report in 1965. A
transverse crack along the austenite - martensite
interface was generated by brine quenching after
end-quenching for a given period of time. This
interface might be intended to serve as themetallurgical notch from his consideration.
Shimoda [16] considered a cause of quench cracks infull-size rolls using stress distributions by an analyticaltechnique and measurements by the Sachs method [8].
He described the transverse crack generation in the rolloccurred at the point, where the maximum tensile stress
was produced in the pearlite region, from observing afracture section. The same explanation on the crack was
carried out by Melloy[15]. Also Shimoda and Melloy
identified the influence of residual hydrogen content on
the crack in the roll.
Toshioka et al. [17] calculated peaks of axial andcircumferential stresses at just below the surface andthe center of a Cr-Mo steel roll that was imperfectly
hardened by using an analytical technique. They also
observed quench crack generation from a point justbelow the surface of a Cr-Mo forged steel roll, 400 mm
in diameter, quenched in water from 850°C. They
reported that cracks occur when plastic deformation
cannot absorb the stress generation.
Kunitake and Sugisawa [18] performed quench
cracking tests of ring specimens by spray cooling, andexamined crack susceptibility based on “equivalentcarbon”. The size of their ring specimen was 75 mm
outer diameter, 35 mm inner diameter and 10 mmheight. Materials of the specimens were Mn steels andNi-Cr-Mo steels with various compositions. Elements,
Al, Nb and B were also added to the Mn steel
specimens for evaluating their effects. They reported
that the higher degree of purity of steels is effective indecreasing the crack generation rate.
Mikita et al. [19] conducted tests for tool steel
specimens, diameters from 10 to 40 mm andaustenitizing temperatures from 750°C to 950°C, by
quenching in ice water. They reported that only the 25
mm cylinder generated a longitudinal crack whenaustenitized at 900 and 950°C. In addition, when anannular V-type notch was machined on the central partof the cylinders and the austenitizing temperature was
set to 900°C or greater, a longitudinal crack occurred in
all the specimens.

3

Mikita et al. [20] investigated different crack types
by drilling a large hole in a cylindrical test specimen,
25 mm in diameter and 25 mm long, to create a thinring, 25 mm outer diameter, 5 mm width, and 1 mm
thick, on the one end of the cylinder. This type of
specimen was prepared by Chapman and Jominy [13]for their study. Mikita et al. reported that quenchingcracks occurred at the root of the ring or on the cylindersurface, or at both positions, depending on
concentrations and agitation conditions of polymer
quenchants.
Narazaki et al. [21] performed quench cracking tests
using disk specimens made from two steels, a carbon
steel and a tool steel, with an eccentric hole. Theyvaried water cooling conditions, surface roughness andsurface texture and then investigated these influenceson crack generation. The specimen in this test was
originally shown in the report by Chapman and Jominy[13] and was used for the experiments conducted on
quench cracking under the Japan Society for Heat
Treatment [22].

and then they created the new “effective carbon
content” for this purpose.
It is useful to make the following classification of thespecimens according to the dimension of geometricmodels for simulation.
(1) one-dimensional models: for a center part ofcylinder.
(2) two-dimensional models: for a cylinder，a steppedcylinder with 2 different diameters, a cylinder with athin ring, a disk, a ring, etc.
(3) three-dimensional models: for a disk with an
eccentric hole, a notched-cylinder, a notched-disk, anotched-ring, etc.
In quenching a cylinder with a sufficient length, itscenter part can be treated as a one-dimensional model
having only the radial variable for observing thephenomenon in the section. However a twodimensional model is needed for examining the cracks
at the edges of the cylinder. One or two-dimensionalmodels are recommended for case studies because ofrestrictions of the calculation time.

2. Classification of Quench Cracking Tests

3. Quench Cracking Simulation

Various quench cracking tests described in theformer review section can be classified into thefollowing two categories according to their purposes.
(1) For investigating a cause of cracking
Tests for investigating a cause of quenching cracks
are fundamentally focused on the relation between
stress distributions and crack generations. Hence
simple shapes like a cylinder have been chosen as a
specimen for easily estimating a stress distribution in
many cases. Generally types of steels, diameters ofcylinders,austenitizing
temperatures,coolingcharacteristics of quenchants, etc. are varied forstudying their contribution to crack generation i.e.
stress distributions. The tests by Scott [5], BuhlerScheil [7], Nishikiori-Iwaki [9], Isomura-Sato. [14],Shimoda [16], Toshioka et al. [17] and Mikita et al.
[19] can be classified into this type of experiment.
(2) For determining crack susceptibility
The crack susceptibility of steels alloys,
characteristics of quenchants, etc. may be needed forpractical reasons. Tests to address the susceptibility ofsteels to cracking were devised by Udy-Barnett [10]and Wells et al. [11] as described before. The minimum
depth of the notch when cracking was adopted as a“crack susceptibility index”. The experiments by
Chapman et al. [13] and Kunitake et al. [18] also
estimate the crack susceptibility of steels although they
do not report a value such as the crack susceptibility
index. The limitation of the crack generation was
obtained from their test for carbon content in steels, Ms,
quench hardenability, etc. Kunitake et al. [18]examined the value, which shows the limitation clearly,

The heat treatment simulation is useful for predicting
the metallic phases, temperatures, stresses, strains anddistortions during the processes. Since many
researchers have indicated that stress distributions
contribute to quench cracking, simulated stresses may
be utilized for predicting its generation.
Here, a simulation was applied to the several
successful cracking tests of cylinders for investigating a
cause of their generation. Tendencies of cracking
phenomena in the tests were explained using thesimulated results. For the more complex shape than acylinder, the works by Arimoto et al. [3, 4] was used forconsidering the origin of cracks.
3.1 Cylindrical Specimens
Software used for the simulation of cylindrical
specimens was verified by comparing experimental andsimulated stress distributions in quenched cylinders by
the procedures shown in the report by Arimoto et al.
[23]. The effect of transformation plasticity to stress
distribution was examined carefully according to thestudies by Denis et al. [24] and Rammerstorfer et al.
[25].
One-dimensional axisymmetric elements wereapplied to describe the phenomenon in the center partof the cylinder. The heat transfer coefficient on thesurface during quenching was estimated using coolingcurves of silver probe by the method proposed by
Narazaki et al. [26]. Material data and heat transfer
coefficients set for these simulations were not so strict
because these were just for the preliminary studies.

4

Table 1 Composition (mass %) of Tool Steel
Steel
SK6
SK5
SK4
SK3

C
0.73
0.82
0.94
1.05

Si
0.31
0.30
0.21
0.24

Mn
0.34
0.41
0.44
0.38

P
0.013
0.013
0.017
0.021

S
0.015
0.016
0.021
0.016

Ms(C)
248
215
174
136

Stress, MPa

Isomura and Sato [14] performed the quench
cracking test using cylindrical specimens made fromfour carbon tool steels of the Japanese standard, SK3,
SK4, SK5, and SK6. Chemical compositions of thesteels are given in Table 1. The specimens, 18mm
diameter and 100mm long, were quenched into water
after 30 minutes heating at 900, 950 or 1000°C. Eachtest was conducted five times under the same condition.
Table 2 shows the results of their cracking tests. For
example, only the SK6 steel specimen did not generate
quenching cracks when austenitizing at 1000°C.
The simulation was applied to the tests using thespecimens made from all types of steels, however, only
1000°C was selected for the austenitizing temperature.
In this simulation, thermal properties of steels werereproduced from the data by BISRA [27]. Mechanicalproperties of steel were derived from data of the steels
having similar compositions. Ms of the steels wascalculated by the empirical equation by Kunitake et al.
[28] as shown in Table 1. The kinetics of martensitic
transformation was described by the KoistinenMarburger equation [29].
The simulated circumferential stress distributions
after quenching are shown in Fig. 1. For thecomparison, the measured circumferential residual
stress for the SK6 steel cylinder quenched from 1000°C
by Isomura and Sato [14] are indicated by the dottedlines as shown in Fig. 1. Tendencies of the stress
distributions in the SK6 steel specimen by

SK6

SK5

SK4

SK3

Simulated
Measured1

2

3

Austenitizing
Temp. (C)
900
950
1000

SK6

SK5

SK4

○
○
○

○
○

○

▲

SK3

▲

▲
▲

x

x

○:No cracked, ▲: Partly cracked, x: All cracked

3.1.1 Effect of Steel Alloys

300
200
100
0
-100
-200
-300
-400
-500
0

Table 2 Results of Quench Cracking Test for Tool
Steel Specimens

4 5 6
Radius, mm

78measurement and simulation agree well, because theyshow compression stress in the core, a tensile stresspeak below the surface and compression stress on thesurface. Figure 1 also shows the trend that the tensilestress peak moves to the surface and decreases its
amount when the steel having the higher carbon
content.
Isomura and Sato reported that the SK4 steel
specimen quenched from 900°C generated alongitudinal crack after removing the surface layer of
0.5 to 0.8 mm by acid corrosion. From their stressmeasurements, they reported that crack generation inthis test originated in the tensile stress peak induced
just below the surface. However they also reported thatcracks can also initiate on the surface when producing
the enough tensile stress to be cracked there.
The tests by Isomura and Sato [14] showed thathigher cracking susceptibility is found in the specimens
quenched from the higher austenitizing temperature asshown in Table 2. They considered that this crack
generation tendency is due to the lower toughness ofthe martensite produced from the higher temperature
austenite according to the Iijima’s work. Iijima [30, 31]
reported the effect of austenitizing temperature to thetoughness of martensite from the measured results by
the static torsion test.
3.1.2 Effect of Cooling Characteristics
Isomura and Sato [14] quenched cylindrical
specimens, 18 mm diameter and 100 mm long, madefrom the bearing steel, Japanese standard SUJ2, under
the different cooling conditions. Table 3 shows thechemical composition of the SUJ2 steel of their
specimens. They reported that a crack occurred in waterquenching after 1 hr heating at 1000°C, while crack
generation was not found in oil quenching after 1 hrheating at 1100°C. In addition, although a crack on thesame bearing steel specimens was not observed inwater quenching after 1hr heating at 900°C, it occurredin water quenching after oil quenching for 5 to 20 s.
Table 4 describes the results of cracking tests when

9

Fig. 1 Circumferential Stress Distribution in SK Tool
Steel Specimens

Table 3 Composition (mass %) of Bearing Steel
Steel
SUJ2

C
0.98

Si
0.30

Mn
0.36

P
0.012

S
0.006

Cr
1.39

5

Table 4 Results of Quench Cracking Test for
Bearing Steel Specimens
Water
quenching

Oil cooling period (s)
10
15
20
30

5

○
○
○

○

○

x
x

x
x
x

x
x

○

60

○
○
○

x
x

○
○
○

○:No cracked, x: cracked
austenitizing at 900°C for each different coolingcondition. Three rows in the table mean that each test
carried out three times under the same condition. For
examples, the table explains all three specimens
cracked in water quenching after 15 s period of oil
cooling.
Figure 2 shows the simulated distributions ofcircumferential residual stress for the different coolingconditions after 1 hr heating at 900°C. The tendenciesof the stress distributions after water and oil quenching
agree with experimental results austenitized at 850°C
reported by Isomura et al. [14]. The highest tensilestress was calculated on the surface in the condition
combined by oil quenching for 30 s and waterquenching, although there were no cracks in the tests asshown in Table 4. However cases of oil quenching for
10 to 35 s show the higher tensile stress on the surface
than that of only water or oil quenching.
Buhler and Scheil [7] observed a crack by the similar
combined cooling condition, initially cooled in furnaceand then quenched in water, as mentioned in the former
review section. Their measured stress distributions
showed the tensile stress on the surface.
In this simulation, Ms data was based on the study by
Grange and Stewart [32]. Their measured curves on themartensite formation in the 52100 bearing steel can beused to define that Ms for austenitizing at 843 and
1066°C is 241 and 115°C, respectively for use as aparameter of the Koistinen-Marburger’s equation [29].

Stress, MPa

300
200

Simulated(austenitized at 900C)
Measured(austenitized at 850C)

5s

35s

200
150

0

-100
-300
0

10s
40s

Oil

-200
2

3

4 5 6
Radius, mm

7

25 dia.
20 dia.

100
50

30 dia.

40 dia.

10 dia.

0-5050s, 60s and oil

1

Mikita et al. [19] performed tests for examining theeffect of specimen size to quench crack generation.
Cylindrical specimens were made from the Japanesestandard SKS3 steel, containing 0.98%C, 0.8%Cr. and
0.7%W. Their diameters varied from 10 to 40 mm in 5
mm increments and their length was 4 times eachdiameter. The specimens were quenched in ice water
after heating in a furnace and preventing oxidizationand decarburization. They reported that only the 25 mm
cylinder produced a longitudinal crack whenaustenitized at 900 and 950°C, in once per five tests
under the same conditions.
For the simulation, thermal, mechanical andtransformation properties were derived by the sameprocedure of the SK steels, except Ms, 153°C, wasreferenced from the TTT diagram of 105 WCr 6 steel inthe data book compiled by Max-Planck-Institute [34].
Figure 3 shows the circumferential residual stress
distributions obtained from the simulation for thedifferent diameter specimens quenched from 900°C.
The peak of tensile stress on or below the surface of thespecimens increases in the larger diameter specimen.
However, a very narrow region of decreasing stressappeared below the surface of the specimen greater

30s
15s 20s

Water

100

3.1.3 Effect of Specimen SizeStress, MPa400

Ms for austenitizing at 900°C was set at 209°C byinterpolating the above two values for this simulation.
Grange and Stewart considered that the difference ofMs was due to the austenitizing temperature caused by
the influence of undissolved carbide content in theaustenite. The same phenomenon regarding Ms wasreported by Harris and Cohen [33]. This kind of effectmay also occur in the SK steels. Hence the estimatedMs values for the SK steels by the empirical equation
should be used keeping this fact in mind. It is also
known that Ms affects stress distributions from thesimulated results by Arimoto et al [23].

89Fig. 2 Circumferential Stress Distribution in SUJ2
Bearing Steel Specimens

-100
0

5

10
Radius, mm

1520Fig. 3 Simulated Circumferential Stress Distribution in
SKS3 Tool Steel Specimens

6

than 30 mm in diameter.
The above-simulated results may be not enough to
explain the reason why cracks occur in the limited
diameter of the specimen. This should not be concluded
without measuring the stress distribution. The similartendency of the diameter effect shown in Fig. 3 wasfound in the measured residual stress distributions in
1.1%C steel cylinders, 5, 7 and 9 mm in diameter,
water quenched from 900°C by Fujisawa [35]. His 7
and 9 mm diameter specimen showed the decreasingstress range below the surface, although the range was
not observed in the 5 mm diameter case.
Mikita et al. reported only the 25mm diameter
specimen generated a crack. However Scott [5]mentioned that cracks occurred in the diameter range
between 1/4 in. (6.4 mm) and 1/2 in. (12.7 mm) of thecylinders, made from tool steel containing 0.9%C,
1.2%Mn, 0.2%Si, 0.5%Cr and 0.5%W, by waterquenching from 850°C.
3.2 Complex Shape Specimens
Cylindrical specimens have been used for the studies
on the cause of the quench cracking for many years,
because only their stress distributions can be measured.
However, quench cracks occurring in more complicatedshapes may be caused by another situation. For
considering this kind of crack, simulated results for a
stepped cylinder and a disk with an eccentric hole wereused.
A quench crack on the stepped cylindrical specimen
made from the 2%Cr steel was observed by Inoue at al.
[36], and its generation was simulation by Arimoto et al.
[3]. This specimen had a step by combining two
cylinders, 100 mm and 50 mm in diameter, and 100
mm and 20 mm length, respectively. A circumferential
crack occurred on the middle of the step surface of thespecimen during water quenching from 1200°C.
Simulated results showed that a concentration of theradial tensile stress distribution occurred on the step
surface near the cracked location at 150 s after starting
the quench. It was also clear from simulated results thatthe martensite was almost transformed in this position.
The quench cracking of the disk with an eccentric
hole was simulated by Arimoto et al. [4]. This
simulated disk test was selected from the research by
Narazaki et al. [21]. The disk made from Japanese SK4tool steel, 30 mm in diameter and 10 mm thick,contained an eccentrically located 10 mm diameter holeat 8 mm distance from the center. Quench cracks
occurred near the hole of the disk at 4 s after starting
the quench. A concentration of the tensile stress
distribution of the maximum principle stresses wasappeared at the position where a crack generated and at
the time of its initiation in the simulated results. It wasalso observed that martensitic transformation wasalmost completed in the cracked location.
The above two examples may be typical case of thequench cracking in more complex shape when it occurs
during cooling. The origin of these cracks may be froma high tensile stress concentration on the surface of thepart transformed to the martensite due to the thermal
contraction and/or transformation expansion duringcooling. The position, which induced a concentration oftensile stress in the complicated shapes, depends on the
shape of the work and the distribution of thermal,transformational, plastic and transformation plasticstrains. It may be different from that when simple outerloads are applied to the part.
Other simulated results on the quench cracking incomplicated shapes have not been found by the authors.
In the notched simple shape specimens tested by Udy etal. [10] and Wells et al. [11], the stress distribution near
the notch may contribute to the crack generation fromthe experimental results. However, under the current
simulation environment, it is thought that the casestudies for the notched specimens require too muchtime.

4. Quench Crack Prevention by Computer
Simulation
The simulation technique is expected for preventing
the quenching cracks, while the conventional
experimental methods are still used for the practicalcases. As already stated, this technique is to predict
crack generation using the simulated stress. Here, thesubject for the utilization of the quench crack
prevention by computer simulation is summarized.
4.1 Quench Crack Tests for Verifying the Simulation
The simulation of quench cracking is still in the
beginning stage. Its potential is evaluated byapplication to several problems. Detailed comparisonswith experimental and simulated results are needed forverifying the simulation technique. Although the pastexperiments for investigating the cause of cracks may
be meaningful, these were not conducted in a positionof the comparison with the simulation. Hence thereported data is not sufficient for verification, and thesetests should be performed again. The following
cracking tests serve as candidates of re-examinations.
(1) A longitudinal crack on the cylinder
Conditions of the crack generation in the tests using
cylindrical specimen are comparatively clear. For
example, there are tests by Isomura-Sato [14], Mikita etal. [19], Nishikiori-Iwaki [9], Scott [5], etc.
(2) A circumferential crack on the step surface ofthe stepped cylinderThis type of crack occurs in the stepped specimen
during cooling [36]. The circumferential crack on the7step surface may be easier to examine by the twodimensional simulation.
(3) A transverse crack in the one-end quench
specimen
This transverse crack was observed by Melloy [15].
Since this cracking test has high reproducibility and its
fracture surface is simple, the test results may be usefulfor making a criterion of the crack generation.
It is recommended that other tests using more
complicated shape specimens should be tried after theabove three examinations because of their complexity.
In the test, the following points take into account forderiving precise measurements.
(1) Contents of the specimen material are analyzed
strictly. The characteristics data for the simulation likeTTT diagram, Ms, stress-strain relations, etc. iscollected by the tests.
(2) Cooling curves at the several points in thespecimen are measured by thermocouples. They are
utilized for predicting heat transfer coefficients along
the surfaces of the specimen for the simulation [26].
(3) For the specimens without cracks after quenching,
the measurement of stresses and distortions arerecommended for verifying the simulation. The Heyn
method [6] and Sachs method [8] can be applied for the
stress measurement in cylinders, while the X-ray
method and the neutron method [37] are useful for
more complicated specimens.
(4) For the specimens with cracks after quenching,fracture surfaces are examined by the fractography for
determining a beginning point of cracks.
(5) A crack generation time is measured during
quenching for comparing the time of inducing a
concentration of the tensile stress in a specimen bysimulation. There are examples which detected thegeneration time by the measurement of sound or
vibration [19].

of this destruction. For example, there are degrees ofsteel purity, surface notches, nonmetallic inclusions,segregations, metallurgical notches, etc.
(3) For cracks which occurred in the middle of thequenching, the thermal shock characteristics of loads,
i.e., the rate of stress changes, and distribution patternsof the stress concentrations might be considered for theevaluation.

5. Conclusions
Considerable research on quench cracking has been
performed to obtain a thorough and correctunderstanding of this phenomenon and its prevention.
In this study, preliminary work for establishing acriterion of crack prevention by heat treatment
simulation was conducted resulting in the following
conclusions:(1) The prediction of the stress state at the time of thequench crack generation is possible by simulation,although a few examples are found.
(2) For the present, it is necessary to increase theapplications of quench crack predictions by acomparison between repeated experiments of thesuccessful tests and their simulated results.
(3) Since much work is needed for establishing acriterion of quench crack prevention, a systematic
full-scale research program will be required.
The thermal process simulator, FINAS/TPS,
developed by CRC Solutions Corp., was used for thesimulation in this study.
References
12

4.2 Criterion of Quench Crack Prevention
If the stresses in quenched works are found with
sufficient accuracy during processes by simulation, aproblem comes out for judging quench crack
generation from the simulated results. Our goal is toestablish a criterion what types of stress states canprevent the quench crack generation in a certain steel
product. It is thought that the following items are
required for the work.
(1) The measurements of strength and toughness inmartensitic phase are needed for the practical steels.
For example, we have such kind of data, torsion
strength, plastic torsion angle and absorbed energy,
were derived from the static torsion test for several
carbon steels and low alloy steels by Iijima [30, 31].
(2) Since the quench cracking is a brittle fracture
phenomenon, it is necessary to examine characteristics

3

4

5
6
7

Totten G E, Bates C E and Clinton N A. Handbook ofQuenchants and Quenching Technology. 1993, Materials
Park: ASM International, 441-494.
Narazaki M, Totten G E and Webster G E. Hardening by
Reheating and Quenching. In Totten G E, Howes M andInoue T, Eds. Handbook of Residual Stress and Deformationof Steel. 2001, Materials Park: ASM International, 248-295.
Arimoto K, Li G, Arvind A, and Wu W T. The Modeling ofHeat Treating Process. In Wallis R A and Walton H W, Eds.
Proceedings of the 18th Heat Treating Conference.
Rosemont: ASM International, 1998, 23-30.
Arimoto K., Lambert D, Lee K, Wu W T and Narazaki M.
Prediction of Quench Cracking by Computer Simulation.
Midea S J and Paffmann G D Eds. Proceedings of the 19th
Heat Treating Conference, Cincinnati: ASM International,
1999, 435-440.
Scott H. Origin of Quenching Cracks. Scientific Papers of
the Bureau of Standards, 1925, 513, Sep.: 399-444.
Heyn E. Internal Strains in Cold-Wrought Metals, and Some
Troubles Caused Thereby. J. Inst. Metal., 1914, 12: 3-37.
Buhler H and Scheil E. Combined Effect of Thermal andTransformation Stresses in Quenched Steel. Arch.

8

8

9

10

11

12
13

14

15

16
17

18

19

20

21

22
23

24

25

Eisenhutten., 1933, 6(7): 283-288. (in German)
Sachs G. The Determination of Residual Stresses in Rods
and Tubes. Z. Metallkunde, 1927, 19(9): 352-357. (inGerman)Nishikiori K and Iwaki T. Origin of Quench Cracks in
Tungsten Steels and Their Prevention. Tetsu-to-Hagane,
1936, 22(10): 786-791. (in Japanese)
Udy M C and Barnett M K. A Laboratory Study of Quench
Cracking in Cast Alloy Steels. Trans. ASM, 1947, 38:
471-487.
Wells C, Sawyer C F, Broverman I and Mehl R F. A Quench
Cracking Susceptibility Test for Hollow Cylinders. Trans.
ASM, 1950, 42: 206-232.
Spretnak J W and Busby C C. Pre-Bore Quench for Hollow
Cylinders. Trans. ASM, 1950, 42: 270-282.
Chapman R D and Jominy W E. A Test for Measuring
Quench Crack Sensitivity of Engineering Alloy Steels.
Metal Progress, 1953, Sep.: 67-72.
Isomura R and Sato H. On Quench-Cracking Phenomena as
Viewed from the Aspect of Quenching Stresses. J. Japan
Inst. Metals，1961, 25(5): 360-364. (in Japanese)
Melloy G F. Development of an Improved Forged
Hardened-Steel Roll Composition. Iron and Steel Engineer,
1965, May: 117-126.
Shimoda S. Quench Cracking. Netsu-shori，1965, 5(3):166-174. (in Japanese)
Toshioka T, Fukagawa M and Saiga Y. Computation ofInternal Stress for Steel Bar during and after Quenching.
Tetsu-to-Hagane, 1971, 57(14): 2230-2242. (in Japanese)
Kunitake T and Sugisawa S. The Quench-Cracking
Susceptibility of Steel. The Sumitomo Search, 1971, 5,
May: 16-25.
Mikita Y, Kawano Y, Nakabayashi I, Mori T and Sakamaki
K. Shape Effects of the Test Piece on Quench Crack
Susceptibility. Bull. Facl. Eng. Univ. Tokushima, 1988, 33:
39-49. (in Japanese)
Mikita Y, Nakabayashi I and Sakamaki K. How Quench
Conditions Affect Cracking in Tapered Cylinders. Heat
Treating, 1989, Dec.: 21-24.
Narazaki M, Fuchizawa S and Kogawara M. Effects ofSurface Roughness and Surface Texture on Quench
Cracking of Steel. Netsu-shori, 1993, 33(1): 56-63. (inJapanese)Owaku S. Criterion of Quench Cracking – Its Sources andPrevention. Netsu-shori, 1990, 30(2): 63-67. (in Japanese)
Arimoto K, Lambert D and Wu W T. Finite Element
Analysis of Internal Stresses in Quenched Steel Cylinders.
Midea S J and Paffmann G D Eds. Proceedings of the 19th
Heat Treating Conference, Cincinnati: ASM International,
1999, 425-434.
Denis S, Gautier E, Simon A and Beck G. Stress – Phase
Transformation Interactions – Basic Principles, Modelling,
and Calculation of Internal Stresses. Mats. Sci. Tech., 1985,
1: 805-814.
Rammerstorfer F G, Fischer D F, Mitter W, Bathe K J and
Snyder M D. On Thermo-Elastic-Plastic Analysis of

26

27

28

29

30

31

32
33

34

35

36

37

Heat-Treatment Processes Including Creep and Phase
Changes. Computer and Structures, 1981, 13: 771-779.
Narazaki M，Kogawara M，Shirayori A and Fuchizawa S.
Accuracy of Evaluation Methods for Heat Transfer
Coefficients in Quenching. In Wallis R A and Walton H W,
Eds. Proceedings of the 18th Heat Treating Conference.
Rosemont: ASM International, 1998, 509-517.
The British Iron and Steel Research Association. Physical
Constants of Some Commercial Steels at ElevatedTemperatures. 1953, London: Butterworths Scientific
Publications.
Kunitake T and Ohtani H. Calculating the Continuous
Cooling Transformation Characteristics of Steel from Its
Chemical Composition. The Sumitomo Search, 1969, 2,
Nov.: 18-21.
Koistinen D P and Marburger R E. A General Equation
Prescribing the Extent of the Austenite-Martensite
Transformation in Pure Iron-Carbon Alloys and Plain
Carbon Steels. Acta Met., 1959, 7: 59-60.
Iijima K. The Effect of Austenitizing Condition on
Hardenability and on Mechanical Properties of Hardened
Carbon Steel. J. Japan Inst.Metals，1962, 26(7): 412-416. (inJapanese)
Iijima K. The Effects of Austenitizing Temperature, Carbon
Content and Subzero Treatment on the Mechanical
Properties of Hardened Steels. J. Japan Inst.Metals，1965,
29(12): 1227-1233. (in Japanese)
Grange R A and Stewart H M. The Temperature Range ofMartensite Formation. Trans. AIME, 1946, 167: 467-501.
Harris W J and Cohen M. Stabilization of theAustenite-Martensite Transformation. Trans. AIME, 1949,
180: 447-470.
Max-Planck-Institute for Iron Research. Atlas to Heat
Treatment of Steel. Vol. 1, 1954, Dusseldorf : Verlag
Stahleisen mbH. (in German)
Fujisawa M. Residual Stresses of Quenching of Steel
Cylinders (2nd Report). J. Japan Inst. Metals，1954, 18(9):513-516. (in Japanese)
Inoue T, Haraguchi K and Kimura S. Stress Analysis during
Quenching and Tempering. J. Soc. Mat. Sci. Japan, 1976,
25(273): 521-526. (in Japanese)
Inoue K, Sugimoto M, Horikawa T, Maeda H, Minakawa N,
Moriai A, Kamiyama T and Ikuta F. Neutron Diffraction
Study of Residual Stress in the Induction Hardened S45C
Round Bar. In Akiniwa Y, Kimur H and Tanaka K, Eds.
Proceedings of International Conference on Advanced
Technology in Experimental Mechanics 2003, Nagoya:
JSME-MMD, 2003, Paper No. OS04W0182.

Corresponding author: Mr. Kyozo Arimoto,
Email: arimo@arimotech.com,
Mail address: 822-10 Asonaka, Kaizuka, Osaka 597-0081 Japan,
Tel & Fax: +81-724-28-0272