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Journal of Minerals & Materials Characterization & Engineering, Vol. 7, No.3, pp 277-289, 2008
jmmce.org Printed in the USA. All rights reserved
Effect of Melting Temperature on the Wear Characteristics of
Austenitic Manganese Steel
S.A. Balogun, D.E. Esezobor, J.O. Agunsoye
Department of Metallurgical and Materials Engineering
University of Lagos, Lagos, Nigeria.
The practice in most manganese steel melting furnace is to raise the melting and pouring
temperatures to 1500
C and above so as to enhance fluidity of the molten metal and ease
removal of slag. High temperature promotes micro and macro carbide segregation of alloy
elements and formation of embritting transformation products. The presence of segregation at
the grain boundaries, acts as barrier to dislocation movement. This could be responsible for
uneven, inconsistent wear rate and pattern of the steel.
This paper studies the effect of pouring/melting temperature on the propensity of carbide
segregation of austenitic manganese steel and by translation on the wear characteristics of jaw
Austenitic manganese steel (AMS) was subjected to different heat/melt temperatures
ranging from 1380 to 1550
C (H1-H3) in an induction furnace of 1-ton capacity. Samples
obtained from the edge, middle and mounting section of the heat treated steel were examined by
means of optical metallurgical microscope and the relative abundance of elements was
determined by means of energy dispersed X-ray (EDX) elemental spectrometer. The results
indicated high segregation of alloy elements at high melting temperatures. However, uniform
dispersion of carbide particles in the base of the austenitic grains was noticed at pouring
temperature range of 1400-1500
Keyword: austenitic jaw crusher, manganese steel, melting temperature chrome-carbide, wear
life, segregation, quenching
278 S.A. Balogun, D.E. Esezobor, J.O. Agunsoye
Hadfield steel invented in 1882 has an enormous capacity for work-hardening upon
impact and it is commonly used for railroad components such as frogs and crossings and for
rock-handling equipment. It has nominal composition of iron, 1.0 and 1.4 % carbon and 10 to 14
% manganese in a 1 to 10 ratio in accordance with ASTM –A128 specification [1, 2].
Due to its unique service properties, it has been used widely in a number of applications
like rail tracks, dredge buckets, jaw crushers and a number of high impact and wear resistance
operations with minor or no modifications in composition and heat treatment.
Many variations of the original austenitic manganese steel (AMS) are available, often in
unexploited patents [2-6], but only a few have been adopted as significant improvements. These
usually involve variations of carbon and manganese, with or without additional alloys such as
chromium, nickel, molybdenum, vanadium, titanium, and bismuth. .
The mechanical properties of AMS vary with carbon and manganese content. As carbon
is increased it becomes increasingly difficult to retain all of the carbon in solid solution, which
may account for reduction in tensile strength and ductility. Nevertheless, as the carbon increases
above 1.2 %, the abrasion resistance increases, while, the ductility is lowered. The carbon
content is usually below 1.4 % and 13 % manganese due to the difficulty of obtaining an
austenitic structure sufficiently free of grain boundary carbides, which are detrimental to strength
and ductility .
In the as-cast condition, AMS contains carbides and embritting transformation product
. A full solution treatment can be obtained between 1000
C and 1100
C with soak times
appropriate for the section thickness of the part. Higher solution treatment temperature (STT)
should be avoided because carbon segregation may cause incipient melting, and scaling and
decarburization may occur. Moreover, commercial quenching rates limit carbon concentrations
retained in solution . Although some grain growth may occur during solutioning, it is the pour
temperature and solidification rate that strongly influence the final austenitic grain size [1, 9].
Carbides form in castings that are cooled slowly in the molds. Regardless of mold
cooling rates, carbides are formed when the as-cast contains more than 1.0 % C [8, 10]. They
form in heavy section castings during heat treatment if quenching is ineffective in producing
rapid cooling throughout the entire section thickness. Carbides can form during service at
temperatures above about 275
Heat treatment involving solution annealing and quenching in water can enhance yield
strength and abrasion resistance . However, as the section size of manganese steel increases,
tensile strength and ductility decrease substantially in heat treated castings . This occurs
Vol.7, No.3 Effect of Melting Temperature 279
because heavy sections do not solidify in the mold fast enough to prevent coarse grain size. This
condition can not be altered by heat treatment. At a given temperature and grain size, nickel and
manganese additions are beneficial for enhancing impact strength [10, 12], while higher carbon
and chromium levels are not.
The continuous development of industry, and, in particular, mining and metallurgy in
Nigeria, coupled with the government favorable policy and on the local content demands are
ever increasing use of mining metal parts, working under hard impact-abrasion conditions, where
high manganese steels are found to be among the best. Combination of high strength, density and
plasticity together with capability of Hadfield manganese steel to increase several times the
surface hardness under impact load, as well as relative simplicity and cheapness of its
production, ensured its wide use.
In Nigeria, the AMS is widely used in the mining industry as wear plates of cone and jaw
crushers. Majority of these jaw crushers were imported into the country until recently when a
number of local foundries in Nigeria began to produce jaw crushers . However, the locally
produced jaw crushers are characterized with high level of reject (15-25 %) due to the
appearance of cracks after mould-shakeout, during fettling, and after heat treatment.
This paper studies the effect of pouring temperature on the propensity of carbide
segregation of AMS and consequently on the wear characteristics of jaw crushers.
2. MATERIALS AND METHODS
2.1 Melting and Casting
380 Kg of manganese returns with 450 Kg steel scraps, 15 Kg ferro-chrome, 110 Kg
ferro-manganese and 3 Kg ferro-silicon were melted in an induction furnace of 1-ton capacity to
obtain the typical local jaw plate composition. The quantity and chemical composition of the
charge make-up are shown in Table 1. The resultant spectrometric analysis of the New Spec Jaw
Plate (NSJP) is shown in Table 2.
Three batches of the materials weighing 330 kg each were subjected to three different
heat/melt temperatures shown in Table 3.
The molten metals were cast into preheated sand moulds. The mould is made from
sodium silicate bonded sand mixture in accordance with BS14 standard. The surface temperature
of the cast was measured at various points with the aid of a digital probe pyrometer. Removal of
the mould was done 32 hours after the casting.
280 S.A. Balogun, D.E. Esezobor, J.O. Agunsoye
Table 1. Estimated charge make up.
Element Composition, (%)
C Si Mn P S Cr Mo Ni
380 1.31 0.66 12.10 0.03 0.03 1.82 -
450 0.43 0.32 0.32 0.21 0.21 - -
15 0.64 - - - - 61.95 -
110 4.33 - 55.48 - - - -
3 - 70.25 - - - - -
958 1.23 0.63 13.57 0.02 0.02 1.69 -
Table 2. Chemical composition of manganese steel, %.
s/n Description C Si Mn Ni P S Cr Al Fe
2 New Spec Jaw Plate
(NSJP) 1.23 0.60 12.80 - 0.005 0.006 2.40
Plate * 1.27 0.90 12.6 0.40 0.60 0.05 2.10 0.08 Bal
Jaw Plate 1.02 0.50 13.00 0.077 0.002 0.001 1.40 0.006 Bal
Typical local jaw plate contains 0.06 % Mo, 0.05 % V and 0.16 % Sn
Table 3. The Batch/Heat and its corresponding pouring temperature.
Vol.7, No.3 Effect of Melting Temperature 281
2.2 Heat Treatment
The jaw plates were austenitized in an industrial muffle furnace at a temperature of
C for 4 hours.
The different set of samples were soaked for 5 min in a 10,000-litre water tank fitted with
10 HP submersible pumps to ensure that no vapor formation occurred during quenching at the
interface of hot casting and the water for quenching.
The entire surface of the sample was tested using a piece of magnet (horseshoe) after shot
blasting to confirm the degree of full-austenitic transformation.
Samples with dimensions 25 mm x 25 mm x 12.5 mm were obtained from the edge (a),
middle i.e. thickest section (b), and the mounting section (c) of the heat treated jaw crusher plate.
The surface of the sample was prepared for metallographic examination using nital as etchant
after preliminary grinding and polishing operations. An optical metallurgical microscope was
used to obtain 250X photomicrographs of the processed samples. The micrographs are shown in
Figures 1, 3 and 5. The relative abundance of element on samples surface showed in Figures 2, 4
and 6 were determined by Energy Dispersed X-ray (EDX) elemental spectrometers in
accordance with ASTM F 1375-92 (2005).
2.4 Wear Characteristics
The performances of the local and foreign jaw plates along side with the NSJP produced
at H1 were monitored in Ratcon Quarry. The Utility of the plate in percent was evaluated as
weightFinal- weight Initial
The initial weight of all the samples of the plates was 1018 kg.
3. RESULTS AND DISCUSSIONS
The micrographs of the selected three sections of the plate at H1 reveal non-uniform
distribution of carbides in the austenite matrix (see Figure 1). High concentration of carbide
particles was noticed at the grain boundaries at higher temperature. The relative abundance of
alloy element as shown by EDX examination also reveals high degree of chromium and
manganese segregation (Figure 2.)
282 S.A. Balogun, D.E. Esezobor, J.O. Agunsoye
At H2, few carbide particles are seen dispersed in the austenite matrix (Figure 3). The
segregation of alloy elements is also indicated in the EDX scan. However the extent of
segregation is at a lower level. The scans are characterized by the presence of uniformly
distributed semi fine-dispersed chromium carbide within its matrix (Figure 4).
a b c
X250 X250 X250
Coarse segregation of Cr-
Carbide in Mn-Steel Matrix
Figure 1. The Microstructures of the edge (
), middle (
) and mounting(
sections of the jaw crusher plate at H1. These microstructures are characterized by the
ce of irregular, segregated chromium carbides around the grain boundary.
Figure 2. Relative Abundance of elements at H1
Vol.7, No.3 Effect of Melting Temperature 283
The micrographs of the plates at H3 as shown in Figure 5 do not show any concentration
of carbides at the grain boundaries of the austenite matrix. The dark carbide particles are
observed to be uniformly dispersed in the matrix. The results of the EDX scan in Figure 6 also
reveal a very minimal degree of segregation.
Figure 4. Relative Abundance of Element at H2
a b c
X250 X250 X250
Semi fine dispersion of Cr-
Carbide in Mn-Steel Matrix
Figure 3. The Microstructures of the edge (
), middle (
) and mounting
of the jaw crusher plate at H2.
Fine dispersion of Cr
-Carbide in Mn-Steel Matrix
a b c
X250 X250 X250
Figure 5. The Microstructures of the edge (
), middle (
) and mounting (
) sections of
the jaw crusher plate at H3.
284 S.A. Balogun, D.E. Esezobor, J.O. Agunsoye
The results obtained in Figures 1-6 show a steady increase in segregation as the melting
temperature increases. At high temperatures, the high segregation observed is due to the
increased solidification time as a result of wider solidification (i.e. liquidus/ solidus lines) range.
In industrial practice, high pouring temperatures is usually carried out mainly due to poor
furnace linings / refractories. This leads to rapid heat loss and in an effort to compensate for the
heat loss, the furnace temperature is usually increased to temperatures above 1600
superheating the melt in the process.
The relative abundance of the alloy elements at various melting temperatures as shown in
the EDX curves substantiates the segregation of these elements in the austenite matrix.
Figure 7 below shows that the silicon element remains uniformly distributed in the
austenite matrix irrespective of the pouring temperature, i.e. there is little or no silicon
segregation in the structure. However, there is a sharp increase in segregation of chromium as the
pouring temperature increases beyond 1450
C. The manganese steel contains higher amount of
chromium, 2.4 % (see Table 2), which leads to the formation of a large quantity of coarse
carbide, whose distribution in the grain boundaries is non-uniform and segregates at the grain
boundary.Segregation as a phenomenon is due to the wide differential cooling of the casting in
the mould, which is a direct function of the pouring temperature (see Figure 7). The most
significant factor is the peak temperature of melting, since at high temperature, melting process
guarantees segregation, which once formed can not be reversed by altering pouring temperature.
Figure 6. Relative Abundance of element at H
Vol.7, No.3 Effect of Melting Temperature 285
The practice in most local foundries is to melt and pour at very high temperatures (≥ 1500
C) as a means to enhance fluidity of the melt and ease removal of slag, particularly in an
induction-melting furnace. This practice has been found to be counter productive because
melting above 1500
C encourages excessive slag formation as a result of the reaction between
manganese and the refractory lining. This phenomenon enhances superheating that hastens the
erosion of furnace lining. This may eventually leads to furnace leakage; where metal could
penetrate through refractory wall. This practice employed by the local foundry shortens the life
of the furnace. Resulting repair or complete replacement are both time consuming and
The summary report of the jaw plate performance as monitored in Ratcon Quarry for 6
weeks along side the performance of the new spec produced through H3 is presented in Table 4.
The result shows that the wear pattern across the operational surface of NSJP is uniform
compared to the wear on the local jaw plates.
286 S.A. Balogun, D.E. Esezobor, J.O. Agunsoye
The locally produced crusher plate is characterized by inconsistent and uneven wear rate
when compared to the foreign crusher of equivalent specifications. Investigation conducted at
local client/quarry company operations revealed that at equivalent composition and shapes of the
crusher under the same condition of service, the local crusher plate produced 150,000 tones of
crushed rock compared to 170,000 tones and 200,000 tones produced by the NSJP and the
imported plates respectively (Table 4).
Table 4. The summary report of the jaw plate performance as monitored in Ractcon Quarry for 6
100rock crushed of increase %×
The schematic diagram of used imported and local plates of jaw crushers are shown in
figures 8 and 9 respectively. Although the wear rate of the foreign plate may be faster than the
wear rate of the local or new spec plates (see Table 5), the wear in the former is uniform, while
the wear behavior of the local is uneven leading to variable feed sizes. The uneven wear behavior
of the local plate can be attributed to the pronounced segregation of chromium carbide (Cr
the austenite matrix at grain boundaries
Table 5. The weight loss of the jaw plate during 6 weeks operations.
Crushed rock (,000 tons)
NSJP (H3) rushed rock (,000 tons)
Vol.7, No.3 Effect of Melting Temperature 287
Figure 9. Worn-Out Plate of Local Jaw Crusher.
The presence of chromium in purely austenite Hadfield manganese steel leads to the
appearance of cracks due to elevated internal stresses associated with the liberation of carbides,
which may segregate, mainly at the grain boundary. At high temperatures, segregation is very
severe. There is little or no elemental segregation at temperatures between 1370
C and 1400
(see Figure 5). Hence, a jaw crusher produced at this range of temperatures will exhibit better
On the other hand, there is evidence of high degree of segregation at melting temperature
C (see Figure 3). As the melting temperature is reduced, the order of dispersion of
carbides in the matrix reduces, while, at 1450
C the carbides are relatively less dispersed in the
matrix. Segregation impedes the movement of dislocation around the grain boundaries where
aggregate of CrC particles is highly pronounced.
The conventional solution heat treatment of the jaw crusher employed by local foundries
does not eliminate the segregation as this can only impact positive effect on the microstructure.
The macro segregation of alloying elements remains unaltered by solution heat treatment.
EDX analysis has shown that high pouring temperature above 1450
C should be
discouraged as it promotes segregation on the micro and macro levels. The presence of
segregation particularly in locally produced manganese steel is responsible for its uneven,
out plate of imported jaw crusher
288 S.A. Balogun, D.E. Esezobor, J.O. Agunsoye
inconsistent wear rate and pattern. The segregation around grain boundaries acts as barrier and
impedes the movement of dislocation around the grain boundaries where the Cr-C segregation is
highly pronounced. The increased metallic inclusion through back charging with foundry returns
depreciates the ratio of mobile dislocation to immobile dislocation to a value lower than unity.
This ratio translates to higher densities of immobile dislocation and subsequently poor work
hardening property of the AMS. Thus, the material is favoured to fail by cracking when the
energy of the mobile dislocation becomes lower than the energy of the immobile dislocation.
The pouring temperatures of 1400 - 1450
C will promote uniform dispersion of carbide
particles within the structure and thereby enhancing the wear property of the jaw crusher [1, 9].
However, the low pouring temperatures diminish the fluidity of the molten metal and results in
casting defects, low yield put and high operational costs.
This phenomenon of segregation, arising from high temperature pouring can be reduced
by using neutral refractory to line the lip pouring ladles as against the current practice of using
sand. This will conserve heat in the ladle and reduce the rate of temperature drop. In the
alternative, the use of bottom-pour ladle should be considered.
Finely dispersed carbides formed during cooling in the segregation zones promote
efficient hardening of steel . The uniformly distributed chromium carbides in the base of the
austenitic grains provides higher resistance to impact abrasion wear, which improves the strength
and work hardening of the plate under repeated and severe impact.
The authors acknowledge financial support by grants from the Nigerian Foundries
Limited, Ilupeju Industrial Estate Lagos and the exclusive use of her facilities to carry out this
The authors would like to express sincere thanks to Engineer Anandar, the Factory
Manager of Racton Quarry, Ibadan for his support during onsite monitoring and data collection
from his company and also Teniola Sadiz who facilitated the EDX scan in Orarobot University,
The material in this paper is intended for general information only. Any use of this
material in relation to any specific application should be based on independent examination and
verification of its unrestricted availability for such use, and determination of suitability for the
application by professionally qualified personnel. No license under any patents or other
Vol.7, No.3 Effect of Melting Temperature 289
proprietary interest is implied by the publication of this paper. Those making use of or relying
upon the material assume all risks and liabilities arising from such use or reliance.
1 Avery, H.S., “Austenitic Manganese Steel” Metals Handbook, American Society for
Metals, volume 1, 8
edition, 1961 pp. 834 to 842
2. Steel Founders Society. Steel Castings Handbook. 5
3. Patent No 5601782. Saburo Kunioko Hiroshi Toriyama. Abrasive Resistant High
Manganese Cast Steel. Appl. No 532768 issued 11:02. 1997 filed 27.09-1995
4. USA patent 4394168. Hartving Tor, Fjeucheum Petter. Austenitic wear resistant steel.
Appl. No 230630 filed 02.02. 1981 publ. 19.07. 1983
5. Patent CA 1221560 KOS Bernd. Work hardenable austenitic manganese steel and
method for the production thereof. Appl. (21) 439018 issued 12 may 1987 filed Oct 14.
6. European Patent EP 1337679. Kucharczyk Jerzy Funk, Karl Kos Bernd. Grain-refined
austenitic manganese steel casting having micro-additions of vanadium and fibranium
and method of manufacturing. Appl EP 20010979440 Date 03:10 2001 publ. 27/08/2003
7. Tasker, J., Austenitic Manganese steel-fact and fallacy. Intermountain Minerals
Symposium. Vail; Colorado, 3-6 August, 1982 pp 3-19
8. Subramanyam, D.K.; Swansieger, A.E and Avery, H.S., “Austenitic Manganese Steels”.
ASM Metal Handbook, American Society of Metals, Volume 1, Tenth Edition, 1990, pp.
822 to 840.
9. American Society for Metals. Metals Handbook 9
Edition Vol 3. Properties and
Selections: Stainless Steels, Tool Materials, and Special Metals. ASM, 1980
10. Avery, H.S., “Austenitic Manganese Steel for Railway Trackwork”, Case Report Number
429-12, Abex Corporation Research Center, Mahwah, New Jersey, September 1981,
11. Muki Satya Permana. Casting practice of Hadfield manganese steel alloy and effect of
solution treatment on its microstructure. Master Theses for JBPTITBPP/2001-09-11
12. Effect of deformation temperature and heat treatment on the structure and properties of
high-manganese steel. Metal Science and Heat treatment. Vol 13 No5, May, 1971 p. 390-
13. Machine Shop Production Report. Nigeria foundries Limited Ilupeju, Lagos, Nigeria