154 Livarski vestnik, letnik 70, št. 3/2023 
K. Delijić
1
, M. Filipović
2
, V. Manojlović
2
1 
Univerza v Črni Gori, Črna Gora / University of Montenegro, Montenegro, 
2 
Univerza v Beogradu, Srbija / University of Belgrade, Serbia
Korozijsko vedenje krogel za mletje iz belega litega železa z 
visoko vsebnostjo kroma, izdelanih s cepivom Al5Ti1B
Corrosion Behavior of High-Chromium White Cast Iron 
Grinding Balls Produced with Al5Ti1B Inoculant
Povzetek
Korozijsko vedenje krogel za mletje iz zlitine belega litega železa z visokim deležem kroma 
(HCWCI), izdelanih z udrobnjevalcem Al5Ti1B (masni delež 0,5–2,0 wt.%), smo ocenili z 
elektrokemijskimi metodami, ki jim je sledila analiza mikrostrukture in merjenje trdote. Kot 
inokulant smo uporabili predzlitino Al5Ti1B, ki ima dvojno vlogo: je sredstvo za razplinjanje 
in sredstvo za modifikacijo, saj poleg aluminija vsebuje tudi karbidotvorne elemente, tj. 
titan in bor. Korozijske preskuse smo opravili v 0,1 M NaCl in v sladki vodi. Vzorce smo 
preskusili v litem stanju. Zlitina HCWCI, modificirana z 0,5 wt.% Al5Ti1B, je zagotovila 
optimalno kombinacijo preskušenih lastnosti.
Ključne besede: belo lito železo z visoko vsebnostjo kroma, krogle za mletje, cepiva 
Al5Ti1B, korozija
Summary
Corrosion behavior of high-chromium white cast iron (HCWCI) alloys for grinding balls 
produced with the addition of Al5Ti1B grain refiner (0,5 - 2,0 wt.%), were evaluated by 
electrochemical methods, followed by microstructure analysis and hardness measuring. An 
Al5Ti1B master alloy is used as an inoculant, having a double role: a degassing agent and 
a modification agent since in addition to aluminum, it contains carbide-forming elements, 
titanium and boron. Corrosion tests were performed in 0,1 M NaCl and fresh water. The 
samples were tested in the as-cast conditions. The HCWCI alloy modified by 0,5 wt.% of 
Al5Ti1B, showed the optimal combination of tested properties.
Keywords: high-chromium white cast iron, grinding balls, Al5Ti1B inoculants, corrosion
1 Uvod
Belo lito železo z visoko vsebnostjo kroma 
(HCWCI) je odličen obrabni material 
in predstavlja tretjo generacijo te vrste 
materialov z ugodnim razmerjem med 
obrabo zaradi abrazije in žilavostjo [1, 
2, 3]. Dobra odpornost proti obrabi je 
predvsem posledica prisotnosti velikega 
volumskega deleža zelo trdih evtektičnih 
1 Introduction
High-chromium white cast irons (HCWCIs) 
represent excellent wearable materials, as 
a third generation of this type of material, 
with a favorable ratio of abrasion wear and 
toughness [1, 2, 3]. Good wear resistance 
is a consequence primarily of the presence 
of high-volume fraction of very hard eutectic 
carbides in a strong supporting matrix in their 

 Livarski vestnik, letnik 70, št. 3/2023 155
karbidov v močni podporni matrici v 
njihovi mikrostrukturi [4, 5, 6, 7]. Obstaja 
veliko člankov in modelov, povezanih z 
razmerjem med obrabo in mikrostrukturnimi 
lastnostmi belega litega železa z visoko 
vsebnostjo kroma [12]. Vendar so obrabni 
elementi HCWCI pogosto izpostavljeni 
delu v korozivnem okolju, informacije o 
vedenju HCWCI v korozivnih okoljih pa so v 
dostopni literaturi razmeroma omejene [12]. 
Obstajajo eksperimentalni dokazi, da je belo 
železo z visoko vsebnostjo kroma z dobrimi 
mehanskimi lastnostmi manj odporno proti 
koroziji in da te zlitine v korozivnih pogojih 
postanejo manj odporne proti obrabi [13]. 
Korozijska odpornost zlitin HCWCI je 
odvisna od kemijske sestave železove 
matrice in koncentracije prostega Cr v 
matrici, ki povečuje korozijsko odpornost 
zlitin HCWCI, ter od razmerij Cr/C in Cr
M7C3
/
Cr
matrix 
[12, 13, 14, 15]. Dodajanje drugih 
legirnih elementov, kot so Si, Mo, Ni, Cu, 
V, Ti itd., prav tako vpliva na korozijsko 
vedenje. 
Namen tega prispevka je predstaviti 
nekatere rezultate in razmisleke o vplivu 
inokulacije HCWCI z Al5Ti1B (od 0,5 wt.% 
do 2,0 wt.%) na mikrostrukturo in korozijske 
lastnosti zlitin HCWCI. V primeru želez z 
visoko vsebnostjo kroma ima predzlitina 
Al5Ti1B dvojno vlogo: je sredstvo za 
razplinjanje in sredstvo za tvorbo/
modifikacijo karbidov, saj poleg aluminija 
vsebuje tudi karbidotvorne elemente, tj. 
titan in bor.
2 Materiali in metode
Kemijska sestava preskušenih zlitin HCWCI 
je navedena v Preglednici 1. Vzorci so 
bili izdelani z dodatkom Al5Ti1B (0,5–2,0 
wt.%). Taljenje zlitin je potekalo v indukcijski 
peči, krogle za mletje s premerom 60 mm 
pa so bile ulite v vodno hlajene trajne forme. 
microstructure [4, 5, 6, 7]. There are many 
articles and models related to the wear and 
microstructure properties relationship of 
HCWCIs [12]. However, wearable HCWCI 
elements are often exposed to work in a 
corrosive environment, and information 
on the behavior of HCWCIs in corrosive 
environments is relatively limited in the 
open literature [12]. There are experimental 
evidences that HCWCIs with high 
mechanical properties are less resistant 
to corrosion and these alloys become less 
resistant to wear under corrosive conditions 
[13]. The corrosion resistance of HCWCI 
alloys depends on the chemical composition 
of the ferrous matrix and the concentration 
of free Cr in the matrix, which increases 
the corrosion resistance of HCWCI alloys 
as well as on the Cr/C and Cr
M7C3
/Cr
matrix
 
ratios [12, 13, 14, 15]. The addition of other 
alloying elements, such as Si, Mo, Ni, Cu, V, 
Ti, etc., also affects the corrosion behavior. 
This paper aims to present some results 
and considerations related to the influence 
of the inoculation of HCWCIs with Al5Ti1B 
(as 0,5 wt.% - 2,0 wt.%) on microstructure 
and corrosion properties of HCWCI alloys. 
In the case of high-chromium master master 
alloy would have a double role: a degassing 
agent and a carbide forming/modification 
agent, since in addition to aluminum, it also 
contains carbide-forming elements, titanium 
and boron.
2 Materials and Methods
The chemical composition of tested HCWCI 
alloys is listed in Table 1. The samples 
were produced by the addition of Al5Ti1B 
(0,5 - 2,0 wt.%). The melting of alloys was 
performed in induction furnace and grinding 
balls with 60 mm of diameter were cast 
in water-cooled permanent molds. The 
casting temperature was 1470 
o
C - 1490 
o
C 

156 Livarski vestnik, letnik 70, št. 3/2023 
Temperatura litja je bila 1470 
o
 C–1490 
o
 
C, temperatura forme pa 130 
o
C–140 
o
C. 
Ulite krogle so bile v formi 3 minute, po 
odstranitvi iz form so se ohlajale na zraku. 
Litje in preskušanje »osnovne zlitine« 
HCWCI (kemijska sestava, določena 
s standardom ASTM A532-IIE) sta bila 
izvedena pod enakimi pogoji, in sicer da bi 
ju lahko primerjali z lastnostmi ulitih krogel, 
izdelanih s cepivom Al5Ti1B.
Vzorci so bili preskušeni v litem stanju. 
Mikrostrukturo vzorcev smo preiskali 
z optičnim in vrstičnim elektronskim 
mikroskopom. Korozijsko vedenje zlitin 
HCWCI smo analizirali s potenciostatom/
galvanostatom Ametek Versa 3. Za analizo 
elektrokemičnih podatkov smo uporabili 
programsko opremo VersaStudio (različica 
2.62.2.0). Pri korozijskih preskusih smo 
uporabili standardno celico, sestavljeno 
iz vzorca kot delovne elektrode, grafitne 
protielektrode in elektrode Ag/AgCl kot 
referenčne elektrode. Taflove polarizacijske 
preskuse smo izvedli z uporabo postopka, 
ki samodejno izbere podatke, ki ležijo 
znotraj Taflovega območja (±250 mV glede 
na korozijski potencial). Preskuse linearne 
polarizacije smo izvedli s postopkom, 
ki samodejno izbere podatke, ki ležijo 
v območju ±20 mV glede na korozijski 
potencial. Pred vsako meritvijo smo testno 
površino brusili z brusnim papirjem iz 
and the mold temperature was 130 
o
C -140 
o
C. The cast balls were kept in the mold for 
3 minutes and, subsequently, taken out and 
cooled in ambient air. Casting and testing of 
HCWCI “base alloy” (chemical composition 
defined by ASTM A532-IIE) were performed 
under the same conditions, in order to 
compare with properties of as-cast balls, 
produced with Al5Ti1B inoculant.
The samples were tested in the as-cast 
temper. The microstructure was investigated 
by optical and scanning electron microscopy. 
The corrosion behavior of HCWCI alloys 
was analyzed using Ametek Versa 3 
potentiostat/galvanostat. The VersaStudio 
software (version 2.62.2.0) was used for all 
electrochemical data analysis. A standard 
cell composed of a specimen as a working 
electrode, graphite counter electrode and 
Ag/AgCl electrode as a reference electrode 
was used in the corrosion tests. Tafel 
polarization tests were carried out using the 
routine that automatically selects the data 
that lies within the Tafel region (±250 mV 
with respect to the corrosion potential). The 
linear polarization tests were performed 
under the routine that automatically selects 
the data that lies within the region ±20 mV 
concerning the corrosion potential. Before 
each measurement, the test surface was 
ground with silicon carbide papers and 
rinsed with acetone. Electrochemical 
Preglednica 1. Kemijska sestava zlitin HCWCI, uporabljenih v poskusih, wt.%
Table 1. Chemical composition of HCWCI alloys used in experiments, wt.%
Zlitina / Alloy C Si Mn P S Cr, Mo Cu Ni Al B Ti V
Osnovni / 
Base HCWCI
2,91 0,83 0,79 0,029 0,016 17,83 1,15 0,84 0,11 0,051 <0,002 0,021 0,041
HCWCI + 0,5 
wt.% AlTiB
3,08 0,78 0,69 0,019 0,021 18,37 1,13 0,84 0,11 0,495 <0,002 0,046 0,043
HCWCI + 1,0 
wt.% AlTiB
2,93 0,79 0,68 0,022 0,019 18,68 1,17 0,83 0,12 1,173 0,003 0,074 0,043
HCWCI + 2,0 
wt.% AlTiB
2,90 0,79 0,78 0,029 0,015 15,53 1,24 0,76 0,09 2,271 0,021 0,16 0,043

 Livarski vestnik, letnik 70, št. 3/2023 157
silicijevega karbida in jo oprali z acetonom. 
Elektrokemične preskuse smo opravili v 0,1 
M NaCl in sladki vodi (HCO
3
 =74,5 mg/l; 
K
+
 < 0,5 mg/l; Mg
2+ 
<0,1 mg/l; Na
+
 = 48,3 
mg/l; Ca
2+
 < 3 mg/l; SiO
2 
=45 mg/l). Trdoto 
zlitin smo preskusili z Rockwellovo metodo 
(HRC; obremenitev: manjša 10 kg, večja 
150 kg; čas: 10 s), pri čemer smo izračunali 
povprečne vrednosti za prerez krogel za 
mletje.
3 Rezultati in razprava
Mikrostrukture ulitih krogel za mletje v 
litem stanju z različnimi vsebnostmi cepiva 
Al5Ti1B ob površini in v sredinskih conah 
prerezov so predstavljene na optičnih 
mikrografijah na Sliki 1. Predstavljena je 
tudi mikrostruktura osnovne zlitine HCWCI, 
in sicer z namenom opazovanja sprememb, 
ki jih povzroči dodajanje različnih vsebnosti 
Al5Ti1B. Mikrostruktura v vseh preiskovanih 
zlitinah je sestavljena iz dendritov 
primarnega avstenita in evtektičnih kolonij, 
ki so v sestavljene iz mešanice karbidov 
in avstenita M
7
C
3
. Mikrogrami SEM, ki 
prikazujejo mikrostrukturo osnovne zlitine 
HCWCI in zlitine z dodatkom 1,0 wt.% 
Al5Ti1B, so prikazani na Sliki 2. Na podlagi 
analize mikrostrukture (Sliki 1 in 2) je jasno 
razvidno, da lahko z modifikacijo HCWCI z 
dodatkom inokulanta Al5Ti1B zagotovimo 
bistveno bolj fino strukturo. Struktura 
postane bolj fina, velikost primarnih 
avstenitnih dendritov in evtektičnega karbida 
M
7
C
3
 pa se v HCWCI z 0,5 wt.% Al5TiB1 
v primerjavi z osnovno zlitino zmanjša. 
Zlitina HCWCI, modificirana z 1,0 wt.% 
Al5Ti1B, ima nekoliko bolj grobo strukturo 
kot zlitina z 0,5 wt.% Al5Ti1B. Z nadaljnjim 
povečanjem deleža Al5Ti1B do 2,0 wt.% 
postane struktura v primerjavi z drugimi 
modificiranimi zlitinami bolj groba, vendar še 
vedno bolj fina v primerjavi z osnovno zlitino 
tests were conducted in 0,1 M NaCl and 
freshwater (HCO
3
=74,5 mg/l; K
+
 < 0,5 mg/l; 
Mg
2+ 
<0,1 mg/l; Na
+
 = 48,3 mg/l; Ca
2+
 < 3 
mg/l; SiO
2 
=45 mg/l). The hardness of alloys 
was tested by the Rockwell method (HRC; 
load applied: minor 10 kg, major 150 kg; 
time: 10 s), with calculating the average 
values for the cross-section of the grinding 
balls.
3 Results and Discussion
Microstructures of as-cast grinding balls 
with different contents of Al5Ti1B inoculant, 
near the surface and in the central zones of 
the cross-sections, are presented in optical 
micrographs in Fig. 1. The microstructure 
of the base HCWCI alloy is also presented 
to observe the changes caused by the 
addition of different Al5Ti1B contents. 
The microstructure in all investigated 
alloys consists of dendrites of primary 
austenite and eutectic colonies, which are 
essentially a mixture of M
7
C
3
 carbides and 
austenite. SEM micrographs showing the 
microstructure of the base HCWCI alloy 
and the alloy with the addition of 1,0 wt.% 
Al5Ti1B is shown in Figure 2. Based on the 
microstructure analysis (Fig. 1 and Fig. 2), 
it is clearly seen that a much finer structure 
can be obtained by modifying of HCWCIs 
with the addition of Al5Ti1B inoculant. The 
structure becomes finer, and the size of the 
primary austenite dendrites and eutectic 
M
7
C
3
 carbide are decreased in HCWCI with 
0,5 wt.% of Al5TiB1 if compared to the base 
alloy. The HCWCI was modified with 1,0 
wt.% Al5Ti1B has a slightly coarser structure 
than the alloy with 0,5 wt.% of Al5Ti1B. With 
a further increase of the Al5Ti1B up to 2,0 
wt.%, the structure becomes coarser if 
compared to the other modified alloys, but 
still finer compared to the base HCWCI 
alloy. The size, morphology and volume 

158 Livarski vestnik, letnik 70, št. 3/2023 
HCWCI. Velikost, morfologija in volumski 
delež faz v površinskih in sredinskih conah 
se pri vseh preiskovanih zlitinah razlikujejo. 
Vendar so s povečevanjem vsebnosti 
fraction of the phases in the surface and 
central zones differ in all investigated alloys. 
However, with an increase in the Al5Ti1B 
content, the differences in the structure 
Slika 1. Optične mikrografije mikrostrukture kroglic za mletje v litem stanju z različnimi vsebnostmi 
inokulanta Al5Ti1B
Figure 1. Optical micrographs of the as-cast microstructure of grinding balls produced with different 
contents of Al5Ti1B inoculant
Slika 2. Mikrogrami SEM, ki prikazujejo mikrostrukturo osnovne zlitine HCWCI in zlitine HCWCI z 
dodatkom 1,0 wt.% cepiva Al5Ti1B, glede na oddaljenost od površine preskušenih krogel za mletje
Figure 2. SEM micrographs showing the as-cast microstructure of base HCWCI and HCWCI alloy 
with the addition of 1,0 wt.% of Al5Ti1B inoculant, depending on the distance from the surface of the 
tested grinding balls

 Livarski vestnik, letnik 70, št. 3/2023 159
Al5Ti1B razlike v strukturi od površine 
do sredine ulitih krogel manj izrazite, 
struktura pa je bolj homogena. V osnovni 
zlitini HCWCI in HCWCI z 0,5 % Al5Ti1B 
je opazna prisotnost martenzita, predvsem 
v mejni coni primarnega in evtektičnega 
avstenita ter evtektičnih karbidov M
7
C
3
 
karbidov (Slika 1). Poleg tega se volumski 
delež martenzita zmanjšuje od površine 
proti sredini, Slika 3.
V površinskih conah je perlit prisoten 
v zelo majhnih količinah, medtem ko je 
v sredinski coni opazen nekoliko večji 
volumski delež, Slika 3. Stopnja pretvorbe 
avstenita v perlit je bistveno višja v zlitinah 
HCWCI, modificiranih z dodatkom 2,0 wt.% 
Al5Ti1B (Slika 1 in Slika 3), pri čemer se 
volumski delež perlita povečuje od površine 
proti sredini ulitih kroglic (Slika 1).
Vpliv dodatka Al5Ti1B na trdoto ulitih 
kroglic je prikazan na Sliki 4. Dodatek 
0,5 wt.% Al5Ti1B povzroči povečanje 
povprečne vrednosti trdote za 1,5 HRC v 
primerjavi z osnovnim HCWCI, pri čemer 
se z nadaljnjim večanjem vsebnosti Al5Ti1B 
do 2 wt.% trdota ne spremeni bistveno in se 
giblje med 53,8 in 54,1 HRC.
from the surface to the center of the as-cast 
balls are less pronounced, and the structure 
is more homogeneous. The presence of 
martensite, mainly in the boundary zone 
of both primary and eutectic austenite and 
eutectic M
7
C
3
 carbides, is observed in base 
HCWCI alloy and in HCWCI with 0.5% 
Al5Ti1B (Fig. 1). Additionally, the volume 
fraction of martensite decreases from the 
surface to the center, Fig.3.
Pearlite is present in very small 
amounts in the surface zones, while in 
the central zone, a slightly larger volume 
fraction can be observed, Fig. 3. The 
degree of transformation of austenite into 
pearlite is significantly higher in HCWCI 
alloys modified by the addition of 2,0 wt.% 
Al5Ti1B (Fig. 1 and Fig. 3), noting that the 
volume fraction of pearlite increases from 
the surface to the center of the as-cast balls 
(Fig. 1).
The influence of the Al5Ti1B addition 
on the hardness of the as-cast balls is 
illustrated in Fig.4. The addition of 0,5 wt.% 
Al5Ti1B causes an increase in the average 
hardness value of 1,5 HRC, if compared to 
the base HCWCI, noting that with further 
Figure 3. Optical micrographs of the as-cast microstructure of grinding balls produced with different 
contents of Al5Ti1B, “near-surface zone” and “central zone”
Slika 3. Optične mikrografije mikrostrukture kroglic za mletje, izdelanih z različno vsebnostjo Al5Ti1B, 
»cona blizu površine« in »sredinska cona«

160 Livarski vestnik, letnik 70, št. 3/2023 
Trdota vseh preskušenih krogel v litem 
stanju se zmanjšuje v smeri od površine do 
sredine, razen pri zlitini z 2,0 wt.% Al5Ti1B, 
kjer je opaziti rahlo povečanje trdote v smeri 
od površine do sredine, Slika 5. Razlika v 
trdoti med površino in sredino pri osnovni 
HCWCI je 6,3 HRC. Dodatek 0,5 wt.% 
Al5Ti1B to razliko zmanjša na 1,6 HRC, Slika 
5, kar pomeni, da dodatek 0,5 wt.% Al5Ti1B 
ne samo poveča povprečno vrednost trdote, 
temveč tudi znatno zmanjša razpršenost 
vrednosti trdote na prerezu krogel, kar je 
posledica bolj homogene strukture. HCWCI, 
modificirana z 1,0 wt.% Al5Ti1B, ima bolj 
fino strukturo, transformacija avstenita v 
martenzit je bolj enakomerna po celotnem 
prerezu, v primerjavi z osnovno zlitino pa 
je v sredinski coni opazna zelo majhna 
količina perlita (Slika 3). S tem se poveča 
povprečna trdota in zmanjša razlika v trdoti 
med površino in sredino. Pri HCWCI z 2,0 
% Al5Ti1B smo opazili nasprotno težnjo 
(povečanje trdote v smeri od površine proti 
sredini) kot posledico povečanja stopnje 
transformacije avstenita v zelo fin perlit in 
martenzit (Sliki 1 in 3) z majhnimi deleži 
preostalega avstenita. 
increase in the content of Al5Ti1B up to 2 
wt.%, hardness remains approximately the 
same, and ranges between 53,8 and 54,1 
HRC.
The hardness of all tested as-cast 
balls decreases in direction surface-
center, except for the alloy with 2,0 wt.% 
Al5Ti1B, where a slight increase in surface-
center hardness is observed, Fig. 5. The 
difference in surface-center hardness in 
the base HCWCI is 6,3 HRC. The addition 
of 0,5 wt.% of Al5Ti1B decreases this 
difference to 1,6 HRC, Fig. 5, noting that 
the addition of 0,5 wt.% of Al5Ti1B not only 
increases the average hardness value, but 
also significantly reduces the dispersion 
of hardness values on the cross-section 
of the balls, as a consequence of a more 
homogeneous structure. The HCWCI 
modified with 1,0 wt.% of Al5Ti1B has a finer 
structure, the transformation of austenite 
into martensite is more uniform across the 
cross-section, and a very small amount of 
pearlite is noticeable in the central zone 
(Fig. 3) if compared to the base alloy. 
This increases the average hardness and 
decreases the difference in surface-center 
Slika 4. Vpliv dodatka Al5Ti1B na trdoto krogel 
v litem stanju
Figure 4. The influence of the Al5Ti1B addition 
on the hardness of as-cast balls
Slika 5. Vpliv dodatka Al5Ti1B na razliko v trdoti 
v sredinski coni površine
Figure 5. The influence of the Al5Ti1B addition 
on the hardness difference in the center-surface 
zone

 Livarski vestnik, letnik 70, št. 3/2023 161
Taflove krivulje preskušenih HCWCI v 
0,1 M NaCl so prikazane na Sliki 6.a skupaj z 
ustreznimi korozijskimi podatki, Preglednici 
2. Dodatek Al5Ti1B zlitinam HCWCI 
premakne Taflove krivulje modificiranih 
belih želez z visoko vsebnostjo kroma k 
manj negativnim vrednostim potencialov 
v okolju kloridne korozije, Slika 6.a. 
Premiku Taflovih krivulj proti bolj žlahtnim 
vrednostim potenciala zaradi modifikacije z 
Al5Ti1B sledi zmanjšanje vrednosti gostot 
korozijskih tokov v primerjavi z osnovno 
nemodificirano osnovno zlitino, Preglednica 
2. Pri »osnovni zlitini« (Cr/C=6,1) so bile 
zabeležene najvišje vrednosti gostote 
korozijskega toka (71,1 µA/cm2 ) in najbolj 
negativen potencial E
(I=0)
 (-458 mV) v 
primerjavi z vsemi drugimi preskušenimi 
modificiranimi zlitinami HCWCI v 0,1 M 
NaCl. Pri zlitini HCWCI z 0,5 wt.% Al5Ti1B 
(Cr/C=6) so bile zabeležene najnižje 
vrednosti gostote korozijskega toka v 0,1 M 
NaCl (23,3 µA/cm
2
) in izračunana vrednost 
korozijske hitrosti (0,2 mm/leto). Podobne 
vrednosti korozijskih tokov (in hitrosti 
korozije) za zlitine HCWCI z dodatkom 0,5 
wt.% Al5Ti1B (Cr/C=6) in 1,0 wt.% Al5Ti1B 
(Cr/C=6,3) so zabeležene v 0,1 M NaCl. 
Enakovredno vedenje zlitin HCWCI je 
razvidno iz preskušanja v sladki vodi, Slika 
6.b. Taflove krivulje modificiranih belih želez 
z visoko vsebnostjo kroma so v primerjavi 
s Taflovo krivuljo osnovne zlitine v poljih 
manjših negativnih vrednosti potencialov. 
Pri osnovni zlitini HCWCI (Cr/C=6,1) so bile 
zabeležene vrednost gostote korozijskega 
toka 21,5 µA/cm2 in najbolj negativen 
potencial E
(I=0)
 (-389 mV) v primerjavi z 
vsemi modificiranimi zlitinami HCWCI, 
Preglednica 2. Podobne vrednosti E
(I=0)
 za 
zlitine HCWCI, ki vsebujejo 0,5 wt.% (Cr/
C=6) in 1,0 wt.% (Cr/C=6,3) Al5Ti1B, so bile 
zabeležene tudi pri korozijskih preskusih v 
0,1 M NaCl.
hardness. The opposite tendency was 
observed in the HCWCI with 2.0% Al5Ti1B 
(an increase in hardness in the direction 
surface-center) as a result of an increase 
in the degree of transformation of austenite 
into very fine pearlite and martensite (Fig. 
1 and 3) with small fractions of residual 
austenite. 
The Tafel curves of tested HCWCIs 
in 0,1 M NaCl are shown in Fig. 6.a. with 
corresponding corrosion data given in Table 
2. The addition of Al5Ti1B into the HCWCI 
alloys shifts the Tafel curves of modified 
high-chromium white irons toward less 
negative values of potentials in chloride 
corrosion ambiance, Fig.6. a. The shift of 
the Tafel curves toward more noble values 
of the potential due to modifying with 
Al5Ti1B is followed by a decrease in the 
values of the corrosion current densities, 
compared to the basic unmodified base 
alloy, Table 2. The “base alloy” (Cr/C=6,1) 
recorded the highest values of corrosion 
current density (71,1 µA/cm
2
) followed by 
the most negative potential E
(I=0)
 (-458 mV) 
if compared to all other tested modified 
HCWCI alloys in 0,1 M NaCl. The HCWCI 
alloy with 0,5 wt.% Al5Ti1B (Cr/C=6) 
recorded the lowest values of corrosion 
current density in 0,1 M NaCl (23,3 µA/cm2) 
and calculated the value of corrosion rate 
(0,2 mm/year). Similar values of corrosion 
currents (and corrosion rates) for HCWCI 
alloys with the addition of 0,5 wt.% Al5Ti1B 
(Cr/C=6) and 1,0 wt.% Al5Ti1B (Cr/C=6,3) 
are recorded in 0,1 M NaCl. The equivalent 
behavior of HCWCI alloys is indicated by 
testing in fresh water, Fig. 6.b. Tafel curves 
of modified high-chromium white irons are 
placed in the fields of les negative values 
of potentials compared to the Tafel curve 
of the base alloy. The base HCWCI alloy 
(Cr/C=6,1) recorded the value of corrosion 
current density of 21,5 µA/cm2 followed by 
the most negative potential E
(I=0)
 (-389 mV) 

162 Livarski vestnik, letnik 70, št. 3/2023 
Korozijski podatki, pridobljeni z linearno 
polarizacijo zlitin HCWCI v 0,1 M NaCl in 
vodi, so prikazani v Preglednici 3. Tako 
kot pri preskušanju v raztopini natrijevega 
klorida se z dodatkom Al5Ti1B zlitinam 
HCWCI vrednosti E
(I=0)
 vseh modificiranih 
zlitin v primerjavi z osnovno nemodificirano 
zlitino HCWCI v obeh korozijskih okoljih 
premaknejo k bolj žlahtnim vrednostim 
potencialov. Zaznanemu premiku 
potenciala E(I=0) proti žlahtnim vrednostim 
if compared to all modified HCWCI alloys, 
Table 2. Similar values of E
(I=0)
 for HCWCI 
alloys containing 0,5 wt.% (Cr/C=6) and 
1,0 wt.% (Cr/C=6,3) of Al5Ti1B are also 
recorded, as well as in corrosion tests in 
0,1M NaCl.
Corrosion data obtained by linear 
polarization of HCWCI alloys in 0,1 M NaCl 
and water are presented in Table 3. As 
well as when testing in a chloride solution, 
the addition of Al5Ti1B into the HCWCI 
  
Slika 6. Taflove krivulje osnovnih in modificiranih zlitin HCWCI v (a) 0,1 M NaCl in (b) sladki vodi
Figure 6. Tafel curves of HCWCI base and modified alloys in (a) 0,1 M NaCl and (b) fresh wate
Preglednica 2. Rezultati korozije zlitin HCWCI v 0,1 M NaCl in vodi; Taflove ekstrapolacije
Table. 2. Corrosion results of HCWCI alloys in 0,1 M NaCl and water; Tafel extrapolations
Vrsta zlitine /  
Type of alloy
Korozijsko okolje / Corrosion ambiance: 0,1 M NaCl
OCP [mV]
Stopnja korozije [mm/leto] /  
Corrosion rate [mm/year]
E
(I=0)
, [mV] I
corr
,[µA/cm
2
]
Osnovni / Base HCWCI -436 0,637 -458 71,1
HCWCI + 0,5 wt.% AlTiB -388 0,200 -372 23,3
HCWCI + 1,0 wt.% AlTiB -418 0,210 -440 23,5
HCWCI + 2,0 wt.% AlTiB -327 0,353 -359 40,6
Korozijsko okolje: voda / Corrosion ambience: water
Vrsta zlitine /  
Type of alloy
OCP [mV]
Stopnja kor. [mm/leto] /  
Corrosion rate [mm/year]
E
(I=0)
, [mV] I
corr
,[µA/cm
2
]
Osnovni / Base HCWCI -387 0,192 -389 21,54
HCWCI + 0,5 wt.% AlTiB -266 0,118 -304 13,52
HCWCI + 1,0 wt.% AlTiB -271 0,174 -297 19,93
HCWCI + 2,0 wt.% AlTiB -212 0,347 -250 39,87

 Livarski vestnik, letnik 70, št. 3/2023 163
potencialov sledijo nižji korozijski tokovi/
stopnje, izmerjeni v obeh uporabljenih 
korozijskih medijih, 0,1 M NaCl in sladki 
vodi, Preglednica 3 in Slika 7..
Zlitina HCWCI, ki vsebuje 0,5 wt.% 
Al5Ti1B, je imela najnižjo vrednost 
korozijskega toka v 0,1 M NaCl (7,59 µA/
cm
2
) in v sladki vodi (3,29 µA/cm
2
), v 
primerjavi z osnovno zlitino HCWCI in 
drugimi modificiranimi zlitinami je bila manj 
alloys shifts the values of E(I=0) of all 
modified alloys toward more noble values 
of potentials in both corrosion ambiances, 
compared to the base unmodified HCWCI 
alloy. The recorded shift of the potential 
E(I=0) towards noble potential values is 
followed by lower corrosion currents/rates 
measured in both used corrosion media, 
0,1 M NaCl and fresh water, Table 3 and 
Fig.7.
a) b) 
Slika 7. Vpliv dodatka Al5Ti1B na I
corr
 zlitin HCWCI v (a) 0,1 M NaCl in (b) sladki vodi; linearna 
polarizacija
Figure 7. The influence of the Al5Ti1B addition on Icorr of HCWCI alloys, in (a) 0,1 M NaCl and (b) 
fresh water; linear polarization
Preglednica 3. Rezultati korozije zlitin HCWCI v 0,1 M NaCl in vodi; linearna polarizacija
Table. 3. Corrosion results of HCWCI alloys in 0,1 M NaCl and water; linear polarization
Vrsta zlitine /  
Type of alloy
Korozijsko okolje / Corrosion ambiance: 0,1 M NaCl
Stopnja kor. [mm/leto] /  
Corrosion rate [mm/year]
Rp, 
[kΩ]
E
(I=0)
, [mV] I
corr
,[µA/cm
2
]
Osnovni / Base HCWCI
0,319 0,609 -392 35,66
HCWCI + 0,5 wt.% AlTiB
0,066 2,861 -331 7,59
HCWCI + 1,0 wt.% AlTiB
0,110 1,721 -359 12,62
HCWCI + 2,0 wt.% AlTiB
0,234 0,807 -283 26,91
Korozijsko okolje: voda / Corrosion ambience: water
Vrsta zlitine /  
Type of alloy
Stopnja kor. [mm/leto] /  
Corrosion rate [mm/year]
Rp, 
[kΩ]
E
(I=0)
, [mV] I
corr
,[µA/cm
2
]
Osnovni / Base HCWCI
0,049 3,951 -348 5,50
HCWCI + 0,5 wt.% AlTiB
0,029 6,590 -226 3,29
HCWCI + 1,0 wt.% AlTiB
0,035 5,426 -235 4,00
HCWCI + 2,0 wt.% AlTiB
0,048 3,946 -178 5,51

164 Livarski vestnik, letnik 70, št. 3/2023 
korodirana. Osnovna zlitina HCWCI je imela 
najvišje vrednosti gostote korozijskega toka 
in je bila podvržena večji koroziji tako v 
0,1 M NaCl kot v sladki vodi v primerjavi 
z vsemi preskušenimi zlitinami HCWC, 
modificiranimi z Al5Ti1B.
Dodatek 0,5 wt.% Al5Ti1B premakne 
potencial E
(I=0)
 v bolj žlahtna območja 
(-226 mV), sledijo nižje vrednosti 
gostote korozijskega toka (3,29 µA/
cm
2
) v primerjavi z nemodificirano zlitino. 
Nadaljnje povečanje vsebnosti Al5Ti1B 
povzroči povečanje gostote korozijskega 
toka, pri čemer so bile za zlitino HCWC, ki 
vsebuje 2,0 wt.% Al5Ti1B, in osnovno zlitino 
zabeležene podobne vrednosti I
corr
. Opaziti 
je mogoče, da so medsebojna razmerja 
med korozijskimi značilnostmi, pridobljena 
z linearnim polarizacijskim preskusom 
v sladki vodi, podobna razmerjem, 
zabeleženim s potenciodinamičnimi 
(Taflovimi) polarizacijskimi preskusi. Glede 
na zagotovljene korozijske lastnosti je zlitina 
HCWCI, modificirana z 0,5 wt.% Al5Ti1B, 
pokazala znatno zmanjšanje korozijskih 
izgub, z najboljšo korozijsko odpornostjo v 
primerjavi s preskušeno osnovno zlitino in 
drugimi modificiranimi zlitinami HCWCI.
4 Sklepi
Dodatek Al5Ti1B vpliva na postopek 
strjevanja krogel iz belega železa z visoko 
vsebnostjo kroma in na transformacije v 
trdnem stanju med ohlajanjem ulitih krogel. Z 
modifikacijo HCWCI z dodatkom inokulanta 
Al5Ti1B lahko zagotovimo bistveno bolj fino 
strukturo. Najbolj izrazit učinek je opazen 
pri dodatku 0,5 wt.% Al5TiB1.
Dodatek 0,5 wt.% Al5Ti1B povzroči 
povečanje povprečne vrednosti trdote v 
primerjavi z osnovnim HCWCI in zmanjša 
razpršenost vrednosti trdote na prerezu 
The HCWCI alloy containing 0,5 wt.% 
of Al5Ti1B recorded the lowest value of 
corrosion current in 0,1 M NaCl (7,59 µA/
cm
2
) and in fresh water (3,29 µA/cm
2
) 
and suffered less corrosion compared to 
the base HCWCI alloy and other modified 
alloys. The base HCWCI alloy had the 
highest values of corrosion current density 
and undergo more corrosion in both 0,1 M 
NaCl and fresh water compared to all tested 
HCWC alloys modified with Al5Ti1B.
The addition of 0,5 wt.% of Al5Ti1B 
shifts the potential E
(I=0)
 towards more noble 
regions (-226 mV), followed by lower values 
of the corrosion current density (3,29 µA/
cm
2
) compared to the unmodified alloy. 
A further increase in the Al5Ti1B content 
causes an increase in the corrosion current 
density, noting that similar I
corr
 values were 
recorded for the HCWC alloy containing 
2,0 wt.% Al5Ti1B and the base alloy. It 
is noticeable that the mutual relations 
between the corrosion characteristics 
obtained by the linear polarization test 
in fresh water are similar to the relations 
recorded by the potentiodynamic (Tafel) 
polarization tests. According to the obtained 
corrosion characteristics, the HCWCI alloy 
was modified with 0,5 wt.% Al5Ti1B showed 
a significant reduction in corrosion losses, 
with the best corrosion resistance compared 
to the tested base alloy and other modified 
HCWCI alloys.
4 Conclusion
The addition of Al5Ti1B affects the 
solidification process of high-chromium 
white iron balls and the transformations in 
the solid state during the cooling of the cast 
balls. A much finer structure can be obtained 
by modifying of HCWCIs with the addition 
of Al5Ti1B inoculant. The most pronounced 

 Livarski vestnik, letnik 70, št. 3/2023 165
krogel, kar je posledica bolj homogene 
strukture.
Dodatek Al5Ti1B zlitinam HCWCI 
premakne Taflove krivulje modificiranih 
HCWCI proti manj negativnim vrednostim 
potencialov v obeh uporabljenih korozijskih 
okoljih, sledi zmanjšanje vrednosti gostot 
korozijskih tokov v primerjavi z osnovno 
nemodificirano osnovno zlitino. Zlitina 
HCWCI z 0,5 %Al5Ti1B (Cr/C=6) je v obeh 
uporabljenih korozijskih okoljih (0,1 M NaCl 
in sladka voda) dosegla najnižje vrednosti 
gostote korozijskega toka in izračunane 
hitrosti korozije, prav tako je bila tudi najbolj 
korozijsko odporna izmed preizkušenih 
zlitin HCWCI.
Glede na zabeležene korozijske 
podatke in vrednosti trdote je zlitina, 
modificirana z 0,5 wt.% Al5Ti1B, zagotovila 
optimalno kombinacijo preskušenih 
lastnosti. Na podlagi rezultatov raziskave je 
prav tako mogoče sklepati, da je mogoče 
predzlitino Al5Ti1B uporabljati kot cepivo v 
belih litinah z visoko vsebnostjo kroma za 
krogle za mletje.
5 Zahvala
To delo sta podprla Ministrstvo za 
izobraževanje, znanost in tehnološki 
razvoj Republike Srbije in Ministrstvo za 
gospodarski razvoj Črne gore v okviru 
pogodbe št. E!13302CastBalls: White iron 
composition and processing design for 
highly efficient casted milling balls.
effect is observed in the case of the addition 
of 0,5 wt.% Al5TiB1.
The addition of 0,5 wt.% Al5Ti1B 
causes an increase in the average hardness 
value, if compared to the base HCWCI 
and reduces the dispersion of hardness 
values on the cross-section of the balls, as 
a consequence of a more homogeneous 
structure.
The addition of Al5Ti1B into the 
HCWCI alloys shifts the Tafel curves of 
modified HCWCIs toward less negative 
values of potentials in both used corrosion 
ambiances, followed by a decrease in the 
values of the corrosion current densities, 
compared to the basic unmodified base 
alloy. The HCWCI alloy with 0,5 %Al5Ti1B 
(Cr/C=6) recorded the lowest values of 
corrosion current densities, and calculated 
corrosion rates, in both used corrosion 
ambiances (0,1 M NaCl and fresh water), 
with the best corrosion resistance between 
tested HCWCI alloys.
According to recorded corrosion data 
and hardness values, the alloy was modified 
by 0,5 wt.% Al5Ti1B,showed the optimal 
combination of tested properties. Based on 
the obtained research results, it can be also 
concluded that Al5Ti1B master alloy can be 
used as a modifier in high-chromium white 
cast irons for grinding balls.
5 Acknowledgment
This work has been supported by the 
Ministry of Education, Science and 
Technological Development of the Republic 
of Serbia, and the Ministry of Economic 
Development of Montenegro, under 
contract No. E!13302CastBalls: White iron 
composition and processing design for 
highly efficient casted milling balls

166 Livarski vestnik, letnik 70, št. 3/2023 
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