Influence of carbides morphology on fracture toughness of cast steel G200CrMoNi4-3-3
We analyze the influence of small modification of chemical composition of G200CrMoNi4-3-3 cast steel on the morphology of carbides and on material crack resistance. Using the Termo-Calc software the volume fraction of carbide phase was determined and the results correlated with microstructure observ...
Збережено в:
| Дата: | 2008 |
|---|---|
| Автори: | , , |
| Формат: | Стаття |
| Мова: | English |
| Опубліковано: |
Інститут проблем міцності ім. Г.С. Писаренко НАН України
2008
|
| Назва видання: | Проблемы прочности |
| Теми: | |
| Онлайн доступ: | https://nasplib.isofts.kiev.ua/handle/123456789/48430 |
| Теги: |
Додати тег
Немає тегів, Будьте першим, хто поставить тег для цього запису!
|
| Назва журналу: | Digital Library of Periodicals of National Academy of Sciences of Ukraine |
| Цитувати: | Influence of carbides morphology on fracture toughness of cast steel G200CrMoNi4-3-3 / Z. Stradomski, A. Pirek, D. Dyja // Проблемы прочности. — 2008. — № 1. — С. 137-140. — Бібліогр.: 6 назв. — англ. |
Репозитарії
Digital Library of Periodicals of National Academy of Sciences of Ukraine| id |
nasplib_isofts_kiev_ua-123456789-48430 |
|---|---|
| record_format |
dspace |
| spelling |
nasplib_isofts_kiev_ua-123456789-484302025-02-23T17:56:10Z Influence of carbides morphology on fracture toughness of cast steel G200CrMoNi4-3-3 Влияние морфологии карбидов на вязкость разрушения литой стали G200CrMoNi4-3-3 Stradomski, Z. Pirek, A. Dyja, D. Научно-технический раздел We analyze the influence of small modification of chemical composition of G200CrMoNi4-3-3 cast steel on the morphology of carbides and on material crack resistance. Using the Termo-Calc software the volume fraction of carbide phase was determined and the results correlated with microstructure observations. Crack resistance of cast steel was determined using SENB specimens and finding critical values of stress intensity factor KQ. Metallographic and fractographic observations of fracture surfaces allowed identifying the mechanism of cracking. Исследуется влияние незначительной модификации химического состава литой стали G200СгМоNi4-3-3 на морфологию карбидов и трещиностойкость материала. С использованием расчетной программы Termo-Calc были выполнены оценка объемной доли карбидной фазы и сравнительный анализ полученных результатов с данными микрструктурных исследований. Трещиностойкость литой стали исследовалась на образцах с краевой трещиной, для которых определялись критические значения коэффициента интенсивности напряжений KQ. Металлографические и фрактографические исследования поверхностей разрушения позволили определить механизм трещинообразования. 2008 Article Influence of carbides morphology on fracture toughness of cast steel G200CrMoNi4-3-3 / Z. Stradomski, A. Pirek, D. Dyja // Проблемы прочности. — 2008. — № 1. — С. 137-140. — Бібліогр.: 6 назв. — англ. 0556-171X https://nasplib.isofts.kiev.ua/handle/123456789/48430 539.4 en Проблемы прочности application/pdf Інститут проблем міцності ім. Г.С. Писаренко НАН України |
| institution |
Digital Library of Periodicals of National Academy of Sciences of Ukraine |
| collection |
DSpace DC |
| language |
English |
| topic |
Научно-технический раздел Научно-технический раздел |
| spellingShingle |
Научно-технический раздел Научно-технический раздел Stradomski, Z. Pirek, A. Dyja, D. Influence of carbides morphology on fracture toughness of cast steel G200CrMoNi4-3-3 Проблемы прочности |
| description |
We analyze the influence of small modification of chemical composition of G200CrMoNi4-3-3 cast steel on the morphology of carbides and on material crack resistance. Using the Termo-Calc software the volume fraction of carbide phase was determined and the results correlated with microstructure observations. Crack resistance of cast steel was determined using SENB specimens and finding critical values of stress intensity factor KQ. Metallographic and fractographic observations of fracture surfaces allowed identifying the mechanism of cracking. |
| format |
Article |
| author |
Stradomski, Z. Pirek, A. Dyja, D. |
| author_facet |
Stradomski, Z. Pirek, A. Dyja, D. |
| author_sort |
Stradomski, Z. |
| title |
Influence of carbides morphology on fracture toughness of cast steel G200CrMoNi4-3-3 |
| title_short |
Influence of carbides morphology on fracture toughness of cast steel G200CrMoNi4-3-3 |
| title_full |
Influence of carbides morphology on fracture toughness of cast steel G200CrMoNi4-3-3 |
| title_fullStr |
Influence of carbides morphology on fracture toughness of cast steel G200CrMoNi4-3-3 |
| title_full_unstemmed |
Influence of carbides morphology on fracture toughness of cast steel G200CrMoNi4-3-3 |
| title_sort |
influence of carbides morphology on fracture toughness of cast steel g200crmoni4-3-3 |
| publisher |
Інститут проблем міцності ім. Г.С. Писаренко НАН України |
| publishDate |
2008 |
| topic_facet |
Научно-технический раздел |
| url |
https://nasplib.isofts.kiev.ua/handle/123456789/48430 |
| citation_txt |
Influence of carbides morphology on fracture toughness of cast steel G200CrMoNi4-3-3 / Z. Stradomski, A. Pirek, D. Dyja // Проблемы прочности. — 2008. — № 1. — С. 137-140. — Бібліогр.: 6 назв. — англ. |
| series |
Проблемы прочности |
| work_keys_str_mv |
AT stradomskiz influenceofcarbidesmorphologyonfracturetoughnessofcaststeelg200crmoni433 AT pireka influenceofcarbidesmorphologyonfracturetoughnessofcaststeelg200crmoni433 AT dyjad influenceofcarbidesmorphologyonfracturetoughnessofcaststeelg200crmoni433 AT stradomskiz vliâniemorfologiikarbidovnavâzkostʹrazrušeniâlitojstalig200crmoni433 AT pireka vliâniemorfologiikarbidovnavâzkostʹrazrušeniâlitojstalig200crmoni433 AT dyjad vliâniemorfologiikarbidovnavâzkostʹrazrušeniâlitojstalig200crmoni433 |
| first_indexed |
2025-11-24T05:34:30Z |
| last_indexed |
2025-11-24T05:34:30Z |
| _version_ |
1849648711783677952 |
| fulltext |
UDC 539. 4
I n f lu e n c e o f C a r b id e s M o r p h o lo g y o n F r a c tu r e T o u g h n e s s o f C a s t S te e l
G 2 0 0 C r M o N i4 -3 -3
Z . S trad om sk i,1a A . P irek ,1b and D . D y ja 1,c
1 Czestochowa University o f Technology, Institute of Materials Engineering, Czestochowa, Poland
a zbigniew@mim.pcz.czest.pl, b pireka@mim.pcz.czest.pl, c dyjad@mim.pcz.czest.pl
We analyze the influence o f small modification o f chemical composition o f G200CrMoNi4-3-3 cast
steel on the morphology o f carbides and on material crack resistance. Using the Termo-Calc
software the volume fraction o f carbide phase was determined and the results correlated with
microstructure observations. Crack resistance o f cast steel was determined using SENB specimens
and finding critical values o f stress intensity factor K q . Metallographic and fractographic
observations o f fracture surfaces allowed identifying the mechanism o f cracking.
K e y w o rd s : fracture toughness, hardness, carbides, rolls.
In trod u ction . A specific and separate group o f tool materials is represented by steels
and cast steels for m ill rolls. Hypereutectoid steels are largely represented in this group, in
w hich the abrasion resistance is guaranteed by large carbide precipitates according to the
fo llow ing Zum Gahr equation [1]:
j3 /2 T/
w = H r ' ( 1)
w here d is size o f carbides, VV is volum e fracture, X is m ean free path, and W is wear
resistance.
Substantial initial diameters o f rolls as w ell as the need o f m achining related to the
surface wear or changes in the pass geom etry m ake that the heat treatment o f those cast
steels is very limited. It is reduced m ost often to norm alizing and stress-relief annealing.
H ow ever, not too hard pearlitic matrix under conditions o f dry friction show s very good
resistance to abrasive wear, w hat is indicated by literature data [1 -3 ] and ow n authors’
research [4, 5].
Cast steels containing substantial amounts o f carbon have a drawback consisting in the
presence o f large carbide precipitates, w hich create more or less continuous network o f
ledeburite and hypereutectoid cem entite. Such microstructure, though favorable from the
point o f v iew o f tribological properties, strongly reduces the material crack resistance [3, 6].
Taking into consideration the above aspects o f microstructure, w e have used
parameters o f fracture m echanics to optim ize the structure o f G 200C rM oN i4-3-3 cast
steel. The paper has been focused on determination o f the influence o f sm all m odification
o f chem ical com position o f G 200C rM oN i4-3-3 cast steel on the m orphology o f carbides
and the material crack resistance.
M a ter ia ls and M eth od ology . High-carbon low -a lloy cast steel has been used in the
investigation, in w hich diversified carbides content w as obtained through small modification
o f chem ical com position resulting, how ever, in substantial increased in volum e fraction o f
carbide phase. The material for studies w as taken from upper neck o f m ill rolls w eigh ing
around 10000 kg. The chem ical com position (in m ass %) o f studied G 200C rM oN i4-3-3
cast steels w as specified in Table 1.
R esidual stresses and the character o f microstructure w ere analyzed after the as-cast
rolls have been subjected to long-term heat treatment (about 160 h) consisting o f
normalizing and tempering at a temperature below • Based on the chemical composition
© Z. STR A D O M SK I, A. P IR EK , D. D Y JA , 2008
ISSN 0556-171X. Проблемы прочности, 2008, № 1 137
mailto:zbigniew@mim.pcz.czest.pl
mailto:pireka@mim.pcz.czest.pl
mailto:dyjad@mim.pcz.czest.pl
Z. Stradomski, A. Pirek, and D. Dyja
o f exam ined heats the transformation temperatures o f eutectic (E ', C ) and eutectoid (S )
transformation have been determ ined using the Termo-Calc computer software. Volume
fractions o f primary carbides Vyiedeburite and o f hypereutectoid cem entite VV FeaC have
been determined, taking into account also the normalizing temperature (point in A c line).
T a b l e 1
Chemical Composition of the Cast Steels
Rolls C Mn Si P S Cr Ni Mo Cu
1 1.89 0.58 0.42 0.028 0.007 1.15 0.58 0.З7 0.09
2 2.10 0.54 0.58 0.0З8 0.010 1.59 0.48 0.52 0.11
З 2.12 0.72 0.55 0.017 0.005 1.1З 0.74 0.З8 0.12
4 2.16 0.67 0.56 0.025 0.016 1.07 0.62 0.З9 0.14
5 2.20 0.59 0.5З 0.019 0.006 1.11 0.65 0.40 0.11
6 2.22 0.74 0.61 0.026 0.010 1.06 0.64 0.З7 0.12
R esults. The influence o f carbide-forming elem ents on the position o f transformation
temperatures and carbides volum e fractions is specified in Table 2. The obtained results
have been confirm ed by microstructural analysis o f selected rolls. Som e o f micrographs
are presented in Fig. 1.
T a b l e 2
The Influence of Carbide-Forming Elements on the Position of Transformation
Temperatures of Fe-Fe3C System and Carbides Volume Fractions
Rolls Chemical
compositions
Point o f Fe-C Vy yy M yy
C Cr Mo E C ' S ' ledeburite Fe3C ledeburite + Fe3C
% % C % %
1 1.89 1.15 0.37 2.021 4.3745 1.38 0 10.90 10.9
2 2.10 1.43 0.52 2.006 4.3725 1.34 4.14 16.63 20.8
З 2.12 1.1З 0.38 2.020 4.3750 1.34 4.43 17.14 21.6
4 2.16 1.07 0.39 2.019 4.3749 1.34 6.36 18.18 24.5
5 2.20 1.11 0.40 2.018 4.3746 1.34 8.36 19.24 27.6
6 2.22 1.06 0.37 2.021 4.3752 1.34 9.23 19.78 29.0
Fig. 1. Microstructure of the G200CrMoNi4-6-3 cast steel.
138 ISSN 0556-171Х. Проблемы прочности, 2008, № 1
Influence o f Carbides Morphology on Fracture Toughness
Precipitations o f transformed ledeburite in the cast steel o f heat 1, show n in Fig. 1a,
in w hich according to Table 2 the eutectic reaction should not occur, result from
segregation processes ensued by solidification o f m assive castings.
The fraction o f cem entite eutectic, low ered by precipitations o f hypereutectoid
cem entite, increases from the value o f 11 to 29% in cast steel 5 containing 2.22% C
1.06% Cr, and 0.37% M o (Fig. 1). Very sm all changes in carbide-form ing elem ents
contents have a significant influence on carbides amount and morphology. A s compared
to the as-cast state, the norm alizing causes d issolution o f part o f thick network o f
hypereutectoid cem entite, also in a W idmannstatten microstructure.
Hardness w as measured b y the B rinell m ethod according to the PN -E N ISO
6506-1:2002 standard under a load o f 7355 N w ith a steel ball o f a diameter o f 5 mm. The
results are specified in Fig. 2.
W ith increasing volum e fraction o f carbide phase (ledeburite and hypereutectoid
cem entite precipitated in the form o f more or less continuous network) the propensity for
brittle fracture propagation increases in the structure. The crack resistance o f cast steel
w ith diversified content o f carbide phase w as evaluated based on the stress intensity factor
K q , determ ined in accordance w ith A ST M E 399-90 recom m endations. SEN B specim ens,
w ith dim ensions 8 0 X 10X 20m m and m echanically cut 10 m m depth notch, were tested by
three-point bending. R esults o f tests carried out on an M T S-810 testing m achine are
presented in Fig. 3.
Fig. 2 Fig. 3
Fig. 2. Influence o f the carbon content on the hardness.
Fig. 3. Influence o f the chemical composition on the fracture toughness.
Fig. 4 Fig. 5
Fig. 4. Microstructure o f the cast steel below notch in SENB specimens.
Fig. 5. SEM microphotographs of the cast steel.
ISSN 0556-171X. npoôneMbi npoHHocmu, 2008, № 1 139
Z. Stradomski, A. Pirek, and D. Dyja
Approxim ately 200% growth in the carbide phase amount, precipitated m ainly at
primary boundaries o f austenite grains, is accom panied by around 25% decrease in K q
value. Strong decline in K q o f roll 2 results from substantial amount o f phosphorus
precipitated in the form o f brittle phosphorus eutectic, revealed both b y m icroscopic and
fractographic examinations.
The m echanism o f cracking w as analyzed using a scanning and optical m icroscope
on m etallographic m icrosections taken from regions below the specim ens notch root. The
results o f observations show that the fracture proceeds along the network o f transformed
ledeburite and precipitations o f hypereutectoid cem entite (Fig. 4), w hile it goes through
the pearlitic matrix on ly in short sections.
Fractographic exam inations (Fig. 5) confirm observations o f the material m icro
structure. The material is cracking both along grain boundaries ‘decorated’ w ith carbides,
w hat is frequently accom panied by brittle fracture, as w ell as through pearlite grains,
cracking in a ductile m ode. D uctile m echanism o f pearlite cracking is caused m ainly by
fine globular precipitations o f secondary carbides.
C onclu sions
1. Increase in carbon content from 1.89% to 2.22% caused a tw o-tim es increase in
the volum e fraction o f ledeburite and hypereutectoid cem entite, precipitated in the form o f
more or less continuous network.
2. Two-tim es increase in the content o f carbide phase precipitated in the form o f
network resulted in around 20% increase in hardness, parallel to crack resistance
decreased by 25%.
3. L ow value o f stress intensity factor K q for heat 2 resulted from the presence o f
phosphorus eutectic in the alloy misrostructure.
4. The higher than recom m ended phosphorus content, in particular in high-carbon
cast steels, results in substantial increase in their brittleness and m ay cause a premature
damage to the roll.
1. K. H. Zum Gahr, “Microstructure and wear o f materials,” in: Tribology, Series 10, Elsevier,
Amsterdam (1987), pp. 227-252.
2. Y. S. Liao and R. H. Shiue, “Effect o f carbide orientation on abrasion of high Cr white cast
iron,” Wear, 193, 16-24 (1996).
3. You Wang, Tingquan Lei, and Jiajun Liu, “Tribo-metallographic behavior o f high carbon
steels in sliding,” Wear, 231, 1-11 (1999).
4. Z. Stradomski and S. Stachura, “Role o f microstructure in the mechanism o f abrasive wear of
high-carbon steel,” Acta Metall. Slovaca, R. 8, No. 2/2, 388-393 (2002).
5. Z. Stradomski, S. Stachura, A. Pirek, and P. Chmielowiec, “The affect o f the amout of
primary carbides on the wear resistance o f the G200CrMoNi4-6-3 (L200 HNM) cast steel,”
Inzynieria Materialowa, No. 3, XX-XXIII (2004).
6. S. C. Lim, M. F. Ashby, and J. H. Brunton, “Wear-rate transitions and their relationship to
wear mechanisms,” Acta Metall., 35, No. 6, 1343-1348 (1991).
Received 28. 06. 2007
140 ISSN 0556-171X. npo6neMbi nponuocmu, 2008, № 1
|