Hot-cracking of high-alloyed steels evaluated by wedge rolling test
We present a new methodology of determination of hot-cracking f metallic materials, which is based on laboratory application of the wedge rolling test and computer processing of the results obtained. The experiment was made with selected new types of high-alloyed free-cutting (ferritic and austeniti...
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| Опубліковано в: : | Проблемы прочности |
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| Дата: | 2008 |
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Інститут проблем міцності ім. Г.С. Писаренко НАН України
2008
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| Цитувати: | Hot-cracking of high-alloyed steels evaluated by wedge rolling test / I. Schindler, P. Suchanek, S. Rusz, P. Kubecka, J. Sojka, M. Heger, M. Liska, M. Hlisnikovsky // Проблемы прочности. — 2008. — № 1. — С. 60-63. — Бібліогр.: 3 назв. — англ. |
Репозитарії
Digital Library of Periodicals of National Academy of Sciences of Ukraine| _version_ | 1859974893825687552 |
|---|---|
| author | Schindler, I. Suchanek, P. Rusz, S. Kubecka, P. Sojka, J. Heger, M. Liska, M. Hlisnikovsky, M. |
| author_facet | Schindler, I. Suchanek, P. Rusz, S. Kubecka, P. Sojka, J. Heger, M. Liska, M. Hlisnikovsky, M. |
| citation_txt | Hot-cracking of high-alloyed steels evaluated by wedge rolling test / I. Schindler, P. Suchanek, S. Rusz, P. Kubecka, J. Sojka, M. Heger, M. Liska, M. Hlisnikovsky // Проблемы прочности. — 2008. — № 1. — С. 60-63. — Бібліогр.: 3 назв. — англ. |
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| container_title | Проблемы прочности |
| description | We present a new methodology of determination of hot-cracking f metallic materials, which is based on laboratory application of the wedge rolling test and computer processing of the results obtained. The experiment was made with selected new types of high-alloyed free-cutting (ferritic and austenitic) steels. The initial specimens underwent an additional modification enabling easier development of cracks which consisted in milling out of the defined V-shaped notches on a side wall of a specimen. After taking specimens from the rolled material, we performed the metallographic analysis of microstructures by means of optical microscopy as well as a SEM analysis of the cracks. The resulting microstructure in the propagating crack vicinity was markedly influenced by this fracture. In the crack vicinity, a noticeable refinement of grains was observed due to the stress-induced recrystallization and occurrence of deformation zones that were pronounced by the rolled-out and stretched sulphides. As a rule, fractures were created by the ductile failure with visible pits, caused by tearing of sulphides from the material. Susceptibility of the studied steels to hot-cracking was evaluated and compared.
Представлен новый метод определения горячих трещин в металлических материалах, основанный на лабораторной методике прокатки на клин и компьютерной обработке результатов. Эксперименты выполняли на отобранных высоколегированных автоматных (ферритных и аустенитных) сталях нового типа. В исходных образцах фрезеровали У-образные надрезы на их боковой стороне, что облегчало развитие трещин. После вырезки образцов из прокатанного материала выполняли металлографический анализ микроструктуры с помощью оптической микроскопии и анализ трещин с помощью сканирующей микроскопии. Разрушение в значительной мере влияло на микроструктуру, возникшую вблизи развивающейся трещины. Вблизи трещины наблюдалось заметное изменение зерен вследствие рекристаллизации, вызванной напряжениями, и появления зон деформирования, соответствующих прокатанным и вытянутым сульфидам. Как правило, разрушение возникало за счет пластического разрыва с видимыми ямками, вызванного отрывом сульфидов от материала. Оценивалась и сравнивалась склонность изучаемых сталей к образованию горячих трещин.
|
| first_indexed | 2025-12-07T16:23:00Z |
| format | Article |
| fulltext |
UDC 539. 4
H o t -C r a c k in g o f H ig h -A llo y e d S te e ls E v a lu a te d b y W e d g e R o ll in g T e s t
I. S ch in d ler ,1a P . S u c h a n e k , 1 S . R u sz , 1 P . K u b e c k a , 1 J . S o jk a ,1 M . H e g e r , 1
M . L is k a ,2b a n d M . H lis n fk o v sk y 3,c
1 VSB - Technical University of Ostrava, Ostrava, Czech Republic
2 VITKOVICE - Research & Development, Ltd., Ostrava, Czech Republic
3 TRINECKE ZELEZARNY, a.s., Trinec-Stare Mesto, Czech Republic
a ivo.schindler@vsb.cz, b miroslav.liska@vitkovice-vyzkum.cz, c marek.hlisnikovsky@trz.cz
We present a new methodology o f determination o f hot-cracking o f metallic materials, which is
based on laboratory application o f the wedge rolling test and computer processing o f the results
obtained. The experiment was made with selected new types o f high-alloyed free-cutting (ferritic
and austenitic) steels. The initial specimens underwent an additional modification enabling easier
development o f cracks which consisted in milling out o f the defined V-shaped notches on a side wall
o f a specimen. After taking specimens from the rolled material, we performed the metallographic
analysis o f microstructures by means o f optical microscopy as well as a SEM analysis o f the cracks.
The resulting microstructure in the propagating crack vicinity was markedly influenced by this
fracture. In the crack vicinity, a noticeable refinement o f grains was observed due to the
stress-induced recrystallization and occurrence o f deformation zones that were pronounced by the
rolled-out and stretched sulphides. As a rule, fractures were created by the ductile failure with
visible pits, caused by tearing o f sulphides from the material. Susceptibility o f the studied steels to
hot-cracking was evaluated and compared.
K eyw o rd s : hot-cracking, w edge rolling test, free-cutting stainless steel, microstructure.
In trod uction . B ased on the long-term research o f plastic properties o f m etallic
materials, a new m ethodology o f hot form ability w as developed on the basis o f w edge
rolling test realized in laboratory conditions o f the Institute o f M odeling and Control o f
Forming Processes at V A B -T U Ostrava [1]. A sim ple laboratory test perform ed by rolling
o f the wedge-shaped specim en on plain rolls provides a possibility o f effective investigation
o f hot deform ation behavior o f m etallic materials, due to im plem entation o f a w ide range
o f height reductions in a single specim en. The w edge rolling test is suitable for fast
evaluation o f form ability as w ell as, in com bination w ith subsequent m etallographic
analyses, for study o f selected structural processes. Sim ilarity o f laboratory and industrial
rolling provides conditions for the appropriate quantitative com parison and application o f
results in practice.
L ab ora tory H ot R ollin g C ond ition s. The experim ent w as made w ith tw o selected
types o f h igh-alloyed free-cutting stainless steels - the ferritic steel 17043ST iM od (with
0.05 C, 0 .30 Mn, 0.12 Si, 0 .50 S, 16.4 Cr, 0 .34 Ti in wt.%) and the austenitic steel
17247SC uTi (0 .04 C, 0.23 Mn, 0.14 Si, 0 .20 S, 1.41 Cu, 8.9 N i, 17.0 Cr, 0.41 Ti). Initial
w edge specim ens w ith trapezoid shape have the fo llow ing dim ensions: w idth 15 mm,
m inim um thickness 3 m m , length 9 4 -1 5 0 m m (depending on the predicted rolling forces),
and angle 4°34'. They underwent an additional m odification enabling easier developm ent
o f cracks w hich consisted in m illing out o f the defined V -shaped notches on a side w all o f
the specim en. The single-pass rolling o f specim ens in the laboratory m ill stand K 350 was
used, after heating directly to the form ing temperature (i.e., 800-1100°C for the ferritic
steel, and 800-1250°C for the austenitic steel). The rolls w ith diameter o f 140 m m rotated
at nom inal speed o f 110 m in _1 , final thickness o f the rolled specim ens w as 3.2 m m on
average.
© I. SCHINDLER, P. SUCHANEK, S. RUSZ, P. KUBECKA, J. SOJKA, M. HEGER, M. LISKA,
M. HLISNIKOVSKY, 2008
60 ISSN 0556-171X. Проблемы прочности, 2008, № 1
mailto:ivo.schindler@vsb.cz
mailto:miroslav.liska@vitkovice-vyzkum.cz
mailto:marek.hlisnikovsky@trz.cz
Hot-Cracking o f High-AHoyed Steels
Im m ediately after rolling, each specim en w as cooled dow n in a water bath w ith the
aim o f fixing o f the structure. Its plan w as scanned to the form o f bit maps w hich enabled
calculation o f deform ation and speed relations along the length o f the rolled product [2 ].
The program KLIN [1] has been specially developed on the basis o f computer im age
analysis and gradual com parison o f the total and partial volum es o f the initial specim en
and the rolled product. The m ain advantage o f the above program is that it can operate
w ith arbitrary irregular plan shape o f the rolled product and take into account the
influence o f uneven spread and changing thickness along the rolled product in the
calculation. Figure 1 illustrates the shape o f the selected rolled specim en as w ell as the
calculated quantities.
0 25 50 75 100 125 150 175
Length [mm]
Fig. 1. Plan shape o f the rolled out wedge and strain/speed relations along the rolling stock
(austenitic steel, temperature 900°C).
P rocessin g o f E xp erim en ta l D ata. In case o f the rolled products from the austenitic
steel, larger elongation can be observed, as compared to those from the ferritic steel,
whereas the latter exhibited larger spread. The steel 17247SC uTi w as characterized by
relatively poor plastic properties - cracks occurred even at the highest forming temperature
T = 1250oC. W ith decreasing rolling temperature frequency o f cracks raised, w hich is
show n in Table 1 sum marizing the achieved results and Fig. 2a.
T a b l e 1
Occurrence of Cracks in Particular Rolled Out Specimens near Notches V1 to V8
Steel grade T , о C V1 V2 V3 V4 V5 V 6 V7 V 8
17043STiMod 1100
1000 x x x x
900 x x О О
800 x x О О О
17247SCuTi 1250 x x x
1200 x x x x
1100 x x x x x
1000 x x x x x x
900 x x x x О О
800 x x x О О О
Note: X = an evident crack; O = absence of notch due to necessary shortening o f the specimen.
ISSN G556-Î7ÎX. Проблемы прочности, 2008, № І 61
I. Schindler, P. Suchanek, S. Rusz, e t al.
a b
Fig. 2. Details o f cracks after rolling o f selected specimens: (a) austenitic steel rolled at 900°C -
notch V 6 ; (b) ferritic steel rolled at 800°C - notch V5.
The steel 17043STiM od w as characterized b y m uch better plastic properties (Fig. 2b).
N o cracks developed even at the highest form ing temperature 1100°C. W ith decreasing
form ing temperature the number o f cracks initiated in the area o f notches increased, but
differences observed at forming temperatures 800 to 1000°C are by no m eans considerable.
The flow o f the material spread, appearance o f side surfaces and character o f cracks are
very different as compared w ith the investigated austenitic steel.
S tru ctu ra l and F ractu re A n alysis. M icrographs in Fig. 3 demonstrate shapes o f
selected cracks under notches that were subjected to the largest deform ation. Structure o f
the specim ens from steel 17043ST iM od (Fig. 3a) is created purely by ferrite w ith
separated sulphidic inclusions. It is very probable that the m ain cracks were developed
under the material surface: they did not ascend to surface in the notch area. In the vicinity
o f the crack, refinem ent o f the structure is observed due to a higher deform ation and
stress-induced recrystallization. The developed fractures were controlled by a m ixed
(transcrystalline and intercrystalline) ductile fracture m echanism , w hich is illustrated by
Fig. 4a, b (rolling at 1000°C). Specim ens from steel 17247SC uTi have an austenitic
structure w ith very h igh occurrence o f large sulphidic inclusions. Evident deform ation
zones are v isib le in the surroundings o f the propagating crack, pronounced by deform ed
and elongated sulphides (Fig. 3b). Fine cracks, perpendicular to the axis o f the m ain crack,
occur again. The crack started obviously from the surface o f the rolled product but w ith
proceeding deform ation it w as closed by influence o f the material flow. The cracks were
created by a ductile fracture m echanism w ith large occurrence o f pits caused by tearing o f
sulphides from the material - see Fig. 4c, d (rolling at 800°C).
Fig. 3. Metallographic photographs o f cracks under last notches (the largest height reduction):
(a) ferritic steel rolled at 1000°C; (b) austenitic steel rolled at 800°C.
C onclu sions. In this study o f formability, the results o f conventional plastometric
(e.g ., torsion [3]) experim ents exhibited h igh response o f the studied material to varying
therm om echanical conditions o f forming, but have often been burdened w ith data
scattering (m ainly due to premature fracture o f sm all specim ens containing relatively large
defects). The w edge rolling test g ives the results that can be evaluated in a more difficult
w ay and, in addition to that, it is suitable on ly for materials w ith im paired plasticity. In the
62 ISSN 0556-171X. npo6n.eubi npounocmu, 2008, № 1
Hot-Cracking o f High-Alloyed Steels
Fig. 4. Photographs from SEM - view of cracks under last notches (the largest height reduction).
case o f m ost steel grades, it is necessary to im prove its sensitivity by the m illed notches,
w hich function like initiators o f cracks in spreading parts o f the rolled product.
A s far as rollability is concerned (w hich is evaluated by a number o f cracks, their
shape and location in the rolled products), it can be concluded that, in com parison w ith
similar tests perform ed w ith other types o f steel, reduced form ability w as observed for
both free-cutting steels w ith sulphur, notwithstanding som e differences in their deformation
behavior. The specim ens from the ferritic steel 17043ST iM od had better plastic properties
in com parison to the austenitic steel 17247SCuTi.
In the crack surroundings, a refinem ent o f the structure w as observed due to the
stress-induced recrystallization and occurrence o f deformation zones that were pronounced
by the rolled-out and stretched sulphides. A s a rule, fractures w ere created by a tough
failure w ith v isib le pits, caused by tearing o f sulphides from the material containing high
level o f detrimental sulphur.
Acknowledgments. The methodology o f wedge rolling test has been developed under the
Research Plan MSM6198910015 (Ministry o f Education o f the Czech Republic). The tested
materials have been obtained in the framework o f solution o f the Project Impuls FI-IM 2/043
(Ministry o f Industry of the Czech Republic).
1. M. Heger, I. Schindler, J. Franz, and K. Cmiel, in: CO-MAT-TECH 2003, STU Bratislava
(2003), p. 255.
2. P. Suchanek, I. Schindler, P. Turonova, et al., in: Steel Strip 2006, Steel Strip Society (2006),
p. 349.
3. I. Schindler and J. Boruta, Utilization Potentialities o f the Torsion Plastometer, PS Katowice,
Poland (1998).
Received 28. 06. 2007
ISSN 0556-171X. npoöxeMU npouuocmu, 2008, № 1 63
|
| id | nasplib_isofts_kiev_ua-123456789-48459 |
| institution | Digital Library of Periodicals of National Academy of Sciences of Ukraine |
| issn | 0556-171X |
| language | English |
| last_indexed | 2025-12-07T16:23:00Z |
| publishDate | 2008 |
| publisher | Інститут проблем міцності ім. Г.С. Писаренко НАН України |
| record_format | dspace |
| spelling | Schindler, I. Suchanek, P. Rusz, S. Kubecka, P. Sojka, J. Heger, M. Liska, M. Hlisnikovsky, M. 2013-08-19T19:38:59Z 2013-08-19T19:38:59Z 2008 Hot-cracking of high-alloyed steels evaluated by wedge rolling test / I. Schindler, P. Suchanek, S. Rusz, P. Kubecka, J. Sojka, M. Heger, M. Liska, M. Hlisnikovsky // Проблемы прочности. — 2008. — № 1. — С. 60-63. — Бібліогр.: 3 назв. — англ. 0556-171X https://nasplib.isofts.kiev.ua/handle/123456789/48459 539. 4 We present a new methodology of determination of hot-cracking f metallic materials, which is based on laboratory application of the wedge rolling test and computer processing of the results obtained. The experiment was made with selected new types of high-alloyed free-cutting (ferritic and austenitic) steels. The initial specimens underwent an additional modification enabling easier development of cracks which consisted in milling out of the defined V-shaped notches on a side wall of a specimen. After taking specimens from the rolled material, we performed the metallographic analysis of microstructures by means of optical microscopy as well as a SEM analysis of the cracks. The resulting microstructure in the propagating crack vicinity was markedly influenced by this fracture. In the crack vicinity, a noticeable refinement of grains was observed due to the stress-induced recrystallization and occurrence of deformation zones that were pronounced by the rolled-out and stretched sulphides. As a rule, fractures were created by the ductile failure with visible pits, caused by tearing of sulphides from the material. Susceptibility of the studied steels to hot-cracking was evaluated and compared. Представлен новый метод определения горячих трещин в металлических материалах, основанный на лабораторной методике прокатки на клин и компьютерной обработке результатов. Эксперименты выполняли на отобранных высоколегированных автоматных (ферритных и аустенитных) сталях нового типа. В исходных образцах фрезеровали У-образные надрезы на их боковой стороне, что облегчало развитие трещин. После вырезки образцов из прокатанного материала выполняли металлографический анализ микроструктуры с помощью оптической микроскопии и анализ трещин с помощью сканирующей микроскопии. Разрушение в значительной мере влияло на микроструктуру, возникшую вблизи развивающейся трещины. Вблизи трещины наблюдалось заметное изменение зерен вследствие рекристаллизации, вызванной напряжениями, и появления зон деформирования, соответствующих прокатанным и вытянутым сульфидам. Как правило, разрушение возникало за счет пластического разрыва с видимыми ямками, вызванного отрывом сульфидов от материала. Оценивалась и сравнивалась склонность изучаемых сталей к образованию горячих трещин. The methodology of wedge rolling test has been developed under the Research Plan MSM6198910015 (Ministry of Education of the Czech Republic). The tested materials have been obtained in the framework of solution of the Project Impuls FI-IM 2/043 (Ministry of Industry of the Czech Republic). en Інститут проблем міцності ім. Г.С. Писаренко НАН України Проблемы прочности Научно-технический раздел Hot-cracking of high-alloyed steels evaluated by wedge rolling test Оценка образования горячих трещин в высоколегированных сталях методом прокатки на клин Article published earlier |
| spellingShingle | Hot-cracking of high-alloyed steels evaluated by wedge rolling test Schindler, I. Suchanek, P. Rusz, S. Kubecka, P. Sojka, J. Heger, M. Liska, M. Hlisnikovsky, M. Научно-технический раздел |
| title | Hot-cracking of high-alloyed steels evaluated by wedge rolling test |
| title_alt | Оценка образования горячих трещин в высоколегированных сталях методом прокатки на клин |
| title_full | Hot-cracking of high-alloyed steels evaluated by wedge rolling test |
| title_fullStr | Hot-cracking of high-alloyed steels evaluated by wedge rolling test |
| title_full_unstemmed | Hot-cracking of high-alloyed steels evaluated by wedge rolling test |
| title_short | Hot-cracking of high-alloyed steels evaluated by wedge rolling test |
| title_sort | hot-cracking of high-alloyed steels evaluated by wedge rolling test |
| topic | Научно-технический раздел |
| topic_facet | Научно-технический раздел |
| url | https://nasplib.isofts.kiev.ua/handle/123456789/48459 |
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