Ladle and In-mold Modification Methods for Obtaining Castings from Cast Irons with Various Graphite Morphology
Introduction. In the world practice of foundry, modification has reached the status of leading direction of research and applied work to improve the technological and service properties of structural cast irons. Problem Statement. Modifying treatment of liquid iron provides for not only the creati...
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Видавничий дім "Академперіодика" НАН України
2019
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| Назва видання: | Наука та інновації |
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| Цитувати: | Ladle and In-mold Modification Methods for Obtaining Castings from Cast Irons with Various Graphite Morphology / E.V. Zakharchenko, O.I. Shinsky, G.A. Baglyuk, S.I. Klimenko, V.Ya. Kurovsky, E.A. Sirenko, A.L. Goncharov // Наука та інновації. — 2019. — Т. 15, № 1. — С. 53-62. — Бібліогр.: 18 назв. — англ. |
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nasplib_isofts_kiev_ua-123456789-1738722025-02-09T15:49:22Z Ladle and In-mold Modification Methods for Obtaining Castings from Cast Irons with Various Graphite Morphology Ковшові та внутрішньоформові способи модифікування для отримання виливків із чавунів з різною морфологією графіту Ковшовые и внутриформовые способы модифицирования для получения отливок из чугунов с различной морфологией графита Zakharchenko, E.V. Shinsky, O.I. Baglyuk, G.A. Klimenko, S.I. Kurovsky, V.Ya. Sirenko, E.A. Goncharov, A.L. Науково-технічні інноваційні проекти Національної академії наук України Introduction. In the world practice of foundry, modification has reached the status of leading direction of research and applied work to improve the technological and service properties of structural cast irons. Problem Statement. Modifying treatment of liquid iron provides for not only the creation of certain types of modifiers, but also for the development of such methods for introducing modifier into the melt, which are adaptable to the conditions of foundries and take into account the requirements for specific groups of castings. Purpose. To develop a pilot technology for the modification of electric furnace melts of cast iron in unsealed ladle with removable bowl caver and casting molds using complex reagents in the form of pressed powder briquettes and lumpy fused master alloys for the production of castings with lamellar, vermicular and spherical graphite. Materials and Methods. The following materials have been used in the research: gray cast iron, as an object of research for modifying treatment, magnesium-lanthanum-containing lumpy and briquetted powder modifiers, as well as nitrogencontaining lumpy and briquetted powder modifiers to produce cast iron with various forms of graphite, depending on the requirements for castings. Results. A pilot technology for cast irons using pressed powder nitriding briquettes to increase twice the tensile strength of structural gray cast irons (from 200 MPa to 400 MPa) without alloying and heat treatment and a ladle process for modifying molten iron melts with lanthanum-containing modifiers have been developed. The prospects for the production of nitrated iron with vermicular graphite with a sulfur content of up to 0.1% wt. by re-melting the nitrogenous metal charge and fresh and rotary cast irons and therefore with the possible minimum additional introduction of nitrogen in the furnace or in the ladle or in the mold have been substantiated. Conclusions. The pressed powder composite modifiers are recommended as the most effective ones for the mentioned modifying methods, depending on the requirements for castings. Вступ. У світовій практиці ливарного виробництва модифікування досягло статусу провідного напряму науково-дослідних та прикладних робіт з поліпшення технологічних і службових властивостей конструкційних чавунів. Проблематика. Модифікуюча обробка рідких чавунів передбачає створення не тільки певних типів модифі каторів, а й розробку таких способів введення модифікатора в розплав, які адаптовані до умов ливарних цехів, а також враховують вимоги до конкретних груп виливків. Мета. Розробка дослідної технології модифікування електропічних розплавів чавуну в негерметизованих поворотних ківшах і ливарних формах з використанням комплексних реагентів у вигляді пресованих порошкових брикетів і кускових плавлених лігатур для отримання виливків з пластинчастим, вермикулярним і кулястим графітом. Матеріали й методи. Сірий чавун як об'єкт дослідження модифікуючої обробки, магній-лантанвміщуючі кускові та брикетовані порошкові модифікатори, а також азотовмісні кускові й брикетовані порошкові модифікатори для отримання чавунів з різною формою графіту залежно від вимог до виливків. Результати. Розроблено дослідну ківшову технологію азотування чавунів з використанням пресованих порошкових азотвміщуючих брикетів, що дозволяє підвищити тимчасову розривну міцність сірих конструкційних чавунів вдвічі — з 200 МПа до 400 МПа, без легування й термічної обробки, а також розроблено ковшовий процес модифікування розплавів чавунів магній-лантанвміщуючими модифікаторами. Обґрунтовано перспективність виробництва азотованого чавуну з вермикулярним графітом з вмістом сірки до 0,1 % мас. шляхом переплавлення азотної металошихти, а також свіжих і поворотних чавунів, з мінімальним додатковим введенням азоту в піч, ківш чи ливарну форму. Висновки. Пресовані порошкові модифікатори рекомендовано до використання як найбільш ефективні для вказаних способів модифікування залежно від вимог до виливків. Введение. В мировой практике литейного производства модифицирование достигло статуса ведущего направления научно-исследовательских и прикладных работ по улучшению технологических и служебных свойств конструкционных чугунов. Проблематика. Модифицирующая обработка жидких чугунов предусматривает создание не только определенных типов модификаторов, но и разработку таких способов ввода модификатора в расплав, которые адаптированы к условиям литейных цехов, а также учитывают требования к конкретным группам отливок. Цель. Разработка опытной технологии модифицирования электропечных расплавов чугуна в негерметизированных поворотных ковшах и литейных формах с использованием комплексных реагентов в виде прессованных порошковых брикетов и кусковых плавленых лигатур для получения отливок с пластинчатым, вермикулярным и шаровидным графитом. Материалы и методы. Серый чугун, как объект исследования модифицирующей обработки, магний-лантансодержащие кусковые и брикетированные порошковые модификаторы, а также азотсодержащие кусковые и брикетированные порошковые модификаторы для получения чугунов с различной формой графита, в зависимости от предъявляемых требований к отливкам. Результаты. Разработана опытная ковшовая технология азотирования чугунов с использованием прессованных порошковых азотирующих брикетов, позволяющая повысить временную разрывную прочность серых конструкционных чугунов вдвое — с 200 МПа до 400 МПа, без легирования и термической обработки, а также разработан ковшовый процесс модифицирования расплавов чугунов лантансодержащими модификаторами. Обоснована перспективность производства азотированного чугуна с вермикулярным графитом с содержанием серы до 0.1 % масс. путем переплава азотистой металлошихты, а также свежих и возвратных чугунов, что минимизирует дополнительное введение азота в печь, ковш или литейную форму. Выводы. Прессованные порошковые модификаторы рекомендованы к использованию как наиболее эффективные для указанных способов модифицирования в зависимости от требований к отливкам. 2019 Article Ladle and In-mold Modification Methods for Obtaining Castings from Cast Irons with Various Graphite Morphology / E.V. Zakharchenko, O.I. Shinsky, G.A. Baglyuk, S.I. Klimenko, V.Ya. Kurovsky, E.A. Sirenko, A.L. Goncharov // Наука та інновації. — 2019. — Т. 15, № 1. — С. 53-62. — Бібліогр.: 18 назв. — англ. 1815-2066 DOI: doi.org/10.15407/scin15.01.053 https://nasplib.isofts.kiev.ua/handle/123456789/173872 en Наука та інновації application/pdf Видавничий дім "Академперіодика" НАН України |
| institution |
Digital Library of Periodicals of National Academy of Sciences of Ukraine |
| collection |
DSpace DC |
| language |
English |
| topic |
Науково-технічні інноваційні проекти Національної академії наук України Науково-технічні інноваційні проекти Національної академії наук України |
| spellingShingle |
Науково-технічні інноваційні проекти Національної академії наук України Науково-технічні інноваційні проекти Національної академії наук України Zakharchenko, E.V. Shinsky, O.I. Baglyuk, G.A. Klimenko, S.I. Kurovsky, V.Ya. Sirenko, E.A. Goncharov, A.L. Ladle and In-mold Modification Methods for Obtaining Castings from Cast Irons with Various Graphite Morphology Наука та інновації |
| description |
Introduction. In the world practice of foundry, modification has reached the status of leading direction of research and
applied work to improve the technological and service properties of structural cast irons.
Problem Statement. Modifying treatment of liquid iron provides for not only the creation of certain types of modifiers,
but also for the development of such methods for introducing modifier into the melt, which are adaptable to the conditions
of foundries and take into account the requirements for specific groups of castings.
Purpose. To develop a pilot technology for the modification of electric furnace melts of cast iron in unsealed ladle with
removable bowl caver and casting molds using complex reagents in the form of pressed powder briquettes and lumpy fused
master alloys for the production of castings with lamellar, vermicular and spherical graphite.
Materials and Methods. The following materials have been used in the research: gray cast iron, as an object of research
for modifying treatment, magnesium-lanthanum-containing lumpy and briquetted powder modifiers, as well as nitrogencontaining
lumpy and briquetted powder modifiers to produce cast iron with various forms of graphite, depending on the
requirements for castings.
Results. A pilot technology for cast irons using pressed powder nitriding briquettes to increase twice the tensile strength
of structural gray cast irons (from 200 MPa to 400 MPa) without alloying and heat treatment and a ladle process for modifying
molten iron melts with lanthanum-containing modifiers have been developed. The prospects for the production of nitrated
iron with vermicular graphite with a sulfur content of up to 0.1% wt. by re-melting the nitrogenous metal charge and fresh
and rotary cast irons and therefore with the possible minimum additional introduction of nitrogen in the furnace or in the
ladle or in the mold have been substantiated.
Conclusions. The pressed powder composite modifiers are recommended as the most effective ones for the mentioned
modifying methods, depending on the requirements for castings. |
| format |
Article |
| author |
Zakharchenko, E.V. Shinsky, O.I. Baglyuk, G.A. Klimenko, S.I. Kurovsky, V.Ya. Sirenko, E.A. Goncharov, A.L. |
| author_facet |
Zakharchenko, E.V. Shinsky, O.I. Baglyuk, G.A. Klimenko, S.I. Kurovsky, V.Ya. Sirenko, E.A. Goncharov, A.L. |
| author_sort |
Zakharchenko, E.V. |
| title |
Ladle and In-mold Modification Methods for Obtaining Castings from Cast Irons with Various Graphite Morphology |
| title_short |
Ladle and In-mold Modification Methods for Obtaining Castings from Cast Irons with Various Graphite Morphology |
| title_full |
Ladle and In-mold Modification Methods for Obtaining Castings from Cast Irons with Various Graphite Morphology |
| title_fullStr |
Ladle and In-mold Modification Methods for Obtaining Castings from Cast Irons with Various Graphite Morphology |
| title_full_unstemmed |
Ladle and In-mold Modification Methods for Obtaining Castings from Cast Irons with Various Graphite Morphology |
| title_sort |
ladle and in-mold modification methods for obtaining castings from cast irons with various graphite morphology |
| publisher |
Видавничий дім "Академперіодика" НАН України |
| publishDate |
2019 |
| topic_facet |
Науково-технічні інноваційні проекти Національної академії наук України |
| url |
https://nasplib.isofts.kiev.ua/handle/123456789/173872 |
| citation_txt |
Ladle and In-mold Modification Methods for Obtaining Castings from Cast Irons with Various Graphite Morphology / E.V. Zakharchenko, O.I. Shinsky, G.A. Baglyuk, S.I. Klimenko, V.Ya. Kurovsky, E.A. Sirenko, A.L. Goncharov // Наука та інновації. — 2019. — Т. 15, № 1. — С. 53-62. — Бібліогр.: 18 назв. — англ. |
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Наука та інновації |
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53
Zakharchenko, E.V. 1, Shinsky, O.I. 1, Baglyuk, G.A. 2, Klimenko, S.I. 1,
Kurovsky, V.Ya. 2, Sirenko, E.A. 1, and Goncharov, A.L. 1
1 Physico-Technological Institute of Metals and Alloys, the NAS of Ukraine,
34/1, Acad. Vernadsky Blvd., Kyiv, 03680, Ukraine,
+380 44 424 3515, metal@ptima.kiev.ua
2 Frantsevich Institute for Problems of Materials Science, the NAS of Ukraine,
3, Krzhizhanovsky St., Kyiv, 03142, Ukraine,
+380 44 390 8751, vvk@ipms.kiev.ua
LADLE AND IN-MOLD MODIFICATION METHODS
FOR OBTAINING CASTINGS FROM CAST IRONS
WITH VARIOUS GRAPHITE MORPHOLOGY
© ZAKHARCHENKO, E.V., SHINSKY, O.I., BAGLYUK, G.A.,
KLIMENKO, S.I., KUROVSKY, V.Ya., SIRENKO, E.A.,
and GONCHAROV, A.L., 2019
Introduction. In the world practice of foundry, modification has reached the status of leading direction of research and
applied work to improve the technological and service properties of structural cast irons.
Problem Statement. Modifying treatment of liquid iron provides for not only the creation of certain types of modifiers,
but also for the development of such methods for introducing modifier into the melt, which are adaptable to the conditions
of foundries and take into account the requirements for specific groups of castings.
Purpose. To develop a pilot technology for the modification of electric furnace melts of cast iron in unsealed ladle with
removable bowl caver and casting molds using complex reagents in the form of pressed powder briquettes and lumpy fused
master alloys for the production of castings with lamellar, vermicular and spherical graphite.
Materials and Methods. The following materials have been used in the research: gray cast iron, as an object of research
for modifying treatment, magnesium-lanthanum-containing lumpy and briquetted powder modifiers, as well as nitrogen-
containing lumpy and briquetted powder modifiers to produce cast iron with various forms of graphite, depending on the
requirements for castings.
Results. A pilot technology for cast irons using pressed powder nitriding briquettes to increase twice the tensile strength
of structural gray cast irons (from 200 MPa to 400 MPa) without alloying and heat treatment and a ladle process for modifying
molten iron melts with lanthanum-containing modifiers have been developed. The prospects for the production of nitrated
iron with vermicular graphite with a sulfur content of up to 0.1% wt. by re-melting the nitrogenous metal charge and fresh
and rotary cast irons and therefore with the possible minimum additional introduction of nitrogen in the furnace or in the
ladle or in the mold have been substantiated.
Conclusions. The pressed powder composite modifiers are recommended as the most effective ones for the mentioned
modifying methods, depending on the requirements for castings.
K e y w o r d s: ladles, intra-form modifying, magnesium-lanthanum- and nitrogen-containing complex modifiers.
ISSN 1815-2066. Nauka innov. 2019, 15(1): 53—62 https://doi.org/10.15407/scin15.01.053
According to the forty-sixth census of world
foundry production [1], the global annual output
of shaped castings of ferrous and non-ferrous al-
loys reaches 100 million metric tons, including
25 million ton CNG (cast iron with nodular
graphite) and CVG (cast iron with vermicular
graphite). 90% of total CNG and CVG tonnage
(22.5 million tons worth about USD 40.5 bil-
lion) is manufactured using ladle modification
methods, while the remaining 10% (2.5 million
tons worth about USD 4.5 billion) is obtained
54 ISSN 1815-2066. Nauka innov. 2019, 15 (1)
Zakharchenko, E.V., Shinsky, O.I., Baglyuk, G.A., Klimenko, S.I., Kurovsky, V.Ya., Sirenko, E.A., and Goncharov, A.L.
by in-mold methods for modifying treatment of
liquid iron. The annual proceeds from sales of
CNG and CVG castings amount to USD 45 bil-
lion, which makes it possible to assess the scale and
significance of this large sector of world found -
ry production.
The most effective ladle method, as the prac-
tice has shown, is a method called tandish-cover
in the USA and known under this name in many
countries. The method involves the use of un-
sealed ladles with a removable or fixed lid-bowl
and a refractory partition in the bottom of the
ladle.
The first versions of tandish-cover ladles were
developed in the USA in the late 1970s [2—5].
They enabled on the whole to solve the actual
problem of economy, simplicity, and safety of the
modification process, to significantly reduce the
pyroeffect and smoke evolution, to increase the
assimilability of magnesium and other modifier
elements up to 70—80% by installing a bowl on
the ladle of a removable or stationary casting lid.
The purpose of this publication is to present
data on modern designs and experience in the op-
eration of unsealed ladle with a lid-bowl, and also
to substantiate the choice of modifiers for the
production of castings from CNG and CVG using
the ladle and the in-mold methods.
UNSEALED LADLES WITH LID, A BOWL
FOR MODIFYING TREATMENT OF LIQUID CAST IRON
This highly efficient and relatively simple
method involves the use of a removable or fixed
lid-refill lid and a pouring outlet. The cast iron
melt is poured through the lid that is a bowl into
the ladle, in the reagent chamber of which there is
a magnesium-containing modifier (Figs. 1, 2).
Figs. 3—6 show several other effective designs
for ladle tandish covers, to release the cast iron
from the ladle through the hole in the same bowl.
In comparison with the known ladle methods
"pour-over" and "sandwich", this method has the
following advantages: a higher and reproducible
assimilation of magnesium (60—80%); the ab-
sence of pyroeffect and a sharp decrease in smoke
evolution; reduced losses of carbon and tempera-
ture of liquid iron; a less violent reaction; a more
efficient ladle design; and a smaller amount of
slag formed during the modifying treatment.
The thickness of steel cover is set taking into
account the weight of refractory lining and liquid
Fig. 1. Scheme of a tandish-cover ladle with a removable cap
on the bowl [6—7]: a — the lid-bowl; b — pouring and ex-
haust hole; c — a spheroidizer or vermicularizer; d — fire-
proof partition; e — the upper level of filling the ladle with
liquid iron; h — average height of the melt layer in the bowl
Fig. 2. Scheme of a tandish-cover ladle with a stationary cap
of a bowl [7]: a — the upper level of the melt (mass — 455 kg);
b — inlet/outlet port; c — fireproof partition; d — MgFeSi
alloy; e — cover material; h — is the average height of the
melt layer in the bowl
h
a
b
c
d
e
h
e
d
c
b a
584
2
4
1
1
0
0
6
1
0 Ф444
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Ladle and In-mold Modification Methods for Obtaining Castings from Cast Irons with Various Graphite Morphology
iron in the sprue bowl. The skirt is a reflector and
the bowl is made of a thinner steel sheet. No spe-
cial refractories for the lid are required. When
calculating the diameter of casting-outlet ope-
ning it is assumed that the molten iron must re-
main in the bowl until the reaction between the
modifier and the cast iron melt ceases.
The calculation is based on the well-known
Ozanna formula for cast iron [5]:
F0 =
G ,
3 μ0,31 hч
where F0 is the area of the cup opening, cm2; 3 is
duration of filling, s; μ is the dimensionless flow
coefficient when the metal flows out of the cup
opening (approximately μ = 0.85); 0.31 is coeffi-
cient with the dimension of kg / (cm2.5 · s); hч is
the average metallostatic head (average height of
the melt layer in the bowl), cm; G is the mass of
the metal poured into the ladle, kg.
When the mass of iron is less than 1 ton, h
should be within 10—15 cm, and the height of
bowl’s cavity should be 2—3 times larger. In lad-
les with a fixed cover for insertion of the magne-
sium modifier into the ladle cavity and relief of
excess pressure, a special hole is provided in the
ladle. To create a reagent and a metal receiving
chamber in the ladle cavity, a refractory separa-
tion partition should be used. The use of partition
and a cover material with appropriate fluxes redu-
ces the intensity of build-up in the ladles. It is de si-
rable to use a circular ring of fibrous ceramic insu-
lators between the lid and the ladle lining, which
acts as a cushion and seals the junction area.
Fig. 4. Scheme of a tandish-cover ladle with a semi-stationary
lid-cup [7]: a — funnel for loading the modifier into the ladle;
b — a gear transmission; c — steel cork; e — filling hole; f —
pouring bowl; g — a passage sealed with a clay mass; h —
modifier of MgSiFe; i — sensor for measuring gravity
Fig. 5. Teak type ladle tandish cover with one port for liquid
cast iron [7]: a — cast-iron ladle cover; b — funnel for loading
the modifier into the ladle; c — pouring bowl; d — cover; e —
device for fixing the ladle cover; f — fireproof packing; g —
spheroidizing modifier; h — refractory tube
Fig. 3. Scheme of a tandish-cover ladle with removable-sli-
ding lid-bowl. Arrows 1, 2 and 3 indicate the direction of mo-
vement of the lid-bowl [7]
1
2
3
3
2
1
а
b
d
e
f
g
h
c
а
f
g
h
i
j
e
b
с
56 ISSN 1815-2066. Nauka innov. 2019, 15 (1)
Zakharchenko, E.V., Shinsky, O.I., Baglyuk, G.A., Klimenko, S.I., Kurovsky, V.Ya., Sirenko, E.A., and Goncharov, A.L.
The variant of the tandish-cover method with
the use of multi-position carousel tables enables
to provide a high performance of spheroidizing
treatment.
Specialized firms in the USA have mastered the
production of several types of tandish-cover lad-
les and supply them to foundries that manufac-
ture CNG castings. American Foundation Funds
have developed a series of 10 models of DE Tait-
cover ladles with a nominal capacity of 0.45 to
4.5 tons (Fig. 7). The ladle consists of three bol-
ted parts: a "Tait-cover" cover, a body, and a de-
tachable bottom. The joints of the assembled
units are sealed with refractory paste. The lid fi-
xed to the upper part of the ladle body, is not re-
moved until the next repair or replacement of the
lining. It consists of a receiving-pouring bowl with
a grooved toe and a hole for the outlet-metal in-
let; tubes for loading a portion of shredded sphe-
roidizer provided with a quick-acting and tightly
fitted weighted cap-latch; self-sealing vent to re-
lieve excess gas pressure and to insert a burner to
preheat the ladle, and a window with a quick-re-
lease door for slag discharge.
The ladle body is equipped with a gear mecha-
nism for turning the ladle and with an upper sus-
pension frame. The removable bottom is divided
by a vertical partition into a reagent- and a metal-
receiving chamber. When the ladle is filled with
cast iron, the bowl must be filled to, at least, half
its height, which prevents aspiration of air into
the ladle.
Accurate weight control of the cast iron is re-
quired to avoid overfilling the ladle and filling
the vent hole and the tube. The rate at which the
metal leaves the ladle depends on the diameter of
the hole in the bowl. The ladles are delivered
without refractories, but are balanced for a cer-
tain thickness of the liner. The delivery set also
includes special metal plates with models for lin-
ing the slag window, the main body, and the bot-
tom. These models have a rigid structure, so the
lining mass for all ladle assemblies, with the ex-
ception of the bowl, can be compacted by tam-
ping, pouring or vibrating (the mass for the bowl
Fig. 6. Teapot type ladle tandish cover with two ports for
liquid cast iron [7]: a — outlet port; b — ladle cover with an
edge grip of the ladle shell; c — cork (plug) used when filling
the ladle with a modifier; d — filling port; e — reflecting
plate; f — a spheroidizer (vermicularizer)
Fig. 7. Scheme of the "De Tait Cover" ladle for spheroi dizing
graphite for processing molten iron [2]
a
b
c
d
e
f
57ISSN 1815-2066. Nauka innov. 2019, 15 (1)
Ladle and In-mold Modification Methods for Obtaining Castings from Cast Irons with Various Graphite Morphology
is sealed only with the packing). The modifier is
loaded through a removable funnel with a diame-
ter of 90 or 115 mm. On average, assimilation of
magnesium in a ladle of the “DE Tait-cover” type
makes up 60—70%, depending on the magnesium
content in the modifier and on other factors. The
experience of the operation of these ladles has
been considered in [3—4].
Alco Stendad Corporation (USA) produces 13
mo dels of tee-tandish teapots with a nominal ca-
pacity of 0.23—4.6 tons (Fig. 8). Pouring and cas-
ting of cast iron are made through the ladle's toe,
and the the modifier is loaded into the rea gent
pocket through a window equipped with a hinged
lid. An automatic system for loading portions of
spheroidizer into a ladlet has been deve loped. As
compared with the methods of pour-over and
tandish cover (in the De Tait-Cover ladles), the
spheroidizing treatment of cast iron in such ladles
provides a saving of about USD 16 per each ton of
pig iron due to a reduction in the consumption of
magnesium ligature and inocu lator ferrosilicon.
There has been a positive experience in the
production of cupola-melt CGS by treatment with
magnesium-containing ligatures in large unsea-
led tandish ladles equipped with a removable lid-
cup [1]. The Institute of Casting Problems of the
NAS of Ukraine has developed and tested this
technology at the iron foundry of the Novo-Kra-
matorsk Machine-Building Plant, using 10- and
20-ton ladles. The assimilation of magnesium
from Mg-REM-Si-Fe master alloy (6—7% Mg,
0.6% REM) is, at least, 60%. Filling of a 10-ton
ladle with cast iron through a hole 100 mm in
dia meter lasts about 3 minutes. The tandish-cov-
er met hod provides sufficiently high properties
of cast iron in the cast state (
в = 530—680 MPa,
= 330—420MPa, = 3—8%), at a moderate hard-
ness (197—229НВ).
COMPLEX MODIFIERS FOR SPHEROIDIZATION
AND VERMICULARIZATION OF GRAPHITE
IN CAST IRON BY THE LADLE AND INTRA-MOLD
MODIFICATION METHODS
In the composition of complex modifiers, re-
gardless of the method of their production and
the method of modification (in ladles or inside
molds), it is recommended to introduce magne-
sium and lanthanum together without any other
rare-earth metals (especially, cerium) in all cases
where it is required to obtain castings from cast
iron with increased ductility.
Fig. 8. Diagram of a teapot of the "mod-tandish" type for spheroidizing graphite for pro-
cessing molten iron [2]
58 ISSN 1815-2066. Nauka innov. 2019, 15 (1)
Zakharchenko, E.V., Shinsky, O.I., Baglyuk, G.A., Klimenko, S.I., Kurovsky, V.Ya., Sirenko, E.A., and Goncharov, A.L.
The combination of magnesium and lanthanum
into the composition of complex modifiers for
cast iron is not accidental. Magnesium is known
to be the most economical and affordable gra-
phite spheroid in cast iron. Lanthanum is the most
powerful plasticizer of cast irons, regardless of
graphite morphology. It does not form carbides,
due to which it provides a high level of plasticity,
resistance to mechanical and thermal shocks in a
wide range of temperatures, an increase in the
specific number of spheroids (2—3 times, more
than 800 spheroids/mm2) [8] and in the degree of
graphite spheroidization. An exceptionally valu-
able technological property of lanthanum is the
ability to prevent the formation of gas-shrinkage
macrodefects and microporosity in castings and
to improve the quality of the cast surface.
A comparison of the physical properties of lan-
thanum and magnesium (Table 1) shows that, as
compared with magnesium, lanthanum is poten-
tially much safer and more technologically effi-
cient in modifying the treatment of molten iron,
retains the melt modifying effect for a longer
time, has a higher and stable assimilation.
There is one more important qualitative advan-
tage of lanthanum: in the case of lanthanum, the li-
miting solubility in liquid CNG is unlimited, whi-
le in the case of magnesium, it is very low [10—11].
Let's compare the main technical and econo-
mic indices of the two most dissimilar types of
complex modifiers, namely, the fractionated fu-
sed ligatures and the pressed powder briquettes
(Table 2).
The production of 1 ton fractionated master al-
loys obtained by conventional technology pro-
vides a ferrosilicon compound with magnesium
(with magnesium losses reaching 30%), ligature
casting, crushing and sieving by fractions (yield
of 75—80%, the rest is waste in the form of pul-
verized fractions that are not used for modifica-
tion due to the instability of their assimilation).
At the same time, the variation in magnesium
content in the ligature of the same brand reaches
1—2% for magnesium, which is 20—25% of the
magnesium content in the ligature. The produc-
tion of 1 ton briquetted modifiers by the powder
metallurgy technology provides for the operation
of mixing the original powder components and
the briquetting operation. At the same time, en-
ergy consumption for the production of a ton
briquetted powder modifier as compared with
the production of a ton cast fractionated ligature
requires 8—10 times less electricity. The loss of
magnesium in the production of briquetted mo-
difiers is no more than 0.1%, the magnesium con-
tent in the same brand is, at most, 0.1%, which
enables to reduce the consumption of ligature for
modifying cast iron 1.3—1.4 times due to the sta-
bility of its composition.
Table 2
The Technical and Economic Indicators
of Complex Modifiers in the Form
of Fused Fractionated Ligatures and Pressed
Powder Briquettes
Index, Unit
Type of modifier
Fractionated
fused master
alloy
Powder
briquette
modifier
Electricity consumption, kW/h 1500 ± 200 140 ± 20
Assimilation of magnesium in the
manufacture of a modifier, % 70 ± 10 100
Scatter about of magnesium
content in one brand, % by mass. 2 ± 1 0.1
Waste of modifier at crushing, % 30 ± 10 0
Relative consumption of the
modifier, % 100 75 ± 5
Table 1
The Physical Properties of Lanthanum
and Magnesium [9]
Property, unit of measure
Element
Lanthanum Magnesium
Density at 20 °C, g/cm3 6.174 1.74
Melting point, °С 920 651
Boiling point, °С 3469 1103
Latent heat of fusion, kcal/g * 17.3 0.0822
Latent heat of evaporation, kcal/g * 690 1337
The specific heat at 20 °C, kcal/g *
deg 0.048 0.250
Note: * – 1 kcal = 4.184 kJ.
59ISSN 1815-2066. Nauka innov. 2019, 15 (1)
Ladle and In-mold Modification Methods for Obtaining Castings from Cast Irons with Various Graphite Morphology
One of the most important advantages of pow-
dered briquetted modifiers is the possibility of
introducing into their composition components
that cannot be introduced in the cast ligatures in-
cluding, the use of dusty wastes of ferroalloy pro-
duction, serial powder materials, fluxes, inocula-
tors, nitriding or carbide stabilizing constituents,
and ultrafine powders of refractory compounds
(carbides, nitrides, carbonitrides, etc.). The prin-
cipal feature of the powder briquetted modifiers
obtained by the developed technology, in con-
trast to the known ones, is the absence of any
binders that pollute the modifiable alloy in their
composition.
The technology of powder metallurgy enables
to vary the shape (Fig. 9), dimensions, mass, and
chemical composition of briquettes within a wide
range, flexibly adapting them to the conditions of
a particular foundry production (for example, ul-
tradispersed compounds — inoculators, nitrides,
borides of refractory compounds, etc.).
The results are not in favor of ligatures due to
the use of the melting process.
Theoretical and technological foundations of
industrial production of powder briquette modi-
fiers have been developed jointly by two institu-
tes of the NAS of Ukraine: the Institute of Prob-
lems of Materials Science and the Physico-Tech-
nological Institute of Metals and Alloys [12—14].
The lanthanum-containing modifiers ensure
equiaxial crystallization of CNG with an in-
creased number of uniformly distributed centers
of SG crystallization [15]. In this case, the thick-
ness of the columnar crystallization zone is great-
ly reduced, leaving more free channels to com-
pensate for the shrinkage processes. Thus, as
0.15% wt. is added to the jet of cast iron and the
inoculator contains successively 0%, 1.2%, and
2.4% wt. lanthanum, the thickness of the solid-
hard crust of the cylindrical casting at the time
when 50% of the cast iron melt mass is solidified
amounts to 6 mm, 2 mm, and 0.5 mm, respective-
ly, i.e. decreased 12 times [14]. A semi-solid cast
zone contains more solids, which reduces the
amount of liquid phase to compensate for the re-
sulting shrinkage. Lanthanum generates com-
pounds that increase the intensity of nucleation
in the liquid phase of the crystallizing CNG. For
the CNGs obtained by treatment with magne-
sium-lanthanum-containing modifiers, the so-
called bimodal or asymmetric distribution of SG
inclusions is typical, with the number of small
globules predominating in comparison with the
number of large ones. Probably small globules are
formed at the late stage of the SG formation; at
the final stage of the crystallization cycle, when
the late increase in the number of SG inclusions
prevents further shrinkage [18].
We give some data on the composition and ef-
ficiency of industrial use of Mg-La containing
modifiers. Foundry enterprises increase the use
of magnesium-lanthanum-containing modifiers,
in which cerium and other rare-earth metals are
completely replaced by lanthanum. In particular,
100—150 ton FSMg5La modifier (5.2—6.0 Mg,
0.3—0.45 La, 0.4—0.6 Ca, 43—49 Si, 0.8—1.2 Al,
the rest is Fe) [18] is produced at the Chelyabinsk
Research Institute of Metallurgy. NIIM serially
produces modifiers of two more brands [16]:
FeSiМg7La (5.8—6.4 Mg; 0.35—0.55 La; 0.4—
0.6 Ca; 43—49 Si; 0.8—1.2 Al; the rest is Fe);
FeSiМg10La (5.5—6.2 Mg; 0.35—0.6 La; 0.8—
1.2 Ca; 43—49 Si; 0.5—1.0 Al; the rest is Fe).
Fig. 9. Powdered briquette-modifiers of various purposes
for ladle and intramodal ways of production of CNG
and CVG
60 ISSN 1815-2066. Nauka innov. 2019, 15 (1)
Zakharchenko, E.V., Shinsky, O.I., Baglyuk, G.A., Klimenko, S.I., Kurovsky, V.Ya., Sirenko, E.A., and Goncharov, A.L.
Other modifier grades are also produced in the
form of ligatures containing Mg and La, using the
mixture as purified from harmful impurities (As,
Sb, Pb, Bi, Ti, S, P) as possible. By rapid quench-
ing of the melt, self-shedding of casted modifiers
is prevented during their storage and transpor-
tation.
According to consumers of Lamet spheroidi-
zing modifier manufactured by Elkem ASA, Nor-
way (5.0—6.0 Mg, 0.25—0.4 La, 0.4—0.6 Ca, 44—
48 Si, 0.8—1.2 Al, the rest is Fe), the Lamet
modifier has made it possible to significantly im-
prove the clean liness of the surface of cast crank-
shaft from the CNG and significantly reduced the
laboriousness of the castings machining due to a
reduction in the size of graphite globules [18].
Having replaced the FSMG5 master alloy (4.5—
6.5 Mg, 0.7—1.2 rare- earth metal, 0.2—1.0 Ca,
45—55 Si, 1.2 Al) by La met master alloy, one
foundry company decreased the average number
of products with shrinkage defects from 18.92%
to 1.27%, i.e. almost fifteen times. The cost of
good casting has decreased by 14.2%, on average.
The annual economic effect on ly due to reducing
the cost of casting is estimated at EUR 2.2 mil-
lion with the use of intra-mold modified 50 thou-
sand tons of liquid iron [18].
So, the use of unsealed ladles with a lid-cup for
the modification of cast iron melts in the produc-
tion of castings from CNG and CVG, together
with the use of magnesium-lanthanum-contain-
ing complex modifiers, with the complete elimi-
nation of other REMs, especially cerium, from
them enables to significantly improve the techni-
cal and economic indices of the casting process.
The pressed powder briquettes are recom-
mended as the most effective spheroidizers and
vermicularizers for both the ladle and the in-mold
production methods for CNG and CVG, which,
in contrast to ligatures, are based not on the mel-
ting of the batch, but on the pressing of a mixture
of powder components making up their composi-
tion. In comparison with the fractionated liga-
tures, the production of a ton powder briquette
modifier requires 8—10 times less electricity, in-
creases the assimilation of magnesium in the same
brand by one order, eliminates dust formation
and losses due to abandonment of crushing. The
powder briquettes are easily adaptable to chan-
ging requirements and conditions of foundries.
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yego vzaimodeystviya s primesnymi elementami chuguna. Protsessy lit'ya, 1(85), 9—17 [in Russian].
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Received 17.05.18
Е.В. Захарченко 1, О.І. Шинський 1, Г.А. Баглюк 2, С.І. Клименко 1,
В.Я. Куровський 2, К.А. Сіренко 1, О.Л. Гончаров 1
1 Фізико-технологічний інститут металів і сплавів НАН України,
бульв. акад. Вернадського, 34/1, Київ, 03680, Україна,
+380 44 424 3515, metal@ptima.kiev.ua
2 Інститут проблем матеріалознавства імені І. М. Францевича НАН України,
вул. Кржижановського, 3, Київ, 03142, Україна,
+380 44 390 8751, vvk@ipms.kiev.ua
КОВШОВІ ТА ВНУТРІШНЬОФОРМОВІ СПОСОБИ МОДИФІКУВАННЯ
ДЛЯ ОТРИМАННЯ ВИЛИВКІВ ІЗ ЧАВУНІВ З РІЗНОЮ МОРФОЛОГІЄЮ ГРАФІТУ
Вступ. У світовій практиці ливарного виробництва модифікування досягло статусу провідного напряму нау ко-
во-дослідних та прикладних робіт з поліпшення технологічних і службових властивостей конструкційних чавунів.
Проблематика. Модифікуюча обробка рідких чавунів передбачає створення не тільки певних типів модифі ка-
торів, а й розробку таких способів введення модифікатора в розплав, які адаптовані до умов ливарних цехів, а також
враховують вимоги до конкретних груп виливків.
Мета. Розробка дослідної технології модифікування електропічних розплавів чавуну в негерметизованих
поворотних ківшах і ливарних формах з використанням комплексних реагентів у вигляді пресованих порошкових
брикетів і кускових плавлених лігатур для отримання виливків з пластинчастим, вермикулярним і кулястим
графітом.
Матеріали й методи. Сірий чавун як об’єкт дослідження модифікуючої обробки, магній-лантанвміщуючі кускові
та брикетовані порошкові модифікатори, а також азотовмісні кускові й брикетовані порошкові модифікатори для
отримання чавунів з різною формою графіту залежно від вимог до виливків.
Результати. Розроблено дослідну ківшову технологію азотування чавунів з використанням пресованих порош-
кових азотвміщуючих брикетів, що дозволяє підвищити тимчасову розривну міцність сірих конструкційних чавунів
вдвічі — з 200 МПа до 400 МПа, без легування й термічної обробки, а також розроблено ковшовий процес моди фі-
кування розплавів чавунів магній-лантанвміщуючими модифікаторами. Обґрунтовано перспективність виробницт-
ва азотованого чавуну з вермикулярним графітом з вмістом сірки до 0,1 % мас. шляхом переплавлення азотної
ме талошихти, а також свіжих і поворотних чавунів, з мінімальним додатковим введенням азоту в піч, ківш чи ливар-
ну форму.
Висновки. Пресовані порошкові модифікатори рекомендовано до використання як найбільш ефективні для
вказаних способів модифікування залежно від вимог до виливків.
Ключові слова: ківшове, внутрішньоформове модифікування, магній-лантанвмісні та азотвмісні комплексні
модифікатори.
62 ISSN 1815-2066. Nauka innov. 2019, 15 (1)
Zakharchenko, E.V., Shinsky, O.I., Baglyuk, G.A., Klimenko, S.I., Kurovsky, V.Ya., Sirenko, E.A., and Goncharov, A.L.
Э.В. Захарченко 1, О.И. Шинский 1, Г.А. Баглюк 2, С.И. Клименко 1,
В.Я. Куровский 2, Е.А. Сиренко 1, А.Л. Гончаров 1
1 Физико-технологический институт металлов и сплавов НАН Украины,
бульв. акад. Вернадского, 34/1, Киев, 03680, Украина,
+380 44 424 3515, metal@ptima.kiev.ua
2 Институт проблем материаловедения имени И. Н. Францевича НАН Украины,
ул. Кржижановського, 3, Киев, 03142, Украина,
+380 44 390 8751, vvk@ipms.kiev.ua
КОВШОВЫЕ И ВНУТРИФОРМОВЫЕ СПОСОБЫ МОДИФИЦИРОВАНИЯ
ДЛЯ ПОЛУЧЕНИЯ ОТЛИВОК ИЗ ЧУГУНОВ С РАЗЛИЧНОЙ МОРФОЛОГИЕЙ ГРАФИТА
Введение. В мировой практике литейного производства модифицирование достигло статуса ведущего направ-
ления научно-исследовательских и прикладных работ по улучшению технологических и служебных свойств кон-
струкционных чугунов.
Проблематика. Модифицирующая обработка жидких чугунов предусматривает создание не только определен-
ных типов модификаторов, но и разработку таких способов ввода модификатора в расплав, которые адаптированы к
условиям литейных цехов, а также учитывают требования к конкретным группам отливок.
Цель. Разработка опытной технологии модифицирования электропечных расплавов чугуна в негерметизиро-
ванных поворотных ковшах и литейных формах с использованием комплексных реагентов в виде прессованных по-
рошковых брикетов и кусковых плавленых лигатур для получения отливок с пластинчатым, вермикулярным и ша-
ровидным графитом.
Материалы и методы. Серый чугун, как объект исследования модифицирующей обработки, магний-лантансо-
держащие кусковые и брикетированные порошковые модификаторы, а также азотсодержащие кусковые и брикети-
рованные порошковые модификаторы для получения чугунов с различной формой графита, в зависимости от предъ-
являемых требований к отливкам.
Результаты. Разработана опытная ковшовая технология азотирования чугунов с использованием прессованных
порошковых азотирующих брикетов, позволяющая повысить временную разрывную прочность серых конструкци-
онных чугунов вдвое — с 200 МПа до 400 МПа, без легирования и термической обработки, а также разработан ковшо-
вый процесс модифицирования расплавов чугунов лантансодержащими модификаторами. Обоснована перспектив-
ность производства азотированного чугуна с вермикулярным графитом с содержанием серы до 0.1 % масс. путем
переплава азотистой металлошихты, а также свежих и возвратных чугунов, что минимизирует дополнительное вве-
дение азота в печь, ковш или литейную форму.
Выводы. Прессованные порошковые модификаторы рекомендованы к использованию как наиболее эффектив-
ные для указанных способов модифицирования в зависимости от требований к отливкам.
Ключевые слова: ковшовое, внутриформовое модифицирование, магний-лантансодержащие и азотсодержа-
щие комплексные модификаторы.
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