JPS586959A - Centrifugal casting composite roll and its manufacture - Google Patents

Abstract

PURPOSE:To obtain a work roll for cold rolling with high hardness, high wear resistance and toughness by casting a melt-bonded and united roll composed of a wear resistant outer shell layer, a tough inner shell layer and an intermediate layer of a suitable material and by heat treating the roll at a high temp. CONSTITUTION:This composite roll is composed of an outer shell layer consisting of, by weight, 2.5-3.2% C, 0.5-1.5% Si, 0.5-1.5% Mn, <0.08% P, <0.06% S, 1.0-3.0% Ni, 10-23% Cr, 0.5-3.0% Mo and the balance Fe, an intermediate layer consisting of 1.0-2.5%, 0.5-1.5% Si, 0.5-1.5% Mn, <0.1% P, <0.1% S, <=1.5% Ni, 5.0-10.0% Cr, <=0.5% Mo, <=0.1% Ti and the balance Fe, and an inner shell layer consisting of 3.0-3.8% C, 1.8-3.0% Si, 0.3-1.0% Mn, <0.1% P, <0.02% S, <=2.0% Ni, <=0.1% Cr, <=1.0% Mn, 0.02-0.1% Mg and balance Fe.

Description

Detailed Description of the Invention As a work roll for Hijima Tasagi manufactured by the present invention, the outer shell layer 13 is made of a high hardness, high chromium material with particularly excellent wear resistance and roughness resistance, and the inner shell layer is The present invention relates to a centrifugally cast composite roll having a three-layer structure made of a highly tough ductile cast iron material with an intermediate layer interposed between outer and inner shell layers, and a method for manufacturing the same.

Currently, forged steel hardened rolls with a hardness of $85 to 100 are commonly used as rolls for cold rolling.
This type of rolling capacity roll is generally required to have the following properties.

The amount of roll wear in wear-resistant rolling is determined by the amount of carbide and base structure, which affect the hardness of the roll. Therefore, in order to improve the wear resistance of a roll for cold rolling at °C, it is effective to make the layer using KFi high in hardness and to make the structure uniform.

Accident resistance Accident resistance in cold rolling is caused by abnormal grinding of the rolls due to accidents during rolling such as seizure and squeezing, which greatly affects the life of the rolls. On the other hand, the roll as a whole is required to have sufficient toughness in its chest and neck portions in order to withstand large field loads.

However, in the above conventional forged steel quenching roll, in order to ensure high hardness, the tempering temperature after quenching is performed at a low temperature of t-150 to 200°C in the manufacturing process.
Rolling accidents such as 9th slip and squeezing cause abnormal heat generation near the surface, and due to the restraint of other parts, large tensile stress is generated in this part, 9, which has the drawback of easily causing sagging and spalling, and is also affected by heat. Even if the hardness is slight, the high hardness part is tempered and a softened part is formed, which is likely to cause dents and scratches.

Therefore, regarding the application of cold field rolls, instead of the conventional forged steel quenched rolls that have the above-mentioned problems, the outer shell layer, which is the layer used, is made of a high hardness and high chromium material, while the square shell layer is made of a tough and high chromium material. Composite rolls made of cast iron and welded together are coming into use.

'1, I This so-called high-hardness, high-chromium roll has the following features when compared to conventional hardened forged steel rolls. In other words, even when this compound roll is quenched at a slower cooling rate than that of a forged steel roll, high hardness can be obtained from the first surface to the deep interior, and when it is inserted into tempering, it is hardened by a forged steel roll. High hardness is maintained even when the temperature is higher than that of the roll. Also, since the tempering temperature is high, it is insensitive to abnormal heat generation due to rolling accidents.

However, regarding such composite rolls, that is, high hardness and high chromium rolls, the outer layer has very high hardness,
Although wear resistance is obtained, since the outer shell layer is made of a high chromium material and the inner shell layer is integrally welded and cast, the centrifugal force casting method also has low I/CFi,
A problem has been observed in which the alloy components of the outer shell layer, particularly Cr, are unavoidably diffused and mixed into the inner shell layer to some extent, which may impair the toughness of the inner shell layer.

The present invention relates to a composite roll in which the outer shell layer is formed of a high-strength, high-chromium material and the inner shell layer is formed of a tough ductile cast iron material, and the present invention provides a method for diffusing and mixing Cr from the outer shell layer to the inner shell layer. In order to reliably prevent this, the present invention provides a centrifugal force casting composite roll having a new three-layer structure T-, in which an intermediate layer having appropriate chemical composition and material properties is interposed between the inner shell layers. The features and advantages of the present invention are C2.5~3.2 liters, 310.5~1.5%, M
n O, 5 ~ 1.51&, P < 0.081k S
<0.06-1Nl 1.0-3.0%.

Cr 10-23% Mao, 573.0% each weight%
and an outer shell layer consisting of Fe with the remainder being Fe, and an IC of 1.0 to 2.5.
Chi, SiG, 5-1.5 transfer 0.5-1.5%,? <0
．． 1%, s<o, 1s, Ml≦1.5chi, Cr5#~1
An intermediate layer containing 0.0% MO≦0.5%, TI≦0.1% by weight, and the balance consisting of Fe, C3,0-3,8%,
811.8-3.0%, MnO, 3-1.0%, ? <
0.1%, S<0.02%, Nl≦2.0%, C
r≦1.0, MO≦1.0, Mf 0.02 to 0.1% by weight, and integrally welded with the inner shell layer, the remainder of which is Fe, and the outer shell layer is M , C, type eutectic carbide 20~40mm and Mr Cs type secondary carbide, consisting of martensite base structure, hardness Hs8
5 or more. In addition, the present invention provides, as a means for manufacturing such a composite roll, a composite roll tube having the above-mentioned three-layer structure, which is then subjected to an austenitizing treatment, followed by a high-temperature heat treatment of quenching and tempering. It is characterized by this.

The composite roll of the present invention will be described in detail below along with its manufacturing method. First, the outer shell layer, intermediate layer and inner shell layer of the roll tea of the present invention, and the heat treatment method thereof will be explained below.

(outer shell layer) The component range of the outer shell layer and the reason for its limitation will be described.

C: 2.5 to 3.2% The C content is within the range that stabilizes the Cs type carbide (Fe-Cr>v) and is balanced with the amount of a, and determined by the target amount of carbide. If C2.5% or less, it is not possible to obtain the target carbide content of 20 or more along with the Cr content, resulting in insufficient wear resistance, while if C3,2% or more, the Cr content and carbide content exceeds 4%, resulting in mechanical properties. This is not desirable as it causes deterioration.

Sl: 0.5 to 1.5% 0.5% or more is necessary for deoxidizing the 5ite molten metal.If it exceeds ζ1.5%, mechanical properties deteriorate.

Mn: 0.5"1.5% 0.5% or more is required as an auxiliary deoxidizing agent in JP-A-58-6958-69 59 (3), and in order to prevent the bad effects of S as MnS. Although useful, if it exceeds 1.5%, mechanical properties, particularly toughness, deteriorate significantly.

? <0.08% is more desirable for roll materials, and the upper limit is less than 0.08'% from the viewpoint of making the material brittle.

S (0.06%) Since S tends to segregate at grain boundaries and deteriorates mechanical properties, its upper limit is set at less than 0.06%.

Ni: 1.0-3.0% Ni is added to improve hardenability and actively adjust the hardness, but the content range is 1.0 to achieve the target hardness Hs85 or higher. ~3.0 liters is suitable.

Cr: 1G ~ 23% Cr is a component of ker μ'F in cast iron materials along with Fe and C.
tl-i″!”・′-05 The most hardness is 0 and the highest is “Yu°”
, 1,1 type carbide FiCr/C ratio. The amount of MyCs1m carbide produced is C
The amount of r increases as C increases, but it becomes saturated when the ratio reaches about 8th place. Further, when the Cr content is 10 t% or less, carbide becomes MIC type, which is inferior to M, C, and type carbides in terms of toughness and wear resistance. On the other hand, when the Cr content exceeds 23 ml, the carbide becomes of the M□C6 type, which is also inferior to the KM and C1@ types as well as the M and C types. For the above reasons, Cr is limited to a range of 10 to 23 inches.

MO: 0.5 to 3.0 points significantly increases the tempering resistance, and at the same time dissolves in the carbide or matrix, increasing its hardness. This effect is less pronounced at contents below Fio, sz, while 3.0%
Even if the content exceeds %MO, %MO becomes excessive and crystallizes as MO*C, and its effect is saturated.

The high chromium cast iron material forming the outer shell layer contains each of the above components by weight, with the remainder being Fe, but can further contain the following B if desired.

B: 0.001 to 1.0 When 0.001% or more of B is contained in high-height chromium cast iron, the amount of eutectic carbide is increased and the primary crystals thereof are refined. Furthermore, when B tO, 0G or more is contained, the hardening ability in black treatment can be increased, the amount of retained austenite can be reduced, and the base structure can be made into martensite. However, the B content is 1.0%.
If it becomes more than that, a problem arises in the solidified structure whose composition is hypereutectic. Therefore, a B content of 0.001 to 1.0 kg is sufficient.

(Intermediate layer) Next, the components of the intermediate layer and the reasons for their limitations will be described. When the outer shell layer and the inner shell layer made of the above-mentioned high chromium material are directly welded together, the alloy components, particularly Cr, diffuse from the outer shell layer to the inner shell layer, and the inner shell layer (axis core part) This is to prevent the toughness from deteriorating.

c: i, o L5 聚 The C content of the intermediate layer is determined from the perspective of its relationship with the final Cr content and from the standpoint of ensuring the mechanical properties of the intermediate layer itself. That is, when this intermediate layer is cast and welded to the outer shell layer, Cr is diffused and mixed into the intermediate layer, and even if the Cr content in the intermediate layer molten metal before casting is less than 1.0, the final Specifically, if it is uniformly mixed E7, the Cr content of the intermediate layer is i! : 5.0~1
It reaches 0.01. In this way, Cr is inevitably diffused into the intermediate layer from the outer shell layer due to casting, but if the casting temperature of the intermediate layer is high, the amount of Cr mixed in increases even more. As a result, the significance of intervening the middle class is lost. Therefore, from the standpoint of lowering the casting temperature, the intermediate layer material must have a particularly high C content;
That is, the content of C is required to be 1.0% or more. However, on the other hand, if the C content is too high, carbides will increase and the toughness of the intermediate layer itself will be impaired, in which case the significance of the presence of the intermediate layer will be lost. It is necessary to suppress the upper limit of t-2.5% or less.

Si:0.5~1.5-8Iti is necessary on tcO,5-pi to deoxidize the molten metal, but if it exceeds 1.5%, the mechanical properties of the intermediate layer will deteriorate. : 0.5-1.5% Similar to Mn4SI, it has a deoxidizing effect and MnS has a negative effect on S. JP-A-58-6959 (4) KO, 54 or more is required to remove the sound.
If it exceeds 5 degrees, the effect will be saturated, and on the other hand, the mechanical properties will deteriorate, which is not preferable.

p<o, l<, s<o, BP Both P and SFi make the roll material brittle, so keep it to less than 0.1% fR, which will not cause any actual damage.

Regarding Ni≦1.5 and N1, it is normally contained at about 0.3% or more by diffusion from the outer shell layer even if it is not added separately, but if it is contained up to 1.5% or less, there is a problem. If the content exceeds 1.5 inches, the hardenability is good, but the base of the intermediate layer becomes too coarse, which is undesirable from the viewpoint of toughness and residual stress.

Cr: 5.0-10.0% As mentioned above, CrK must be mixed by diffusion from the outer shell layer, but the purpose of providing the middle layer is to diffuse Cr from the middle layer to the next inner shell layer. In order to reduce contamination as much as possible, the content should be as low as possible, and the permissible content of C. should be in the range of 5.0-10.0% □゛'□'
It is surrounded. In addition, in order to keep the Cr content of the intermediate layer within this tolerance range of 13, K is set to 1.0, which is the content before casting.
It is necessary to keep it below 1. In other words, Cr
This is because if the content is high, there is a risk that the total content, including the amount mixed in from the outer shell layer, will exceed the above-mentioned allowable range.

MoS 2.5% MO has the same effect as the above-mentioned Ni, but when it is contained in an amount exceeding 0.5%, the base of the intermediate layer becomes too hard.
It can be kept within a range of 0.5% or less, which does not cause any actual damage.

Ti≦0.1% Ti is necessary for deoxidation, but if it is contained in an amount exceeding 0.1%, it is not preferable because the brush becomes overoxidized and the fluidity of the molten metal decreases.

The components of the material Fi or higher forming the intermediate layer are interlocked by weight,
Remaining! It consists of 1lsFe. In addition, the above component range Fi-t
This specifies the content in the product composite roll.

(Inner shell layer) Next, the range of components of the inner shell layer and the reason for its limitation will be described. Although the inclusion of Cr into the inner shell layer is greatly reduced by the interposition of the intermediate layer 14, compared to the case where it is directly cast into the inner surface of the outer shell layer, the inclusion of Cr cannot be completely prevented. However, the contamination of approximately o,5 to i,o is unavoidable. Therefore, it is necessary to adjust the casting composition of the inner shell layer in advance by taking this Cr increase*1 into account.

C: 3.0 to 3.8% C content is 3.0%j? If the temperature is lower than 1J, the material will become chilled and the toughness of the inner shell layer will deteriorate rapidly, while if it exceeds 3.8J, graphitization will be excessive and the strength of the inner shell material will be insufficient and the toughness of the inner shell layer will deteriorate. This is because the hardness decreases, making the neck part more likely to become rough during use. Therefore, for this reason, the C content is set to 3.0 to 3.8 inches.

Si: 1.8-3.0% With Si content below 1.8%, graphitization is poor and a lot of cementite precipitates, the strength of the inner shell layer deteriorates and casting cracks are likely to occur due to residual stress. On the other hand, if it exceeds 3.0%, graphitization becomes excessive and strength deteriorates.
18 is not desirable.

Mn: 0.3-1.0% Mn combines with S and removes the negative influence of S as a function of S. [1
5% of VC is effective, but if it is less than 0.3%, this effect is lost, and on the other hand, if it is more than 1.0%, the deterioration of the material is extremely undesirable.

P (0.1% PTL Increases the fluidity of molten metal, but the material has 11kWRtc
Therefore, the lower the content, the more desirable it is, and the content should be kept to less than 0.1%.

S (0.02% S makes the material brittle like P, and also combines with #'iMf in ductile cast iron to form ws, so it is necessary to keep the Fis content low in order to make graphite spheroidal. ,
Less than 0.02%* [Regulated.

Ni≦2. 〇- Regarding N1, it is included as a stabilizer for graphite, but 2
．． If it exceeds 0%, there will be no significant effect and it will be disadvantageous in terms of cost, so it should be set at 2.0% or less.

Cr≦1.0% Contamination of CrK to some extent is unavoidable due to the intervention of the above-mentioned intermediate layer, and the lower the content, the more desirable it is, but when considering the balance with Si, 1. Content below OS is acceptable. In addition, it is necessary to suppress the inner shell to 0.5 inches or less. In other words, if the Cr content exceeds 0.5%, the Cr content may exceed 1.0% after being integrated into the intermediate layer by welding, and in that case, the cementite material may This is because the amount increases and the toughness deteriorates.

MO≦1.0 - No need to add MOFi, but its content is 1, which does not cause any harm.
．． It's below zero.

Ml: 0.02 to 0.1 ml Mfll KO, 02% or more is required to make the graphite in the inner shell layer spheroidized into tough ductile cast iron.

However, if Mp exceeds 0.1 ml, it is unfavorable in terms of its chilling effect and dross formation.

The ductile cast iron material forming the inner shell layer contains each of the above components in weight percent, with the remainder being Fe. Regarding the inner shell layer, the above component range also defines the content in the product composite row. □Part 1 (Heat Treatment) Next, the conditions and characteristics required for the outer shell layer of the composite roll for 17 purposes will be described as well as the high temperature heat treatment method according to the manufacturing method of the present invention.

The composite roll targeted by the present invention is required to have a hardness of Hs85 or higher in its outer shell layer made of high chromium cast iron material. The reason for this is that in general, in applications for cold finishing work rolls, there is a strong correlation between hardness and wear resistance. This is because the product becomes unsatisfactory.

In order to obtain a hardness of Hs85Ju or more in the outer shell layer, the eutectic carbide must be of the M, C, or C type, and the base structure thereof must be a structure mainly consisting of martensitic carbide. Of these, the former condition is controlled by adjusting the Cr/C ratio, as the morphology of the eutectic carbide is largely determined by the Cr/C ratio as described above, but in order to satisfy the latter condition, it is necessary to It is necessary to add suitable alloying ingredients and to perform appropriate surface heat treatment. In other words, the base structure of the high chromium cast iron material that forms the outer shell layer is austenite during casting.
L18 In order to transform into a martensitic structure,
This requires a heat treatment in which the material is held at a high temperature and then rapidly cooled.

The high temperature heat treatment method according to the manufacturing method of the present invention will be detailed as follows. The heat treatment temperature must be maintained at 950°C or higher. That is, 950°C is the AC point at which the outer shell layer components of the main roll die, and if the AC is maintained at 8 points or higher, Cr in the base will not diffuse in the center and will become secondary 1n-aitu. Highly hard trigonal PI&Q type carbide is precipitated as Cmrblde, and as a result, the solid solution Cr concentration decreases, preventing soustenite stabilization, and the critical cooling rate decreases, resulting in the formation of simartinite during quenching. It is. Further, the quenching rate must be 125° C./Hrpl or higher. That is, at a speed lower than this, pearlite transformation occurs in the outer shell layer and high hardness cannot be obtained. Furthermore, tempering after quenching is carried out at a temperature range of F1400 to 600°C.

When tempering is performed in this temperature range, martensite is not significantly affected by the hardening, and its strain is sufficiently removed to a 1× pupil. On the other hand, at a tempering temperature of 400°C or lower, the strain relief effect cannot be sufficiently achieved, and at a tempering temperature of 600°C or higher, martensite is tempered and the hardness decreases. In addition, the high chromium cast iron material forming the outer shell layer contains Ni and MO, which have a hardening effect, as additive elements.
l- Since each of the above-mentioned appropriate amounts is contained, martensite formation by heat treatment is easily performed.

After the high-temperature heat treatment as described above, the outer shell layer of the composite roll exhibits a martensitic matrix structure in which MyCs-type secondary carbide is precipitated, and the MyCs of the appropriate 20 to 40%, which can be obtained by adjusting the Cr/C ratio. Due to the synergistic effect with type eutectic carbide, the outer shell layer contains the desired purpose and Hs85.
This results in higher hardness.

In addition, if wood heat treatment is performed, the middle layer and inner shell layer will also become 9 at the same time.
It is strengthened through high-temperature heat treatment at temperatures above 50°C. That is, the intermediate layer has a mixed structure of ferrite and cementite as its cast structure, but the mixed structure is made finer and more granular by high-temperature heat treatment, making it tougher. In the inner shell layer, the spheroidal graphite decomposes and becomes spheroidized, and the matrix becomes granular and toughened. As described above, by performing the high-temperature heat treatment according to the present invention, the outer shell layer of the composite roll becomes highly hard, while the intermediate layer and inner shell layer become tougher.

Next, a method for casting the composite roll of the present invention will be explained. In general, the hollow casting method, sliding generator method, and centrifugal force casting method are adopted as the casting method for composite rolls, but in the case of this roll, the control of the outer shell layer thickness,
In light of the problem of Cr diffusion into the inner shell layer, centrifugal casting is the easiest and most economical method to manage.

To briefly explain the method of casting this roll using the centrifugal force casting method, first, a mold whose inner surface is coated with an appropriate refractory material is rotated on a centrifugal force casting machine, and an outer shell is placed inside the mold. Should form layers! 1I Molten iron is poured and the entire intermediate layer is to be formed while the inner surface is not solidified.

Inject. After the outer shell layer and the middle layer have completely solidified, the mold is set up vertically, and the molten ductile cast iron that is to form the inner shell layer is poured into the mold from the top to completely metallurgically bond the two layers. Then, a single roll is cast. In addition, when casting the inner shell layer, it is possible to cast the mold entirely horizontally or with a steep slope, and in this case, it is not necessary to wait for complete solidification of the outer shell layer and the intermediate layer. The thus cast nine-fold apricot roll is kept at a high temperature in a furnace, then taken out of the furnace and quenched in a spray water cooling or oil bath, and then subjected to the above-described heat treatment method, in which it is again subjected to low-temperature heat treatment for strain relief in the furnace.

FIGS. 1 and 2 show an example of the structure of a composite roll having a three-layer structure according to the present invention manufactured in this manner, and
ll#-i shows the outer shell layer, (ri shows the middle layer, and (3) shows the inner shell layer (axis core part).

Next, specific examples of the present invention will be described along with their manufacturing methods.

Embodiments The zero embodiment is an example in which the present invention was applied to a roll having a product body diameter of 570 mm and a body length of 1400 mm.

Outer shell layer casting conditions - 22 As the outer shell layer, high chromium cast iron molten metal with a wall thickness of 80 m (casting weight 1200 mm) was poured into a rotary mold on a centrifugal casting machine at a temperature of 1
It was cast at 400°C. □ Intermediate layer casting conditions 18 minutes after the start of casting of the outer shell layer, the intermediate layer molten metal is
5fi (casting weight 4009) and subsequently poured into a rotary mold at a casting temperature of 1470°C. Approximately 30 minutes after the start of casting of the outer shell layer, the outer shell layer and the intermediate layer were completely solidified.

Inner shell layer casting conditions After solidification of the outer shell layer and intermediate layer is completed, the mold is stood vertically, and molten ductile cast iron is poured from the top of the mold as the inner shell layer at a casting temperature of 1380°C to completely fill the inside of the mold. , the upper surface of which was covered with a riser heat insulator 0. Heat treatment conditions: After the inner shell layer was completely solidified, the roll was removed from the mold, placed in a furnace, heated to 1000°C, and held for 2 hours. When the roll body was taken out of the furnace and sprayed with water, the surface was cooled to 470°C. The cooling rate during this period was 260'e/H. In this state, the roll was held in the furnace again at 500''cVc, and then cooled in the furnace.

Test results The molten metal and product chemical components of each layer and the hardness obtained in the body outer shell layer are shown in Table 1.2 above.

H891 was obtained.

Seiha JP 58-6959 (7) After machining both of the above composite rolls, the body was subjected to ultrasonic testing and fracture investigation, and it was found that the thickness of the outer shell layer was washed away by the intermediate layer. It was around 60t11. On the other hand, the thickness of the intermediate layer is 30 to 35 m, and the Cr
The content was 6.0-8.0%. The outer shell layer, middle layer, and inner shell layer were completely combined, and structural continuity was also observed.

As described in detail above, the present invention is a composite roll in which the outer shell layer is made of a high-hardness, high-chromium material and the inner shell layer is made of a strong ductile cast iron material, and the present invention prevents diffusion and mixing of Cr between the two. Since the intermediate layer is interposed between the two layers, the amount of Cr mixed into the inner shell layer can be reduced by half, and based on this, the outer shell layer corresponding to the layer used can be It can be made of high hardness. In addition, the composite roll of the present invention can easily have the desired high hardness of Hs85pt or higher by suitable high-temperature heat treatment and by adjusting the shape and structure of the carbide. According to the 9E process, its high hardness layer is superior to conventional forged steel hardened rolls. 26 This kind of conventional intermediate layer has the property that it can be stably obtained and spreads to the depth of the layer, and at the same time, the intermediate layer and inner shell layer are also strengthened. Compared to a composite roll that does not involve any intervention, it can be effective in solving this problem.

Specific applications of the composite roll of the present invention include finishing work rolls for cold and hot strip mills, rolls for hot skin passes, and rolls for finishing wire rods.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view showing an example of the structure of a composite roll according to the present invention, and FIG. 2 is a cross-sectional view. fl+... Outer shell layer, (2)... Middle layer, (3)...
・Inner shell layer (axis core). Procedural amendment (voluntary) 1. Incident indication: 1982 Patent Application No. 103802 2, Invention
Famous centrifugal casting composite roll and its manufacturing method 3, Person making the amendment 4, Agent @577 5, Date of notice of reasons for refusal (date of amendment order) 2, Claims L C2, 5-3, 2%, SfO, 5-1.5%
, Mn 0.5-1.5%, P<0.08%-S
<0.06%-Nl 1.0-3.0%, Cr 10
~23%, lJo o, s ~ S, O% by weight, and an outer shell layer consisting of Fe, and C1,O ~2.5%,
SiO, 5-1.54 Mn 05-1.5%. p<o, 1s, S<0.1s, Nl≦1.5%
-Cr 5.0-10.0<, M. ≦0.5%TI≦01%', the balance a Fe
an intermediate layer consisting of C3, 0 to 3.8%, SI 1.
8-3.0 L Mn 0.3-1.0%+ p<o,
List S<0.02'%, Nl≦2.0哄, Cr≦1.0
%. It contains MO≦1.0 duck, MP 0.02-0.1 duck, and the rest is welded and integrated with an inner shell layer consisting of ゛. and the outer shell layer is My Cs type eutectic carbide 20-4
A centrifugal force casting composite roll made of a T-frame machine, consisting of a martensite base structure containing 0 and 1i & Ca1l secondary carbides, and having a fineness of Hs85p), with an outer shell layer KBO,001~ The centrifugally cast composite roll according to claim 1, comprising a weight noise of 1.0. Kame By centrifugal force casting method, C2.5~3.2%, S
l O,5~1.5L Mn O,5~1.51L P
<0.08%, s<o, os%-NI 1.0-3
．． 0 Mo 3%, Cr 1G-23-Mo 0.5-3.0%, the remainder @'1 Karana & outer shell layer, C1,0
~2.5%, SIo, 5-1.5 duck, Mn 0.5~
1.5%, P<0.1L s<o, tc Ni≦1.
5%, Crs, o ~10. oL M<0.5<,
TI≦0.1<f each including amount s. Remaining 11&Fe*-La fk Jl middle class and C3,0~3
．． 8%, Si 1.8~3.0'f-, MnO, 3~
1.0L P≦0.1%-8<0.02%, Nl≦2
．． 0%. Cr≦0.1LMn≦1.0%, MP 0.02~0
．． 1% by weight of each metal is melted and integrated with the inner shell layer consisting of the remaining a Fe. Next, a composite roll is cast. After that, the cast composite roll is austenitized, and then quenched and tempered. A manufacturing method for centrifugal casting composite rolls using a machine. The method for manufacturing a centrifugally cast composite roll according to claim N3, wherein the outer shell layer contains a 50% carbon dioxide (KBO).

Claims (1)

[Claims] L C2,5~3.2%, 81 0.5~
1.5%, Mn 0.5-1.5%, P 0.0
8%, S<o, oac Ni 1.0-3.0
%, Cr1O-13%, MO0.5-3.0% l each weight ratio, the remainder being Fe, and an outer shell layer consisting of C1.0-2.
5 list 5105-13 (work 0.5-1.5 (P < 0.
1'LS<0.1%, Ni≦1.5%, Cr
5.0-10.0%, Ms≦0.5%, Ti≦0.1% by weight, with the balance being Fe, and C3,0
,~3.8S, Si 1.8~3.0%, Mn0.3
~1.0 &p<0.1%,s<o, ozs, Nl≦2
．． 0%, Cr≦1.0%, MO≦1.0%, MfO
, 02 to 0.1 liters per weight, and the remainder is welded and integrated with an inner shell layer consisting of Fe, and the outer shell layer is M
Contains r C, type eutectic carbide 20-40 and MyCs type secondary carbide! A centrifugally cast composite roll comprising a rutinsite base structure and having a hardness Is of 8% or more. 2 The scope of claim 2 in which the outer shell layer further contains 0.001 to 1.0% by weight of B! ! I @ Section 1 Moth centrifugal casting composite/roll. Turtle C2,5~3.2 grade SiO by centrifugal casting method
,5-1.5-1Mn0.5-1.5%, p<o, os
%, s<o, oas, Ni 1.0-3.0-2Cr
an outer shell layer containing 10 to 23% Me O, 5 to 3.0% by weight, and the balance consisting of Fe;
SIo, 5-1.5 o, Mn 0.5-1. ! Slk
p<o, ts, S<0.1%%Ni≦1.5%, C
r5.0-10.0%, ldo≦O, 1%, TI≦0
．． 1% by weight, with the remainder being Fe;
3, O~3.8%, Si1.8~3.0-1Mn0.3
~1.0%, P≦0.1%, s<o, oz%, N1≦2
．． 0chi, Cr≦0.1 (Mu≦1.0%, Mf 0.
After casting a composite roll in which the inner shell layer containing 02 to 0.1% by weight and the remaining IIF'e is welded and integrated, the cast composite roll is austenitized, and then quenched and tempered. A method for manufacturing a centrifugally cast composite roll, characterized by: ζ A method for producing a centrifugally cast composite roll according to claim aSS, wherein the outer shell layer further contains BO,001 to 1.0% by weight.