JP2000317509A - Composite sleeve roll for rolling and its manufacture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To weld the main body of a roll of a high melting material excellent in toughness with a sleeve of a material excellent in wear resistance by a static casting method in a composite sleeve roll for rolling. SOLUTION: By casting the molten metal for sleeves by the static casting method on the outer periphery of the main body 12 of the roll on which a carburized layer 18 is formed by applying carburizing treatment on the outer periphery, at least the surface part of the carburized layer of the main body of the roll is melted by the molten metal for sleeves. By solidifying together with molten metal for sleeves, a composite sleeve roll 10 in which the main body of the roll and the sleeve 14 are welded is formed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a composite sleeve roll used for rolling steel wires and bars.

[0002]

2. Description of the Related Art Rolls for rolling require abrasion resistance on the outer surface side in contact with the rolled material and toughness on the core side.

As this kind of roll, a ductile cast iron or graphite steel having excellent toughness is used for the roll body, and a high-speed cast iron material having excellent wear resistance is used for a sleeve surrounding the roll body. There is a composite sleeve roll in which the roll body and the sleeve are metallurgically integrated by welding the inner surface of the sleeve.

[0004] This composite sleeve roll is made in the following manner.

First, a solid cylindrical roll body is produced by static casting. Next, a stationary casting method is formed such that a predetermined annular space is formed with the roll body, and a molten metal for a sleeve is cast into the annular space with the roll body arranged. The melting temperature of the high-speed cast iron material forming the sleeve is about 1450 ° C., whereas the melting point of the ductile cast iron or graphite steel forming the roll body is about 1100 ° C.
Since it is 1200 ° C., by supplying the molten metal for the sleeve,
The outer surface of the roll body is melted by the heat of the melt, and then solidifies with the melt of the sleeve, so that the outer periphery of the roll body and the sleeve are metallurgically integrated.

[0006]

By the way, due to the recent tendency to increase the rolling load, it is required to select a material for the roll body which is more tough than ductile cast iron.

As examples of these tough materials, various structural alloy steels (SC, SMn, SMnC, S
CM, SNC, SNCM, SCr, etc.)
Since these alloy steels generally have a carbon content of about 0.5% by weight or less, their melting points are as high as about 1400 ° C. or more,
There is no significant difference from the molten metal temperature of the high-speed cast iron used for the sleeve. In the static casting method, since there is no device for heating the molten metal again, when using alloy steel for the roll main body and high-speed cast iron material for the sleeve, it is impossible to melt the surface of the roll main body with the heat of the molten metal of the sleeve molten metal. No, the roll body and the sleeve cannot be metallurgically integrated.

[0008] If the molten metal temperature of the high-speed cast iron material for the sleeve is higher than an appropriate temperature, the surface of the roll body can be melted and metallurgical integration becomes possible. It is not preferable because it causes coarsening.

As a casting method for metallurgically integrating the core material and the sleeve, there is a continuous casting overlay method. By this method, it is possible to metallurgically integrate the sleeve of the high-speed cast iron material on the outer periphery of the roll body of the various alloy steels described above.

In this continuous casting overlaying method, as shown in FIG. 3, a molten metal for a sleeve (24) placed in a ladle (22) is formed between a roll body (12) and a water-cooled mold (26). The molten metal gradually solidifies in the water-cooled mold (26) to form the sleeve (14), and the roll body (12) is intermittently pulled out to form the composite sleeve roll (10). Is done.

On the upstream and downstream sides of the tundish (32),
A preheater (34) and a heater (36) are provided, and the roll body (12) and the molten metal poured into the annular space are heated by high-frequency induction heating. For this reason, since the surface of the roll body (12) is melted and then re-solidified, the roll body (12) and the sleeve (14) of the composite sleeve roll (10) are metallurgically integrated.

However, in the continuous casting overlaying method, it is difficult to determine the timing of pulling out the solidified sleeve (14) from the mold (26), and if this timing is delayed, the welded portion between the roll body and the sleeve is formed. On the other hand, if the timing is too early, there is an inconvenience that a bonding failure occurs.

Further, when the sleeve roll compounded by casting is pulled out, unevenness of the solidified structure is formed due to the drawing interval, and there is a problem that a pattern is formed at the time of rolling.

Therefore, a technique for welding a sleeve to a core material having a high melting point by a static casting method is desired.

[0015] An object of the present invention is to form a metal body having a substantially uniform thickness into a roll body made of a high melting point material having excellent toughness and a sleeve made of a material having excellent wear resistance by a static casting method. An object of the present invention is to provide an integrated composite sleeve roll and a method for manufacturing the same.

[0016]

In order to achieve the above object, a method of manufacturing a composite sleeve roll for rolling according to the present invention comprises forming a carburized layer by performing a carburizing treatment on an outer periphery of a cast roll main body. The molten metal for the sleeve is cast around the outer circumference of the roll body by static casting, and at least the surface portion of the carburized layer of the cast roll body is melted with the molten metal for the sleeve and then re-solidified to form the roll body. The sleeve and the sleeve are metallurgically integrated.

Further, in the composite sleeve roll for rolling according to the present invention, a carburized layer is formed on the outer periphery of a roll main body made of an alloy steel having a C content of 0.5% by weight or less, and the sleeve surrounding the roll main body is formed by a roll. It is welded and integrated with the carburized layer of the main body.

[0018]

When a carburized layer is formed on the outer periphery of the roll body, the carburized layer has a high C (carbon) content, so that the melting point is lowered.
For example, the melting point of an alloy steel having a C content of about 0.5% or less is about 1400 ° C. or more, but when the C content is about 1.0%, the melting point is about 1300 ° C. and the C content is about 1.6%. , The melting point becomes about 1200 ° C.

For this reason, the molten metal for a sleeve (liquidus temperature of about 1310
C, molten metal temperature of about 1450 ° C), the carburized layer portion of the roll body is melted by the heat of the molten metal, solidified together with the molten metal for the sleeve, and the roll body and the sleeve are metallurgically integrated. A sleeve roll is formed.

In order to perform proper welding, the melting point of the carburized layer of the roll body should be about 150 ° C. higher than the melting temperature of the molten metal for the sleeve.
It is preferable to form the carburized layer so that the temperature becomes lower by 200C to 200C.

For example, when a high-speed cast iron material is used for the sleeve, the carbon concentration on the surface of the carburized layer of the roll body is preferably set to about 1% or more. If the C content of the carburized layer is less than 1%, the melting point will be higher than about 1300 ° C,
The casting temperature of the molten metal for the sleeve for performing proper welding is about 1450 ° C. to about 1500 ° C. However, when the temperature of the molten metal reaches about 1500 ° C., the solidified structure becomes coarse and problems such as rough skin occur. It is.

[0022]

BEST MODE FOR CARRYING OUT THE INVENTION In a composite roll for rolling according to the present invention, a sleeve made of a wear-resistant material is welded to the outer periphery of a roll body made of a tough material.

As a tough material constituting the roll body,
Alloy steel having a C content of about 0.5% by weight or less, specifically,
Various structural alloy steels (SC, SMn,
SMnC, SCM, SNC, SNCM, SCr, etc.).

As a wear-resistant material constituting the sleeve,
High-speed cast iron is preferably used. As a high-speed cast iron material, C: 1.0 to 3.0%, Si: 0.1% by weight.
2.0%, Mn: 0.1-2.0%, Cr: 3.0-1
0.0%, Mo: 0.1 to 10.0%, W: 1.5 to 10.
0%, 3.0 to 10.0 in total of one or two of V and Nb
% And the balance substantially consisting of Fe. If necessary, this high-speed cast iron material
i: 10.0% or less, or Co: 0.5 to 10.0%, or B: 0.01 to 0.50%, or Al: 0.01 to 0.5
0%, Ti: 0.01 to 0.50% and Zr: 0.01 to
At least one selected from the group consisting of 0.50% can be included.

As another example of the high-speed cast iron material, C: 1.8 to 3.6%, Si: 1.0 to 3.5%, M
n: 0.1 to 2.0%, Cr: 0.2 to 10.0%, Mo:
0.1 to 10%, W: 0.1 to 10%, V, Nb: One or two kinds containing a total of 1.5 to 10.0% and the balance substantially consisting of Fe Can be. If necessary, this high-speed cast iron material may have Ni: 10.0% or less, Co: 0.5 to 10.0%, or B: 0.01 to 0.50.
% Or Al: 0.01 to 0.50%, Ti: 0.01 to
At least one selected from the group consisting of 0.50% and Zr: 0.01 to 0.50% can be included.

A solid cylindrical roll body is made of, for example, SCM
It is manufactured by casting a 435 molten metal by static casting.

[0027] The roll body thus produced is carburized in an outer peripheral area to be enveloped by a sleeve. The carburizing process is performed in a carburizing furnace, and the roll body is
A known carburizing inhibitor is applied to (where it is not enveloped by the sleeve) and then charged into the furnace.

The carburizing step is carried out, for example, under the conditions of 1000 ° C. × 4 hours. In the outer peripheral region to be wrapped by the sleeve of the roll body, the surface carbon amount is about 1.28% by weight and the effective carburizing depth is about 2. A carburized layer of 3 mm is formed.

The melting point of the parent phase of the SCM435 material is about 1450.
Although it is about ℃, the melting point of the surface of the carburized layer after the carburizing treatment is about 1260 ℃.

Next, as shown in FIG. 1, a bottom casting type static casting method (4) in which a predetermined annular space is formed with the roll body.
0) is prepared. After arranging the roll body (12) having the carburized layer (18) formed at a predetermined portion on the outer periphery in the casting method, the sleeve is transferred into the annular space between the roll body (12) and the sand mold (42). The molten metal (24) is cast.

As a sleeve material, for example,
C: 2.0%, Si: 0.8%, Mn: 0.7%, Ni:
0.3%, Cr: 7.5%, Mo: 5.0%, W: 5.1
%, V: 4.0%, the balance being a high-speed cast iron material consisting essentially of Fe. The liquidus temperature of this material is about 13
10 ° C. and the melt temperature is about 1450 ° C.

As described above, the temperature of the molten metal for the sleeve (24) supplied to the casting method (40) is about 1450 ° C., and the melting point of the surface of the carburized layer (18) of the roll body (12) is about 1260 ° C. Therefore, the surface of the carburized layer (18) is melted by the molten metal for the sleeve (24) and then solidified together with the molten metal for the sleeve, as shown in FIG.
(14) forms a composite sleeve roll (10) welded at the location of the carburized layer (18).

[0033]

According to the present invention, a composite sleeve roll in which the roll body and the sleeve are metallurgically integrated can be produced by a static casting method by utilizing the melting point drop caused by the formation of a carburized layer. Thus, a composite sleeve roll in which the welding layer between the roll body and the sleeve has a substantially uniform thickness can be stably manufactured, so that the manufacturing process can be stabilized.

Further, since the roll body uses a tough material, a composite sleeve roll that can withstand an increase in the rolling load can be obtained.

[Brief description of the drawings]

FIG. 1 is an explanatory view of a static casting method used for manufacturing a composite sleeve roll.

FIG. 2 is a longitudinal sectional view of the composite sleeve roll of the present invention.

FIG. 3 is an explanatory view of a continuous casting overlaying apparatus used for manufacturing a composite sleeve roll.

[Explanation of symbols]

 (10) Composite sleeve roll (12) Roll body (14) Sleeve (18) Carburized layer

Continued on the front page (72) Inventor Kaoru Matsuda 64 Nishimukaijima-cho, Amagasaki-shi, Hyogo F-term in Kubota Amagasaki Plant (reference) 4E016 AA04 AA05 DA04 EA01 EA03 FA01 FA05

Claims (2)

[Claims] 1. A method for producing a composite sleeve roll for rolling comprising a sleeve encased on the outer periphery of a roll body, wherein a step of subjecting the outer periphery of the cast roll body to a carburizing treatment to form a carburized layer, A step of pouring the molten metal for the sleeve into the outer periphery by a stationary casting method, by melting at least a surface portion of the carburized layer of the cast roll main body with the molten metal for the sleeve and then re-solidifying the roll main body and the sleeve. And a method for producing a composite sleeve roll for rolling. 2. A composite sleeve roll for rolling in which a roll body is encased by a sleeve, wherein a carburized layer is formed on the outer periphery of a roll body made of an alloy steel having a C content of 0.5% by weight or less, and A composite sleeve roll for rolling, wherein a sleeve made of cast iron is welded to a carburized layer of the roll body.