JP3040944B2 - Composite roll and method for producing the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

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

[0002]

2. Description of the Related Art As a roll used for rolling a wire, a bar, or the like, a composite roll in which a carbide ring formed of a carbide metal is fitted to a roll body is known. For composite rolls,
A mechanically assembled carbide ring on the roll body,
Casting a carbide ring has been implemented. In the former case, the number of parts is increased, the assembling is troublesome, and the cost is increased.

[0003] The latter can reduce the cost as much as the necessity of assembling is required, but there is a problem that the roll is easily cracked in the production method. In the latter roll manufacturing method, first, as shown in FIG. 8, the outer periphery of a carbide ring (2) is embedded in the inner peripheral surface of a mold (1) formed of a sand mold (step 1). template
Pour the molten metal as the cast-in metal (30) into (1) (step 2). The molten metal is naturally cooled and solidified in the mold (1), and the solidified portion is formed into a roll body (3) (step 3). The as-cast product taken out of the mold (1) is heat-treated (step 4). The as-cast product is machined into a desired shape and dimensions (Step 5).

[0004]

The temperature of the molten metal poured into the mold (1) in step 2 is to melt the surface of the carbide ring (2) in order to increase the bonding force between the carbide ring (2) and the roll body. It is about high temperature. Therefore, the boundary between the as-cast metal (30) and the carbide ring (2) is in a metal-bonded state. However, since the difference in thermal expansion between the carbide ring (2) and the cast metal (30) is large, when the cast metal is thermally deformed, if the metal is bonded to the carbide ring (2), deformation is free. The degree is suppressed. For this reason, residual stress is generated in the roll. This residual stress may cause the roll to crack. Further, even if no cracking is observed in the cooling stage, cracking may occur if a post-process is performed with residual stress remaining.

[0005] If high Ni cast iron or the like having a thermal expansion difference close to that of the cemented carbide ring (2) is used as the material of the cast-in metal (30), the occurrence of roll cracking can be suppressed. Is expensive. The present invention is to clarify a composite roll formed by assembling and solving the above problem and a method of manufacturing the same.

[0006]

Means for Solving the Problems The composite roll of the present invention comprises:
A super hard ring (2) formed of a super wear-resistant material such as a super hard alloy, ceramics, cermet, etc. is exposed and its outer peripheral surface is exposed and cast with cast iron or cast steel, and the cast iron or cast steel portion is roll body (3). Carbide ring in the combined roll
The side of (2) has an uneven surface with a step in the roll rotation direction.
(21) is formed, and the roll body (3) is engaged with and engaged with the uneven surface (21).

The method of manufacturing the composite roll according to the present invention is to adjust the temperature of the molten metal so that the cemented metal ring (30) and the cemented carbide ring (2) having the uneven surface (21) on the side surface are not metal-bonded. Adjust and pour the molten metal into the mold (1) and set the solidified part of the molten metal to a carbide ring
It is cut into the uneven surface (21) of (2).

[0008]

[Function and effect] The temperature of the molten metal is lower than the temperature at which the surface of the cemented carbide ring (2) is melted, and the cast-in metal (30) and the cemented carbide ring (2) are merely in contact with each other and are bonded together. Without
Therefore, the degree of freedom of thermal deformation of the as-cast metal is increased. For this reason, the residual stress of the roll can be kept low, and the crack of the roll caused by the residual stress can be prevented. Carbide ring
Since the metal of (2) and the cast-in metal (30) are not metal-bonded, the material width of the cast-in metal (30) can be widened. For example, even if a special component such as high Ni cast iron is not used as the cast-in metal (30), cracks and the like do not occur in the roll in the roll manufacturing process. A relatively inexpensive material such as certain ductile cast iron can be used, and the cost can be kept low.

A gap is formed between the inner surface of the carbide ring (2) and the roll body (3) due to the difference in thermal expansion coefficient between the cemented carbide and the cast-in metal. Even if the material expands thermally, the gap remains between the carbide ring (2) and the roll body.
By absorbing the difference in thermal expansion of (3), no tensile stress acts on the inner surface of the carbide ring (2), so that thermal stress cracking can be prevented. Carbide ring (2) and roll body (3)
(2) Since the roll body (3) is engaged with the uneven surface of the side surface, the carbide ring (2) does not idle with respect to the roll body (3).

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below.
Details will be described with reference to the drawings. The composite roll according to the present invention comprises a roll body (3) and a carbide ring (2) whose peripheral surface is exposed and cast into the body. Roll body (3)
Is formed of cast iron or cast steel, and the cemented carbide ring (2) may be formed of a cemented carbide, other ceramics, or a super-abrasive material such as cermet. An uneven surface (21) having a step in the rotation direction of the roll is formed on a side surface of the carbide ring (2), and the roll body (3) is engaged with and engaged with the uneven surface (21).

FIG. 1 is a sectional view of the mold (1). template
(1) is a sand mold formed around an iron frame (not shown). The inner surface is configured such that the upper and lower parts are reduced in diameter and the lower part is closed. A holding ring (4) for fixing the carbide ring (2) to the mold (1) is shrink-fitted and fixed to the outer periphery of the ring. The retaining ring (4) is removed in the above step 5 after removing the roll from the mold. Uneven surface on the side of carbide ring (2)
(21) may be formed on both side surfaces of the ring, or may be formed on either one of the side surfaces. In short, the carbide ring (2) and the roll body (3) are integrated by an uneven surface so that the carbide ring (2) does not idle with respect to the roll body (3) during roll rolling use. It is only necessary that they mesh properly.

[Method of Manufacturing Composite Roll] [Step 1 (Fixing and Preheating of Carbide Ring)] Carbide Ring (2)
Center of the mold (1) coincides with the axis of the mold (1), the retaining ring (4) of the ring (2) is cut into the inner surface of the mold (1), and the ring (2) is fixed in the mold (1). I do. Preheat the carbide ring (2) to 100-500 ° C. At this time, the preheating of the carbide ring (2) is performed at approximately
When the following conditions are satisfied, the thermal shock during casting the molten metal causes the carbide ring
(2) may be broken. When preheating to 500 ° C. or higher, the surface of the carbide ring (2) is oxidized, so that it is necessary to perform a surface treatment such as Ni plating, which is troublesome.

[Step 2 (Pouring of molten metal)] Carbide ring
After preheating (2), it is heated to a temperature lower than the temperature at which the surface of the carbide ring (2) melts, and the molten metal is poured.

[Step 3 (Cooling)] After the molten metal is poured into the mold (1), the molten metal solidifies and is left to cool to room temperature to be naturally cooled slowly.

[Step 4 (heat treatment)] In the above step, the mold (1)
An antioxidant is applied to the exposed portion of the as-cast carbide ring (2) of the as-cast product taken out from the above, and heat treatment for strain removal is performed.

[Step 5 (Machining)] The heat-treated product prepared in the above step is machined to form a retaining ring (4).
And finish the roll outer diameter to a desired size.

However, the temperature of the molten metal is lower than the temperature at which the surface of the cemented carbide ring (2) is melted, and the cast-in metal (30) and the cemented carbide ring (2) are merely in contact with each other and are not welded. ,
Therefore, the degree of freedom of thermal deformation of the as-cast metal is increased. For this reason, the residual stress of the roll can be kept low, and the crack of the roll caused by the residual stress can be prevented. Carbide ring
Since (2) and the cast-in material are not metal-bonded, the material width of the cast-in material can be widened. For example, even if a special component such as high Ni cast iron is not used as the cast-in metal (30), cracks and the like do not occur in the roll in the roll manufacturing process, so that the difference in thermal expansion between the cemented carbide ring (2) and the cemented carbide ring (2). A relatively inexpensive material such as certain ductile cast iron can be used, and the cost can be kept low.

A gap is formed between the inner surface of the carbide ring (2) and the roll body (3) due to the difference in the coefficient of thermal expansion between the cemented carbide and the cast-in material. Even if the thermal expansion occurs, the gap absorbs the difference in thermal expansion between the carbide ring and the roll body, and no tensile stress acts on the inner surface of the carbide ring, so that thermal stress cracking can be prevented. Carbide ring
(2) and the roll body (3) are made of carbide ring (2)
Since the roll body is engaged with (21), the carbide ring
(2) does not idle with respect to the roll body (3).

Example 1 [Carbide ring] Dimensions: outer diameter φ210 mm, inner diameter φ120 mm, width length 72 mm Uneven surface shape: On both sides of the ring, on a virtual circle having a diameter of 142 mm with the center of the ring as the radius center, Diameter 12mm, depth 2mm
(20) are equally spaced (FIGS. 1 and 2). Ingredients: WC 75% by weight + binder metal 25% by weight Binder metal composition: Co 12% by weight, Ni 12% by weight, C
r 1% by weight Residual Fe Coefficient of thermal expansion: The average coefficient of thermal expansion from room temperature to 500 ° C. is 7 × 10 ⁻⁶ (1 / ° C.) [Cast-in material] Component (unit;% by weight) C Si Mn Ni Cr Fe 3.3 2.2 0.4 1.0 0.2 Rest Coefficient of thermal expansion: 12 × 10 ^-6 (1 / ° C) [Assembling condition] Static casting in which preheated carbide ring is heated to 220 ° C and molten metal casting temperature is set to 1330 ° C [Heat treatment [Condition] A strain removing heat treatment is performed by placing the substrate in a temperature atmosphere of 530 ° C. for 15 hours.

Example 2 [Carbide ring] Dimensions: outer diameter φ210 mm, inner diameter φ120 mm, width length 68 mm (excluding the following ridge height) Uneven surface shape: curvature of the ring center on both sides of the ring Four arc-shaped ridges (22) having a center and a height of 2 mm and a width of 12 mm protrude inward from the radial center of the thickness of the ring. The gap (23) between adjacent ridges is smaller than the length of the ridge (FIG. 3). Ingredients: WC 75% by weight + binder metal 25% by weight Binder metal composition: Co 12% by weight, Ni 12% by weight, C
r 1% by weight Residual Fe Coefficient of thermal expansion: The average coefficient of thermal expansion from room temperature to 500 ° C. is 7 × 10 ⁻⁶ (1 / ° C.) [Cast-in material] Component (unit;% by weight) C Si Mn Ni Cr Fe 3.3 2.2 0.4 1.0 0.2 Remainder Coefficient of thermal expansion: 12 × 10 ^-6 (1 / ° C) [Assembling condition] Static casting in which the carbide ring is preheated to 240 ° C and the molten metal casting temperature is 1340 ° C [Heat treatment Condition] A strain removing heat treatment is performed in a temperature atmosphere of 530 ° C. for 15 hours.

In each of Examples 1 and 2, no residual stress cracking and no thermal stress cracking were observed, and during use (during rolling),
The carbide ring (2) did not run idle.

FIGS. 4 to 7 show the uneven surface of the carbide ring (2).
FIG. 4 shows another embodiment (21), in which grooves 24 extending in the radial direction are provided on the side surface of the ring at equal intervals in the circumferential direction. Ridges can be used instead of grooves. Figure 5 shows the ring
On the side surface of (2), an irregular surface (21) having irregularities in the rotational direction is formed. FIG. 6 shows an uneven surface in which convex portions (25) and concave portions (26) are alternately continuous in a wavy manner in the rotation direction on the side surface of the ring (2).
(21) is formed. In FIG. 7, a frusto-conical projection (27) protrudes from the side surface of the ring (2). In each of the above embodiments, the uneven surface (21) on the side surface of the ring has a difference in height between the concave portion and the convex portion of about 1 mm, so that even when rolling is used, the ring (2) does not run idle. The unitary rotation of the roll body (3) can be guaranteed.

The description of the above embodiments is for the purpose of illustrating the present invention and should not be construed as limiting the invention described in the claims or reducing the scope thereof. Further, the configuration of each part of the present invention is not limited to the above-described embodiment, and it is needless to say that various modifications can be made within the technical scope described in the claims.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a mold for explaining a production method of the present invention.

FIG. 2 is a perspective view of the first embodiment of the carbide ring.

FIG. 3 is a perspective view of a second embodiment of the carbide ring.

FIG. 4 is a perspective view of a third embodiment of the carbide ring.

FIG. 5 is a perspective view of a fourth embodiment of a carbide ring.

FIG. 6 is a perspective view of a fifth embodiment of the carbide ring.

FIG. 7 is a perspective view of a sixth embodiment of the carbide ring.

FIG. 8 is a cross-sectional view of a mold for explaining a conventional manufacturing method.

[Explanation of symbols]

 (1) Mold (2) Carbide ring (21) Uneven surface (3) Cast-in metal

 ──────────────────────────────────────────────────続 き Continuation of front page (56) References JP-A-9-38763 (JP, A) JP-A-8-158004 (JP, A) JP-A-54-86465 (JP, A) JP-A-53-86 142322 (JP, A) JP-A-61-199567 (JP, A) JP-A-58-138551 (JP, A) JP-A-55-144373 (JP, A) JP-A-49-5825 (JP, B1) JP-B-47-14007 (JP, B1)

Claims (2)

(57) [Claims] 1. A composite roll having a cemented carbide ring (2) with its outer peripheral surface exposed and cast with cast iron or cast steel material, and a cast iron or cast steel material portion serving as a roll body (3). A composite roll in which an uneven surface (21) having a step in the roll rotation direction is formed on the side surface of (2), and the roll body (3) is engaged with and engaged with the uneven surface (21). 2. A method of manufacturing a composite roll in which a cemented carbide ring (2) is fixed to a mold (1) and a molten metal is poured into the mold (1) to solidify the cemented carbide ring (2). An irregular surface (21) having a step in the circumferential direction is formed, and the molten metal is poured into the mold (1) by adjusting the temperature of the molten metal so that the cemented carbide ring (2) and the molten metal are not bonded to each other. The solidified part is the uneven surface of the carbide ring (2)
(21) A method of producing a composite roll, wherein the composite roll is bitten into.