JP3065270B2 - Composite sleeve roll and manufacturing method thereof - Google Patents

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 made of a cemented carbide having a high hardness, a high Young's modulus and a high rigidity, and a method for producing the same.

[0002]

2. Description of the Related Art In the production of steel sheets, steel wire rods and steel bars, for example, a Sendzimir roll or a wire rod is used.
Due to demands for higher grade steel products and energy saving,
Rolls made of a cemented carbide material having high hardness, high Young's modulus and excellent wear resistance have been developed and used. These hard metal alloy rolls were relatively small in diameter due to the shape of the material to be handled, for example, small rolls having a diameter of about 20 to 80 mm, or a diameter of about 50 to 150 mm and a length of about 100 to 200 mm were mainly used. .

Recently, there has been a demand for an increase in the size of a cemented carbide roll due to the necessity of long-term continuous operation for improving the quality of steel materials and reducing manufacturing costs.

In general, the above-mentioned Sendzimir roll is made of a solid cemented carbide, and a wire roll or the like has a shaft portion and a shaft portion having a central axis substantially equal to the diameter of the shaft portion around the shaft portion. It is manufactured by applying a compressive force in the axial direction to a sleeve having a hollow portion with an inner diameter of, or by applying a compressive force in the circumferential direction by a wedge-shaped ring or the like to fix the surface to the shaft portion and finish the surface. However, when manufacturing a large-sized roll (usually indicating a diameter of 150 mm or more and a length of 500 mm or more) by a conventional method of manufacturing a composite roll in which a sleeve of a cemented carbide is fitted to the shaft portion,
The sleeve is usually rubber molded from cemented carbide metal powder,
A single hollow member whose center shaft is hollow (equivalent to the diameter of the shaft) is machined, calcined, and then subjected to main sintering and hot isostatic pressing (HIP processing). Although it is fixed to the shaft part, since the hollow member is large and is made of a cemented carbide material in particular, large distortion occurs in the material during heat treatment such as temporary sintering, and subsequent processing becomes difficult Often.

When the hollow member is subjected to rubber molding, a metal rod of a cemented carbide is sufficiently densely filled around a core rod having the same diameter as the shaft part, and then the core rod is removed to obtain a molded body. When the hollow member is large, it is difficult to remove the core rod, and there are many problems such as a difficulty in workability such as a large deformation of the shape of the molded body and an unnecessary force.

[0006]

SUMMARY OF THE INVENTION The present invention relates to a method of manufacturing a composite sleeve roll which is free from distortion of the above-mentioned material and has good workability when manufacturing a long large roll using a cemented carbide material. It is another object of the present invention to provide a composite sleeve roll having high hardness, high Young's modulus and excellent wear resistance.

[0007]

Means for Solving the Problems The present inventors have conducted various studies to solve the above-mentioned problems, and as a result, rubber-molded a plurality of hollow members divided at a plane intersecting the center axis of the roll, After pre-sintering, by integrating the hollow member by hot isostatic pressing, it is possible to suppress the generation of distortion due to heat in pre-sintering, and to produce long large rolls with good workability. The present invention has been completed.

That is, according to the present invention, a sleeve having a hollow portion having an inner diameter substantially equal to the diameter of the shaft portion around the shaft portion around the shaft portion is inserted, and the shaft portion is inserted into the hollow portion. A roll in which the sleeves are fitted and fixed to each other, wherein the sleeve is a sleeve formed by previously integrating a plurality of molded members divided by a surface intersecting with the center axis of the roll, The present invention relates to a sleeve roll and a method for manufacturing the same.

Next, an embodiment of the present invention will be described in more detail with reference to the drawings. FIG. 1 is an external view of a hollow member constituting a sleeve used in the present invention, and FIG. 2 is a cross-sectional view taken along a center axis of a roll manufactured in the present invention. In the drawing, 1 is a hollow member constituting a sleeve, 2 is a hollow portion of the hollow member, 3 is an integrated sleeve, 4 is a shaft member, and 5 is a side end ring.

The material of the roll used in the present invention is a cemented carbide powder, for example, WC, TaC, TiC or the like. In the present invention, it is preferable to use coarse particles, for example, having a diameter of 1 to 10 μm as compared with cemented carbide powder used as a material for conventional tools. In the packing density is improved, high wear resistance,
A molded article having toughness can be obtained. When WC is used as a raw material, a mixed powder with Co (Co: 5 to 50 wt%) is used. For example, WC powder and Co powder having a diameter of 1 to 2 μm are mixed in a medium made of a common material under an inert atmosphere. Are preferably used in combination.

In order to form a molded body (1 in the figure) which forms a hollow member using the powder of the cemented carbide, a rubber mold, for example, an outer cylinder having a predetermined diameter and a depth (length) ) A pipe-shaped double cylinder composed of an inner cylinder having a diameter smaller than the diameter of the outer cylinder having a common central axis in a direction, and a rubber mold made of, for example, rubber, which is thin and has high elasticity. Using the center axis of the inner cylinder in the longitudinal direction, the center axis is also aligned, and a core rod having a diameter substantially equal to the inner diameter is inserted into the center axis portion, and the inner wall of the outer cylinder and the outer wall of the inner cylinder are inserted. The formed space is filled with ultra-hard powder of a roll material in a sufficiently dense state using, for example, a hammer-type filling machine.

The rubber mold used here is used for ordinary cold isostatic pressing (CIP processing) molding, and is determined by the size of a product roll in the present invention. Inner diameter 200-600mm, inner cylinder outer diameter 100-500mm,
It has a depth (length in the vertical direction) of about 300 to 1500 mm, and is characterized in that it is larger and longer than a conventional roll sleeve made of a super-hard material. Further, as the core rod, a rod, a hollow pipe or the like made of a material having high compression strength and having a diameter substantially corresponding to the shaft portion of the roll is used.

It is preferable that the outer periphery of the rubber mold is protected and fixed by, for example, a metal container so as to maintain a constant shape when the powder is filled. It is preferable to use a container having a large number of through-holes in its wall surface or the like so that a uniform pressure is applied to the surface of the molded product in the subsequent CIP treatment. still,
When the ultra-hard powder is filled in a mold, wax, stearic acid, camphor and the like as a lubricant used by being mixed with the filler powder in the conventional CIP molding may be formed into a sufficiently dense molded body without being particularly used in the present invention. it can.

After the ultra-hard powder is sufficiently densely filled, the core rod inserted into the center shaft of the rubber mold is removed, and a rubber molded body having a cavity (2 in the figure) in the center shaft is obtained. This removal of the core rod is a preferable embodiment in the subsequent CIP treatment, in that the surface of the central axis (cavity) and the surface of the outer peripheral portion of the molded body are brought into a uniform pressurized state substantially in accordance with the similarity rule.

The molded body with the core rod removed and the central shaft portion hollowed out is directly subjected to CIP molding.
A good 5 to 60 minutes in ~3000kgf / cm ^2.

The CIP treatment improves the dimensional accuracy and reduces the amount of machining after preliminary sintering, so it is better to perform the CIP treatment, but it is not necessary to perform it.

The molded product obtained by the CIP process through the above-described steps has good dimensional accuracy and can be obtained as a molded product substantially as designed. Deformation such as shrinkage due to heating is conceivable. Therefore, in the preliminary sintering process, it is preferable to use a jig such as a graphite core material in consideration of such deformation prevention. Further, it is more preferable to apply a reaction inhibitor such as boron nitride (BN) to the surface of the jig to prevent unnecessary reaction at the contact interface between the jig and the molded body.

The molded body subjected to the CIP molding is subjected to a temporary sintering process. The conditions are preferably placed horizontally, that is, when performed in a vacuum furnace heated in a state where the center axis thereof is substantially horizontal, in order to prevent the deformation of the molded body, the sintering conditions are preferably: For example, 550 to 800 ° C. and about 1 to 3 hours are preferable. The pre-sintered molded body has good dimensional accuracy, and has a strength enough to withstand such processing even when a predetermined shape processing by a diamond tool, a lathe or the like is required.

The present invention is characterized in that a plurality of pre-sintered or pre-sintered shaped bodies are joined and used as an integrated sleeve, and each of the formed bodies has a surface which intersects the central axis. The two are superimposed on each other so as to have the same central axis, and integrated by a method such as pressure sintering. In the pressure sintering, the pressing and the sintering (main sintering) may be performed simultaneously, or the pressing may be performed after the main sintering.

In the case of simultaneous pressurization and sintering, the CIP molded body or the pre-sintered molded body is machined to improve dimensional accuracy, and set in a state where a plurality of molded bodies are joined, and this is And perform HIP processing. Main sintering H performed here
The IP treatment is performed, for example, in an Ar atmosphere at 1000 to 2000 kgf / c.
m ² , 1100-1200 ° C, after holding for 0.5-2 hours, then 1300-13
It is recommended to hold at 50 ° C for 1 to 3 hours. Alternatively, a method of applying a binder to the bonding surface may be used. Note that Co, Ni, Cr and the like are preferable as the binder.

When pressure treatment is performed after the main sintering, a highly accurate cylindrical material, a core material, and upper and lower lids are prepared by machining a graphite molded product, and a sleeve material is superimposed and set thereon. While maintaining a ^10-3 to ^10-5 mmHg atmosphere while introducing a small amount of hydrogen gas, and after maintaining at 1000 to 1200 ° C for 0.5 to 2 hours, 12
Main sintering is preferably performed at a temperature of 00 to 1350 ° C. for another 1 to 3 hours. The two-stage heating is a treatment for uniformly performing shrinkage deformation during sintering. The sintered body after the main sintering is approximately 94 to 98% of the true specific gravity.
In an atmosphere, HIP treatment is carried out at 1000 to 2000 kgf / cm ² at 1200 to 1350 ° C. for 1 to 3 hours.

In the two methods described above, pressure sintering is performed, and finally HIP processing is performed to integrate the hollow members. Gives a favorable result for improving the properties.

The integrated hollow member sleeve obtained by pressure sintering is further subjected to grinding, polishing and the like by machining if necessary, and a shaft member of a roll is inserted and fitted into the hollow portion. It is advisable to fix them by a usual method such as grilling and cooling.

The shaft member is prepared by tempering chromium steel, chromium molybdenum steel, high-speed steel, and the like, and has a diameter equal to the diameter of the hollow portion of the sleeve and a length of 1000. A size of about 5000 mm is used.

As an example, the physical properties of the parts processed by the above method using the WC-15% Co mixed powder were as follows. The hardness (HRA) was 86.0, the density was 13.8 g / cm ³ , and the transverse rupture strength was 210 to 250 kgf / mm ² .

The composite sleeve roll obtained in this manner is a large-sized long roll having a thick portion substantially at the center in the longitudinal direction of the shaft member. Used for rolling.

[0027]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to embodiments.

Example 1 A mixed powder obtained by mixing WC having a particle diameter of about 3 to 5 μm and Co having a diameter of about 1 to 2 μm (Co: 15 wt%) for 2 days using a WC ball as a mixing medium. , The inner diameter of the outer cylinder is about 400mm,
The outer cylinder and inner cylinder are made of a double-cylinder rubber with a depth of 850 mm and a pipe-shaped core rod with a diameter of about 180 mm and a length of 1000 mm inserted into the center axis of a double cylinder with an inner diameter of about 180 mm. The configured gap was filled. For the filling, a method was employed in which a rubber mold was placed on a hammer-type filling machine, the powder was filled in equal amounts, and then the step of pressing was repeated.

Next, the core rod was pulled out to obtain a molded body whose central axis portion was hollow and penetrated. Similarly, two molded bodies were manufactured. The molded body is then held at 2850 kg / cm ² for 10 minutes and CIP
Processing was performed. The molded product obtained by CIP processing has an outer diameter of 330 m.
m, a hollow member with an inner diameter of 160 mm and a length of 730 mm, which is further machined to smooth the surface, inner surface and joint surface,
Finished to predetermined dimensions, attached two hollow members to graphite core material, introduced a small amount of hydrogen in a vacuum furnace, 10 ^-3 ~ 10 ^-5 mmHg
At 1120 ° C. for 2 hours. The primary sintered body was further mounted on a graphite core material and secondary sintered at 1250 ° C. for 2 hours. This sintered body was subjected to HIP treatment at 1330 ° C., 1000 kgf / cm ² for 2 hours in an Ar atmosphere. The transverse rupture strength at the joint of the molded body as the sleeve subjected to the HIP treatment was 180 to 220 kgf / mm ² . The hardness was 86 to 88 HRA.

Next, 5% chrome steel was tempered to a diameter of about 140 mm,
Approximately 3500mm length shaft material, outer diameter 280mm, inner diameter 140mm, length
It was inserted into a 1230 mm sleeve and machined into rolls. Using this roll, a steel plate was rolled, and a good thin plate was obtained without roll breakage.

[0031]

The composite sleeve roll of the present invention is relatively long with little distortion, and the manufacturing method of the present invention does not cause distortion of the material even when the cemented carbide sleeve is subjected to heat treatment, and the workability is improved. In addition, a large-sized long composite sleeve roll having high hardness, high Young's modulus and excellent wear resistance can be produced.

[Brief description of the drawings]

FIG. 1 is an external view of two hollow members used in the present invention.

FIG. 2 is an explanatory view of a cross section cut along a central axis of a roll manufactured according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Hollow member which comprises a sleeve 2 Hollow part of a hollow member 3 Integrated sleeve 4 Shaft part 5 Side end ring

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification code FI B30B 11/00 B30B 11/00 E (72) Inventor Kazuhito Kenmochi 1 Kawasakicho, Chuo-ku, Chuo-ku, Chiba-shi, Chiba Pref. In-house (72) Inventor Hirotaka Kano 1 Kawasaki-cho, Chuo-ku, Chiba-shi, Chiba Prefecture Kawasaki Steel Engineering Co., Ltd. Inventor Osamu Sonobe 1 Kawasaki-cho, Chuo-ku, Chiba City, Chiba Prefecture Inside the Technical Research Laboratory, Kawasaki Steel Corporation (56) 59-81502 (JP, U) Japanese Utility Model sho 59-148160 (JP, U) Japanese Utility Model sho 60-38603 (JP, U) Japanese Utility Model hei 2-118603 (JP, U) (58) Field surveyed (Int. Cl. ⁷ , D B name) B21B 27/00 B22F 7/08 B30B 5/02 B30B 11/00

Claims (8)

(57) [Claims] 1. Around the shaft portion around the shaft portion as a central axis,
A roll in which a sleeve having a hollow portion having an inner diameter substantially equal to the diameter of the shaft portion is fixed by inserting the shaft portion into the hollow portion and fixing them, and the sleeve intersects the center axis of the roll. A composite sleeve roll, which is a sleeve in which a plurality of molded members divided by a surface are previously integrated. 2. Cold isostatic pressing (CIP) of a cemented carbide material powder
The composite sleeve roll according to claim 1, wherein a sleeve obtained by molding is used. 3. The composite sleeve roll according to claim 2, wherein the superhard material is a WC-Co mixture. 4. The sleeve according to claim 1, wherein the plurality of molded members are formed by sintering and / or hot isostatic pressing (HIP) with their central axes substantially coaxial. 3. The composite sleeve roll according to any one of 3. 5. Around the shaft portion around the shaft portion as a central axis,
A roll in which a sleeve having a hollow portion with an inner diameter substantially equal to the diameter of the shaft portion is fixed by inserting the shaft portion into the hollow portion and fixing them, and is divided at a plane intersecting the central axis. A method for manufacturing a composite sleeve roll, wherein a sleeve constituted by integrating a plurality of molded members in advance is fitted and fixed to a shaft member. 6. Cold isostatic pressing (CIP) of a cemented carbide material powder
The method for producing a composite sleeve roll according to claim 5, wherein a sleeve obtained by molding is used. 7. The method for producing a composite sleeve roll according to claim 5, wherein the cemented carbide material is a WC-Co mixture. 8. The sleeve according to claim 5, wherein the plurality of molded members are integrally formed by sintering and / or hot isostatic pressing (HIP) with their central axes substantially coaxial. 8. The method for producing a composite sleeve roll according to any one of 7.