JP3192449B2 - Sheet 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 processing roll used in a rolling line for steel sheets and the like, a surface treatment line, and the like.

[0002]

2. Description of the Related Art Process rolls used in rolling lines, surface treatment lines, and the like are manufactured to withstand abrasion, deformation, and the like due to a strong load received during use. Usually, centrifugal casting rolls and forging rolls are used. , Such as sheet rolls, etc., according to the manufacturing method.

[0003] A plate wound roll can be formed relatively easily and is inexpensive as compared with other rolls, and is usually manufactured as follows.

[0004] That is, an appropriate metal plate is cold- or hot-rolled into a roll by an appropriate bending method, and the roll base material is butt-joined with a bevel at the beginning and end of the roll, and a commercially available welding material is used. After joining by carbon dioxide gas or argon gas welding or submerged arc welding or the like, it is formed by appropriately performing heat treatment.

[0005] However, the joining portion of the plate wound roll manufactured as described above often has a defect that a pinhole is present, and the welding material is different from that of the roll base material. The effect of the heat treatment applied, that is, the hardness and the respective structures are different, and as a result, irregularities are generated in the plate roll main body and the welded portion during use, for example, a problem that the roll cannot be used as a process roll. There is.

[0006]

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a sheet-wound roll free of the above-mentioned defects and problems and a method of manufacturing the same.

[0007]

Means for Solving the Problems The structure of a sheet winding roll made for the purpose of solving the above-mentioned problems is as follows. A roll base material formed by rolling a steel plate or the like into a roll shape is provided with a groove. The groove is welded by filling a material substantially equivalent to the base material as a welding material to form a weld. The weld boundary where proeutectoid ferrite occurs in this welding is defined as an electron beam, Laser, plasma, T
The ferrite is extinguished by re-melting with an IG arc or the like to adjust the welded portion to the same quality as that of the base material for the roll, and a predetermined process is performed to form a cylindrical hollow roll. .

In the above-mentioned method for manufacturing a sheet-wound roll, the base material for the roll is welded with a welding material of substantially the same material as the base material, and then the welding boundary is welded with an electron beam, a laser,
Re-melted by plasma, TIG arc, etc. to form a welded part of the same quality as the base material for the roll, formed into a predetermined cylindrical shape, heat-treated by high-frequency induction heating, etc. It is characterized by having a hardened layer and hardness.

That is, a sheet-wound roll in which a joint is welded by a conventional welding method has the above-described defects and problems because the base material and the material of the weld are different.
To solve this, the joint must be made of the same material as the base material, but it has been almost impossible to select a welding rod of the same quality as the base material by the conventional welding method.

Therefore, the inventor of the present invention has conducted intensive studies with the aim of solving such a problem. As a result, in order to obtain a welded portion having the same quality as the base metal, the same material as the base material was used as the welding material. After welding, this welding boundary is electron beam, laser,
The present invention was accomplished by knowing that re-melting should be performed by plasma, TIG arc, or the like.

The outline of the present invention will be described as follows. First, as the metal plate used as the base material for the roll in the present invention, a steel plate such as S50C, SCM440, HITEM80 and the like can be mentioned, and this plate material is almost rolled or cut in half by a three-point roll method or press bending. The material is bent into a roll base material. Examples of the metal plate used as the base material for the roll include a stainless steel or nickel alloy-based plate and a non-ferrous metal plate in addition to the above-mentioned steel plate.

Next, a material obtained by melting substantially the same material as that of the base material is filled as a welding material into the groove portion of the roll base material to form a plate-wound roll with the groove portion welded thereto. . However, in the above-mentioned research process, it was found that a pro-eutectoid ferrite band was linearly formed at the weld boundary in the plate-wound roll as welded. The proeutectoid ferrite had a low quenching hardness even when heat-treated by high-frequency induction heating or the like, and could not have a uniform hardened layer and hardness as a whole including the welded portion.

This can be understood from the following. That is,
In the "iron-carbon system equilibrium diagram", for example, C is 0.4%
For steel, when it reaches the _three points A when cooled from A ₃ point or higher temperatures (about 800 ° C.), since the pro-eutectoid ferrite is reported to precipitate in the grain boundary.

Thus, in the above-mentioned sheet-wound roll as-welded, even when a material substantially equivalent to the base material for the roll is used as the welding material, the pro-eutectoid ferrite precipitates at the boundary of the welded portion. Therefore, it precipitates in a band shape over the entire weld boundary (see FIG. 3). Pro-eutectoid ferrite inventors became the band shape of the present invention, previously said welded boundary by heating for heat treating the plate winding roll does not easily disappear even when heated above again A ₃ points Learned in the research process.

The present inventors have confirmed that this proeutectoid ferrite causes a decrease in quenching hardness and depth even when heat treatment is performed using high-frequency induction heating as a heating means. Then, it was confirmed that such proeutectoid ferrite could not be improved by the reheating treatment performed in the conventional manufacturing process of the sheet roll. Then, the present inventors have tried to re-melt the vicinity of the welded portion by electron beam, laser, plasma, TIG arc, etc., and as a result, have found that proeutectoid ferrite at the weld boundary can be eliminated.
Through repeated experiments, a method was established for uniformizing the material of the joints by welding of the rolls.

[0016] Since the material of the joining portion of the obtained roll obtained by welding is the same as that of the base material, the above-mentioned problem is solved. When the surface of the above-mentioned roll is manufactured and subjected to a surface treatment such as plating or thermal spraying, a uniform hardened layer is formed on the roll surface, and a uniform hardness is obtained. It should be processed.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, the process of forming a sheet roll according to the present invention will be described with reference to the drawings. In Fig. 1, 1 is S45C, thickness 30m
m, a base material for rolls formed by bending a steel plate with a width of 1000 mm into a roll shape with a diameter of 600 mm, and an I-shaped groove 2 with a gap of about 30 mm formed by the start and end of bending.
And the part to be welded.

Next, the roll base material 1 is held in such a posture that the groove 2 to be welded stands upright, and the groove 2 is filled with the same material as the base material 1 in a molten state. The groove 2 is welded. This welding utilizes the principle of electroslag welding.

That is, in FIG. 2, reference numeral 3 denotes a welding material of S45C, which is substantially the same as the base material 1, and is formed of an appropriate S45C material. Reference numeral 4 denotes a feed roller for the welding material 3 disposed above the groove 2 of the roll base material 1, reference numeral 5 denotes an electrode, and reference numeral 6 denotes a cold mold for covering the front and rear surfaces of the groove 2; If a large current is applied between the base material 1 and the electrode 5 as shown in FIG.
Since the welding material 3 is fed downward while gradually moving the cooling mold 6 upward, the molten portion of the welding material 3 is filled in the entire groove 2. Become.
As a result, the base material 1 can be welded with the welding material 3 substantially equivalent thereto.

In the above welding, cracks may occur due to the material of the welding material S45C. Therefore, the welded portion may be appropriately preheated before welding or post-processed appropriately after welding.

Further, the sheet roll of the present invention can be formed without using the principle of the electroslag welding method as described above. That is, in this case, although not shown, a melt of substantially the same material as the base material 1 is prepared in another place, and the molten metal is poured into the groove 2 to be welded and welded to the base material 1. is there. In this case, the molten metal in the groove may be heated in order to prevent the temperature of the molten metal from lowering.

After the above-mentioned welding, in the prior art, normalizing or the like is performed at 830 to 870 ° C., and a process for eliminating the difference in the material between the base metal and the welded portion by adjusting the structure of the welded portion is performed. Was. However, it has been found that in such a conventional welding method, a ferrite band is formed at the weld boundary to form a boundary, which hinders the uniformity of the material. Therefore, in the present invention, this weld boundary 1a is formed. The material is re-melted by the method illustrated in FIGS. 5 and 6 to make the material uniform.

That is, the re-melting shown in FIG.
Is set at a distance of 1 to 3 mm from the welded roll base material 1, the TIG electrode 41 is relatively moved along the welding boundary 1a, an arc is generated between the base material and the TIG electrode 41, and the welded portion is re-melted. Let it do. Of course, shielding of an inert gas such as Ar gas is performed. Incidentally, reference numeral 51 in FIG. 6 denotes a mounting table.

In FIG. 5, 31 is a vacuum chamber of the electron beam welding apparatus, 42 is an electron beam gun movably disposed in the vacuum chamber 31, and 52 is a sample mounting table installed in the vacuum chamber 3. The base material 1 is mounted on the mounting table 52 to re-melt the welding boundary 1a. The re-melting of the boundary 1a is performed as follows.

First, the base material 1 is set on the mounting table 52 with the welding boundary 1a facing upward, the vacuum chamber 31 is evacuated to a high vacuum by the vacuum pump 61, and the electron beam gun 42 or the base material 1 is moved. The electron beam is moved along the groove while irradiating the welding boundary 1a and re-melted, but when electrons accelerated at high speed in a high vacuum collide with the welding boundary 1a,
The groove generates heat and melts due to the impact, and remelting is performed. The mounting table 51 may be moved for the movement of the gun 42 with respect to the boundary 1a.

[0026] The remelting by the electron beam has the advantages that the welded portion is not contaminated by the atmosphere, has a very deep penetration, has a small thermal effect, and has a small distortion.
The above-mentioned sheet-wound roll has a joint portion of the same quality as the base material, does not generate pinball at the welded portion, and is extremely good in quality as compared with conventional products. When the hardness of the roll base material and the welded portion actually joined by this method was examined, the hardness on the outer surface side was almost uniform (see FIG. 4).
In the present invention, welding by laser or plasma beam may be used instead of the electron beam.

The roll base material 1 after the remelting of the welding boundary portion 1a is subjected to a post-heat treatment or the like, and after being corrected to a predetermined perfect circular shape, including the distortion removal caused by the heat treatment. By performing heat treatment by high-frequency induction heating or the like, a hardened layer having a uniform surface and a plate-shaped roll having hardness are formed. The heat treatment may be performed by gas heating.

[0028]

As described above, according to the present invention, even in a plate-wound roll obtained by welding the same material as the base material for a roll as a welding material, proeutectoid ferrite is precipitated in a band at the welded portion. Therefore, even if heat treatment is performed after welding, the above-mentioned conventional plate-winding roll in which the proeutectoid ferrite does not disappear and therefore the desired hardness and material homogeneity were not obtained, the welding boundary portion is irradiated with an electron beam or the like. By re-melting, the pro-eutectoid ferrite disappears and the material of the whole sheet winding roll can be made uniform, so that the sheet winding roll obtained in this way has no pinholes and is uniform and has sufficient hardness. Since it can be provided, it is extremely useful as a process roll.

Incidentally, in the conventional plate-wound roll, if the surface hardness of the roll is not uniform, thermal spraying and plating unevenness occur, and this is transferred to the sheet passing material. However, according to the roll of the present invention, such a phenomenon is eliminated. .

[Brief description of the drawings]

FIG. 1 is a perspective view of an example of a roll base material.

FIG. 2 is a partial front view of a main part showing an example of a welding state of a roll base material.

FIG. 3 is a partially enlarged sectional view of a boundary portion between a base material for a roll and a welded portion.

FIG. 4 is a distribution diagram of the cross-sectional hardness of the sheet-winding roll of the present invention.

FIG. 5 is a front sectional view of an example of a remelting process.

FIG. 6 is a front view of another example of the re-melting process.

[Explanation of symbols]

 1 Base material for roll 1a Welding boundary 31 Vacuum chamber 41 TIG electrode 42 Electron beam gun 51, 52 Mounting table

────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI C22B 9/16 C22B 9/16 C23C 4/04 C23C 4/04 F16C 13/00 F16C 13/00 A (56) References JP JP-A-50-13237 (JP, A) JP-A-63-277722 (JP, A) JP-A-3-169412 (JP, A) JP-A 2-175079 (JP, A) JP-A-49-110552 (JP, A) , A) Japanese Patent Publication No. 3-25275 (JP, B2) Japanese Patent Publication No. 51-49573 (JP, B2) (58) Fields investigated (Int. Cl. ⁷ , DB name) B23K 9/00 B21B 27/00 B21B 27/03 B23K 9/025 C21D 9/38 C22B 9/16 C23C 4/04 F16C 13/00

Claims (4)

(57) [Claims] 1. A groove formed by rolling a steel sheet or the like into a roll shape is filled with a welding material filled with a material substantially equivalent to the material of the base material as a welding material. The welded part is formed by welding, and the weld boundary where proeutectoid ferrite occurs in this welding is defined as an electron beam,
The ferrite is extinguished by laser, plasma, TIG arc or the like to eliminate the ferrite, thereby adjusting the welded portion to have the same quality as that of the base material for the roll, and performing predetermined processing to form a cylindrical hollow roll. Roll to roll. 2. A method for manufacturing a sheet-wound roll, comprising: heat-treating the sheet-wound roll according to claim 1 by high-frequency induction heating or the like so as to have a uniform hardened layer and hardness as a whole including a welded portion. 3. The plate-wound roll according to claim 1 is heat-treated by high-frequency induction heating or the like to give a uniform hardened layer and hardness including the welded portion, and the surface of the plate-wound roll is hard. A method for producing a plate-winding roll, comprising forming a coating layer. 4. The hard coating layer is made of chrome plating, V · CC
4. The method for manufacturing a flat roll according to claim 3, wherein the roll is formed by spraying a cermet material such as O or a ceramic material such as alumina or chromium oxide.