JPH09122714A - Manufacture of composite roll - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a roll having wear resistance and resistant to large rolling load by using a roll-core material on which grooved parts in the circumferential direction in positions where the arrangement of caliber is planned and carving calibers in the circumferential direction on the outer-layer metal after depositing the outer-layer metal on the surface of the roll-core material. SOLUTION: After heating the outer layer of the roll-core material 5 by a high frequency, the molten metal for outter-layer metal of high-speed steel containing W which is separately melted is poured into a molding flask provided on the circumference of the roll-core material and the outer-layer metal is deposited on the roll-core material 5. After that, the caliber roll is manufactured by carving the calibers in the parts equivalent to the groove parts by cutting by machining and making the thickness in the flat parts of barrel except the calibers uniform. In this way, even when the depth (t) of the caliber is greater than the deposite thickness T of the outer-layer metal, the bottom of the caliber 3 does not reach the roll-core material 5 and the whole surface of the calibers 3 of the roll is covered with the outer-layer metal excellent in wear resistance and surface roughening resistance.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to an abrasion resistant material,
The present invention relates to a method for manufacturing a rolling roll having a caliber, which has rough surface resistance and sufficient breakage resistance to withstand a large rolling load.

[0002]

2. Description of the Related Art A rolling roll having a caliber used for hot rolling a steel bar or a shaped steel is made of alloy cast iron having a large amount of carbide and having a large amount of wear resistance in order to secure wear resistance in a hot state. Is beginning to be used. High Cr forged steel rolls are also used to improve the roll unit. However, most of them are ductile cast iron, cast steel rolls or cast iron rolls whose surface layer is light forged.

In recent years, in hot rolling of steel bar or shape steel,
To improve the material properties of rolled steel bar or section steel, T
Controlled rolling called hermo Mechanical Control Process (abbreviated as TMCP) is in widespread use. In this controlled rolling, the rolling temperature and the amount of reduction in each rolling pass are set to conditions suitable for improving the material of the bar steel or shaped steel, but these conditions are often severe conditions for the rolling rolls. For this reason, in a conventional integral type roll in which the core portion and the surface layer portion are formed by using the molten metal of the same charge and the core portion and the surface layer portion have the same chemical composition, the breakage resistance of the core portion tends to be insufficient, or the surface layer The wear resistance of the part tends to be insufficient, and therefore improvement is required.

As a method for producing a composite roll in which a surface core metal is welded to a roll core material and the core portion and the surface layer portion have different chemical components, continuous high-frequency heating disclosed in JP-B-44-4903 is used. Overlaying method, JP-A-58-19
A build-up method and the like utilizing the electroslag remelting method disclosed in Japanese Patent No. 7232 are known. FIG. 2 is an explanatory view of a vertical cross section of a rolling roll manufactured by these methods.

In the figure, 1 is a roll core material, and 2 is a surface metal. That is, the roll core 1 and the surface metal 2 which are the shafts are formed of different metals having different chemical components, and the roll core 1
When combining the surface metal 2 with the surface metal 2, the surface of the roll core 1 is preheated, and the surface metal 2 having a chemical component excellent in abrasion resistance, surface roughening resistance, etc. is welded to the outer surface of the roll core 1. However, there is no description in the known method regarding a method for producing a composite roll having a caliber.

[0006]

FIG. 3 is an explanatory view of problems in manufacturing a composite roll having a caliber by using the above-mentioned known method for manufacturing a composite roll having no caliber. 3 is an example of caliber. On this occasion,
In the case of FIG. 3 (A) in which the welding thickness T of the surface layer metal is smaller than the depth t of the caliber, the bottom of the caliber 3 reaches the roll core material 1, so that the wear resistance and the rough surface resistance of the caliber 3 are reduced. The effect of improving sex becomes insufficient.

The deposition thickness T of the surface metal is the depth t of the caliber.
In the case of FIG. 3B, which is larger than the above, the roll core 1 does not appear at the bottom of the caliber 3, and the entire surface of the caliber can be covered with the surface metal. However, the surface metal becomes excessively thick, the control of the metal structure of the surface metal becomes insufficient, the effect of the surface metal tends to be insufficient, and the manufacturing cost of the composite roll increases.

An object of the present invention is to provide a method for producing a composite roll having a caliber in which the surface metal in the caliber-free portion does not become excessively thick and the roll core material is not exposed on the surface of the caliber. I am trying.

[0009]

The present invention provides a method for producing a composite roll in which a roll core material is preheated and a surface metal having a chemical composition different from that of the roll core material is welded to the roll core material.
Using a roll core material provided with a circumferential groove portion at a position where a caliber is to be arranged, and engraving a circumferential caliber on the surface metal of the groove portion after welding the surface metal to the surface of the roll core material. And a method for producing a composite roll.

FIG. 1 is an explanatory view of the present invention, and FIG. 1 (A) is an explanatory view of a longitudinal section of a roll core material 5 of the present invention having a groove portion 4,
FIG. 1 (B) is an explanatory view of a longitudinal section in which a surface layer metal 2 having a chemical component different from that of the roll core material 1 is welded thereto,
FIG. 1C is an explanatory view of a vertical cross section of the composite roll of the present invention in which the caliber 3 is engraved on the surface layer metal 2 of the groove portion 4.

The material of the roll core material 5 is a material having sufficient strength and toughness as a roll shaft portion, such as Cr,
It is possible to use a medium carbon alloy steel or the like containing an appropriate amount of Ni, Mo or the like. The surface metal preferably has wear resistance and surface roughening resistance, such as Cr, V, or high-speed steel.
Steels and high Cr containing components that form carbides such as Mo
Cast iron or the like can be used.

As a method for welding the surface layer metal 2 to the surface of the roll core material 5, for example, the above-mentioned Japanese Patent Publication No. 44-490.
The continuous build-up method by high frequency heating described in JP-A No. 3 or the electro-slag build-up method described in JP-A-58-1972232 can be used.

The shape and size of the groove 4 provided in the roll core material 5 and the thickness of the surface metal layer 2 are such that when the caliber 3 is formed, the roll core material 5 is not exposed on the surface of the caliber 3 and the surface metal layer is not exposed. Choose appropriately so that 2 covers the entire surface of the caliber.

In the roll core material after the surface layer metal is welded in the present invention, even if the deposition thickness of the surface layer metal other than the groove part is thin, the surface layer metal having a sufficient thickness is formed at the position where the caliber is engraved in the groove part. Has been done. Therefore, in the composite roll of the present invention in which the caliber is engraved in the groove, the roll core material is not exposed on the surface of the caliber even if the surface metal of the portion without the caliber is thin, and the entire surface of the caliber is covered with the surface metal. It is being appreciated.

Therefore, according to the present invention, the caliber depth t
Even if is larger than the welding thickness T of the surface layer metal, the bottom of the caliber 3 does not reach the roll core material 5, and the entire surface of the caliber 3 of the manufactured roll has a surface layer excellent in wear resistance and rough surface resistance. It is covered with metal.

Further, in the present invention, the thickness of the surface metal 2 in the portion where there is no caliber is smaller than the depth t of the caliber, and the surface metal can be prevented from becoming excessively thick. As a result, the excellent material properties of the surface layer metal 2 are not impaired, and the manufacturing cost of the composite roll can be reduced.

[0017]

Example: C having a diameter of 380 mm and a length of 2600 mm
R-Mo steel was used as a roll core material by forming circumferential grooves having inclined walls with a width of 100 mm and a depth of 50 mm at three predetermined positions where a caliber is arranged.

After heating the surface of the roll core by high frequency, the melt of the surface metal of W-containing high-speed steel separately melted is poured into a molding frame provided around the roll core to obtain the outer diameter of the surface metal. The surface layer metal was welded to the roll core material so that the thickness was uniformly 436 mm. A predetermined heat treatment is carried out after welding, and then a depth of 3 at the corresponding portions of the three grooves by machining.
A 0 mm caliber was engraved by cutting, and the flat portion of the body other than the caliber was uniformly cut to have a thickness of 3 mm to prepare a caliber roll having a body length of 1200 mm and a body diameter of 430 mm.

The core portion of this caliber roll is made of Cr-Mo.
The steel has sufficient breakage resistance, and the surface of the caliber is covered with W-containing high-speed steel and has sufficient wear resistance and rough surface resistance, and can be sufficiently used even under severe rolling conditions in TMCP. It was a thing.

[0020]

EFFECTS OF THE INVENTION According to the present invention, a composite roll having a caliber in which the surface metal in the caliber-free portion is not excessively thick and the core material of the roll is not exposed on the surface of the caliber is manufactured. However, since the surface of the caliber is covered with the surface metal, this composite roll has excellent wear resistance and surface roughening resistance of the surface metal. Further, since the surface metal is not excessively thick, it has sufficiently excellent performance. Further, since the composite roll having the caliber of the present invention has a thin deposition thickness of the surface metal, it is possible to suppress an increase in manufacturing cost.

[Brief description of the drawings]

FIG. 1 is an explanatory view of the present invention, (A) is an explanatory view of a vertical cross section of a roll core material provided with grooves, and (B) is an explanatory view of a vertical cross section in which a surface layer metal is welded thereto. (C) is an explanatory view of a longitudinal section of a composite roll in which a caliber is engraved on a surface metal at a position corresponding to a groove.

FIG. 2 is an explanatory view of a composite roll according to a known method.

FIG. 3 is a diagram illustrating a problem when a composite roll having a caliber is manufactured by using a known method for manufacturing a caliber-free composite roll.

[Explanation of symbols]

1: Roll core material, 2: Surface metal, 3: Caliber,
4: Grooves provided on the roll core material, 5: Roll core material used in the present invention.

Claims (1)

[Claims] 1. A method for producing a composite roll in which a roll core material is preheated and a surface metal having a chemical component different from that of the roll core material is welded to the roll core material. A method for producing a composite roll, comprising: using a roll core material; and depositing a surface metal on the surface of the roll core material, and engraving a caliber in the circumferential direction on the surface metal of the groove.