JPH059081Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to a roll mill for kneading, dispersing, etc. materials.

(Prior art and problems) A roll mill is designed to knead, disperse, etc. by pressing several rolls strongly against each other and applying shearing force to the material to be processed between the two rolls. A strong frictional force acts on the surfaces, and since they are pressed against each other, a bending load acts inside the roll. Therefore, the roll is required to have a base material having toughness and a surface having wear resistance.

In order to meet this purpose, the surface of the roll is chilled to increase its hardness, and the inside is often made of relatively tough gray cast iron.
There is a limit to the ability of conventional chilled castings to harden the roll surface; for example, if a chilled roll is used to treat metal pigments, streaks will appear on the surface in about 2 to 3 months, necessitating repair. In addition, metals are mixed into the processed material due to wear, which adversely affects the product.

(Means for solving the problem) According to the present invention, in order to eliminate such defects, a superhard material such as tungsten carbide or ceramic is thermally sprayed on the surface of the roll base material having toughness.
A roll mill is provided, the surface of which is polished to form a thermally sprayed coating layer with a thickness of 100 μm or more.

In addition, the thermal spray coating layer should be sprayed to a thickness of 200 μm or more so that it will not crack or peel off from the roll surface due to the pressure force or shear force between the rolls, and the surface will be smooth. The thickness of the coating layer thus formed is from 100μ to less than 200μ.

(Function) The roll of the present invention has high surface hardness, increased durability, and no metal contamination.

(Example) In the figure, a roll mill has three rolls 1,
2 and 3, the rolls are pressed together, and a shearing force is applied to the processing material (not shown) supplied between the rolls 1 and 2, and the material is transferred from roll 2 to roll 3.
The number of rotations of each roll is controlled so that the rolls move sequentially. In addition to the embodiment shown in the figures, the number of rolls may be two or more than four.
The processed material is processed into minced meat while passing between the rolls.
It is processed into uniform particles, dispersed, etc.

The roll is made by forming a base material 4 of a tough metal material such as S45C, and spraying a superhard material such as tungsten carbide (WC) or ceramic onto the surface of the base material 4. The surface of the roll base material may be chilled if desired, and the surface may be treated to make it suitable for thermal spraying. Thermal spraying is carried out by a known metal spraying method, etc., and a thin thermal sprayed film is formed on the surface of the base material, which is overlapped to cover the entire circumference. At this time, various thermal spraying methods are known, but in order to use them in the roll mill of the present invention,
Especially explosive (deflagration) thermal spraying (detonation gun)
Coating) is preferred. For example, in a thermal spraying method that uses an oxygen-acetylene flame as a heat source and supplies WC or ceramic as a powder, the WC or other powder is sent to a thermal spray gun in a nitrogen flow, and a spark is created between the spark plugs installed in the gun. The oxygen-acetylene mixture generated and supplied to the gun is detonated, imparting large kinetic energy to the powder, causing it to fly out of the muzzle of the gun and collide with the surface of the roll base material disposed in front. The above WC powder thereby generates heat to a temperature above its melting point and forms a coating of several microns on the surface of the base material in a molten state, so this operation is repeated.
Forms a sprayed film of 200μ or more. In addition, in the case of high melting point ceramics, plasma spraying may be used. The sprayed film obtained in this manner is extremely dense and has strong adhesion to the base material.

Further, in the roll of the present invention, the surface of the roll sprayed with the above-mentioned WC etc. is polished to a thickness of 100μ to less than 200μ, preferably 100μ to about 150μ to form the spray coating layer 5. The surface of the thermal spray coating layer 5 is made smooth by polishing, and the treatment material does not adhere or remain on the surface. It should be noted that if the thermal spray coating layer 5 is thinner than the above-mentioned thickness, it may cause cracks or have problems in terms of strength, and if it is too thick, it tends to peel off easily.

Tungsten carbide was thermally sprayed onto the surface of a chilled roll to a thickness of 200 μm, and then polished to 150 μm. Metal pigments were treated using the roll of the present invention. However, with the roll of the present invention, no significant wear phenomenon was observed even after operating for 10 to 15 times as long as the conventional chilled roll.

(Effects of the invention) The present invention is constructed as described above, and a thermally sprayed coating layer is formed on the surface of the tough roll base material by thermally spraying a carbide material, thereby increasing the surface hardness and increasing wear resistance. However, brittleness can be reduced depending on the toughness of the base material, and the above-mentioned thermal spray coating layer is made by polishing the superhard material sprayed to a thickness of 200μ or more to a thickness of 100μ or more.
Since it is formed to a thickness of less than 200 μm, the surface is smooth and the treated material does not adhere or remain on the roll surface. Moreover, the thin coating layer does not cause cracks, and the thick coating layer prevents the base material from being damaged. There is no fear of peeling off from the surface, and it can be suitably used for processing metal pigments that do not want to be contaminated with metal.

[Brief explanation of drawings]

The drawings show an embodiment of the present invention, with FIG. 1 being a front view and FIG. 2 being a partially enlarged sectional view of the roll. 1, 2, 3...Roll, 4...Roll base material, 5
...Thermal spray coating layer.

Claims (1)

[Scope of utility model registration request] In a roll mill that compresses multiple rolls and applies shear force to the processed material supplied between the rolls to knead and disperse the processed material, a superhard material such as tungsten carbide or ceramic is applied to the surface of the tough roll base material. A roll mill characterized in that the sprayed coating layer is thermally sprayed to a thickness of 200μ or more and polished to form a thermal spray coating layer with a thickness of 100μ to less than 200μ.