JPS63160708A - Work roll for rolling - Google Patents

Abstract

PURPOSE:To prolong a service life of a roll and to bring surface grain sizes of a rolled stock to be good by forming la vapor deposition layer consisting of a metal having a hardness lower than that of a sintered hard alloy on the surface of a roll body consisting of a sintered hard alloy. CONSTITUTION:On the surface of a roll body 1 consisting of a sintered hard alloy, a thin layer 2a of a metal having a hardness lower than of the sintered hard alloy used for the body 1 is vapor deposited and the secondly vapor deposited thin layer 2b is laminated on the layer 2a; their total thickness is 5-50mum. Thus, the service life of a work roll for very thin sheet rolling is prolonged by increase of a roll dia.; fine recesses on the surface of the roll body 1 are eliminated by the vapor deposited layers so that the surface grain sizes of a rolled stock are improved.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a rolling work roll that is particularly suitable for rolling thin metal materials with high tensile strength.

[Conventional technology]

Thin cold-rolled products of stainless steel and other special steels have been widely used in high-tech related equipment, but as their development progresses, the demand for even thinner, ultra-thin products is increasing.

As a characteristic of these metal materials, when cold rolling is continued, rolling stress increases due to work hardening. In the case of stainless steel, which is highly work-hardened, the rolling stress of approximately 50 kg/- before rolling often reaches approximately 200 kg/-. A cold rolling mill having a small diameter work roll is used, and representative rolling mills include a Sendzimir mill and a lawn mill.

In such cold rolling, flattening of the rolling work roll may occur depending on conditions such as the diameter of the rolling work roll, the material, and the rolling stress of the material to be rolled, so the minimum thickness that can be rolled is It is constrained as expressed by the following equation.

t: Minimum thickness that can be rolled: Constant D = Rolling work roll diameter μ: Coefficient of friction between the rolling work roll and the rolled material So: Rolling stress on the rolled material S: Acting on the rolled material during rolling Tension E: In order to make the Young's modulus of the rolling work roll, that is, the minimum plate thickness t, as small as possible, the smaller the diameter of the rolling work roll, the better.

In addition, the smaller the friction coefficient μ, the better, so good lubricity is a condition, but if the rolled material requires surface brightness, poor lubricity will result in better results. Therefore, μ cannot be made extremely small due to constraints on the lubricity of the lubricant.

Young's modulus E is 21.0 in the most common case where ferrous metals are used as the material for rolling work rolls.
It is about 00 kg/-. On the other hand, when a cemented carbide such as Igetalloy (trade name, manufactured by Sumitomo Electric Industries, Ltd.) is used, the Young's modulus E is as large as about 60.000 kg/-. In this way, if cemented carbide is used, even if the roll diameter of the work roll for rolling is kept as large as possible and the work roll is rolled very thinly, the same effect as when the roll diameter is made small will be brought about. In this way, if cemented carbide is used for rolling work rolls, the roll diameter of the rolling work rolls can be increased, which not only extends the life of the rolling work rolls but also simplifies the structure of the rolling mill. Furthermore, when the roll diameter is the same as that of work rolls for rolling ferrous metals, it becomes possible to cold-roll the material to be rolled to a thinner plate thickness.

In view of the above, rolling rolls made of cemented carbide have been put to practical use as work rolls for rolling ultra-thin objects, and have been used in some cases.

[Problem that the invention seeks to solve]

However, this rolling work roll made of cemented carbide also has the following problems.

One is that cemented carbide is made by bonding fine powder with a binder and sintering it at high temperature and pressure, so fine pinhole-like depressions remain on the polished roll surface. When rolled, the surface roughness of the rolled material is poor, making it impossible to obtain a good product.

Another problem is that rolling work rolls are relatively expensive. This is not only due to the price, but also because the cost of grinding the rolls, which is frequently done, requires the use of special grindstones and long grinding times due to the high hardness of the roll surface and the ability to grind in difficult places. be. For these reasons, rolling work rolls made of cemented carbide are not often used.

[Means for solving problems]

An object of the present invention is to provide a rolling work roll that makes effective use of the high Young's modulus of cemented carbide and solves the above problems.

That is, one of the present inventions is that a vapor deposited layer consisting of one or more thin layers of a metal having a hardness lower than that of the cemented carbide is laminated on the surface of a roll base made of a cemented carbide. Regarding a rolling work roll characterized by (
Hereinafter, this may be referred to as the first invention).

Another aspect of the present invention relates to a rolling work roll characterized in that, in addition to the structure of the first invention, the surface of the vapor deposited layer is further coated with a hard chromium plating layer (hereinafter referred to as the second invention). (sometimes called invention).

[Description of Structure] The structure of the rolling work roll according to the present invention will be explained below with reference to the drawings.

FIG. 1 and FIG. 2 are respectively partial sectional explanatory views of a rolling work roll according to the present invention.

In the drawings, 1 is a roll base made of cemented carbide. Cemented carbide refers to those specified in JIS H5501.1 For example, the above-mentioned IGETALLOY (trade name, Sumitomo Electric Co., Ltd. M) is one type, and has a hardness of HV 900 to 1800, R
83.0-92.5. Tensile strength is 94-183kg/-
1 Abrasion resistance (CCPA) is 2 to 60 CC/rev, Young's modulus is 4.6 to 6.4 (X10'kg/-), 2 is a vapor deposited layer formed on the surface of the roll base 1 A thin layer 2a in which a metal (hereinafter sometimes referred to as vapor-deposited metal) whose hardness is lower than the cemented carbide used for the roll base 1 is first deposited on the surface of the roll base 1.

It consists of one or more laminated layers, such as the second deposited layer 2b, with a total thickness of 5-50/I .mu.m.

Reference numeral 3 denotes a hard chromium plating layer formed on the surface of the vapor deposited layer formed on the surface of the roll base 1. The vapor deposited layer 2 is in contact with the rolled material directly in the case of the first invention, and indirectly through the hard chromium plating layer 3 in the case of the second invention. Therefore, the vapor-deposited metal constituting the vapor-deposited layer 2 may be any metal conventionally used in ordinary rolling work rolls, and metals such as die steel, high-speed steel, etc., are used depending on the characteristics of the material to be rolled. Further, since very high pressure is applied to the rolling work roll, the adhesion between the roll base 1 made of cemented carbide and the vapor deposition layer 2 is important. Therefore,
A metal with particularly good adhesion to the cemented carbide of the roll base 1 is used as the vapor-deposited metal for the first thin layer 2a, and a metal suitable for the characteristics of the material to be rolled is used as the vapor-deposited metal for the second thin layer 2b. Their use makes the invention more effective and is preferred.

These vapor-deposited metals may be vapor-deposited on the surface of the roll base 1 by any conventionally known method.

Generally, when depositing an alloy, each component of the alloy composition is evaporated from a separate evaporation source, and the evaporation ratio is adjusted so that the component composition after evaporation becomes a predetermined value. After that, it is preferable to harden it by heat treatment.

In this way, the rolling work roll according to the first invention having the configuration shown in FIG. 1 is obtained.

In the second invention, the outermost layer of the rolling work roll of the first invention is further coated with a hard chromium plating layer 3 as shown in FIG. This hard chromium plating layer 3 can significantly reduce wear on the surface of the rolling work roll.

〔effect〕

The rolling work roll according to the present invention has a vapor-deposited layer made of a metal whose hardness is lower than that of the cemented carbide used in ordinary rolling work rolls, on the surface of the roll base made of cemented carbide. .

Same advantages as rolling work rolls made of cemented carbide, namely as rolling work rolls for ultra-thin objects.

It has the advantages of extending the life of the roll by increasing the roll diameter, simplifying the structure of the rolling mill, and making it possible to roll to an even thinner roll by reducing the roll diameter. By eliminating this, it is possible to improve the surface grain size of the rolled material and reduce the grinding cost for roll regeneration.

In particular, roll costs can be significantly lowered for those in which the vapor deposited layer is further covered with a hard chromium plating layer.

As described above, the rolling work roll according to the present invention makes it possible to roll ultra-thin sheets of stainless steel or the like easily and at low cost, and greatly contributes to the spread of high-tech related equipment.

[Brief explanation of the drawing]

FIG. 1 and FIG. 2 are explanatory partial cross-sectional views of a rolling work roll according to the present invention, respectively. 1... Roll base 2... Vapor deposited layer 2a... First vapor deposited layer 2b... Second vapor deposited layer 3... Hard chrome plating layer

Claims (1)

[Claims] 1. Formed on the surface of a roll base made of a cemented carbide is a vapor deposited layer consisting of one or more thin layers of a metal having a lower hardness than the cemented carbide. Characteristic rolling work rolls. 2. The rolling work roll according to claim 1, wherein the thickness of the vapor deposited layer is 5 μm to 50 μm. 3. The rolling work roll according to claim 1 or 2, wherein the vapor deposited layer is hardened by heat treatment. 4. A vapor deposited layer consisting of one or more thin layers of a metal having a hardness lower than that of the cemented carbide is laminated on the surface of a roll base made of a cemented carbide, and further, the surface of the vapor deposited layer is A rolling work roll characterized by being coated with a hard chrome plating layer. 5. The rolling work roll according to claim 4, wherein the thickness of the vapor deposited layer is 5 μm to 50 μm. 6. The rolling work roll according to claim 4 or 5, wherein the vapor deposited layer is hardened by heat treatment.