JP3514917B2 - Industrial rolls - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention requires industrial rolls, particularly at least one of physical or chemical functions such as heat resistance and abrasion resistance, corrosion resistance, non-adhesiveness, and releasability. Rolls, for example, hot rolling rolls for metals, hearth rolls for annealing equipment, glass forming rolls, plastic forming rolls, film or papermaking casting rolls, film heat treatment rolls, textile processing rolls, of various substances The present invention relates to an industrial roll in a broad sense suitable for use as a coating roll and the like.

[0002]

2. Description of the Related Art Although there are various types of industrial rolls,
Many of them need to endure severe heat loads and wear. For example, rolls used for hot rolling in the manufacturing process of metal products such as steel sheets are used under severe conditions in which they are brought into contact with a high-rolled material having a temperature of more than 1000 ° C and heating and cooling are repeated. . In recent years,
Several hundreds of hearth rolls are widely used in continuous annealing equipment for thin steel sheets and annealing furnaces before hot dip galvanizing.
It is used in a high temperature atmosphere of ℃, and its surface constantly contacts the steel plate passing at high speed.

The above-mentioned hot rolling is a process in which the material to be rolled heated to a high temperature is repeatedly passed between rolls rotating at high speed to gradually adjust the shape. Since the roll and the material to be rolled are repeatedly contacted and released under a high pressure, wear occurs. When the roll comes into contact with the material to be rolled, the roll surface is instantly exposed to a high temperature, and the roll surface locally and rapidly expands. On the other hand, when released from the material to be rolled, cooling is performed with water, and the roll surface is rapidly cooled and contracts. These effects cause cracks called heat cracks in the roll. In addition, the cooling water contains various substances, and when these substances are combined with the above temperature conditions, corrosion occurs on the roll surface.

A hearth roll of a steel sheet annealing furnace or the like is contacted with a thin steel sheet beautifully finished by cold rolling at a high temperature. Since this steel plate is pulled by the tension between the rolls, slippage occurs between the rolls and the steel plate. Therefore,
The roll is abraded and further roughened due to baking. If the roll surface has even a slight defect such as rough surface, it damages the surface of the steel sheet and impairs its product value.

As can be inferred from the above examples, the main properties required for industrial rolls are strength, heat resistance and wear resistance, but in addition to these, the occurrence of defects such as heat cracks and seizures. Excellent surface properties are required.

From the viewpoint of roll material, for example, as materials for hot rolling rolls, adamite cast iron, high chromium cast iron, high alloy grain cast iron, ductile cast iron, high alloy chilled cast iron, etc. are used. Many inventions relating to improvement have been proposed.

On the other hand, in terms of surface treatment, an invention has been made in which chromium, nickel, or an alloy thereof is plated on the roll surface in order to improve wear resistance, seizure resistance, corrosion resistance, etc. Japanese Unexamined Patent Publication No. 61-165212, Japanese Patent Laid-Open No.
-211902 gazette, Unexamined-Japanese-Patent No. 1-210105 gazette, reference). Further, in JP-A-60-196209, a nickel plating layer, a nickel-phosphorus alloy plating layer, on the surface of a hot rolling roll,
Also disclosed is an invention in which three-layer plating including a chrome-plated layer is performed.

[0008] Chromium plating has a high hardness and is excellent in wear resistance, and is therefore widely used in a part requiring high hardness or a part requiring wear resistance. However, chrome plating has a problem in corrosion resistance because there are numerous microcracks.

Further, chromium plating has a high hardness at room temperature, but its hardness remarkably decreases at a high temperature, so that it is difficult to expect high-temperature wear resistance. Furthermore, since hexavalent chromium, which is harmful, is used in the plating work, careful attention and a large amount of expense are required for safety measures for workers and prevention of pollution.

On the other hand, nickel plating is not preferable as a surface coating for hot rolling rolls because it has few coating defects such as cracks but has low hardness and poor wear resistance.

The above-mentioned three-layer plating was developed in order to improve these drawbacks, and three layers of plating films each having a different coefficient of thermal expansion are applied, and an intermediate nickel-phosphorus alloy plating film is used for abrasion resistance. And so on. Nickel-phosphorus alloy plating is known to increase its hardness up to a certain temperature, but when it exceeds that temperature, the hardness sharply decreases and the wear resistance also decreases accordingly. In addition, there is a problem in that such multi-layer plating is complicated because the number of plating steps increases and the roll production efficiency is poor.

Also in the field of glass industry, rolls are frequently used for molding and heat treatment of glass products. Further, in the field of the plastics industry, rolls are used for molding resin products, particularly films and sheets, heat treatment, laminating and the like. In addition, rolls are often used for various purposes in the paper industry, textile industry, coating industry, and the like. Therefore, as an industrial roll, the wear resistance,
In addition to heat resistance and corrosion resistance, non-adhesiveness that does not easily adhere to glass and plastics, and mold releasability are also required.

Regarding a drum for processing a plastic film, it is proposed to perform nickel-chromium double-layer plating (Japanese Patent Laid-Open No. 61-195994), and a heat pipe constituting the drum is metal-plated (copper, nickel, etc.). Plating)
There is a proposal (Japanese Patent Laid-Open No. 56-123827). However, these plating treatments are not intended to impart various characteristics to the drum as described above.

[0014]

As described above, the characteristics required for industrial rolls are diverse. Moreover, once
Rolls that have been worn, cracked, seized, etc. must be replaced and repaired, and the labor and work required for the replacement lead to a large decrease in production efficiency. In other words, the rolls that do not easily cause the above defects and have a long life contribute to the improvement of production efficiency and the product quality, and help to reduce the manufacturing cost of the product.

An object of the present invention is to provide an industrial roll which has excellent wear resistance, crack resistance, seizure resistance, corrosion resistance and adhesion resistance as well as heat resistance and has a long service life.

[0016]

DISCLOSURE OF THE INVENTION The present invention is characterized by having an electroplated film of "a ternary alloy of nickel, tungsten and boron (however, unavoidable impurities are allowed) on the surface thereof. Roll ”is the gist.

The above electroplating alloy film is preferably an alloy film containing 3 to 50% by weight of tungsten and 0.01 to 5% by weight of boron, with the balance being nickel and inevitable impurities. More desirable is the following composition.

Tungsten: 10 to 50% by weight (more preferably 25 to 45% by weight) Boron: 0.01 to 3% by weight (more preferably 0.
Nickel: balance (however, unavoidable impurities are allowed.) The above-mentioned plated roll body is made of cast iron-based material, cast steel-based material, tool steel, heat-resistant steel, etc. Any of As these materials, those having necessary strength, heat resistance, etc. may be selected depending on the application of the roll. The "roll" includes not only a solid roll but also a hollow roll (so-called drum type roll) through which a cooling medium is passed. The above electroplating can be applied to any material and shape.

[0019]

BEST MODE FOR CARRYING OUT THE INVENTION The plating layer of the roll of the present invention is a ternary alloy in which a small amount of boron is added to a tungsten-nickel alloy. Plating of a binary alloy of tungsten and nickel is already known (see, for example, Japanese Patent Laid-Open No. 61-6291). This binary alloy plating has good heat resistance and wear resistance, and as described in the above publication, can be sufficiently used for molds for molding glass products and the like. However, as a plating film for a roll used under extremely severe conditions as described above, the hardness at high temperature, that is, the high temperature wear resistance is not sufficient. There is also a problem in corrosion resistance.

In the present invention, the above-mentioned tungsten-nickel binary alloy plating is further improved and the optimum chemical composition is selected as a plating film on the roll surface. The base of the plating alloy of the roll of the present invention is nickel,
This is because the coefficient of thermal expansion of nickel is not so different from that of the iron-based material that constitutes the substrate (roll body). If the difference in coefficient of thermal expansion is large, the film on the surface layer when heat is applied to the roll,
It expands or contracts more than the substrate, and the difference in expansion causes cracks in the film, which eventually leads to film peeling. That is, the nickel-base alloy plating has excellent adhesion to the roll substrate and does not generate microcracks unlike chromium plating.

The tungsten content of the plating film is 3 to 50.
It is desirable to set it as the weight%. If it is less than 3% by weight, the heat resistance and abrasion resistance are insufficient, while if it exceeds 50% by weight, the amount of nickel in the base is too small and the above advantages are lost. Further, the coefficient of thermal expansion of tungsten is much smaller than that of nickel and iron, so if the content of tungsten exceeds 50% by weight, the difference in the coefficient of thermal expansion between the plating film and the substrate becomes too large, which causes the above-mentioned problems. May occur. More desirable range of tungsten content is
10 to 50% by weight, most preferably 25 to 45% by weight.

The plating alloy of the roll of the present invention is characterized in that it contains boron. This boron increases the hardness of the plating film at high temperatures and enhances the high temperature wear resistance. Also,
It also contributes to improving the corrosion resistance and seizure resistance of the plating film. These effects are not significant when less than 0.01% by weight. On the other hand, when the content of boron exceeds 5% by weight, the adhesion to the substrate deteriorates, and cracks or peeling of the film easily occur when the roll is exposed to repeated heating and cooling. Therefore, the preferred content of boron is 0.01-5% by weight, more preferably 0.01-3% by weight, most preferably 0.05-1%.
% By weight.

An invention relating to plating in which boron is added to nickel plating is proposed by the present applicant in Japanese Patent Publication No. 4-59064. However, the plating is for surface treatment of a copper or copper alloy mold for continuous casting, and is not intended for surface treatment of rolls. As shown in Examples (Table 2) described later, the boron-nickel binary alloy plating is inferior in wear resistance and seizure resistance and is not suitable for roll plating.

The roll of the present invention is plated by electroplating. As the plating bath, nickel having the above composition is used.
Any type of tungsten-boron alloy plating film can be used as long as it can be obtained. For example, the following bath compositions are available.

Nickel sulphate: 5-80 g / L sodium tungstate: 25-55 g / L citric acid: 40-70 g / L boric acid・ ・ ・ ・ ・ ・ ・ ・ 20 to 30 g / L Dimethylamine borane ・ ・ ・ ・ ・ 0.01 to 0.3 g / L Nickel carbonate other than nickel sulfate as the nickel source,
Nickel chloride and other soluble nickel salts can also be used within a range satisfying the above nickel concentration. Further, instead of dimethylamineborane as a boron source, other organic boron compounds such as trimethylamineborane can be used.

The plating conditions are: current density: 8-10
A / dm ² , plating bath temperature: 45 to 60 ° C., pH: 8 to 9 may be used, and the plating thickness may be selected in the range of about 10 to 500 μm in accordance with various conditions used by the roll.

[0027]

【Example】

[Example 1] JIS SUJ 1 (high carbon chrome bearing steel) 150 (L)
On a substrate of × 80 (W) × 5 (T) (mm) size, 44% by weight of tungsten (W) -0.3% by weight of boron (B) -the balance of nickel (Ni) shown in Table 1 and a film thickness of 30 μm It was plated. The composition of the plating bath used is as follows, and the bath temperature was 50 ° C.
The pH was adjusted to 8.8.

Nickel sulfate: 20 g / L Sodium tungstate: 40 g / L Dimethylamine borane: 0.1 g / L Boric acid: 25 g / L Citric acid: 50 g / L The current density was 7 A / dm ² , and the energization time was 1.5 hours.

The plated substrate was subjected to 1 at each temperature shown in Table 1.
A heat treatment of heating for an hour was performed, and the hardness of the plated film after cooling was measured. The results are also shown in Table 1.

[0030]

[Table 1]

As shown in Table 1, the heat treatment significantly increases the hardness of the plating film.

Next, a hot abrasion test was conducted on the plated substrate. The test method is to fix the plated substrate to the sliding device, heat it to 500 ° C from the top, put a steel ball on the hot-plated surface, set the load to 3 kg, and operate the sliding device for 30 minutes. Is the method. As a result, no damage such as abrasion or seizure was observed on the plated surface.

Further, a test in which a heating-cooling cycle in which the plated substrate was heated to 600 ° C. by high-frequency heating of 7 kHz, and then water-cooled to room temperature was repeated 1000 cycles was conducted. As a result, no cracks were generated in the plating film and no peeling of the plating film from the substrate was observed.

[Example 2] The various types of plating shown in Table 2 were examined for hot wear resistance and seizure resistance in the same manner as in Example 1. The example of the present invention is the same as that of the example 1 (the thickness of the film is 30 μm). In all comparative examples, the film thickness is 3
It is plated with 0 μm.

Comparative Example 1 is a nickel-tungsten alloy plating proposed in JP-A-61-26291, and Comparative Example 2 is a three-layer plating proposed in JP-A-60-196209. Example 3 corresponds to nickel-boron alloy plating disclosed in Japanese Patent Publication No. 4-59064, and Comparative Example 4 is general hard chrome plating. Table 2 shows the test results
Also described in.

[0036]

[Table 2]

As shown in Table 2, the wear depth of Comparative Examples 2 to 4 exceeds the plating film thickness (30 μm). this is,
Means that the substrate has also been subject to wear. The tungsten-nickel alloy plating of Comparative Example 1 has good wear resistance and seizure resistance, but it does not reach the invention examples. It is clear that the plating of the present invention exhibits excellent wear resistance and seizure resistance.

Example 3 With respect to the four types of plating shown in Table 3, the hardness after heat treatment, the high temperature hardness and the corrosion resistance were examined. The example of the present invention is the same plating as that of example 1, the comparative example 5
And Comparative Example 7 is the same as Comparative Example 1 and Comparative Example 4 of Example 2 (Table 2). However, in both cases, the plating film thickness was 50 μm. Comparative Example 6 is the second layer of phosphorus-nickel alloy plating of Comparative Example 2 of Example 2 (Table 2).

The hardness after the heat treatment is the hardness after heating at the indicated temperatures for 1 hour and cooling, as in Example 1. The high temperature hardness is measured in a state of being heated to each temperature shown.

Corrosion test is performed by applying 0.1N to the plating film at room temperature.
Was applied with a brush, and the state of corrosion of the coated portion after 1 hour and 24 hours was observed.

Table 3 shows the above test results.

[0042]

[Table 3]

As is clear from Table 3, in the examples of the present invention, the higher the heat treatment, the higher the hardness. Further, the decrease in hardness at high temperature is smaller than that in Comparative Example. That is, it has excellent wear resistance at high temperatures. Regarding the corrosion, there is no problem in the example of the present invention. This is because the plating of the example of the present invention contains boron. The relationship in Table 3 was the same for the current-potential curve.

Example 4 The resin adhesiveness of the plating films of the present invention shown in Table 2, Comparative Examples 1 and 4 (however, the film thickness is 50 μm as in Example 3) was examined. It was The evaluation method is as follows.

Dumilan (trade name) manufactured by Takeda Yakuhin Kogyo Co., Ltd., which is commercially available as an adhesive for laminated glass, was applied onto the plating film, and heated to 110 ° C. for 30 minutes in a vacuum and cooled. Vertically with a cutter knife on this coated surface (20 mm square),
After making cuts at intervals of 2 mm on the side, a commercially available adhesive tape was attached, the tape was peeled off, and the number of 2 mm square dumirans adhered thereto, that is, the number of peeled dumirans was measured. The larger the number, the smaller the adhesiveness of the resin to the plating film and the better the non-adhesiveness. The average values of 5 tests are as follows.

Example of the present invention: 98 pieces Comparative example 1: 60 pieces Comparative example 4: 56 pieces As described above, the present invention is applied to a resin (Dumilan) having high adhesiveness. The plating film of the invention example is superior in non-adhesiveness to both the comparative examples 1 and 4.

Further, similarly, with respect to the plating films having the compositions of the present invention example, Comparative Example 1 and Comparative Example 4, the adhesiveness of glass was examined in the following manner.

A roll for producing a template glass having a diameter of 50 mm and a length of 600 mm and a smooth roll are 1/3 of the length, that is, 200 mm each.
Each of the above three types of plating was applied to a thickness of 30 μm. Pass molten glass (temperature: approx. 1100 ° C) through these rolls,
The amount of glass remaining on each plating film was visually observed. The residual amount of glass was smallest in the examples of the present invention, and then increased in the order of Comparative Example 1 and Comparative Example 4. The surface shape of the roll of the present invention after the test was closer to the shape before the test than any of the comparative examples.

[0049]

EFFECTS OF THE INVENTION The roll of the present invention has a tungsten-boron-nickel ternary alloy plating film on its surface, so that it has extremely excellent heat resistance, abrasion resistance, seizure resistance, corrosion resistance, non-adhesiveness, etc. Has many characteristics. It does not easily generate heat cracks due to repeated heating and cooling, and withstands long-term and harsh conditions. This roll is not only suitable as a metal hot rolling roll or a hearth roll, but can also be used as an industrial roll in various fields such as the plastic industry and the glass industry. Moreover, since excellent characteristics can be imparted by simple electroplating without making the material of the roll itself expensive, there is a great economic advantage that the unit consumption of the roll is reduced.

─────────────────────────────────────────────────── ─── Continuation of the front page (56) Reference JP-A-63-243283 (JP, A) JP-A-60-135593 (JP, A) JP-A-59-54444 (JP, A) JP-A-58- 221298 (JP, A) JP 58-116956 (JP, A) JP 54-24162 (JP, A) JP 6-94028 (JP, A) JP 5-59582 (JP, A) JP-A-4-120297 (JP, A) JP 43-26724 (JP, B1) JP 47-4897 (JP, Y1) JP 2002-515090 (JP, A) (58) Fields investigated (58) Int.Cl. ⁷ , DB name) C25D 7/00 C25D 3/56

Claims (2)

(57) [Claims] 1. An industrial roll having an electroplated coating of a ternary alloy of nickel, tungsten and boron on its surface. 2. The industrial roll according to claim 1, wherein the electroplating film is an alloy film containing 3 to 50% by weight of tungsten and 0.01 to 5% by weight of boron, and the balance being nickel and inevitable impurities.