JP2592037B2 - Nickel clad plate for roof and building materials with excellent appearance and corrosion resistance - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a roof and a building material having a favorable color tone and excellent corrosion resistance or weather resistance.
Te suitable relates to nickel clad plate of nickel and carbon steel, and the base material plate such as stainless steel.

[0002]

2. Description of the Related Art Metal sheets are used in many buildings because of their excellent strength, fire resistance and workability. At that time, surface treatment is often performed in terms of corrosion resistance, aesthetics, and the like.
However, there are few permanent surface treatment methods for harsh outdoor environments. By the way, nickel alone has high corrosion resistance, but is expensive. However, the use can be expanded by reducing the price by cladding. Further, the strength of nickel is lower than that of a stainless steel plate or a normal steel plate, so that it has a drawback that it is not suitable for applications requiring strength, but this drawback can also be solved by cladding with a steel plate. Such nickel-clad steel sheets are variously used for applications that make use of the characteristics of nickel. However, when exposed to the air, they have the drawback that they are easily stained, cause discoloration called Turnish, and have a poor appearance.

[0003]

As a result of studying a method for remedying the above drawbacks, the inventors found that an oxide film formed on a nickel surface by heating a nickel clad plate at a high temperature is as follows:
It has a deep dark green color unique to nickel oxide,
Color and building materials have never been suitable before.
It has been found that the corrosion resistance of the nickel is further enhanced , the surface stains due to the passage of time are reduced, and the nickel is less noticeable. That is, an object of the present invention is to provide a nickel clad plate for a roof and a building material having excellent aesthetics and corrosion resistance.

[0004]

SUMMARY OF THE INVENTION The present invention provides a nickel-clad plate in which nickel is clad on one or both sides of a base material plate made of ordinary steel, stainless steel, other metals, or the like.
Heat to a high temperature of 600-1200 ° C and place Ni on the nickel surface.
The material with the O film formed on the roof
And found to be suitable as building materials.

The gist of the present invention is as follows. 1. A nickel clad plate in which nickel is clad on one or both sides of a base material plate (plain steel, stainless steel, or another metal), and the nickel surface has a thickness of 600 to 12
Nickel oxide (N
iO) A nickel clad plate for roofs and building materials, which has a coating and is excellent in aesthetics and corrosion resistance.

When a metal plate is heated to a high temperature, in the case of an alloy such as stainless steel, various elements are mixed in the formed oxide film, so that it is inevitable that the components change depending on the film thickness. For this reason, color reproduction is difficult, and elements effective for corrosion resistance, such as Cr, are preferentially oxidized, and C
Trouble such as deterioration of corrosion resistance due to formation of an r-deficient layer is likely to occur. On the other hand, in the nickel or nickel clad plate, the oxide film composition is almost N regardless of the film thickness.
Since there is no component change in the composition of iO alone, color reproducibility is good. In addition, since the composition under the oxide film does not change, the corrosion resistance does not deteriorate due to oxidation, and the corrosion resistance is greatly improved because the oxide film is extremely dense.

[0007] The thickness of the oxide film varies depending on the heating temperature and time. When the temperature is lower than about 800 ° C., a color due to an interference color usually called a temper color is obtained. At higher temperatures, depending on the time, the thickness of the oxide increases, so that light interference hardly occurs and changes to a dark green color inherent to nickel oxide. Although the corrosion resistance increases as the thickness of the nickel oxide increases, a considerable improvement in the corrosion resistance is observed even with an oxide film as thin as an interference color.

The reason why the thickness of the Ni layer is limited to 3 μm or more and 20% of the total thickness is described below. The Ni-clad plate is heat-treated after rolling so that the base metal components Fe, Cr, etc.
It diffuses in and changes the composition of the Ni layer near the clad interface, and the corrosion resistance also changes. If the Ni layer is thin, the base metal component diffuses to the surface, and the pure Ni layer disappears. N
Since the diffusion in i is faster than that of Cr, Fe is first diffused on the surface. If the purity of Ni deteriorates, the corrosion resistance deteriorates, so that the oxide film is easily corroded when the oxide film is broken due to a scratch or the like. In addition, since the corrosion product contains Fe, a brownish appearance appears. . In addition, the oxide film contains FeO and the like in addition to NiO, and the protective property of the film deteriorates. Although the critical Ni thickness that does not cause such deterioration of corrosion resistance changes depending on the heat treatment time and temperature, industrial plate coil heat treatment is often heated in a line annealing furnace for only a few minutes. Even in such a short time, in the case of annealing of SUS304 steel, iron diffuses into the Ni layer separated from the interface by 2 to 3 μm. Therefore, if the thickness is smaller than 3 μm, the corrosion resistance of the Ni layer is deteriorated. In the case of a clad of ordinary steel and Ni, if the thickness of Ni is too small, the underlayer is easily formed due to scratches and the like, so the Ni thickness is limited to 3 μm or more. Next, regarding the upper limit of the thickness of the Ni layer, since nickel is an expensive metal, it is economically advantageous that the thickness of the Ni layer is thin, but the thicker the Ni layer, the more advantageous in terms of corrosion resistance. It is. The disadvantages of increasing the thickness of the Ni layer are that, besides the price, the strength ratio of the Ni plate with a lower strength is lower than that of a solid material with a higher Ni ratio. In addition, since warpage is likely to occur due to a difference in thermal expansion during heating and cooling, there may be a problem in use. In addition, in manufacturing, it is easy to warp during rolling, and easily warp during heat treatment. Becomes difficult. Therefore, it is appropriate that the upper limit of the Ni thickness is 20% of the total plate thickness.

The heat treatment temperature for forming an oxide film is 600
The reason for setting the temperature to 1200 ° C. is that if the temperature is 600 ° C. or more, an oxide film contributing to corrosion resistance is formed.
If the temperature exceeds ℃, the base material is highly oxidized, and the cost of the heat treatment increases, which is not practical. The temper color slightly changes depending on the heating temperature, but when the oxide is thickly formed at 1000 ° C. or higher, the oxide turns black-green, has a calm and heavy feeling, and is excellent in aesthetic appearance. When heated at about 600 ° C., the oxide film is thin and in a tempered color state, and a vivid green color can be developed by selecting the heating conditions.

[0010]

EXAMPLES In order to examine the corrosion resistance in an outdoor environment, an atmospheric exposure test in a coastal zone was performed for one year. The following samples were used as atmospheric exposure samples. A base material of SUS304 having a total thickness of 0.5 mm, a nickel thickness ratio of 4% (20 μm) of nickel / SUS304 having a cladding of 1030 mm × approximately 400 m was subjected to an annealing pickling line (heating) as a normal stainless steel production line. After passing through a temperature of about 1,050 ° C.), the SUS304 surface was neatly finished without oxide scale on the surface. On the other hand, a uniform black-green oxide scale remained on the nickel surface. This was cut out to about 100 mm x 150 mm to obtain a sample for exposure to the atmosphere.

The total thickness is 0.5 mm and the base material is SUS30.
4. Nickel with nickel thickness ratio of 4% (20 μm) /
A 650 mm width × about 200 m of the SUS304 clad was passed through a bright annealing (BA) line (heating temperature: about 1,050 ° C.) as a normal stainless steel production line, and both the nickel and SUS304 surfaces were finely finished. This was cut into 100 mm × 150 mm and heated in an experimental furnace set at 600 ° C. for 3 minutes. As a result, a blue temper color was formed on the nickel surface. SUS304 on the other side
Although the surface was not as strong as Ni, a tempered color was generated,
This side was polished and removed with # 320 emery paper to prepare a sample for exposure to the atmosphere.

The above two types of samples were exposed to the air for one year near the coast of Okinawa. After one year later,
In each of the samples, there was no corrosion at all on the Ni side having an oxide film, and dust adhered, but the sample could be easily wiped off with a piece of cloth. On the other hand, the opposite SU
The S304 surface was considerably rusted. SUS316 of the comparative material that was simultaneously exposed as a comparative material also showed considerable rust, although not as large as SUS304.

As described above, it has been confirmed that the oxidation resistance of the nickel surface at a high temperature is extremely high. In addition, it was confirmed that the nickel oxide side of the sample was not attacked by nitric hydrofluoric acid that also dissolves stainless steel, and that the high-temperature oxide film of Ni had extremely high corrosion resistance . When the sample was also immersed in a pickling solution of stainless steel for 5 minutes, most of the sample was not corroded, and the slightly flawed portion was corroded and dissolved. Since the entire surface of the nickel having no oxide film was corroded and dissolved to a considerable depth, the corrosion resistance was improved. But,
In both cases, the underlying nickel dissolves in a strong acid such as nitric hydrofluoric acid because the underlying nickel is exposed even if the scratch is invisible to the extent that the coating is thin. On the other hand, nickel has high corrosion resistance in outdoor environments,
Even if a slight scratch occurs, the surface hardly changes in a one-year air exposure test, and is considered to be a permanent surface for outdoor use.

[0014]

According to the present invention, it follows a relatively simple process
A nickel clad plate with unprecedented aesthetics and excellent corrosion resistance is obtained, and can be expected as a new roof and building material .

 ────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Kazuo Komi 1-30 Oyama-cho, Sagamihara-shi, Kanagawa Japan Metal Industry Co., Ltd. Sagamihara Works (56) References JP-A-4-2716 (JP, A) Kaihei 4-4986 (JP, A)

Claims (1)

(57) [Claims] 1. A base material (common steel, stainless steel, or other metal) having a thickness of 3 μm or more and a total thickness of 2
A nickel clad plate clad with nickel of 0% or less, wherein the nickel surface has a temperature of 600 to 1200 ° C.
Oxide (NiO) formed by high-temperature heating of aluminum
A store with excellent appearance and corrosion resistance characterized by having a coating
Nickel clad plate for roots and building materials .