Metal treatment – Compositions – Heat treating
Patent
1981-05-05
1982-10-19
Kendall, Ralph S.
Metal treatment
Compositions
Heat treating
148 624, C23F 700
Patent
active
043548814
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD
The present invention relates to antirust treatment of steel stocks or materials such as hot-rolled pickled steel plate, cold-rolled steel plate, cast iron and so on.
BACKGROUND OF THE ART
Usually surface treatment is applied to the surface of cold-rolled steel plates, etc. for anticorrosion and preservation of fine appearance.
That is, because a considerable time passes before such various types of steel plates and so on are processed and used, they are coated with an antirust oil or chemically treated or are packed in vaporable antirust paper or are otherwise treated to prevent rust. Any of these prior art methods for anticorrosion, however, has the following drawbacks.
The application of antirust oil will incur, not to mention stickness of oil, the necessity for a degreasing step when the steel plates are in use, followed by the treatment of the exhausted degreasing solution, which is troublesome.
In addition, welding or like processing of materials with antirust oil applied thereto presents problems in that the electrodes become dirty, fuming becomes significant and the preservation of a good working circumstances is adversely affected.
Already publicly known water soluble antirust agents, for example, sodium nitrite, sodium borate, aromatic carboxylic acids, imidazoles, amines and surfactants are used alone or in combination. However, their antirust effect is useful mainly in water or in the air, and is rather poor when the steel plates contact one another in a wet atmosphere or under conditions where water is attached to them or when they are stacked at high temperature and high humidity, namely, in a wet box as specified by JIS Z-0228. Further, there are antirust agents with higher aliphatic amines or higher fatty acids incorporated therein. However, they also have drawbacks that their drying characteristics are bad and that a removal step is required as in the case of the use of antirust oil.
The inventors of the present invention have already discovered that 1-hydroxybenzotriazole has an excellent antirust effect for steel stocks as is described in Japanese patent publication No. 27694/78. However, it has been found that there is in this case a weakness that the discoloration or staining is produced in some cases if water is dropped on a treated steel plate, and another treated one is stacked thereon and allowed to stand at high temperature and high humidity atmosphere, although their antirust properties are very excellent after they are subjected to hot-air drying.
The present invention has overcome these drawbacks of the prior art methods and has further made it possible to exert an extremely good antirust effect without necessity for any further treatment in the subsequent steps.
DISCLOSURE OF THE INVENTION
In summary, the present invention is characterized by adjusting an aqueous solution of 1-hydroxybenzotriazole and an aliphatic dicarboxylic acid to within a neutral range with a neutralizing agent and applying the adjusted solution to the surface of metals to form an antirust coating.
The effects of the present invention are not limited to antirust ones in a particular environment. The antirust effects are excellent not only in water but also in the air, and in an acidic atmosphere or in an atmosphere of high temperature and high humidity where water droplets are present between the contacted treated steel plates or in other various environments where a temper rolling solution is scattered or its vapor attaches as water droplets on steel plates rolled in a high speed temper rolling step.
According to the present invention, a mixed aqueous solution consisting mainly of a 1-hydroxybenzotriazole compound represented by the general formula: ##STR2## Where X and Y represent hydrogen atoms and hydroxy, alkyl, carboxyl, nitro and sulfonic groups, and containing simultaneously an aliphatic dicarboxylic acid, for example, one or more of suberic acid, azelaic acid and brassylic acid, is neutralized with ammonia water, hydrazine or an alkanol amine such as monoethanol amine or tr
REFERENCES:
patent: 1911537 (1933-05-01), Tanner
patent: 3895170 (1975-07-01), Tanaka
Inubushi Akiyoshi
Maeda Chiaki
Manabe Isao
Obi Tatsurou
Otsuka Susumu
Kendall Ralph S.
Nippon Steel Corporation
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