JPH086188B2 - Anticorrosion method for coil made of cold rolled thin steel strip - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of use] The present invention relates to a method for rust prevention of a coil made of cold-rolled thin steel strip.

[Conventional technology]

During the manufacturing process of cold-rolled thin steel strip at a steel mill,
The steel strip (hereinafter referred to as the coil because it is coiled) is stored until the temper rolling is performed after batch annealing. Is long.

Further, the surface of the coil is brightly annealed so that it may have high activity, and rust is likely to occur during storage, so that rust prevention treatment is required.

For this reason, conventionally, the cause of rust is the dew condensation of water in the atmosphere.For example, as described in JP-A-51-119342, dehumidified air is passed around the coil to lower the ambient temperature around the coil. Or, sometimes, the entire storage room is air-conditioned to lower the temperature. FIG. 3 shows an example of the former case of flowing dehumidified air.

In FIG. 3, the annealed coils 1 are stacked on the coil stand 2 in several stages, and the dehumidified air blowing pipes 6 are arranged below the coils.

The dehumidified air discharged from the blow-in pipe 6 rises through the inner diameter of the coil, flows out through the gap between the stacks of the coils, and prevents rusting of the coils.

The dehumidified air takes in the air and is dehumidified by a predetermined dehumidifier 4, and is supplied to each coil stack through a duct 5. As the dehumidifier, a device using a hygroscopic agent (silica gel, lithium chloride, etc.) is generally used. In this case, a regenerating process is required, and 8 fans and 9 heaters for regenerating air are required. .

As described above, in the conventional method, since a large dehumidifier is operated because it is necessary to dehumidify a large amount of air, there is a drawback that the cost for equipment and operation becomes enormous.
3 is a blower fan, 7 is a coil upper cover, and 10 is a filter.

[Problems to be solved by the invention]

The present invention solves the above problems and provides an extremely simple and inexpensive rust preventive method without using dehumidified air.

[Means for solving problems]

The gist of the present invention is to make a coil made of a cold-rolled steel strip rust-proof by flowing air, by contacting a vaporizable rust-preventive agent with the air,
Air containing a rust preventive component is blown to the coil, and a rust preventive film is formed on the surface of the coil so that the coil made of a cold rolled steel strip is prevented from rusting.

 The present invention will be described in detail with reference to FIG.

The vaporizable rust preventive agent 11 is placed in the blowing pipe 6 into which air is blown from below the coil 1 stacked on the second coil stand. By providing the volatile rust preventive agent, the volatile rust preventive agent comes into contact with the air and sequentially vaporizes to add the rust preventive component to the air, and this air flows around the coil to form a rust preventive film on the coil surface. As it is formed, it can prevent rusting.

As the vaporizable rust preventive agent to be used, cyclohexyl ammonium carbonate (CHC), dicyclohexyl ammonium nitrate (DICHAN), diisopropyl ammonium nitrate (DIPAN) or the like may be used alone or in an appropriate mixture.

The amount used should be set at the time of coil loading depending on the number of coil stacks and storage period.

FIG. 2 shows another embodiment of the present invention. Twelve rust preventive agent addition chambers are provided to concentrate the vaporizable rust preventive agent on the air blown to a plurality of coil stacks.

According to this method, it is possible to save the trouble of installing the rust preventive agent when loading the individual coils.

Example Cold-rolled steel strip coil of batch annealing agent, standard SPCC, thickness 1.2m
m, width 1250 mm, single weight 30 Ton / coil were stacked in three stages, and the rust prevention test was carried out by changing the conditions of the type and amount of rust preventive agent and the amount of blown air by the method shown in FIG. One example is shown in Table 1 below. The temperature of the blown air was 20 to 25 ° C and the humidity of the blown air was 50 to 70%.

The coil is normally stored for 5 days, and the maximum is 20 days. The results of the rust prevention test during this period are shown in Table 1. ◎ indicates no rusting, ○ indicates slight rusting, and × indicates large rusting.

According to this, it is apparent that the present invention has an extremely large rust preventive effect as compared with the comparative example in which the rust preventive is not added.

However, it is more advantageous to use a mixture of DIPAN and DICHAN than to add DIPAN alone.

〔The invention's effect〕

As described above, the present invention does not need to produce a large amount of dehumidified air as in the prior art, and a very large rust preventive effect can be achieved by a very simple method of adding a vaporizable rust preventive agent to the air. Rust costs are very cheap.

[Brief description of drawings]

1 and 2 are explanatory views of the method of the present invention, and FIG. 3 is an explanatory view of the conventional method. 1 ... Coil, 2 ... Coil stand, 3 ... Blower fan,
4 ... Dehumidifier, 5 ... Air duct, 6 ... Air blowing pipe, 7 ... Coil upper cover, 8 ... Dehumidifying agent regeneration air blowing fan, 9 ... Heater, 10 ... Filter, 11 ... Evaporative rust preventive agent, 12 ... Rust preventive agent addition room.

Claims (1)

[Claims] 1. When rusting a coil made of cold-rolled steel strip by flowing air, a vaporizable rust preventive agent is brought into contact with the air, and air containing a rust preventive component is blown to the coil so that the surface of the coil is exposed. A method for rust prevention of a coil made of cold rolled steel strip, which comprises forming an anticorrosion film.