JPH07241615A - Manufacture of precoated hot rolled steel - Google Patents

Abstract

PURPOSE:To improve productivity by executing coating treatment on the surface of steel on-line in continuous production without cooling the steel to ordinary temp. after forming the steel with a rolling mill and cutting it. CONSTITUTION:The coating treatment is executed continuously on-line without cooling the hot rolled steel to the ordinary temp. after forming the hot rolled steel and coating is dried by residual heat which is held in the steel itself. Thermal energy for preheating before coating and thermal energy for drying after coating are covered with the holding heat of the hot rolled steel itself. The whole of the steel has the uniform holding heat over the whole surface, so the recoating property and adhesion of a paint are improved. In this way, heating energy is reduced and productivity is improved by shortening heating/ drying time required for coating and omitting a stacking/binding stage. Further, the steel itself has the uniform holding heat on the whole surface, so the recoating property and adhesivity of the paint are improved.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a hot rolled coated steel material.

[0002]

2. Description of the Related Art Conventionally, when painting a steel material formed by hot rolling, as shown in FIG. 2, after the steel material formed in a hot rolling plant is straightened, descaled and cut. Cooling to room temperature, stacking and bundling, then shipping this to another coating factory. Then, in a coating factory, a method is generally used in which the sent steel materials are preheated for coating, coated, dried, stacked, bundled and shipped.

[0003]

However, as in the above-mentioned conventional method, after hot-rolled steel is formed, it is cooled to room temperature and then preheated again in another coating factory for painting. It was a loss of energy. Further, it is necessary to stack and bind the same steel material twice when shipping from the hot rolling factory to the coating factory and when shipping from the coating factory, which is inefficient in work.

The present invention has been made in order to solve the above-mentioned problems, has no loss of heat energy required for coating, is extremely efficient in terms of workability, and has excellent recoatability and adhesion to coating. An object of the present invention is to provide a method for producing an excellent hot rolled coated steel material.

[0005]

As shown in FIG. 1, the present invention for achieving the above object comprises a flat steel (channel steel, chevron steel, H-shaped steel, etc.) flat steel formed by hot rolling. Various steel materials such as steel bars are refined and cut, or after being cut and then refined, the steel surface is continuously produced online without cooling to room temperature. Apply paint treatment. The coating material is dried by the residual heat of the steel material itself, and then stacked, bound and shipped.

Here, the term "correction" as used in the present invention means correction and descaling, and includes the case where descaling is excluded. Further, the temperature at which the hot-rolled steel material is not cooled to room temperature means that the surface temperature of the hot-rolled steel material is maintained in a temperature range of about 50 ° C to 150 ° C. Further, the coating applied to the hot-rolled steel material is performed by a coating method such as a spray method using various coating materials such as water-soluble coating material and oil-based coating material on the steel material having the above surface temperature. Further, the coating drying is a step for drying the coating material after coating, which is performed by utilizing the residual heat of the hot-rolled steel material itself. If there is a shortage, the preheated air such as the exhaust gas from the heating furnace may be used. Forming, cutting, and refining steel materials,
After continuously performing a series of processes from painting and coating drying with residual heat on the online table for production, the product is shipped with normal stacking and binding.

[0007]

According to the above construction, the hot rolled steel material is continuously coated online without being cooled to room temperature after forming, and the coating material is dried by the residual heat of the steel material itself. The heat energy for pre-heating before and the heat energy for drying after painting can be covered by the heat retained by the hot-rolled steel product itself. Further, since the steel material itself has an even heat retention over the entire surface, the recoatability and adhesion of the paint are improved. Furthermore, heating, shortening of drying time,
By partially omitting the stacking and bundling steps, the productivity can be significantly improved.

[0008]

[Example] As one example, angle steel (75 × 75 × 6) was molded by a rolling mill, cut into 6 m through a conditioning step, and sprayed with a water-soluble paint when the surface temperature reached 90 ° C. Painted with gun. The coating was dried by using only the residual heat of the angle steel itself, then cooled to room temperature on a cooling table, stacked, and bundled by a binding machine before shipment.

[0009]

INDUSTRIAL APPLICABILITY As described above, according to the method for producing hot-rolled coated steel material according to the present invention, after the steel material is formed by the rolling mill and cut, the steel material is continuously produced online without cooling to room temperature. Since the surface is painted, see Table 1.
As shown in, the heating energy can be greatly reduced compared to the conventional manufacturing method, and the heating and drying time required for coating can be shortened, and the productivity can be greatly improved by omitting the stacking and binding process. Furthermore, since the steel material itself has a uniform heat retention over the entire surface, it was possible to improve the recoatability and adhesion of the paint.

[0010]

[Table 1]

[Brief description of drawings]

FIG. 1 is a process drawing showing a method for manufacturing a hot-rolled steel product according to the present invention.

FIG. 2 is a process drawing showing a method for producing a conventional general hot-rolled coated steel material.

Claims (2)

[Claims] 1. A steel material formed by hot rolling is refined and cut, and then the surface of the steel material is continuously subjected to a coating treatment without being cooled to room temperature, the surface of the steel material is subjected to a coating treatment, and the steel material itself has A method for producing a hot rolled coated steel material, which comprises drying the coating with residual heat, and stacking and shipping the coating. 2. A steel material formed by hot rolling is cut and refined, and then the surface of the steel material is continuously coated without being cooled to room temperature, and a coating treatment is applied to the surface of the steel material. A method for producing a hot rolled coated steel material, which comprises drying the coating with residual heat, and stacking and shipping the coating.