JPH04294805A - Manufacture of dull roll and dull-finished steel sheet - Google Patents

Abstract

PURPOSE:To offer a dull roll for manufacturing a dull-finished steel sheet excellent in stain removing property. CONSTITUTION:Sharp projecting parts 1 and concave parts 2 are formed by projecting grits on a smooth roll and next the abovementioned projecting parts 1 and concave parts 2 are finished into smooth by projecting shots.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for dull finishing a steel plate and a method for producing dull rolls therefor.

0002

[Prior art] The surface of a steel plate is made to have a matte finish by uniformly roughening the skin of a cold rolling roll and using this to finish the surface of the steel plate in a satin-like, matte state. Because of this, it is often used as exterior materials for stainless steel vehicles and exterior design materials for buildings.

[0003] Rolls have a high level of surface hardness in order to suppress friction. Therefore, conventionally, dull rolls were manufactured by projecting a grid of steel grains with sharp angles onto a rolling roll at high speed.

FIG. 3 is an enlarged sectional view of the surface of a conventional dull roll, and the recesses 101 and the projections 102 are all sharp. The convex portions 102 form sharp depressions in the steel plate.

[0005]

Problems to be Solved by the Invention When dirt such as oil and fat adheres to the sharp recesses of a steel plate, it is very difficult to remove this dirt. Further, since the dull roll as a rolling roll is intended for mass production, it is used frequently. Then, Dallo
The sharp convex portion 102 on the steel plate gradually slopes as shown in FIG. 4, and this forms complicated depressions such as diagonal depressions in the steel plate, which makes the steel plate increasingly difficult to remove stains from.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a dull finished steel plate with good dirt removal properties and a dull roll therefor.

[0007]

[Means and operations for solving the problem] A dull roll is produced by projecting a grid onto a smooth roll and then by projecting a shot. Although sharp irregularities are formed on the roll surface by grid projection, these irregularities are smoothed by the next shot projection.

[0008] On a smooth roll, the grain size is 1.0 to 1.4 m.
m grid, then the particle size is 0.3~1.0 m
m range and the ratio of grid grain size/shot grain size is 1.
By rolling the steel plate with a dull roll made by projecting a shot that is 4 times or more and less than 5 times, we can mass produce dull finish steel plate with excellent roughness and stain removal properties, which are preferred for the exterior materials of current stainless steel vehicles. You can.

[0009]

[Examples] Examples of the present invention will be explained below in comparison with comparative examples. Table 1 shows the manufacturing conditions of the dull roll. The outer diameter of the rolling roll as a raw material is 850 mm, and its surface has a shore hardness in the range of 90 to 100 and is polished with a #400 grindstone. .

0010

[Table 1]

[0011] First, a grid of steel grains having a sharp angle is projected onto this raw roll at the projection speed and projection density shown in Table 1.

FIG. 1 is an enlarged sectional view of the roll surface after grid projection, in which sharp convex portions 1 and concave portions 2 are formed similarly to FIG. 3.

Next, rounded steel grains (
shot) under the conditions shown in Table 1.

FIG. 2 is an enlarged sectional view of the roll surface after shot projection, and the convex portions 1 and concave portions 2 have a generally rounded profile with sharp portions removed. be done.

In the above manner, dull rolls named Roll A to Roll I are manufactured. As is clear from Table 1, in order to obtain the desired roughness and dirt removal properties for the exterior material of stainless steel vehicles, the present invention requires a grid with a particle size of 1.0 to 1.4 m.
m, the shot particle size is 0.3 to 1.0 mm, and the ratio of grid particle size A/shot particle size B is kept at 1.4 or more and less than 5.

On the other hand, in Comparative Examples 1 and 2, the ratio of grid grain size A/shot grain size B was 5 or more or less than 1.4,
Comparative Examples 3 and 4 were subjected to dull rolls (rolls a to
Roll d) is manufactured.

[0017] In Comparative Examples 5 and 6, only grid projection was used;
In Comparative Example 7, dull rolls (roll e to roll g) were manufactured only by shot projection. Table 2 shows the manufacturing method of dull finished steel sheets, and shows rolls A to I and roll a of Table 1.
The results of rolling and finishing a steel plate using rolling rolls ˜g are shown.

[0018] In Table 2, stain removal property refers to 3cm x
30mg of a mixture of grease and copper powder on a 5cm area
It is attached and left to stand for 48 hours, after which the applied material is wiped off with a pressure of 100 g/cm2 and visually judged. ○
= Slightly remaining, △ = 10-30% remaining, × = 3% remaining
Indicates that it exceeds 0%.

[0019]

[Table 2]

[0020] With rolls A to I, the number of passes is 1, and the rolling reduction rate is 1.3.
Or when rolled at 2.3, Ra, Rma shown in Table 2
A dull finish steel plate of x was obtained. These dull finish steel plates are
Good aesthetics and stain removal properties.

On the other hand, the dull-finished steel sheets obtained by rolls a to g are unsatisfactory in both aesthetics and stain removal properties, and cannot be good dull-finished steel sheets.

[0022]

[Effects of the Invention] As described above, the present invention produces a dull roll by a method of projecting a grid onto a rolling roll and then projecting a shot, and this dull roll has excellent dirt removal properties. A dull steel plate can be obtained, and thus, according to the present invention, it is possible to easily mass-produce high-quality dull steel plates.

[Brief explanation of drawings]

[Figure 1] Enlarged cross-sectional view of the roll surface after grid projection

[Figure 2] Enlarged sectional view of the roll surface after shot projection

[Figure 3]
Enlarged cross-sectional view of the surface of a conventional dull roll

[Figure 4] Enlarged cross-sectional view of the surface of a conventional roll after a certain period of use

[Explanation of symbols]

1... Convex portion, 2... Concave portion.

Claims (2)

[Claims] 1. A method for producing a dull roll, which comprises projecting a grid onto a smooth roll to form sharp uneven portions, and then projecting a shot to finish the uneven portions smoothly. 2. A smooth roll with a grain size of 1.0 to 1.
Project a 4mm grid, then a particle size of 0.3-1.0
mm range and the ratio of grid particle size/shot particle size is 1
．． A method for manufacturing a dull-finished steel plate, comprising rolling the steel plate with a dull roll formed by projecting shots of 4 or more and less than 5, thereby imparting a matte finish to the surface of the steel plate.