JPH02281937A - Processing method of steel sheet - Google Patents

Abstract

PURPOSE:To improve the sharpness and corrosion resistance of a coated surface on the surface of a steel sheet, by a method wherein after formation of a galvanized layer on the surface of a clad material by specifying contents of a sulfur ingredient in a basic material and the sulfur and a copper ingredients in a laminated material, laser beams are applied intermittently to a conveying roll of the clad material. CONSTITUTION:A content (a) of a sulfur ingredient in a basic material is made into (a)<=0.045% in a clad material obtained by joining a laminated material to the surface of the basic material. Then contents (b), (c) of the sulfur and a copper ingredients in the laminated material and a ratio (b)/(c) between them are set up respectively at (b)<=0.020%, 0.030%>=(c)>=0.010% and (b)/(c)<=2.0. After performance of smooth finish of the surface of a clad material 12 with a roll by forming a galvanized or zinc-iron alloy plated layer 15, a recessed part row in a fixed pattern is formed by applying intermittently laser beams to a roll 21 conveying the clad material 12. With this construction, improvements in sharpness of a coated surface of the surface and corrosion resistance of an original sheet can be contrived.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to a method for processing a steel plate used for an outer bag plate of a body panel or the like mounted on a vehicle body such as an automobile.

(Prior Art) Generally, steel plates such as cold-rolled steel plates are used for exterior plates such as body panels mounted on the bodies of automobiles and the like. As shown in FIG. 1O, the original steel sheet 1 is subjected to a surface treatment such as galvanization, and then an appropriate surface coating is applied on the surface treatment layer 2.

By the way, as automobiles become more sophisticated, the quality of the paint on the car body has a great impact on its marketability. in this case,
JIS G3141 is used for the original plate 1 of the conventional cold rolled steel plate.
It has a dull finish as specified in . This dull finish is performed, for example, by a shot blasting method as shown in FIG. This is done by projecting steel shot (steel grains) 4 at high speed onto the surface of the roll 3 that conveys the original plate 1 of the cold rolled steel sheet, and roughening the surface of the roll 3. The fine irregularities are transferred onto the surface of the original plate 1 of the cold-rolled steel plate, and a matte finish is applied to the surface of the original plate 1 of the cold-rolled steel plate. Then, by infiltrating the lubricating oil into the minute irregularities on the surface of the original plate 1 of this cold rolled steel plate,
This makes the surface slippery and improves workability.

However, irregularly shaped unevenness 5 as shown in FIG. 12 is formed on the surface of the original plate 1 of the cold rolled steel sheet which has been given a conventional dull finish. The surface treatment layer 2 such as galvanization applied to the surface of the original plate 1 and the irregular irregularities 5 on the surface of the original plate 1 are transferred almost as they are to the surface of the painted surface. Furthermore, there was a problem in that the shape of the irregular irregularities 5 on the surface of the original plate 1 was transferred in an enlarged state (roughened state). As a result, the sharpness (characteristics of both gloss and smoothness) of the painted surface of the original cold-rolled steel plate 1 deteriorates, which poses a problem in improving the appearance of the painted surface of the vehicle body.

In addition, the content of sulfur (S) in the chemical composition of the original cold rolled steel sheet 1 specified in the conventional JIS G3141 is 0.045% or less for one type of 5PCC (general use),
2FM 5PCD (for aperture) is 0.035% or less, 3
5PCE (for deep drawing) of 71 is set to 0.030% or less.

In this case, it is generally known that the lower the content of sulfur (S) in the original steel plate 1, the better the corrosion resistance. However, in the case of the conventional structure described above, for example, when the surface treatment layer 2 such as galvanization applied to the surface of the original plate 1 of the cold rolled steel sheet, the painted surface, etc. are removed due to corrosion, the cold rolled steel sheet There is a possibility that the original plate 1 of the cold-rolled steel sheet is likely to corrode, which poses a problem in improving the corrosion resistance of the original plate 1 of the cold-rolled steel sheet.

(Problems to be Solved by the Invention) A surface treatment layer 2 such as galvanizing is applied to the surface of the original plate 1 of a cold rolled steel sheet that has been given a conventional dull finish, and the surface of the original plate 1 is coated on the surface of the painted surface. The shape of the irregular irregularities 5 on the surface of the original plate 1 is transferred almost as is, or the shape of the irregular irregularities 5 on the surface of the original plate 1 is enlarged (fi (rough shape B) Since the image is transferred to the original plate 1 of the cold rolled steel plate,
The sharpness of the painted surface of the vehicle deteriorates, which poses a problem in improving the appearance of the painted surface of the vehicle body, and the surface treatment such as galvanization applied to the surface of the original cold-rolled steel sheet 1. When the layer 2, the painted surface, etc. are removed due to corrosion, there is a risk that the original plate 1 of the cold rolled steel plate is likely to corrode, which is a problem in improving the corrosion resistance of the original plate 1 of the cold rolled steel plate.

This invention was made in view of the above-mentioned circumstances, and it is possible to improve the appearance of the painted surface of a car body by improving the sharpness of the painted surface of the original steel plate, and to improve the corrosion resistance of the original steel plate. The object of the present invention is to provide a steel plate processing method that can improve the performance of steel sheets.

[Structure of the Invention] (Means for Solving the Problem) The invention of claim (1) is directed to a clad material in which a laminate material is bonded to the surface of the base material.
a≦0.045%, content of sulfur component in the laminated material b, content of copper component c,
The ratio b/c of the content of the sulfur component to the content C of the copper component is set to b≦0.020%, 0.030%≧c≧0.01096 b/c≦2.0, respectively. At the same time, after forming a smooth plating layer made of zinc or zinc-iron alloy on the surface of the cladding material, this smooth surface or the conveying roll of the cladding material is intermittently irradiated with laser light to form a regular plating layer. This method uses laser dulling to form a row of recesses in a predetermined pattern.

In addition, the invention of claim (2) provides that in the cladding material in which the laminate material is bonded to the surface of the base material, the content a of the sulfur component in the base material is a≦0.045%, and the sulfur component in the laminate material is content b, copper component content c,
and the ratio b/c of the sulfur component content and the copper component content C are set to b≦0.020%, 0.030%≧c≧0.010%, and b/c≦2.0, respectively. In addition, this is a method in which a laser dulling process is performed in which a smooth surface of the cladding material or a conveying roll of the cladding material is intermittently irradiated with laser light to form a regular predetermined pattern of concave rows.

(Function) The invention as claimed in claim (1) improves the corrosion resistance of the original steel plate by joining the laminate material with good corrosion resistance to the surface of the base material with relatively poor corrosion resistance, and also improves the corrosion resistance of the base material of the cladding material. After forming a smooth plating layer made of zinc or zinc-iron alloy, this smooth surface or a conveyor roll of clad material is intermittently irradiated with laser light to form a regular pattern of recesses. By performing laser dulling to form a steel plate, the clarity of the painted surface of the original steel plate is improved, and the appearance of the painted surface of the vehicle body is improved.

In addition, in the invention of claim (2), by joining a laminate material with good corrosion resistance to the surface of a base material with relatively poor corrosion resistance, it is possible to improve the corrosion resistance of the original steel sheet and smooth the surface of the cladding material. The sharpness of the painted surface of the original steel plate is improved by laser dulling, which involves intermittently irradiating the surface or the conveyor roll of clad material with laser light to form a regular pattern of concave rows. This is intended to improve the appearance of the painted surface of the vehicle body.

(Embodiment) A first embodiment of the present invention will be described below with reference to FIGS. 1 to 7. FIG. 1 shows a schematic structure of a steel plate 11 processed by the processing method of the present invention, and 12 is a cladding material forming the original plate of this steel plate 11. This cladding material 12 is made by joining a laminating material 14 to the surface of a base material 13. In this case, the content rate a of the sulfur component in the base material 13 is a≦0. 045%, content rate of sulfur component in laminated material 14, content rate of component 11, c, content rate of sulfur component, content rate of copper component C
The ratio b/c is b ≦ 0. 020%, 0, 030%≧c≧0.010% b/c≦2.0, respectively.

Further, when manufacturing the cladding material 12, for example, the base material 13 and the laminate material 14 are prepared separately. And these base materials 1
A clad slab is produced by temporarily welding 3 and the laminating material 14 in a superimposed state.

Next, this clad slab is heated to an appropriate set temperature for hot compression rolling, and rough rolling is performed.

In this case, since it is not possible to apply a large rolling reduction rate, rolling is repeated while expelling the air between the plates.

Furthermore, zinc (Z
n), or a plating layer 15 of an appropriate thickness is formed by electroplating a zinc-iron (Zn-Fe) alloy, hot-dip plating, or the like.

Further, the surface of this plating layer 15 is subjected to a smooth finish (bright skin bath) treatment with a smooth burnt roll, and then a laser beam is intermittently applied to the roll 21 that conveys this cladding material 12. Laser dulling is performed to form a row of recesses in a predetermined pattern. In this case, the laser dull processing apparatus A is provided with a laser beam generator 17 and a chopper 18, as shown in FIG. This chopper 18 is provided with a rotating disk 19. Further, in the outer circumferential portion of the rotating disk 19, laser light insertion holes 20 of different orders are formed in parallel at appropriate intervals along the circumferential direction.

As the rotating disk 19 rotates, the laser beam from the laser beam generator 17 is intermittently output from each laser beam insertion hole 20 on the outer periphery of the rotating disk 19. m1 from this laser dull processing equipment
As shown in FIG. 4, the laser beam that is intermittently output is irradiated onto the surface of the roll 21 that conveys the clad material 12, forming a predetermined pattern of concave rows on the surface of the roll 21. A predetermined pattern of concave portions 22...
・Smooth surface 16 on the surface of plating layer 15 of cladding material 12 in rows
are transferred to form rows of recesses 23 of a predetermined pattern on the smooth surface 16 of the surface of the plating layer 15. Note that this laser dulling process may be performed directly on the smooth surface 16 of the plating layer 15 of the cladding material 12.

Furthermore, Figure 5 shows the relationship between the sulfur content in the steel plate and the amount of corrosion, Figure 6 shows the relationship between the copper content in the steel plate and the amount of corrosion, and Figure 7 shows the sulfur content/W4 content in the steel plate. This shows the relationship between the amount of corrosion and the amount of corrosion.

In this case, as is clear from the characteristic diagram in Figure 5, the higher the sulfur content in the steel sheet, the greater the amount of corrosion on the steel sheet, and it is possible to reduce the amount of corrosion on the steel sheet in the range of b≦0.020%. Recognize. Moreover, from FIG. 6, it can be seen that when the copper content in the steel plate is less than 0.010%, the amount of corrosion in the steel plate is large, and when it is 0.010% or more, the corrosion hole in the steel plate becomes extremely small. Furthermore, from Figure 7, the larger the b/c in the steel plate, the larger the corrosion hole in the steel plate.
It can be seen that in the range of b/c≦2.0, the corrosion hole in the steel plate can be made smaller.

Therefore, according to the above processing method, the content rate a of the sulfur component in the base material 13 of the cladding material 12 forming the original plate of the steel plate 11 is set to a≦0.045%, and the content rate of the sulfur component in the laminated material 14 is set to b5 copper. Component h content C, sulfur component content and copper component content C
The ratio b/c is set to b≦0.020%, 0.030%≧c≧0.010%, and b/c≦2.0, respectively, so that the surface of the base material 13, which has relatively poor corrosion resistance, has corrosion resistance. Since a good quality laminate material 14 is bonded, even if the plating layer 15 applied to the surface of the cladding material 12 forming the original plate of the steel plate 11, the painted surface, etc. are removed due to corrosion, the cladding material will remain intact. Corrosion can be effectively prevented from progressing to the base material 13 side of the cladding material 12 by the laminate material 14 having good corrosion resistance placed on the surface side of the cladding material 12 . Therefore, steel plate 11
It is possible to improve the corrosion resistance of the clad material 12 forming the original plate. Furthermore, since an inexpensive material with relatively low corrosion resistance can be used as the base material 13 of the clad material 12 that forms the original plate of the steel plate 11, it is advantageous in terms of cost. In addition, since the upper limit of the content C of the copper component in the laminated material 14 is set to 0.030%, processing such as deterioration of weldability may occur when the content C of the copper component is 0.030% or more. It is possible to prevent a decline in sexual performance.

Furthermore, after forming a smooth plating layer 15 made of zinc or zinc-iron alloy on the surface of the cladding material 12, the conveying roll 21 of the cladding material 12 is intermittently irradiated with laser light to form a predetermined pattern. Concave portions 22... are formed in regular rows, and are connected to the plating layer 1 of the cladding material 12.
5 is transferred onto the smooth surface 16 of the steel plate 11 to form a regular pattern of concave portions 23 . It is possible to improve the appearance of the painted surface of the vehicle body.

Further, FIGS. 8 and 9 show another embodiment of the present invention. This is done by performing a smoothing treatment (bright skin bath) on the surface of the cladding material 12 having the same structure as in the first embodiment described above using a smooth roll, and then smoothing the cladding material 12. Laser dulling is performed on the surface 31 by intermittently irradiating laser light from the laser dulling device A to form a regular pattern of concave portions 32... rows.

Therefore, in this case as well, the corrosion resistance of the original steel plate 11 can be improved by joining the laminate material 14 with good corrosion resistance to the surface of the base material 13 of the cladding material 12, which has relatively poor corrosion resistance. By intermittently irradiating the Nfi and smooth surface 31 of the cladding material 12 with a laser beam, a regular predetermined pattern of concave portions 32...
By applying laser dulling to form rows, steel plate 1
The sharpness of the painted surface of the original plate No. 1 can be improved, and the appearance of the painted surface of the vehicle body can be improved. Also in this case, similarly to the first embodiment, the conveying roll 21 of the clad material 12 is intermittently irradiated with laser light to form regular rows of recesses 22 in a predetermined pattern. It is also possible to adopt a structure in which a regular predetermined pattern of concave portions 32 is formed in rows by being transferred onto the smooth surface 31 of the cladding material 12.

Note that the invention is not limited to the above embodiments,
Of course, various modifications can be made without departing from the gist of the invention.

[Effect of the invention] According to the invention of claim (1), in the clad material in which the laminate material is bonded to the surface of the base material, the content a of the sulfur component in the base material is set to a≦0.045%. Content rate of sulfur component in the material b11 Content rate of component C5
And the ratio b / c of the content of sulfur component and the content of copper component C is set to b≦0.020%, 0.03096≧C≧0.010% b / c≦2.0, respectively. After forming a smooth plating layer made of zinc or zinc-iron alloy on the surface of the cladding material, this smooth surface or the transport roll of the cladding material is intermittently irradiated with laser light to form a regular plating layer. Laser dulling is applied to form a row of recesses in a predetermined pattern, so it is possible to improve the clarity of the painted surface of the original steel sheet and improve the appearance of the painted surface of the vehicle body. Corrosion resistance can be improved.

Further, according to the invention of claim (2), in the clad material in which the laminate material is bonded to the surface of the base material, the content a of the sulfur component in the base material is a≦0.045%, Content rate of sulfur component % Content rate of copper component C5
and the ratio b/e of the sulfur component content and the copper component content C are set to b≦0.020%, 0.030%≧c≧0.010% b/c≦2,0, respectively. In addition, the smooth surface of the cladding material or the conveying roll of the cladding material is subjected to laser dulling in which a laser beam is intermittently irradiated to form a regular predetermined pattern of concave rows. It is possible to obtain substantially the same effect as the invention described in item 1).

[Brief explanation of drawings]

1 to 7 show the first actual 8Oi example of the present invention, in which FIG. 1 is a vertical cross-sectional view of a steel plate, FIG. 2 is a vertical cross-sectional view showing the main part configuration, and FIG. A schematic configuration diagram of the main parts to explain the processing, Fig. 4 is a perspective view showing the roller during laser dull processing, Fig. 5 is a characteristic diagram showing the relationship between the sulfur content in the steel plate and the amount of corrosion, and Fig. 6 Figure 7 is a characteristic diagram showing the relationship between the copper content in the steel plate and the amount of corrosion. Figure 7 is a characteristic diagram showing the relationship between the sulfur content/copper content in the steel plate and the amount of corrosion.
9 and 9 show a second embodiment of the present invention, FIG. 8 is a longitudinal sectional view of a steel plate, FIG. 9 is a longitudinal sectional view showing the main part structure, and FIGS. 1O to 12 are This shows a conventional example.
Figure 1O is a longitudinal sectional view showing a galvanized steel sheet, Figure 11 is a schematic configuration diagram for explaining the shot blasting method, and Figure 1
FIG. 2 is a longitudinal cross-sectional view showing the configuration of main parts. DESCRIPTION OF SYMBOLS 11... Steel plate, 12... Clad material, 13... Base material, 14... Laminating material, 15... Plating layer, 16.3
1... Smooth surface, 23° 2... Concave part. Sulfur 8 skin 4t ('/・)

Claims (1)

[Scope of Claims] (1) In a cladding material in which a laminate material is bonded to the surface of a base material, the content a of the sulfur component in the base material is a≦0.045%, and the content rate a of the sulfur component in the laminate material is content b, copper component content c, and ratio b/c of sulfur component content b and copper component content c, b≦0.020%, 0.030%≧c≧0.010% After setting b/c≦2.0 and forming a smooth plating layer made of zinc or zinc-iron alloy on the surface of the cladding material, this smooth surface or a conveying roll of the cladding material is formed. 1. A method of processing a steel plate, comprising performing laser dull processing in which a regular predetermined pattern of recessed portions is formed by intermittently irradiating a steel plate with a laser beam. (2) In the cladding material in which the laminated material is bonded to the surface of the base material, the content rate a of the sulfur component in the base material is a≦0.045%, the content rate b of the sulfur component in the laminated material b, the copper component content c, and the ratio b/c of the sulfur component content b and the copper component content c, b≦0.020%, 0.030%≧c≧0.010% b/c≦2. 0, and laser dulling was performed in which the smooth surface of the cladding material or the conveyance roll of the cladding material was intermittently irradiated with laser light to form a regular predetermined pattern of recessed rows. A steel plate processing method characterized by the following.