JPS6284968A - Method of mirror surface finishing for stainless steel - Google Patents

Abstract

PURPOSE:To reduce the surface roughness of stainless steel with a uniform surface structure, by carrying out mirror surface finishing of stainless steel with the use of a process consisting of first successive polishing steps with the use of grind stones, a second polishing step with the use of a solution of nitric acid containing chromium oxide and a third lapping step with the use of a nitric acid solution. CONSTITUTION:The surface of stainless steel W is subjected to mirrored-surface-finishing with the use of a process consisting of first successive polishing steps with the use of grindstones 20' having grain sizes of 600-1,200, a second polishing step with the use of a first solution containing 2.5-3.5% nitric acid and 4.5-5.5% of chromium oxide powder at a temperature of 28-32 deg.C and also with the use of a felt or unwoven lapping material 20'' and a third lapping step with the use of a second solution containing 4.5-5.5% of nitric acid together with a lapping material similar to the lapping material 20'' used in the second step. Then, the structure of the finished surface may be made to be uniform having an extreme small surface roughness. Accordingly, it is possible to fabricate the outer surface of stainless steel with a high degree of accuracy, having a uniform mirror surface. Further, if the outer surface of stainless steel is colored with a coloring process, such as, for example, INCO process, an excellent colored mirror surface having an extremely small difference in color may be obtained.

Description

[Detailed description of the invention] The present invention relates to a method for finishing a stainless steel surface to a mirror finish, and in particular, to a method for finishing a mirror finish as a pre-treatment when coloring the surface of a stainless steel plate. be.

In recent years, stainless steel plates with mirror-finished surfaces have been widely used as interior and exterior materials for buildings, etc.

Furthermore, in recent years, many research and developments related to the coloring of stainless steel have been published, and among them, Japanese Patent Application Laid-Open No. 48-1 called ink-like coloring has been published.
) No. 243 and JP-A No. 49-21339 have good reproducibility and wear resistance, and colored mirror plates of stainless steel have come to be produced using this technology. There is.

In principle, the above coloring method forms a thin transparent oxide film on the surface of stainless steel, and uses the coloring phenomenon caused by the interference of light on this oxide film to color the stainless steel. Therefore, if the thickness and composition of the oxide film are not uniform, uneven color will occur in the product.

However, on the temporary mirror-finished surface of stainless steel, a complex surface structure such as a process-affected layer is formed non-uniformly, and furthermore, the composition of the stainless steel itself may differ depending on the manufacturing loft. These differences in surface texture make the thickness and components of the oxide film formed by the above-mentioned coloring method non-uniform, resulting in color unevenness.

In fact, when the above-mentioned coloring process is applied to a stainless steel plate that has been mirror-finished using a conventional method, the color difference in color unevenness is determined using Hunter's color difference formula using a Suga Test Instruments automatic colorimetric color difference needle. It has almost no commercial value because it has a value of 1.5 or more and is clearly visible to the naked eye as uneven color.

Therefore, in order to solve the above problem, a method of anodizing the mirror-finished surface of stainless steel before coloring and dissolving the surface layer and altered layer has been proposed, for example, in Japanese Patent Publication No. 58-19.
This method has been proposed in Japanese Patent Publication No. 9896 and Japanese Patent Publication No. 58-221283, etc., and it is possible to achieve uniform coloring with a color difference of 1.5 or less. However, since the stainless steel surface is anodized, The surface roughness deteriorates to about 0.1 μm, which impairs the surface reflection gloss and surface finish ti of the mirror-finished surface, reducing the quality of the mirror-finished surface.

Therefore, there is a need for the development of a mirror finishing method that can perform coloring treatment on stainless steel without causing color differences.

. The present invention has been made in view of the above-mentioned problems, and the present invention has been made in view of the above-mentioned problems.
Using a first liquid containing 4.5 to 5.5 wt% of chromium oxide CCr203) powder mixed into a 2.5 to 3.5% nitric acid aqueous solution, a felt or The second step is polishing with a non-woven wrap material.
step, and a second step consisting of a 4.5 to 5.5% nitric acid aqueous solution.
In this method, the surface of stainless steel is polished to a mirror finish using a third step of gF polishing using a felt or non-woven cloth wrap material at a processing temperature of 28 to 32° C. using a liquid.

FIGS. 1 to 3 show an example of a mirror-finishing apparatus used in carrying out the method for mirror-finishing stainless steel according to the present invention.

In the drawings, (1) is a table that reciprocates at a constant stroke in the left-right direction in Fig. 1, and (1a) is this table (1).
A gutter-shaped liquid receiver formed around the entire circumference of the table (1).
The polishing tool (3) is disposed above the table (1) and reciprocates at a constant stroke in a direction perpendicular to the drawing.
) and a constant temperature equipment that keeps the stainless steel plate (W) placed and fixed on the table (1) at a constant temperature, (4) is a liquid supply equipment to the polishing tool (2), and (5) is a The liquid discharge equipment from the receiver (1a) is shown.

As shown in Fig. 2, the polishing tool (2) includes a base member (1)) which is screwed into a vertical adjustment mechanism 9) and a feed screw (10) in a direction perpendicular to the drawing. A hollow shaft (13) rotatably and slidably supported in the axial direction by a base member (1) via a bearing (12);
A donut plate-shaped abrasive attachment part (14) integrally formed at the lower end of the (13) hollow vibrator (15) coaxially disposed inside the hollow shirt (13) and the hollow shaft (13). Key groove (13a) formed in the axial direction at the upper end
a pulley (17) that can swing only in the axial direction via a key (16);
), and an abrasive material (20) attached to the lower surface of the gf abrasive material attachment part (14) via a cutting material (19) such as rubber. be done.

Power is transmitted to the pulley (17) from a motor (not shown) via a belt transmission mechanism (not shown).

Further, as described later, a grindstone or a ramp material is selectively used as the abrasive material (20) for each process.

The liquid supply equipment (4) includes a pipe (22) that supplies cooling water to the annular hollow part (21) between the central shirt l-(13) and the hollow pipe (15), and a pipe (22) that supplies cooling water to the hollow pipe (15). ,2
．． Add 4.5 to 5.5 w of chromium oxide [Cr203] powder, which functions as an abrasive, to a 5 to 3.5% nitric acid aqueous solution.
It consists of a pipe (23) for supplying a first liquid mixed with t%, and a pipe (24) for supplying a second liquid consisting of a 4.5 to 5.5% nitric acid aqueous solution to a hollow pipe (15), Each of the above piping (22) (23) (24) has a switching valve (25) (26) (27) for connecting and disconnecting the liquid supply.
) are connected.

Below, each step of the mirror finishing method according to the present invention will be explained. The stainless steel plate (W) to be finished is
It is assumed that it is placed and fixed on the table (1) in advance.

First, in the first step, the abrasive material (20) has a particle size of 600 to 12
Use a 00 mesh resin whetstone.

For example, as shown in FIG. 3, the resin grindstone is installed in eight resin grindstones (20') (20') each having a fan shape.
0')... is attached to the bottom surface of the mounting part (14) with cushioning material (
19) and are attached radially. Further, the pressure applied by the resin grindstone to the stainless steel plate (W) is adjusted in advance by adjustment step 9). That is, with the above-mentioned grindstone in contact with the stainless steel plate (W), the base member (1)) is moved up and down by the rotation of the adjustment screw 9), and the base member (1)) is The length of the spring (18) compressed between the lower surface and the upper surface of the gf calendar column mounting portion 14)! By adjusting the above spring (18
) to the resin grindstone from 0.1 to 0.5k.
Adjust to an appropriate value within the g/c range of 31.

In this state, the motor 7 (not shown) is started to grind the resin grindstone (20') <20')... into the hollow shirt 1-.
(13) as the axis, and the switching valve (2
5) Open and remove the hollow shirt (13) from the pipe (22).
) and the hollow pipe (15) through the annular hollow part (21) to the resin grindstone (20°) (20')... while the table (1) is fixed in the above-mentioned predetermined direction. The surface of the stainless steel material <W is polished by reciprocating the polishing tool (2) with constant strokes in a direction perpendicular to the direction of operation of the table (1) by reciprocating the polishing tool (2) and continuously reciprocating the polishing tool (10). In addition, the above resin grindstone (20') (2
0')..., the resin grindstone (20') (20")... is replaced with a finer-grained one at predetermined intervals, and after the work is completed, the switching valve is (25) to stop the supply of cooling water.

Next, in the second step, the abrasive material (20) is coated with the resin grindstone (
20°) (20')... A wrap material (20'') made of felt or non-woven fabric is used, and the first liquid used in this process and the stainless steel plate (W) are The constant temperature equipment is used because it is necessary to maintain the temperature within the range of 28 to 32°C.

The pressing force of the lamp material (20") against the stainless steel plate (W) is adjusted as in the first step, and the hollow shaft (13") is driven by a motor (not shown) in the same manner as described above.
), and the first liquid is supplied to the hollow pipe (I5) from the pipe (23). Further, the first liquid and the stainless steel plate (W) are maintained at a predetermined temperature using constant temperature equipment.

In this state, as in the first step, table (1) and g
Polish the stainless steel & I slope (W) by reciprocating the polishing tool 2) in a predetermined direction, and adjust the pressing force of the lapping material (20゛) at predetermined intervals. Step 9) to gradually reduce the size.

Next, in the third step, the switching valve (26) is closed and the switching valve (27) is opened'ζ to interrupt the supply of the first liquid and instead supply the second liquid from the piping (24) into the hollow pipe (15). Polishing is performed using the same lapping material (20") as in the second step. In this step, as in the second step, the stainless steel plate (W) and the second liquid are heated to a predetermined temperature range using constant temperature equipment. Furthermore, the pressing force of the lamp !, t (20'') to the stainless steel plate (W) is also set to a predetermined value by the adjustment method 9).

The method of the present invention can be applied to stainless steel 1 (
The surface of W) is mirror-finished, for example, 1.5 ms [thickness] x 1 m [width] x 2 on stainless steel plate (W).
Using a 304 stainless steel plate with r % nitric acid aqueous solution with chromium oxide (C
r203) Polishing is performed at a processing temperature of 30° C. using a first solution containing 5 wt% of powder, and in the third step, a second solution consisting of a Fell 1 filler material and a 5% nitric acid aqueous solution is polished. When the stainless steel plate was polished at a processing temperature of 30° C., the mirror finish roughness of the stainless steel plate was 0.05 μm or less.

In addition, when the mirror-finished stainless steel plate is colored by the Inco method, the color difference according to Hunter's color difference formula using the above-mentioned Suga Test Instruments integrating sphere automatic colorimeter (AUD-3CH-2) is 1.5. It was within.

As explained above, the method for mirror-finishing stainless steel according to the present invention includes the first step of sequentially polishing with a grindstone with a grain size of 600 to 1200 mesh, and Add 4.5 chromium oxide (Cr20a) powder to nitric acid aqueous solution.
4.5 to 5. A second step of polishing with a wrap material made of felt or nonwoven fabric at a processing temperature of 28 to 32° C. using the first liquid containing 5.5 to 5.5 wt%;
The surface of the stainless steel was mirror-finished in the third step of ui using a 5% nitric acid aqueous solution using the same wrapping material as in the second step, so that The surface structure is uniform and the surface roughness is extremely small.

Therefore, according to the method of the present invention, it is possible to process the surface of stainless steel material to a highly accurate and homogeneous mirror finish, and when the surface of this stainless steel scrap material is colored by a coloring method such as the Inco method, it is possible to achieve an excellent finish with very little color difference. A product having a colored mirror surface can be provided.

Furthermore, since the method of the present invention can be carried out using conventional polishing equipment, it is extremely advantageous from the standpoint of capital investment, in spite of the excellent effects described above.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram showing an example of a polishing apparatus used in carrying out the stainless steel mirror finishing method according to the present invention, FIG. 2 is an enlarged sectional view of the main part of FIG. 1, and FIG. FIG. 3 is a plan view showing an example of arrangement. "・-7

Claims (1)

[Claims] (1) The first step of sequentially polishing with a grindstone with a grain size of 600 to 1200 mesh, and 4.5 to 5.5 wt% chromium oxide [Cr_2O_
3] The second step consists of polishing using a first liquid mixed with powder at a processing temperature of 28 to 32°C with a wrap material made of felt or nonwoven fabric, and a 4.5 to 5.5% nitric acid aqueous solution. A method for mirror-finishing stainless steel, which comprises a third step of polishing with a wrap material made of felt or nonwoven fabric at a processing temperature of 28 to 32° C. using a second liquid.