JP2005314772A - Stainless steel sheet to be photo-etched and manufacturing method therefor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a stainless steel sheet to be photo-etched which surely acquires a smoother etched surface and consequently eliminates an electrolytic polishing step, and to provide a manufacturing method therefor. <P>SOLUTION: The stainless steel sheet comprises, by mass%, each element of 0.08% or less C, 2.0% or less Mn, 5.0 to 15% Ni, 15 to 20% Cr, 3.0% or less Mo, 3.0% or less Cu, 0.30% or less N, each limited element of 1.0% or less Si, 0.045% or less P and 0.05% or less S, and the balance Fe with unavoidable impurities; and contains crystal grains with an average size of 15 μm or smaller. The manufacturing method includes heat-treating a steel ingot or a hot-rolled material for the above stainless steel sheet at a temperature of 1,200°C to 1,400°C for at least ten hours. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention provides a stainless steel plate excellent in smoothness of a surface to be etched (hereinafter referred to as an etching surface) and a method for producing the same, which is preferably used for photoetching.

  Photo-etching is a process that forms an acid-resistant resist film on a metal surface by the photoresist method into a product shape, dissolves unnecessary portions with an etching solution, and then removes the resist film to obtain a product. It is widely used for the processing of stainless steel foil because it is suitable for the production of a wide variety of products.

  Parts manufactured using such processing methods include hard disk gimbal springs, rotary encoder slits, metal masks for vacuum evaporation used as jigs in the production of ICs and LSIs, and paper feed for inkjet printers. There are many such as spurs.

  For example, in the above-mentioned spurs for paper feeding, since glossy paper or the like for exclusive use has come to be used along with the improvement of the quality of printed images, the spurs on the printed paper due to the spurs become a problem Yes. In addition, paper dust may be generated due to the spur rubbing the surface of the printing paper. In this case, the paper dust adheres to the spur, and further, the paper dust absorbs ink and stains the printing paper surface.

  In spurs, the peripheral surface, which is a portion in contact with the printing paper surface, and the vicinity thereof are often processed smoothly by etching. However, it has been found that each of the problems described above occurs because the degree of smoothness of the etched surface of the contact portion with the printing paper surface is low. Therefore, conventionally, in order to make the etched surface of the spur smoother, there has been a case where electropolishing is performed after the etching. However, applying electropolishing leads to an increase in process and cost, and is therefore a process that should be avoided if possible. Therefore, it has been considered to increase the etching rate by reducing the crystal grain size, thereby making the etched surface smoother.

  For example, Patent Document 1 describes that an austenitic stainless steel is heat-treated at a temperature of 500 to 850 ° C. for 10 seconds or more, thereby reducing the crystal grain size to 6 or more and processing the etched surface smoothly. Patent Document 2 discloses that in order to suppress a masking effect caused by a corrosion product called a smut made of carbide, the amount of C is set to 0.03% by mass or less, and the etching rate of grain boundaries is increased. For the purpose, it is described that 0.01 to 0.3% by mass of Nb is contained in order to refine the average crystal grain size to 15 μm or less and further suppress coarse carbide and crystal grain growth.

Japanese Patent No. 2754225 Japanese Patent Laid-Open No. 2003-3244

  However, among the above prior arts, in the former case, carbide is precipitated in the crystal grain boundary by the heat treatment for reducing the crystal grain size, and a chromium-deficient layer is formed in the vicinity of the crystal grain boundary. In some cases, the corrosion resistance deteriorates, and in order to compensate for this, a passivation treatment or the like is required. In addition, the surface roughness that can be reached by the latter technique is at most about 0.3 μm in Ra, and it has been difficult to smooth the surface to Ra: ≦ 0.20 μm, in which electrolytic polishing can be omitted.

  Accordingly, an object of the present invention is to provide a stainless steel plate for photoetching processing that can reliably and significantly improve the smoothness of the etched surface, and can eliminate the need for electrolytic polishing, and a method for manufacturing the same. Yes.

  The outline of the conventional method is described again by increasing the existence frequency (density) per unit area of the crystal grain boundary that is easily etched by reducing the crystal grain size. However, with this method, it is difficult to reach the surface roughness Ra ≦ 0.20 μm of the etched surface that does not require electropolishing. Therefore, as a result of intensive studies in order to achieve the target etching surface roughness: Ra ≦ 0.20 μm, the present inventors have obtained the following knowledge.

  In other words, by controlling the ease of etching of each crystal grain by reducing the component segregation generated during casting, the etching rate of adjacent crystal grains becomes equal and smoother than when component segregation remains. An etched surface can be obtained.

The gist of the present invention based on the above findings is the following stainless steel plate for photoetching and a method for producing the same.
That is, the stainless steel plate for photoetching of the present invention is, in mass%, C: 0.08% or less, Mn: 2.0% or less, Ni: 5.0% or more and 15% or less, Cr: 15% or more and 20 %, Each element is limited to Si: 1.0% or less, P: 0.045% or less, S: 0.05% or less, the balance being Fe and inevitable The average grain size is 15 μm or less, the average segregation amount C _Ni S of Ni component in the plate thickness direction is 0.40% or less, the maximum segregation amount C _Ni MAX is 1.0% or less, The average segregation amount C _Cr S of the Cr component is 0.60% or less, and the maximum segregation amount C _Cr MAX is 2.0% or less. Moreover, as a component, you may contain Mo: 3.0% or less, Cu: 3.0% or less, N: 0.30% or less.

  Next, the manufacturing method of the stainless steel plate for photoetching of this invention is the mass%, C: 0.08% or less, Mn: 2.0% or less, Ni: 5.0% or more and 15% or less, Cr: 15% or more and 20% or less, Mo: 3.0% or less, Cu: 3.0% or less, N: 0.30% or less, each element is contained, Si: 1.0% or less, In manufacturing a stainless steel plate in which each element is limited to P: 0.045% or less and S: 0.05% or less, the balance is Fe and inevitable impurities, and the average crystal grain size is 15 μm or less, A steel ingot, which is a material of a stainless steel plate, is characterized in that heat treatment is performed at a temperature of 1200 ° C. or higher and 1400 ° C. or lower for at least 10 hours. In this manufacturing method, hot rolled material can be used instead of the steel ingot.

The amount of segregation will be described on behalf of Ni. The average segregation amount C _Ni S and the maximum segregation amount C _Ni MAX are values defined as follows.
(1) Average segregation amount C _Ni S (%) = Ana component analysis value (%) × Ci _Ni S (cps) / Ci _Ni ave. (Cps)
(2) Maximum segregation amount C _Ni MAX (%) = Ni component analysis value (%) × Ci _Ni MAX (cps) / Ci _Ni ave. (Cps)
Here, Ci _Ni S: standard deviation (cps) of X-ray intensity
Ci _Ni ave.: Average intensity of all X-ray intensities (cps)
Ci _Ni MAX: maximum X-ray intensity (cps) (= maximum value of X-ray intensity-minimum value)

  The Ni component analysis value (%) is the Ni content of the material and is a value analyzed by a chemical or physical method. The component segregation amount of the so-called plate cross section in the plate thickness direction is obtained by polishing the plate cross section of the product (referred to as the plate thickness direction) and then performing line analysis with an X-ray microanalyzer over the plate thickness direction of the product. . The measurement conditions are as shown in Table 1, and the measurement length is the thickness of the material. Based on the measured X-ray intensity (c.p.s) of the line analysis, the amount of segregation is calculated by the following formula.

  According to the present invention, the smoothness of the etched surface is reliably and greatly improved by specifying the contained elements, the form of the material of the stainless steel plate and the heat treatment conditions of the material, thereby eliminating the need for electropolishing. It is possible to obtain a stainless steel plate for photoetching that can be processed.

The reasons for limitation will be described below with respect to the content range (mass%) of each component contained in the stainless steel plate according to the present invention.
C: 0.08% or less C is an important element for improving strength and stabilizing the austenite phase in austenitic stainless steel, but when carbide is precipitated, it does not dissolve in an etching solution called smut during etching. Corrosion products are generated on the etched surface and hinder the progress of etching. Therefore, the upper limit is made 0.08% in order to roughen the etched surface. However, when the strength and austenite phase stabilization can be replaced by other methods and more severe etching surface smoothness is required, the upper limit of C is preferably 0.03%.

Mn: 2.0% or less Mn is added to improve hot workability. However, if the content exceeds 2.0%, the effect is saturated and the cost is increased. % Was the upper limit.

Ni: 5.0% or more and 15% or less Ni is an element necessary for improving the corrosion resistance and strength of stainless steel. However, if the content is less than 5.0%, the corrosion resistance deteriorates, and if it exceeds 15%, the cost is high. Therefore, it is limited to 5.0% or more and 15% or less.

Cr: 15% or more and 20% or less Cr is the most important element for improving the corrosion resistance. If the content is less than 15%, the corrosion resistance deteriorates, and if it exceeds 20%, the cost increases, so 15% or more and 20% or less. Limited to.

Si: 1.0% or less Si is used as a deoxidizing material, but if the content exceeds 1.0% and the etching rate decreases, the upper limit is 1.0%.

P: 0.045% or less Since the P content exceeds 0.045% and the hot workability deteriorates when the content increases, the upper limit was made 0.045%.

S: 0.05% or less Since S deteriorates hot workability when the content exceeds 0.05% and the content increases, the upper limit was made 0.05%.

Mo: 3.0% or less Mo is an element effective for improving the corrosion resistance of stainless steel, but in order to prevent the etching rate from slowing down and reducing the productivity, the upper limit is set to 3.0%. .

Cu: 3.0% or less Cu is an element effective for stabilizing the austenite phase, but 3.0% was made the upper limit in order to prevent the etching rate from slowing down and reducing the productivity.

N: 0.30% or less N is an element effective for improving the corrosion resistance and strength of stainless steel, and also has the effect of suppressing carbide precipitation when annealed at a low temperature in order to refine the crystal grain size. It is preferable to add. However, when 0.30% or more is added, a nitride is formed, which is smutted and roughens the etched surface by a masking effect. Therefore, the upper limit of N is set to 0.30% or less.

  Next, the reason for setting the average crystal grain size to 15 μm or less is that when the average crystal grain size exceeds 15 μm, the etched surface tends to be roughened.

Next, the reason why the average segregation amount and the maximum segregation amount of Ni and Cr are specified will be described.
In the process of producing a stainless steel sheet, after casting, variation in concentration due to solidification segregation (hereinafter, component segregation) occurs in the product. In particular, in austenitic stainless steel, since Ni and Cr are the two main additive elements, component segregation tends to increase, but this component segregation greatly affects the smoothness of the etched surface. desirable. As numerical values for achieving this, in the case of Ni, the average segregation amount C _Ni S of Ni component was limited to 0.40% or less, and the maximum segregation amount C _Ni MAX was limited to 1.0% or less. In the case of Cr, the average segregation amount C _Cr S of the Cr component was limited to 0.60% or less, and the maximum segregation amount C _Cr MAX was limited to 2.0% or less.

Next, the reason for limiting the heat treatment conditions listed in the production method of the present invention will be described.
In the present invention, the steel ingot or hot-rolled material is heat-treated at a temperature of 1200 ° C. to 1400 ° C. for at least 10 hours. As described above, since component segregation is harmful to the smoothness of the etched surface, it is necessary to reduce component segregation generated during casting. An effective method for reducing component segregation is heat treatment, and the higher the temperature and the longer the time, the higher the effect of reducing segregation.

  For this reason, in order to ensure the effect of reducing segregation, the lower limit temperature of the heat treatment is set to 1200 ° C. However, since the temperature is close to the melting point at temperatures exceeding 1400 ° C. and cracks may occur due to stress applied during heat treatment, 1400 ° C. is set as the upper limit. In addition, the heat treatment time is set to 10 hours because it requires at least 10 hours for the component segregation to be reduced by diffusion.

  In addition, after final annealing, processes such as temper rolling for shape correction and strength improvement, and further stress relief annealing to prevent warping that occurs during etching of temper rolled material deteriorate the smoothness of the etched surface. There is nothing that can be done.

Next, examples that demonstrate the effects of the present invention will be described.
A necessary number of 20 kg of seven types of steel ingots each having the alloy components A, B, C, D, E, F, and G shown in Table 2 are manufactured, and then these steel ingots are hot worked to have a thickness of 7 mm. A hot rolled material was used. Next, these hot-rolled materials were subjected to a solution heat treatment at 1100 °, then made into a thickness of 2.5 mm by cold rolling, further heat-treated at 1100 ° C. for 1 minute, and then water-cooled, and a test stainless steel plate ( Material). In this series of processes, the material was manufactured by dividing the diffusion heat treatment for reducing segregation into those performed at the steel ingot stage and those performed at the forging stage. The conditions for the diffusion heat treatment and the combination conditions of the steel types are shown in No. 3 of Table 3. 1-15.

  Each material is cold-rolled to a thickness of 1 mm, annealed at 850 ° C. for 30 seconds, and further subjected to temper rolling at a rolling rate of 30% and stress-relief annealing at 650 ° C. for 30 seconds. The test piece was obtained.

Next, the maximum segregation amount and average segregation amount of Ni and Cr, average crystal grain size, Vickers hardness, and etched surface roughness were examined for each test piece.
The maximum amount of segregation and the average amount of segregation were determined by the above-described equations (1) and (2). The X-ray microanalyzer used was JXA-8600MX manufactured by JEOL Ltd.

  The average crystal grain size is a crystal grain size in the sheet width direction in a cross section orthogonal to the rolling direction, and this corresponds to the average crystal grain size in the annealed state before temper rolling. The average crystal grain size was measured by the JIS G 0551 (steel austenite grain size test method) counting method.

Etching surface roughness (Ra) is measured by using a ferric chloride solution (temperature: 50 ° C., liquid specific gravity: 1.49, oxidation-reduction potential: 646 mV) on the material surface at a pressure of 2.5 kg / mm ² . The surface etched by spraying for 2 minutes was measured along a direction orthogonal to the rolling direction using a contact-type surface roughness meter (manufactured by Tokyo Seimitsu Co., Ltd., Surfcom 1400A).

The above test results are also shown in Table 3.
According to Table 3, according to the present invention example No. Each of the stainless steel plates 1 to 7 has a smooth etching surface with an etching surface roughness (Ra) of 0.20 μm or less. However, no. The etched surface roughness (Ra) of the 8-15 stainless steel plates exceeded 0.20 μm, and roughening was observed.

The reason is that no. In the case of 8 and 9, it is presumed that the segregation of Ni and Cr is not sufficiently eliminated because the diffusion heat treatment temperature is lower than the conditions of the present invention. No. The stainless steel plates 10 and 11 are presumed to be due to the fact that the diffusion heat treatment time is shorter than the conditions of the present invention, and the segregation is not sufficiently eliminated. No. The stainless steel sheets of 12 to 15 were subjected to diffusion heat treatment according to the present invention, and although the segregation amounts of Ni and Cr were within the scope of the present invention, the content of C and N was higher than that of the present invention, so etching was performed. It is estimated that smut sometimes occurred and the etched surface was roughened.

Claims (4)

In each mass%, C: 0.08% or less, Mn: 2.0% or less, Ni: 5.0% or more and 15% or less, Cr: 15% or more and 20% or less
Further, each element is limited to Si: 1.0% or less, P: 0.045% or less, S: 0.05% or less,
The balance consists of Fe and inevitable impurities,
The average crystal grain size is 15 μm or less,
In addition, the average segregation amount C _Ni S of Ni component in the thickness direction is 0.40% or less, the maximum segregation amount C _Ni MAX is 1.0% or less, and the average segregation amount C _Cr S of Cr component is 0.60% or less. A stainless steel plate for photoetching, wherein the maximum segregation amount C _Cr MAX is 2.0% or less.   2. The photo of claim 1, further comprising, in mass%, each element in a range of Mo: 3.0% or less, Cu: 3.0% or less, and N: 0.30% or less. Stainless steel plate for etching. In mass%, C: 0.08% or less, Mn: 2.0% or less, Ni: 5.0% or more and 15% or less, Cr: 15% or more and 20% or less, Mo: 3.0% or less, Cu: Each element is contained in a range of 3.0% or less and N: 0.30% or less,
Further, each element is limited to Si: 1.0% or less, P: 0.045% or less, S: 0.05% or less,
The balance consists of Fe and inevitable impurities,
In producing a stainless steel plate having an average crystal grain size of 15 μm or less,
A method for producing a stainless steel plate for photoetching, comprising performing a heat treatment on a steel ingot, which is a material of the stainless steel plate, at a temperature of 1200 ° C. to 1400 ° C. for at least 10 hours. The method for producing a stainless steel plate for photoetching according to claim 3, wherein hot rolled material is used instead of the steel ingot.