JP2005320587A - Stainless steel sheet for photoetching and its production method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a stainless steel sheet for photoetching in which the smoothness of the face to be etched can be securely and remarkably improved, thus electrolytic polishing can be made needless, and to provide its production method. <P>SOLUTION: A stainless steel sheet having a composition comprising, by mass, ≤0.03% C, ≤2.0% Mn, 5.0 to 15% Ni, 15 to 20% Cr, 0.01 to 0.03% Nb, 0.03 to 0.2% V and ≤0.30% N, and in which the content of Si is limited to ≤1.0%, P to ≤0.045% and S to ≤0.05%, respectively, and the balance Fe with inevitable impurities is cold-rolled at rolling ratio of ≥30%, and is thereafter heat-treated at 700 to 900°C, so as to be an average crystal grain size of ≤10 μm. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a stainless steel plate excellent in smoothness of a surface to be etched (hereinafter referred to as an etched surface) and suitably used for photoetching and a method for producing the same.

  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 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 carbide smut, 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 Nb is contained in an amount of 0.01 to 0.3% by mass 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.

  First, the carbide of Nb does not dissolve in the etching solution like the carbide of Cr, so that it becomes a smut and may cause a roughened etching surface. However, since the carbide of Nb is finer than the carbide of Cr, the degree of influence is small. Further, V forms fine carbides similarly to Nb, so there is an effect of refining crystal grains. However, since affinity with C is not as high as Nb, even when the amount of C in the base material is the same, There is little production of carbide.

The gist of the present invention made based on the above findings is the following stainless steel plate for photoetching and a manufacturing method thereof.
That is, the stainless steel plate for photoetching of the present invention is in mass%, C: 0.03% or less, Mn: 2.0% or less, Ni: 5.0% or more and 15% or less, Cr: 15% or more and 20 %: Nb: 0.01% or more and 0.03% or less, V: 0.03% or more and 0.2% or less, and N: 0.30% or less. 1.0% or less, P: 0.045% or less, S: 0.05% or less, each element is limited, the balance is made of Fe and unavoidable impurities, and the plate has a cross section perpendicular to the rolling direction. The average crystal grain size in the width direction is 10 μm or less. In the present invention, it is further preferable that the Vickers hardness is 300 or more.

  Moreover, the manufacturing method of the stainless steel plate for photoetching processing of this invention is the mass%, C: 0.03% or less, Mn: 2.0% or less, Ni: 5.0% or more and 15% or less, Cr: 15 %: 20% or less, Nb: 0.01% or more, 0.03% or less, V: 0.03% or more, 0.2% or less, N: 0.30% or less. , Si: not more than 1.0%, P: not more than 0.045%, S: not more than 0.05%, and a stainless steel plate made of Fe and inevitable impurities in the balance, with a rolling rate of 30% After the cold rolling as described above, the heat treatment is performed at a temperature of 700 ° C. or more and 900 ° C. or less to make the average crystal grain size 10 μm or less. In this manufacturing method, after the heat treatment, cold rolling (temper rolling) is performed at a rolling rate of 20% or more and 80% or less, and thereafter, a condition for heat treatment at a temperature of 550 ° C. or more and 700 ° C. or less is added. Is a more preferable form.

  According to the present invention, the smoothness of the etched surface is reliably and greatly improved by specifying the contained elements and the rolling conditions and heat treatment conditions of the stainless steel plate as a material, thereby eliminating the need for electrolytic polishing. 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: 0.03% or less C is easy to form carbide when annealed at a low temperature in order to make the crystal grain size fine, but a Cr-free layer is formed around Cr carbide and deteriorates corrosion resistance. In addition, this carbide causes smut and roughens the etched surface by a masking effect. However, if it is 0.03% or less, the time required for the precipitation of carbides becomes long, and no carbides are generated within the annealing time in normal production equipment, so the upper limit of C was made 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.

Nb: 0.01% or more and 0.03% or less,
Since Nb is an element that forms a strong carbide, the amount of carbide causing smut is larger than that in the case of V addition when the amount of C is the same, and the upper limit should be set to 0.00. 03%. However, removing Nb mixed as an unavoidable impurity or selecting and using a raw material having a low Nb content causes an increase in cost, so the lower limit was made 0.01%.

V: 0.03% to 0.2%,
V is an element that forms carbides, and is an element that has the effect of being finely precipitated and reducing the crystal grain size. These effects are small when the content is less than 0.03%. On the other hand, when the content exceeds 0.2%, the effect is saturated, which causes an increase in cost. Therefore, the content of V is set to 0.03% or more and 0.2% or less.

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 0.30%.

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

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

  Next, the reason why the average grain size in the plate width direction in the cross section perpendicular to the rolling direction is 10 μm or less is that the grain boundaries are more easily etched than in the grains and are not affected by the crystal orientation. This is because the etching surface becomes smooth if the existence ratio of the crystal grain boundaries per unit area is increased. Also, when the Vickers hardness is set to a high hardness of 300 or more by rolling, dislocations are introduced into the crystal grains, and by using this dislocation as the starting point of etching, the difference in etching rate between the crystal grain boundaries and the crystal grains is reduced. As a result, the etched surface tends to be smoother, which is preferable.

Next, the reasons for limiting the conditions listed in the production method of the present invention will be described.
First, the reason for the rolling rate of 30% or more in the first cold rolling is that when the rolling rate is less than 30%, sufficient strain that becomes a driving force for recrystallization does not enter, and a mixed grain structure is formed in the subsequent heat treatment, The etched surface becomes rough. Therefore, the rolling rate is set to 30% or more.

  The heat treatment according to the present invention is annealing, and in the annealing after the cold rolling, since recrystallization does not occur at less than 700 ° C., there may be a problem that a mixed grain structure remains when cold working after etching. . In order to make the average crystal grain size 10 μm or less, the annealing temperature needs to be 900 ° C. or less.

  A preferred additional condition in the production method of the present invention is that after the heat treatment, cold rolling is performed at a rolling rate of 20% or more and 80% or less, and then heat treatment is performed at a temperature of 550 ° C. or more and 700 ° C. or less. is there. The cold rolling in this case is temper rolling, and if the rolling rate of this temper rolling is less than 20%, the etched surface may be roughened. If it exceeds 80%, Ear cracks easily occur and the risk of breakage increases. Accordingly, the rolling rate of the second cold rolling is appropriately 20% or more and 80% or less.

  Further, the heat treatment after temper rolling is stress relief annealing, and if the temperature at this time is less than 550 ° C., warping may occur during etching due to the residual stress inside the stainless steel plate not being homogenized during rolling. . Moreover, at the temperature exceeding 700 degreeC, the effect of temper rolling is lost and it softens. Accordingly, the second heat treatment temperature is suitably 550 ° C. or higher and 700 ° C. or lower.

Next, examples that demonstrate the effects of the present invention will be described.
After forging 6 kg of steel ingots each having the alloy components A, B, C, D, E, and F shown in Table 1 to a thickness of 7 mm, a thickness of 2.5 mm is obtained by solution heat treatment and cold rolling. Further, after heat treatment at 1100 ° C. for 1 minute, it was cooled with water to obtain a test stainless steel plate (material).

  Each of the above materials was cold-rolled to a thickness of 1 mm, and then subjected to annealing-temper rolling-SR treatment (stress removal annealing) under the conditions shown in Table 2 to obtain a test piece.

Next, the average crystal grain size, Vickers hardness (Hv), and etched surface roughness of each test piece were examined.
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. Further, the Vickers hardness was examined using a Vickers hardness meter (manufactured by Akashi Seisakusho, AVK).

Etching surface roughness (Ra) is measured with 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 for 2 minutes. The surface etched by spraying was measured along a direction orthogonal to the rolling direction using a contact-type surface roughness meter (Surfcom 1400A, manufactured by Tokyo Seimitsu Co., Ltd.).

The above test results are also shown in Table 2.
According to Table 2, no. Each of the stainless steel plates 1 to 6 has a smooth etching surface with a surface roughness (Ra) of 0.20 μm or less. However, no. The stainless steel plate No. 7 had an annealing temperature of 925 ° C., which was higher than the conditions of the present invention, so the average crystal grain size was increased and the etched surface was roughened. No. The stainless steel plate No. 8 had a C content of 0.054%, which was higher than the component of the present invention, and as a result, carbides were generated. Thus, smut was generated during etching, and the etched surface was roughened by the masking effect.

No. Since the stainless steel plate No. 9 has a Nb content of 0.06%, which is higher than the component of the present invention, Nb carbide was generated, which became a smut and roughened during etching. No. Since the stainless steel plate No. 10 had a V content of 0.01%, which was less than the component of the present invention, the crystal grains became 10 μm or more and were roughened. No. Since the stainless steel plate of No. 11 has a N content of 0.33%, which is higher than the component of the present invention, a nitride of Cr and V was formed, which became a smut during etching and was roughened by its masking effect.

Claims (4)

In mass%, C: 0.03% or less, Mn: 2.0% or less, Ni: 5.0% to 15%, Cr: 15% to 20%, Nb: 0.01% to 0.03 % Or less, V: 0.03% or more and 0.2% or less, N: 0.30% or less in each range,
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,
A stainless steel plate for photoetching, wherein the average grain size in the plate width direction in a cross section perpendicular to the rolling direction is 10 μm or less.   Furthermore, the Vickers hardness is 300 or more, The stainless steel plate for photo-etching processing according to claim 1 characterized by things. In mass%, C: 0.03% or less, Mn: 2.0% or less, Ni: 5.0% or more and 15% or less, Cr: 15% or more and 20% or less, Nb: 0.01% or more and 0.03 % Or less, V: 0.03% or more and 0.2% or less, N: containing each element in the range of 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,
A stainless steel plate with the balance being Fe and inevitable impurities,
A method for producing a stainless steel sheet for photoetching, wherein the average grain size is 10 μm or less by performing a heat treatment at a temperature of 700 ° C. or more and 900 ° C. or less after cold rolling at a rolling rate of 30% or more. The stainless steel sheet is cold-rolled at a rolling rate of 20% or more and 80% or less after the heat treatment, and then further heat-treated at a temperature of 550 ° C or more and 700 ° C or less. The manufacturing method of the stainless steel plate for photoetching processes of description.