Stainless steel manufacturing method and stainless steel manufacturing system

Abstract

To manufacture a stainless steel having heightened uniformity to the extent that the surface is modified.SOLUTION: A manufacturing method of a stainless steel includes a contact step for bringing liquid or a highly viscous material containing at least one kind of specific material into contact with the stainless steel, and an irradiation step for performing laser irradiation to the stainless steel in the state where the liquid or the highly viscous material has a contact therewith. In the state where the surface of the stainless steel becomes flat by pulling the stainless steel, the irradiation step is carried out in the state where a distance to a radiation part performing laser irradiation is kept approximately constant.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a method and system for producing stainless steel. [Background technology]

[0002] Conventionally, as described in Patent Document 1, there is a method for modifying the surface properties of a substrate made of a metal material such as stainless steel by contacting the surface of the substrate with a solution containing a specific substance and irradiating the surface with laser light. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2011-235570 A Summary of the Invention [Problem to be solved by the invention]

[0004] However, in general, the surface of the substrate may have fine irregularities. When such a substrate is modified using the conventional method described above, the irregularities on the substrate surface make the distance between the substrate surface and the laser head that emits the laser light unstable. In addition, the unevenness also makes the thickness of the solution layer on the substrate 2 unstable. In this case, the fluence energy of the laser irradiated on the substrate surface differs depending on the irradiation position. Therefore, in the conventional method, the degree of modification of the substrate surface is non-uniform, and the quality of the stainless steel 10 produced is not stable.

[0005] One aspect of the present invention is directed to producing stainless steel having an increased uniformity in the extent to which the surface is modified. [Means for solving the problem]

[0006] In order to solve the above problems, a method for producing stainless steel according to one embodiment of the present invention includes a contacting step of bringing a liquid or high-viscosity substance containing at least one specific substance into contact with stainless steel, and an irradiation step of irradiating the stainless steel with a laser while the liquid or high-viscosity substance is in contact with the stainless steel, the irradiation step being performed in a state in which the surface of the stainless steel has been flattened by stretching the stainless steel, and the irradiation step being performed at a substantially constant distance from the irradiation section where the laser irradiation is performed.

[0007] According to the above-mentioned configuration, it is possible to improve the uniformity of the degree to which the surface of the stainless steel 10 is modified.

[0008] In addition, in order to solve the above-mentioned problems, a stainless steel manufacturing system according to one embodiment of the present invention includes a contact unit for bringing a liquid or high-viscosity substance containing at least one specific substance into contact with stainless steel, an irradiation unit for irradiating laser light onto the stainless steel that has been in contact with the liquid or high-viscosity substance, and a tension unit for tensioning the stainless steel at least while the laser light is being irradiated. Effect of the Invention

[0009] According to one aspect of the present invention, stainless steel can be produced that has a more uniform degree of surface modification. [Brief description of the drawings]

[0010] [Figure 1] FIG. 1 is a schematic cross-sectional view of a stainless steel according to a first embodiment of the present invention. [Diagram 2] FIG. 1 is a schematic diagram showing an overview of a manufacturing system used to manufacture stainless steel according to one embodiment of the present invention. [Diagram 3] 11 is a schematic diagram showing another example of a member used in the contact step and the irradiation step. FIG. [Figure 4] FIG. 4 is a diagram showing the state in which the diagram shown in FIG. 3 is viewed from the axial direction of the bridle roll. [Diagram 5] FIG. 4 is a diagram illustrating an example of an irradiation unit. [Figure 6] FIG. 13 is a diagram showing another example of the irradiation unit. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] [Embodiment 1] Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. The following description is provided for better understanding of the gist of the invention, and does not limit the present invention unless otherwise specified. In this application, "A to B" indicates A or more and B or less. In this specification, the term "stainless steel" is used to include "stainless steel plate" and "stainless steel strip". The percentages of the components shown below are expressed in mass%.

[0012] <Configuration of Stainless Steel 10 According to Embodiment 1> Fig. 1 is a schematic cross-sectional view of a stainless steel 10 according to a first embodiment of the present invention. As shown in Fig. 1, a stainless steel contact member is formed from the stainless steel 10. The stainless steel contact member is a member used as a wiring terminal such as a connector for a harness that connects copper or aluminum wires incorporated in an electric / electronic device. The stainless steel contact member is also used as a contact material for a metal dome incorporated in a push button switch or the like.

[0013] As shown in FIG. 1, the stainless steel 10 according to the first embodiment of the present invention has a coating 3 on the surface of the substrate 2. At a position 2 nm from the outermost surface of the coating 3 (the position indicated by the broken line 4 in FIG. 1), the ratio of components constituting the coating 3 is 15-45% Cr oxide, 3-20% Cr metal, 8-25% Fe oxide, 10-40% Fe metal, and 5-56% specific element. The surface roughness Ra of the stainless steel 10 is 0.17 μm or more. The composition of elements (components) at a position 2 nm from the outermost surface of the coating 3 can be measured using a photoelectron spectrometer. More specifically, the component concentration at a position 2 nm from the outermost surface of the coating 3 can be obtained by, for example, etching with Ar ions, followed by irradiating with X-rays and analyzing the spectrum of photoelectrons emitted. The surface roughness Ra of the stainless steel 10 can be measured using a stylus-type surface roughness measuring instrument.

[0014] The total thickness of the coating 3 (the length indicated by the arrow 5 in FIG. 1) is 20 nm or less. The thickness of the coating 3 can be measured by using a photoelectron spectrometer. Specifically, the thickness of the coating 3 is defined as half the maximum O (oxygen) peak measured by the photoelectron spectrometer.

[0015] The stainless steel used as the substrate 2 of the stainless steel 10 is preferably an austenitic, ferritic, martensite, austenitic-ferritic (two-phase), or precipitation hardened stainless steel, etc. Specific examples include SUS301, SUS304, SUS316, SUS410, SUS430, SUS436L, SUS444, SUS410, SUS420J1, SUS420J2, SUS329J1, SUS329J3L, SUS821L1, SUS630, or SUS631. The surface finishing method applied to the substrate 2 includes bright annealing, pickling, light rolling after pickling, temper rolling, HL finishing (with polishing marks), dull finishing (transferred to the substrate using a coarse roll during temper rolling), and mirror finishing (with surface gloss increased by buffing).

[0016] The Cr oxide contained in the film 3 is, for example, Cr2O3 or Cr(OH)3. The Fe oxide is, for example, Fe2O3 or Fe3O4. The specific element is at least one element having an electronegativity of 1.5 to 2.5. When the electronegativity exceeds 2.5, the elements in the film 3 are in an ionic bond state. When the electronegativity is less than 1.5, the elements are in a stable covalent bond state. Therefore, when an element having an electronegativity of less than 1.5 or more than 2.5 is used as the specific element, the electrical conductivity becomes significantly inferior. It is particularly preferable that the specific element is at least one of Al, Si, Sn, Ti, Ag, and Cu.

[0017] Here, the proportions of components contained in the coating 3 and the surface roughness will be described. First, it is believed that metal Cr, metal Fe, Cr oxide, Fe oxide, and the specific element are present in the coating 3 of the stainless steel 10. It is also believed that many of the specific elements are present in the form of oxides. Furthermore, since oxides (oxides of specific elements, Cr oxide, and Fe oxide) have low electrical conductivity and do not easily conduct electricity, the contact resistance of the stainless steel 10 increases as their proportion in the coating 3 increases. Furthermore, since metal elements (metal Cr and metal Fe) have high electrical conductivity, the contact resistance of the stainless steel 10 decreases as their proportion in the coating 3 increases.

[0018] If the specific element exceeds 56%, Cr oxide exceeds 45%, or Fe oxide exceeds 25% in the coating 3, the proportion of areas with very low conductivity will be high in the coating 3. If the metal Cr contained in the coating 3 is less than 3%, or the metal Fe is less than 10%, the proportion of areas with high conductivity will be low in the coating 3. Therefore, stainless steel 10 in which the proportions of components contained in the coating 3 and the surface roughness are outside the above-mentioned ranges is not suitable as a contact member.

[0019] On the other hand, when the metal Cr exceeds 20% or the metal Fe exceeds 10% in the coating 3, the stainless steel 10 becomes a more preferable stainless steel for use as a contact member. However, in the manufacturing method of stainless steel 10 described below, it is difficult to form a coating 3 in which the metal Cr and metal Fe exceed the set ranges.

[0020] Regarding the Cr oxide contained in the coating 3, when the fluence energy of the laser irradiated during the formation of the coating 3 is low, the proportion of Cr2O3 is higher than that of Cr(OH)3. Conversely, when the fluence energy of the laser is high, the proportion of Cr(OH)3 is higher than that of Cr2O3. Here, when the proportion of Cr2O3 in the coating 3 is high, the proportion of the specific element in the coating 3 is also high. Therefore, it is preferable that the proportion of Cr(OH)3 is higher than that of Cr2O3 in the Cr oxide contained in the coating 3.

[0021] Furthermore, the surface roughness of the stainless steel 10 is preferably rougher (higher numerical value) because the contact resistance decreases. Therefore, as described above, the surface roughness Ra of the stainless steel 10 in this embodiment is set to 0.17 μm or more. On the other hand, if the surface roughness of the stainless steel 10 is less than 0.17, the structure of the coating 3 is considered to be uniform. In this case, the contact resistance of the stainless steel 10 becomes high, and therefore the stainless steel 10 is not suitable as a contact member.

[0022] As described above, the stainless steel 10 according to the first embodiment of the present invention is, as an example, a stainless steel used as a stainless steel contact member. In addition, the coating 3 mainly containing a specific element is formed on the surface layer of the substrate 2 in the stainless steel 10. In addition to Cr, the coating 3 preferably contains at least one metal element selected from Al, Cu, Si, Ti, Sn, Ag, Ni, etc., as the specific element.

[0023] <Method of manufacturing stainless steel 10 according to embodiment 1> Fig. 2 is a schematic diagram showing an overview of a manufacturing system 100 used to manufacture stainless steel 10 according to one embodiment of the present invention. Hereinafter, a manufacturing method for stainless steel 10 according to one embodiment of the present invention (hereinafter, sometimes simply referred to as "this manufacturing method") will be described with reference to Fig. 2. This manufacturing method is carried out using a manufacturing system 100 as shown in Fig. 2. The manufacturing system 100 includes a payoff reel 101, a solution bath (contact section) 102, a bridle roll (tension section) 103, an irradiation section 104, a water washing tank 105, a dryer 106, and a tension reel 107.

[0024] This manufacturing method is characterized in that stainless steel manufactured by a general manufacturing process (see explanation below) is tensioned and flattened, and then laser-induced wet modification (immersion and irradiation steps described below) is performed. By the above method, the oxide film (passive film) formed on the surface layer of the stainless steel is modified to become film 3.

[0025] First, a typical method for manufacturing stainless steel will be described. In a typical method for manufacturing stainless steel, after a melting step, a casting step, and a slab surface grinding step are performed, a hot rolling step in which a slab heated to 1100°C to 1300°C is hot rolled to form a hot rolled steel strip, an annealing and pickling step, a cold rolling step, and a finishing step are performed. After the hot rolling step, the annealing and pickling steps and the cold rolling steps are repeated, and the annealed material having the final plate thickness may be used as the substrate 2. Alternatively, a bright annealed finished material or a temper rolled finished material may be used as the substrate 2.

[0026] The substrate 2 manufactured as described above is transported in the manufacturing system 100, during which the substrate 2 is subjected to an immersion process (contact process) and an irradiation process. As a result, a thickening process is performed on the substrate 2 to modify the surface and form a coating 3. The details of this manufacturing method will be described below. First, a coil wound with the substrate 2 is placed on a payoff reel 101 and is paid out. The arrow in FIG. 2 indicates the transport direction of the substrate 2.

[0027] Next, the immersion step and the irradiation step will be described. In the immersion step, the substrate 2 after the finishing step is immersed in a substance containing a specific element. Here, a solution containing a specific element will be taken as an example of the substance to be brought into contact with the substrate 2. However, in the present invention, the substance to be brought into contact with the substrate 2 is not limited to a solution, and may be any liquid or high-viscosity substance that can cause a desired reaction to form the coating 3 by irradiating the substrate 2 with a laser while the substance is in contact with the substrate 2. For example, the substance used in manufacturing the stainless steel 10 may be a metal particle suspension containing a specific metal as metal particles. The high-viscosity substance is a substance that contains a specific element and has high viscosity, such as sodium silicate (water glass), which can be applied to the surface of the substrate 2. The high-viscosity substance may also be a gel-like substance containing a specific element. The metal particle suspension may be a suspension containing at least one metal element selected from Al, Cu, Si, Ti, Sn, Ag, Ni, etc., as the specific element.

[0028] As an example of a form for holding the solution, the solution is held in a solution tank 102 as shown in Fig. 2. Here, the specific element is an element that can improve the surface contact resistance by being contained in the coating 3 formed on the surface layer of the substrate 2. Improving the contact resistance means lowering the contact resistance, which means improving the electrical conductivity of the surface of the stainless steel contact component.

[0029] The solution containing the specific element is preferably at room temperature (about 25° C.) and has a concentration of 40 mass % or less. Specifically, the solution containing the specific element may be an aluminum nitrate aqueous solution, a sodium silicate aqueous solution, a tin sulfate aqueous solution, a titanium sulfate aqueous solution, a silver nitrate aqueous solution, or a copper nitrate aqueous solution.

[0030] The depth of the solution tank 102 is not particularly limited. However, the thickness of the solution on the surface of the substrate 2 transported in the solution tank 102 is preferably adjusted so that sufficient energy can be imparted to the surface of the substrate 2 even if the fluence energy of the laser is attenuated by the solution in the irradiation step described below. The thickness of the solution means the length of the solution present on the surface of the substrate 2 in the direction perpendicular to the surface of the substrate 2. For example, the thickness of the solution in this embodiment refers to the distance from the surface of the substrate 2 to the water surface of the solution tank 102.

[0031] When the solution is thick, in other words when the substrate 2 is transported at a deep position in the solution tank 102, the energy of the laser may be attenuated by the solution, and the modification of the substrate 2 may be insufficient. As an example, the thickness of the solution on the surface of the substrate 2 is about 0.5 mm to 10 mm, and preferably 1 mm to 3 mm. In the irradiation step described below, it is preferable that the thickness of the solution in the area on the surface of the substrate 2 that is irradiated with the laser is as uniform as possible.

[0032] The bridle rolls 103 are two pairs of rolls that sandwich the substrate 2 in the plate thickness direction. In the manufacturing system 100, the bridle rolls 103 are provided in such a manner that at least one pair of rolls is provided upstream of a region where the substrate 2 is irradiated with a laser in an irradiation step described below, and another pair of rolls is provided downstream of the region. The substrate 2 is pulled in the opposite direction to the conveying direction by the pair of rolls on the upstream side, and pulled in the conveying direction by the pair of rolls on the downstream side. Note that the pulling may be relative, and may be realized, for example, by the difference in conveying speed between the upstream roll and the downstream roll.

[0033] While the substrate 2 is immersed in the solution, the substrate 2 is tensioned by the bridle roll 103 as described above, and pulled in a direction parallel to the conveying direction. This stretches out the irregularities on the surface of the substrate 2, and flattens the surface of the substrate 2. Note that in the manufacturing system 100, the member that applies tension to the substrate 2 is not limited to the bridle roll 103, and other devices may be used.

[0034] Next, the substrate 2 is immersed in the solution, and while tension is being applied to the substrate 2 by the bridle roll 103, the surface of the substrate 2 is subjected to a laser irradiation process (irradiation step). In the irradiation step, an irradiation unit 104 capable of irradiating a pulsed or continuous wave laser having a wavelength of 1080 to 1090 nm is used. The fluence energy of the irradiated laser is 0.2 to 6.6 J·cm. -2 , preferably 0.2 to 5.0 J cm -2 The fluence energy of the irradiated laser is 0.2 J cm -2 If the fluence energy of the irradiated laser is less than 6.6 J cm, the amount of the specific element contained in the surface of the substrate 2 will be insufficient, and the coating 3 having the desired composition cannot be obtained. -2 If the laser irradiated thin gauge substrate 2 exceeds this limit, it will be significantly deformed or its appearance will be significantly deteriorated, making it unusable as a contact material. In addition, the upper limit of the fluence energy of the irradiated laser will be set at 5.0 J·cm -2 This is preferable because it is possible to prevent the substrate 2 from being deformed due to the influence of heat, etc. It is preferable that the distance (irradiation distance) between the laser head of the irradiation unit 104 and the surface of the substrate 2 is maintained approximately constant.

[0035] Next, the stainless steel 10 that has been subjected to the irradiation process is transported to a water rinsing tank 105 filled with water, where the water rinsing process is carried out. Specifically, the stainless steel 10 is washed by being transported in the water rinsing tank 105, and the solution adhering to the surface is washed away. After the water rinsing process, the stainless steel 10 is dried by a dryer 106. The dried stainless steel 10 is further transported and wound up by a tension reel 107. This completes the present manufacturing method.

[0036] <Effects of the method for producing the stainless steel 10 according to the first embodiment> The manufacturing method according to the first embodiment of the present invention includes an immersion step of immersing stainless steel in a liquid or a high-viscosity substance containing a specific substance, and an irradiation step of irradiating the stainless steel with a laser in the liquid or the high-viscosity substance, and in the irradiation step, the laser is irradiated with a wavelength of 1080 to 1090 nm and a laser beam of 0.2 J cm when the stainless steel is stretched to make the surface of the stainless steel flat. -2 More than 6.0J cm -2 A laser having the following energy is irradiated. In the above example, the substrate 2 is stretched and the irradiation step is performed during the immersion step, but the irradiation step may be performed after the substrate 2 is immersed and removed from the solution tank 102. In this case, it is sufficient that the substrate 2 is stretched at least during the irradiation step.

[0037] If the irradiation step is performed without pulling the substrate 2, the unevenness of the surface of the substrate 2 makes the distance between the irradiated portion 104 and the surface of the substrate 2 unstable. Furthermore, the unevenness also makes the thickness of the solution on the surface of the substrate 2 unstable. In this case, the fluence energy of the laser irradiated to the surface of the substrate 2 differs depending on the irradiation position, the degree of modification of the surface of the substrate 2 is not stable, and the quality of the stainless steel 10 produced is not stable.

[0038] In contrast, in the present manufacturing method, the bridle roll 103 is used to apply tension to the substrate 2 to flatten it, so that the distance between the irradiation section 104 and the surface of the substrate 2 is maintained substantially constant, and the thickness of the solution on the surface of the substrate 2 is substantially constant. This makes the fluence energy of the laser light irradiated onto the surface of the substrate 2 substantially uniform over the entire region irradiated with the laser. Therefore, according to the present manufacturing method, it is possible to increase the uniformity of the degree to which the surface of the stainless steel 10 is modified, and stainless steel 10 of stable quality can be manufactured.

[0039] Furthermore, in this manufacturing method, the substrate 2 is transported in the manufacturing system 100, and the substrate 2 is planarized while the immersion step and the irradiation step are performed, thereby continuously modifying the substrate 2 to manufacture the stainless steel 10. This allows the stainless steel 10 to be manufactured more efficiently than ever before, improving the productivity of the stainless steel 10. Furthermore, by performing the treatment continuously, the manufacturing cost of the stainless steel 10 can be reduced compared to performing partial modification treatments in multiple stages.

[0040] [Modifications] In the above-mentioned embodiment 1, the stainless steel 10 is manufactured by subjecting the substrate 2 to an immersion step and an irradiation step. However, instead of the immersion step, the substrate 2 may be subjected to a dripping step. The dripping step is a step in which a solution containing a specific element is dripped onto the substrate 2. The solution should be dripped to such an extent that the entire surface of the substrate 2 is wet. Thereafter, the substrate 2 onto which the solution has been dripped is subjected to an irradiation step, thereby manufacturing the stainless steel 10 according to embodiment 1.

[0041] FIG. 3 is a schematic diagram showing another example of members used in the contact step and the irradiation step. FIG. 4 is a diagram showing the state of the diagram shown in FIG. 3 as viewed from the axial direction of the bridle roll 103. In the above-mentioned embodiment 1, in the immersion step, the substrate 2 is transported into the solution tank 102 to bring the solution into contact with the surface of the substrate 2. However, the method of bringing the solution into contact with the surface of the substrate 2 is not limited to immersion. As an example, in the method for producing stainless steel 10, a dripping step of dripping the solution onto the surface of the substrate 2 may be performed as the contact step.

[0042] 3 and 4, in the case where the dropping step is performed as the contact step, the manufacturing system 100 is provided with a solution dropping head 108 upstream of the irradiation unit 104 in the transport direction of the substrate 2. The solution is dropped onto the substrate 2 from the solution dropping head 108.

[0043] Here, when performing the dropping step, the substrate 2 may be fed in an oblique direction as shown in Fig. 3 and Fig. 4. Specifically, the substrate 2 may be transported in an inclined state so that the solution dropped onto the substrate 2 flows from the upstream to the downstream in the transport direction. By causing the dropped solution to flow on the surface of the substrate 2, the thickness of the solution on the surface of the substrate 2 tends to become uniform in the region irradiated with the laser by the irradiation unit 104.

[0044] The position of the laser head of the irradiation unit 104 may be variable in a direction perpendicular to the surface of the substrate 2 (the direction indicated by the arrow in FIG. 4). The position of the laser head of the irradiation unit 104 may be appropriately adjusted in accordance with the plate thickness of the substrate 2.

[0045] The contact step may be a method other than the immersion step or the dropping step. For example, the contact step may be a spraying step in which an atomized solution is sprayed onto the surface of the substrate 2.

[0046] In the above-mentioned first embodiment, a steel strip wound in a coil shape is used as the substrate 2, but the form of the substrate 2 is not limited to this, and may be, for example, a cut plate shape.

[0047] In the above-mentioned embodiment 1, the stainless steel 10 with reduced surface contact resistance was manufactured by using a solution containing a metal element such as Cr, Al, Cu, Si, Ti, Sn, Ag, or Ni as a specific element in the immersion process. However, the solution used in the immersion process is not limited to the above, and the stainless steel 10 obtained is not limited to the above. For example, in the manufacturing method of the stainless steel 10, a solution containing a carboxylic acid or a carboxylate may be used instead of the solution containing the above-mentioned metal element. Examples of the solution include a solution containing oxalic acid or formic acid, or a solution in which these are mixed. Alternatively, the solution containing a carboxylic acid may be a mixed solution containing phosphoric acid, diammonium hydrogen citrate, or the like.

[0048] When stainless steel is subjected to the immersion step and the irradiation step using such a solution, stainless steel 10 is produced, on the surface of which is formed a coating 3 containing carboxylic acid (carboxylic acid is concentrated on the surface).

[0049] In the stainless steel 10 in which the coating 3 contains a carboxylic acid, a functional group, specifically a hydroxyl group, is formed on the surface, improving wettability. In other words, the coating 3 contains a hydroxyl group. Such a stainless steel 10 has improved affinity for resin. The resin is a so-called engineering plastic resin, and examples thereof include polyamide, polypropylene, polycarbonate, polyethylene terephthalate, and polymethyl methacrylate. For example, by interposing a resin between two pieces of stainless steel 10 whose surfaces have been modified as described above, the stainless steels 10 can be bonded together more firmly than before. The specific functional group that can be contained in the coating 3 is not limited to a hydroxyl group. The coating 3 may also contain an organic compound having a specific functional group.

[0050] As described above, by using the above-mentioned solution in the immersion step, the stainless steel 10 with a modified surface can be produced with high efficiency.

[0051] The coating 3 may also be a metal compound coating containing a specific substance. A metal compound coating is, for example, a coating containing at least one of hydroxides, hydrated oxides, ammonium salts, carboxylates, phosphates, carbonates, sulfates, silicates, and fluorides. Stainless steel 10 including coating 3, which is such a metal compound coating, also has improved affinity for resins.

[0052] Examples of solutions that can be used to form the metal compound film as described above include aqueous solutions of hydroxides of Group I elements, salts of Group I elements, hydroxides of Group II elements, salts of Group II elements, hydroxides of Group I elements (elements in Group I of the periodic table) such as lithium, sodium, potassium, rubidium or cesium; salts of Group I elements; hydroxides and salts of Group II elements (elements in Group II of the periodic table) such as beryllium, magnesium, calcium, strontium or barium.

[0053] The hydroxides of Group I elements are, for example, sodium hydroxide and potassium hydroxide. The salts of Group I elements are, for example, sodium orthosilicate, sodium metasilicate, sodium carbonate, potassium carbonate, sodium bicarbonate, potassium bicarbonate, sodium acetate, potassium acetate, sodium laurate, potassium laurate, sodium palmitate, potassium palmitate, sodium stearate, and potassium stearate. The hydroxides of Group II elements are, for example, calcium hydroxide and barium hydroxide.

[0054] The above-mentioned solution may be, for example, ammonia, hydrazine, a hydrazine derivative, or a water-soluble amine compound. The solution may be, for example, a solution of phosphoric acid and a phosphate containing -H2PO4, -HPO4, or -PO4, such as (i) a metal hydrogen phosphate such as zinc hydrogen phosphate, manganese hydrogen phosphate, or calcium hydrogen phosphate, (ii) a metal dihydrogen phosphate such as calcium dihydrogen phosphate, or (iii) a metal phosphate such as zinc phosphate, manganese phosphate, calcium phosphate, calcium sodium phosphate, or zirconium phosphate.

[0055] Furthermore, as the above-mentioned solution, an aqueous solution of a fluoride such as hydrofluoric acid, sodium fluoride, potassium fluoride, ammonium fluoride, ammonium hydrogen fluoride, hydrofluorosilicic acid, ammonium fluorosilicic acid, fluoroboric acid, or ammonium fluoroborate may be used.

[0056] Alternatively, the above-mentioned solution may be an aqueous solution of sulfuric acid or a metal salt of sulfuric acid, such as sodium sulfate, manganese sulfate, calcium sulfate, titanyl sulfate, zirconium sulfate, potassium sulfate, or sodium sulfate.

[0057] Also, the manufacturing system 100 may be constructed by adding each unit for manufacturing the stainless steel 10 to a conventional stainless steel sheet manufacturing system. Specifically, the manufacturing system 100 may be realized by adding a solution tank 102, a bridle roll 103, an irradiation unit 104, and the like downstream of the members that perform the finishing process in a conventional stainless steel sheet manufacturing system.

[0058] Fig. 5 is a diagram showing an example of the irradiation unit 104. Fig. 6 is a diagram showing another example of the irradiation unit 104. As shown in Fig. 5, in the above-mentioned manufacturing system 100, the irradiation unit 104 may be a CW (Continuous Wave) laser that continuously emits laser light. Alternatively, as shown in Fig. 6, the irradiation unit 104 may be configured to reflect a laser emitted in a pulsed manner from a laser head 104A by a galvano scanner 104B and irradiate an arbitrary position of the base material 2 with the reflected laser light.

[0059] The present invention is not limited to the above-described embodiments, and various modifications are possible within the scope of the claims. Embodiments obtained by appropriately combining the technical means disclosed in different embodiments are also included in the technical scope of the present invention. [Explanation of symbols]

[0060] 2 Base material 3. Coating 10 Stainless Steel 100 Manufacturing System 102 Solution tank (contact part) 103 Bridle roll (tension section) 105 Irradiation unit

Claims

1. a contacting step of contacting a liquid or a high viscosity substance containing at least one specific substance with the stainless steel; and an irradiation step of irradiating the stainless steel with a laser while the stainless steel is in contact with the liquid or the high-viscosity substance, The irradiation step is carried out in a state where the surface of the stainless steel is flattened by stretching the stainless steel, and a substantially constant distance is maintained between the surface and an irradiation unit that performs the laser irradiation, A method for producing stainless steel, wherein the liquid or the high-viscosity substance is a liquid or a high-viscosity substance containing at least one of a carboxylic acid or a carboxylate as the specific substance.

2. The method for producing stainless steel according to claim 1 , wherein the irradiation step is carried out continuously while the stainless steel is being transported.

3. 3. A method for producing stainless steel as described in claim 1 or 2, wherein the contacting step comprises: (i) immersing the stainless steel in the liquid or the high-viscosity substance; (ii) dripping the liquid or the high-viscosity substance onto the stainless steel; or (iii) spraying the liquid or the high-viscosity substance onto the stainless steel to contact the stainless steel with the liquid or the high-viscosity substance.

4. The method for producing stainless steel according to claim 1 , wherein the liquid is an aqueous solution or a metal particle suspension containing the specific substance.

5. The irradiation step forms a coating containing the specific substance on the surface of the stainless steel, The method for producing stainless steel according to claim 1 , wherein the coating is a coating containing a specific functional group or a metal compound coating containing a specific compound.

6. a contact portion for contacting a liquid or a high-viscosity substance containing at least one specific substance with the stainless steel; an irradiation unit that irradiates the stainless steel with a laser beam that has come into contact with the liquid or the high-viscosity substance; a tensioning portion that tensions the stainless steel at least while the laser light is being irradiated; Including, A system for manufacturing stainless steel, wherein the liquid or the high-viscosity substance is a liquid or a high-viscosity substance containing at least one of a carboxylic acid or a carboxylate as the specific substance.

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