METHOD OF PRODUCING CYLINDRICAL BODIES WITH BASES

Abstract

The invention proposes a method for producing cylindrical bodies with bottoms, which can achieve both the strength forming process of conventional drawing and inlaying, and the reduction of costs and environmental impact in the washing step. The method of producing cylindrical bottoms involves a broaching step to broach the metal sheet using forming dies, each with a surface hardness of Hv 1500 to 12000, and a rolling step to roll the workpiece into a cylindrical bottom using a coolant, each with a carbon film on its surface, and the coolant being a water-soluble coolant or a coolant with a boiling point lower than 300°C. Alternatively, the method of producing cylindrical bottoms may involve broaching the metal sheet using broaching dies with a surface hardness greater than Hv 1500 to 12000, and broaching punches with a surface hardness of Hv 1000 to 12000.and the process of forming the workpiece into a cylindrical body with a coolant using formwork pieces, each of which has a hardness of Hv 1500 to 12000 on its treated surface, and the coolant meets at least any one of the following conditions: (a) the coolant has a concentration lower than 4.0% by volume of the oil contained, (b) the coolant is water-soluble, and (c) the coolant has a boiling point lower than 300°C.

Description

Manufacturing method of bottomed cylindrical body

[0001] The present invention relates to a method for manufacturing a bottomed cylindrical body, and more particularly to a method for manufacturing a metal bottomed cylindrical body by drawing and ironing.

[0002] A metal cylindrical body with a bottom, for example, a so-called seamless can body, is produced by drawing and ironing using a press mold.

[0003] The punch and die used in the drawing and ironing process are generally placed in a harsh environment, and therefore, dies have been proposed, such as those shown in Patent Documents 2 to 5. That is, it has been proposed to improve the durability of the die by coating the processed surface with a carbon film such as a diamond film or a DLC (diamond-like carbon) film.

[0004] Meanwhile, in the past, when seamless cans were manufactured using aluminum alloys, they were typically formed in a wet environment using lubricants and coolants. In this case, a cleaning process (washing process) is essential after the can manufacturing process, in which processing oils, lubricants, coolants, etc. adhering to the can body are washed away with detergents and chemicals.

[0005] Patent No. 6012804 JP 10-137861 JP 11-277160 JP 2013-163187 International Publication WO 2017 / 033791

[0006] However, the above-mentioned conventional methods for manufacturing seamless can bodies have problems such as the need for a large amount of energy and cost in the cleaning process, and the large environmental impact.

[0007] For example, there has been a demand for reducing the cost and environmental impact of the large amount of water used in the cleaning process, reducing the environmental impact of the chemicals used in the cleaning process, and reducing the energy required to heat the cleaning chemicals in the cleaning process.

[0008] Furthermore, as a result of extensive research, the inventors have discovered that when a bottomed cylindrical body is manufactured using coolant under specific conditions, it is possible to achieve both the conventional harsh processes such as drawing and ironing, as well as cost reduction and a reduction in the environmental impact in the cleaning process, which led to the present invention.

[0009] In order to achieve the above object, a method for manufacturing a bottomed tubular body in one embodiment of the present invention includes: (1) a drawing step in which a metal plate is drawn using a formed member having a hardness of a processed surface of more than Hv 1500 to 12000 Hv; and an ironing step in which a formed member having a carbon film on its processed surface is used to iron the processed member via a coolant to form a bottomed tubular body, wherein the coolant is a water-soluble coolant and / or a coolant having a boiling point of less than 300°C.

[0010] In the above (1), (2) it is preferable that the bottomed cylindrical body is a seamless can. Also, in the above (1) or (2), (3) it is preferable that the metal plate is an aluminum alloy. Furthermore, in any of the above (1) to (3), (4) it is preferable that the carbon film is a diamond film.

[0011] In any of the above (1) to (4), (5) it is preferable that the method further includes a lubricant application step of applying a water-soluble lubricant and / or a lubricant having a boiling point of less than 300°C to the metal plate before the drawing step of drawing the metal plate, and that the hardness of the processed surface of the formed member in the drawing step is Hv 1500 to 12000.

[0012] In any one of the above items (1) to (5), (6) it is preferable that the coolant contains an antiseptic and / or an antirust agent.

[0013] In one embodiment of the present invention, the method for manufacturing a bottomed cylindrical body, in any of the above (1) to (6), preferably further includes (7) a cleaning step for removing lubricant and / or coolant adhering to the surface of the bottomed cylindrical body.

[0014] In one embodiment of the present invention, the method for manufacturing a bottomed tubular body according to any one of the above (1) to (7) preferably further includes (8) a purification step of purifying the wastewater discharged in the ironing step and / or the washing step.

[0015] In order to achieve the above object, in another embodiment of the present invention, a method for manufacturing a bottomed tubular body includes: (9) a drawing step in which a metal plate is drawn using a drawing die having a processed surface hardness of more than 1500 to 12000 Hv and a drawing punch having a hardness of 1000 to 12000 Hv; and an ironing step in which a formed workpiece having a processed surface hardness of 1500 to 12000 Hv is ironed via a coolant to form a bottomed tubular body, wherein the coolant satisfies at least one of the following: (a) an oil concentration of less than 4.0% by volume; (b) being a water-soluble coolant; or (c) having a boiling point of less than 300°C.

[0016] In the above (9), (10) the bottomed cylindrical body is preferably a seamless can. Also, in the above (9) or (10), (11) the metal plate is preferably an aluminum alloy.

[0017] In any one of the above items (9) to (11), (12) it is preferable that a carbon film is formed on the processed surface of the formed member in the drawing step and / or the processed surface of the formed member in the ironing step.

[0018] In any of the above (9) to (12), (13) it is preferable to include a lubricant application step of applying a lubricant to the surface of the metal plate before the drawing step, and the hardness of the processing surface of the drawing die in the drawing step is Hv 1000 to 12000.

[0019] In any of the above (9) to (13), it is preferable that the method further comprises (14) a washing step of purifying wastewater discharged in the squeezing step or in the washing step after the squeezing step.

[0020] The method for producing a bottomed cylindrical body of the present invention includes a step of ironing using a forming member (for example, a punch and a die) having a carbon film on the working surface.

[0021] Therefore, even if a water-soluble coolant and / or a coolant with a boiling point of less than 300°C is used as the coolant in the ironing process, it is possible to obtain a bottomed cylindrical body with an ironing rate similar to or higher than that of conventional products.

[0022] Furthermore, the method for manufacturing a bottomed tubular body of the present invention includes a step of drawing using forming members (e.g., punches and dies) whose working surfaces have a hardness equal to or greater than a predetermined value, which makes it possible to omit the step of applying a lubricant to the surface of a metal plate (flat plate) before drawing.

[0023] Furthermore, the present invention may include a step of applying a water-soluble lubricant and / or a lubricant having a boiling point of less than 300° C. to the surface of the metal plate (flat plate) before drawing. In this case, even if the lower limit of the hardness of the processed surface of the formed member in the drawing step is lowered, it becomes possible to obtain workability that is the same as or better than conventional workability.

[0024] Furthermore, according to this embodiment, since water-soluble lubricants and coolants, as well as lubricants and coolants with boiling points below 300°C, are used in the drawing and ironing processes, cleaning can be performed using water or hot water without using a cleaning agent in the cleaning process. Alternatively, the concentration of cleaning components in the cleaning agent can be reduced. Alternatively, lubricants, coolants, etc. adhering to the can body can be removed by drying after can manufacturing without providing a cleaning process. This makes it possible to reduce the environmental impact and costs of the cleaning process.

[0025] Furthermore, the method for producing a bottomed tubular body of the present invention includes a step of drawing and ironing using forming members (e.g., a punch and a die) whose processed surface has a hardness equal to or greater than a predetermined value. Therefore, when a coolant satisfying at least one of the following conditions is used in the ironing step: (a) an oil concentration of less than 4.0% by volume, (b) a water-soluble coolant, or (c) a boiling point of less than 300°C, a bottomed tubular body can be obtained with an ironing ratio equal to or greater than that of conventional coolants.

[0026] Furthermore, this embodiment makes it possible to omit the process of applying processing oil or lubricant to the surface of the metal plate (flat plate) before drawing. Furthermore, it is possible to use a coolant in the ironing process that satisfies at least one of the following criteria: (a) an oil content of less than 4.0% by volume, (b) a water-soluble coolant, or (c) a boiling point of less than 300°C. Therefore, cleaning can be performed using water or hot water without using a cleaning agent. Alternatively, lubricating components, coolant, etc. adhering to the can body can be removed by drying after can manufacturing, without performing a cleaning process. This reduces the environmental impact and costs of the cleaning process.

[0027] Fig. 1 is a schematic diagram showing a drawing step in a method for manufacturing a bottomed tubular body according to one embodiment of the present invention. Fig. 2 is a schematic diagram showing a squeezing step in a method for manufacturing a bottomed tubular body according to one embodiment of the present invention. Fig. 3 is a schematic diagram showing a flow of a method for manufacturing a bottomed tubular body according to another embodiment of the present invention.

[0028] [Manufacturing Method of Bottomed Cylindrical Body] The applicants of the present invention have discovered a manufacturing method for a seamless can body as disclosed in Japanese Patent Application Nos. 2018-204896 and 2018-204823. Specifically, they have discovered that when press working is performed using a mold with a diamond film or the like having high sliding properties formed on the working surface and with the oil content in the coolant kept below a predetermined level, even when performing severe processing such as ironing, a degree of processing (e.g., a limiting ironing rate) equivalent to or greater than that of a pressed product manufactured using a conventional amount of lubricant can be achieved. Furthermore, the inventors have now discovered a manufacturing method for a bottomed cylindrical body related to the manufacturing method for the seamless can body.

[0029] The method for manufacturing a bottomed tubular body of the present invention will be specifically described below with reference to the drawings as appropriate. Note that the following embodiment is intended to illustrate the contents of one example of the present invention and is not intended to intentionally limit the present invention. Furthermore, in the following embodiment, a seamless can body will be used as an example of a bottomed tubular body, but this is not intended to intentionally limit the present invention.

[0030] First Embodiment First, a method for manufacturing a bottomed tubular body according to a first embodiment will be described. Fig. 1 is a schematic diagram showing a drawing step in the method for manufacturing a bottomed tubular body according to the first embodiment. Fig. 2 is a schematic diagram showing an ironing step in the method for manufacturing a bottomed tubular body according to the first embodiment. Fig. 3 is a schematic diagram showing the flow of the method for manufacturing a bottomed tubular body according to the first embodiment.

[0031] <Metal Sheet> The metal sheet used as the workpiece in this embodiment is not particularly limited as long as it is suitable for general metal press working. For example, various known metal sheets such as aluminum, copper, iron, steel, titanium, and pure metals as well as alloys thereof can be used. Among these, aluminum alloy sheets are particularly suitable for forming seamless can bodies.

[0032] The thickness of the metal plate in this embodiment is not particularly limited, and may be a normal thickness used in the manufacture of seamless can bodies. For example, when an aluminum alloy plate is used for can manufacturing, the original plate thickness (thickness of the original plate) is, for example, 0.1 mm to 0.5 mm.

[0033] <Lubricant Application Step> The manufacturing method for a bottomed tubular body of this embodiment may include a lubricant application step of applying a lubricant to the surface of a metal plate. As is generally known, applying a lubricant makes it possible to process the metal plate into a desired shape, such as a bottomed tubular body, without damaging or breaking it, even when subjected to severe drawing and ironing processes in the subsequent drawing and ironing steps. Note that the lubricant application step is not an essential step in this embodiment and can be omitted as appropriate.

[0034] In this embodiment, the type of lubricant used is preferably a water-soluble lubricant and / or a lubricant with a boiling point of less than 300°C. The water-soluble lubricant in this embodiment is defined as a lubricant that is soluble in water. The use of a water-soluble lubricant is preferred because it makes it possible to remove lubricant components that have adhered after can manufacturing without using chemicals (acids, alkalis, surfactants, etc.). In this embodiment, for example, when washing with water in the washing step described below, it is preferable that the lubricant components and coolant components are removed to an extent that defects such as uneven paint or repellency do not occur in subsequent printing processes.

[0035] In this embodiment, "a water-soluble lubricant and / or a lubricant having a boiling point of less than 300°C" means that the lubricant may contain either a "water-soluble lubricant" or a "lubricant having a boiling point of less than 300°C", or may contain both. Furthermore, it also means that a lubricant having either the property of being "water-soluble" or "having a boiling point of less than 300°C" may be used, or a lubricant having both the property of being "water-soluble" and "having a boiling point of less than 300°C" may be used.

[0036] In addition, the reason why a lubricant with a boiling point of less than 300°C is preferred in this embodiment is that it allows the adhering lubricant components to be vaporized and removed at a relatively low temperature after the can manufacturing process. From the viewpoint of equipment costs, energy costs, etc., it is more preferable that the boiling point of the lubricant be less than 250°C. Specifically, a no-wash oil commercially available as a volatile lubricant can be used as the lubricant in this embodiment. The amount and method of application of the lubricant can be known.

[0037] <Drawing Process> Next, the drawing process in this embodiment will be described. In the drawing process in this embodiment, it is preferable that the processed surface of the formed workpiece in the drawing process (for example, the drawing die or drawing punch) has a predetermined hardness or more. Specifically, the hardness of the processed surface needs to be greater than Hv 1500 to 12000 in Vickers hardness. Furthermore, if a lubricant application process is performed before the above-mentioned drawing process, it is possible to set the lower limit of the hardness of the processed surface of the formed workpiece in the drawing process to Hv 1500. The reason for this is as follows.

[0038] That is, an example of a metal sheet drawing process will be explained with reference to FIG. Ｄ and drawing punch P Ｄ With the metal plate 10 interposed between the drawing punch P Ｄ The drawing process is performed by the drawing die D to manufacture a shallow drawn cup M. Ｄ and drawing punch P Ｄ Since a strong impact load acts on the bearing, it is necessary for it to have high durability and abrasion resistance to withstand mass production.

[0039] In this embodiment, in order to reduce the environmental impact and costs in the cleaning step, the lubricant applied in the lubricant application step is preferably a water-soluble lubricant and / or a lubricant having a boiling point of less than 300° C. In this case, in order to prevent the metal plate from being scratched or broken by the formed member, it is necessary to impart high hardness or slipperiness to the mold.

[0040] From the above viewpoints, the inventors have conducted trial and error and found that in this embodiment, when the hardness of the processed surface of the formed workpiece is set to a Vickers hardness of more than Hv 1500 to 12000, there are no problems in terms of durability, wear resistance, scratches on the metal plate, etc., even when severe drawing is performed.

[0041] In this embodiment, the forming workpiece (mold) in the drawing step may be manufactured from a base material made of a known material, as long as the processed surface has the above-mentioned hardness, or may be manufactured by forming a surface treatment film L (see FIG. 1) on the processed surface of such a base material.

[0042] Specific examples of the material for the substrate in the above-mentioned mold include cemented carbide obtained by sintering a mixture of tungsten carbide (WC) and a metal binder such as cobalt; cermet obtained by sintering a mixture of a metal carbide such as titanium carbide (TiC) or a titanium compound such as titanium carbonitride (TiNC) and a metal binder such as nickel or cobalt; and ceramics.

[0043] As the surface treatment film L formed on the substrate, for example, a carbon film, a ceramic film, or the like can be preferably used.

[0044] Examples of the carbon film include a diamond film, a DLC film, etc. There are no particular limitations on the method for forming these carbon films, and for example, chemical vapor deposition (CVD) or physical vapor deposition (PVD) can be used.

[0045] The ceramic film may be made of silicon carbide (SiC) or silicon nitride (Si ３ N ４ ), alumina (Al ２ O ３ ), zirconia (ZrO ２ Examples of suitable hard ceramics include titanium nitride (TiN), titanium carbide (TiC), and chromium nitride (CrN).

[0046] In this embodiment, the combination of types of forming members used in the drawing step may be such that the same material or surface treatment film is used for both the drawing die and the drawing punch, or different materials or surface treatment films are used. For example, both the drawing die and the drawing punch may be made of cemented carbide, or one of the drawing die or the drawing punch may be made of cemented carbide. Alternatively, a carbon film may be formed on the working surfaces of both the drawing die and the drawing punch, or a carbon film may be formed on the working surface of one of the drawing die or the drawing punch.

[0047] In addition, if the surface treatment film of one of the drawing die and drawing punch is a diamond film, it is preferable that the other be a surface treatment film other than a diamond film, from the viewpoint of dimensional control between the dies and suppression of damage between the dies.

[0048] <Ironing Step> Next, the ironing step in this embodiment will be described. In the ironing step in this embodiment, it is preferable that a carbon film is formed on the processed surface of a formed workpiece (for example, an ironing die or an ironing punch) in the ironing step.

[0049] The ironing step of this embodiment will be described in more detail with reference to the drawings. As shown in FIGS. 2(a) and 2(b), for example, an ironing die D having a diamond film 20 formed on its processing surface is used. Ｉ and an ironing punch P having a surface treatment film 30 different from a diamond film formed on the processing surface. Ｉ With the coolant C in between, the die D Ｉ and Punch P Ｉ The process includes a step of ironing a shallow drawn cup M with the processed surface.

[0050] At that time, the above-mentioned ironing die D Ｉ Toshigoki Punch P Ｉ In this embodiment, the coolant C is required to be a water-soluble coolant and / or a coolant having a boiling point of less than 300°C. Therefore, in order to avoid damage or breakage of the workpiece (metal plate 10 or shallow-drawn cup M), the ironing die DＩ Toshigoki Punch P Ｉ It is necessary that a carbon film having both hardness and slipperiness is formed on any of the above processed surfaces. Examples of the carbon film include a diamond film and a DLC film. There are no particular limitations on the method for forming these carbon films, and for example, chemical vapor deposition (CVD) or physical vapor deposition (PVD) can be used.

[0051] In this embodiment, "a water-soluble coolant and / or a coolant with a boiling point of less than 300°C" means that it may include either a "water-soluble coolant" or a "coolant with a boiling point of less than 300°C", or it may include both. Furthermore, it also means that a coolant that has either the property of being "water-soluble" or "having a boiling point of less than 300°C" may be used, or that a coolant that has both the property of being "water-soluble" and "having a boiling point of less than 300°C" may be used.

[0052] In this embodiment, it is particularly preferable that a diamond film having a Vickers hardness of about Hv 8,000 to 12,000 is formed on the processed surface of either the male or female mold in the ironing process.

[0053] That is, as shown in FIG. 2, the diamond film 20 having high hardness is formed on the ironing die D. Ｉ is formed on the processed surface of the ironing punch P Ｉ A surface treatment film 30 different from the diamond film may be formed on the processed surface of the ironing die, or vice versa (not shown). In general, the ironing die is subjected to heavier processing loads than the ironing punch, so it is particularly preferable to form a diamond film 20 on the processed surface of the ironing die.

[0054] The thickness of the diamond film 20 is preferably 5 μm to 30 μm. If the thickness is less than 5 μm, the resulting diamond film is prone to cracking and peeling, which is not preferred. On the other hand, if the thickness exceeds 30 μm, the internal stress of the diamond film increases, making it prone to peeling, which is also not preferred.

[0055] In this embodiment, the surface roughness Ra (JIS B-0601-1994) of the diamond film 20 is preferably 0.12 μm or less, from the viewpoint of imparting high sliding properties to the mold. Furthermore, if Ra is 0.08 μm or less, the appearance of the workpiece (e.g., a can body) can be made mirror-finished or smooth and close to a mirror-finish, which is more preferable. In this case, the coefficient of friction μ between the diamond film 20 and the workpiece during press working is preferably lower than 0.1.

[0056] Next, the coolant used in the ironing process of this embodiment will be described. The coolant used in this embodiment may contain oil as one of its components, but it is preferable that it can be easily washed in the subsequent washing process, or that it can be removed by drying even if a washing process is not performed. Therefore, the coolant in this embodiment must be a water-soluble coolant and / or a coolant with a boiling point of less than 300°C.

[0057] The water-soluble coolant is defined as a coolant that is soluble in water. The use of a water-soluble coolant is preferred because it makes it possible to remove coolant components that have adhered after can manufacturing without using chemicals (acids, alkalis, surfactants, etc.). In this embodiment, it is preferred that when washing is performed with water in the washing step described below, the lubricant components and coolant components are removed to an extent that does not cause defects such as uneven paint or repellency in subsequent printing processes.

[0058] The reason why a coolant with a boiling point of less than 300°C is preferred is that the adhering coolant components can be vaporized and removed at a relatively low temperature after the can manufacturing process. From the viewpoint of equipment costs and energy costs, it is more preferable that the boiling point of the coolant is less than 250°C. Specifically, the coolant in this embodiment can be a no-wash oil that is commercially available as a volatile lubricant.

[0059] The coolant in this embodiment may contain additives as long as they do not impair the characteristics of water solubility and / or a boiling point of less than 300° C. For example, the coolant may contain water, surfactants, rust inhibitors, extreme pressure additives, coupling agents, non-ferrous metal corrosion inhibitors, preservatives, rust inhibitors, antifoaming agents, chelating agents, coloring agents, fragrances, etc. as appropriate.

[0060] In particular, the coolant of this embodiment preferably contains an antiseptic and / or antirust agent for the following reason: Water-soluble coolants contain many substances that serve as nutrient sources for microorganisms such as bacteria and mold. This makes the diluted coolant susceptible to spoilage, and also poses the problem of rust occurring at locations of machining equipment that come into contact with the coolant.

[0061] In this embodiment, "antiseptic and / or antirust agent" means that either an "antiseptic agent" or an "antirust agent" may be included, or both may be included. Furthermore, it also means that a substance having either an "antiseptic" or an "antirust" property may be used, or a substance having both an "antiseptic" and an "antirust" property may be used.

[0062] As coolant decay progresses, not only does it lose its lubricating and cooling functions, but it also produces a foul odor. Rust can also cause problems, such as a significant shortening of the processing equipment's lifespan and damage to the workpiece. The occurrence of decay and rust also increases the frequency of coolant changes, resulting in cost issues. Furthermore, mold and rust can cause pipe blockages in circulation systems, such as pumps.

[0063] Known substances can be used as antiseptics and antirust agents as long as the coolant is water-soluble and / or has a boiling point of less than 300° C. For example, formaldehyde-releasing or phenolic substances, or amine-based substances may be added as appropriate.

[0064] As described above, in the manufacturing method of this embodiment, even when a water-soluble coolant and / or a coolant with a boiling point of less than 300°C is used, molding defects during can manufacturing can be suppressed, and as a result, molding stability can be improved.

[0065] Furthermore, in this embodiment, as described above, a water-soluble coolant and / or a coolant with a boiling point of less than 300°C is used, which enables cleaning with chemicals or water that have a low environmental impact in the cleaning process described below. Alternatively, the cleaning process itself can be omitted, thereby reducing the environmental impact. Furthermore, since wastewater treatment after cleaning is simplified, when wastewater is recycled and circulated, the recycling rate can be improved, thereby reducing costs and the environmental impact.

[0066] The ironing process of this embodiment preferably includes an ironing step in which the metal material is ironed to form a can body portion at an ironing rate (rate of reduction in plate thickness) of 10% or more. The ironing step may be performed multiple times, and the ironing rate may be varied for each step. For example, the ironing rate in the initial ironing step may be set to 10% or more, and the ironing rate in the final ironing step may be set to 30% or more. The ironing rate in this embodiment is expressed by the following formula, where t0 is the plate thickness before ironing, and t1 is the plate thickness after ironing (at a portion 60 mm from the can bottom): Ironing rate (%) = 100 × (t0 - t1) / t0

[0067] <Cleaning Step> Next, the cleaning step in this embodiment will be described. The cleaning step in this embodiment is a step of bringing a cleaner into contact with the bottomed tubular body obtained in the drawing step and ironing step described above, and removing the lubricant and / or coolant adhering to the inner surface and outer surface of the bottomed tubular body. Note that the cleaning step is not an essential step in this embodiment, and can be omitted as appropriate.

[0068] The method for bringing the cleaning agent into contact with the bottomed cylindrical body can be appropriately selected from known methods. For example, the bottomed cylindrical body may be immersed in the cleaning agent, or the cleaning agent may be sprayed onto the bottomed cylindrical body by spraying or showering.

[0069] The cleaning agent used in this embodiment may be a known alkaline cleaning agent, an acid cleaning agent, a neutral cleaning agent, or water. Examples of alkaline cleaning agents include aqueous solutions of inorganic compounds such as sodium carbonate, potassium carbonate, sodium bicarbonate, sodium hydroxide, and potassium hydroxide. Examples of acid cleaning agents include aqueous solutions of inorganic acids such as sulfuric acid, nitric acid, hydrochloric acid, and hydrofluoric acid. Examples of neutral cleaning agents include surfactants. After cleaning with an alkaline cleaning agent, an acid cleaning agent, or a neutral cleaning agent, it is preferable to perform a water-rinsing treatment to remove any remaining cleaning agent from the metal sheet surface, followed by removing moisture from the metal sheet surface by a method such as air blowing or hot air drying, as is well known.

[0070] When an alkaline cleaner or an acid cleaner is used, the concentration of the cleaning component in the cleaner is preferably 3.0% by volume or less from the viewpoint of reducing costs and environmental impact.

[0071] In the cleaning step of this embodiment, the temperature of the cleaning agent used is preferably less than 70° C. That is, in this embodiment, the lubricant used in the drawing step and the coolant used in the ironing step are both water-soluble and / or have boiling points less than 300° C., so that even if the temperature of the cleaning agent is less than 70° C., it is possible to sufficiently remove oil from the inner surface and the outer surface of the bottomed cylindrical body.

[0072] On the other hand, the lower limit of the temperature of the cleaning agent is preferably room temperature (e.g., 20°C). Generally, when cleaning processing oil or the like in metal press working, the cleaning agent is heated before use to enhance cleaning performance. However, heating the cleaning agent consumes a considerable amount of energy resources. Therefore, in this embodiment, from the viewpoint of cost reduction and reduction of environmental load, the cleaning agent can be used at room temperature as long as its cleaning performance is not reduced.

[0073] Furthermore, in this embodiment, from the viewpoint of cost reduction and environmental load reduction, the cleaning time in the cleaning step is preferably 45 seconds or less. That is, in this embodiment, since both the lubricant used in the drawing step and the coolant used in the ironing step are water-soluble and / or have boiling points below 300°C, the inner and outer surfaces of the bottomed cylindrical body can be sufficiently cleaned even if the cleaning time is 45 seconds or less. While there is no particular lower limit to the cleaning time, a lower limit of, for example, more than 10 seconds is preferred as a cleaning time that allows cleaning without practical problems and does not cause problems in wastewater treatability. Furthermore, when the cleaning method involves spraying the cleaning agent by spray or shower, the amount of the cleaning agent sprayed per can is preferably 60 to 70 ml / second.

[0074] In the cleaning process of this embodiment, the lubricant and coolant adhering to the inner and outer surfaces of the bottomed cylindrical body are removed by the cleaning agent. Therefore, the weight of the bottomed cylindrical body changes before and after cleaning, but the weight change is within 100 mg / m ２ It is preferable that it is less than 10 ...

[0075] That is, in this embodiment, as described above, the lubricant used in the drawing process and the coolant used in the ironing process are both water-soluble and / or have boiling points below 300°C, so it is possible to reduce the amount of lubricant and coolant that adheres to the inner and outer surfaces of the bottomed cylindrical body after the can-making process (drawing process and ironing process).

[0076] Therefore, the weight change of the bottomed cylindrical body before and after cleaning was 100 mg / m ２ By setting the amount of lubricant and coolant contained in the wastewater generated in the cleaning process to less than this, it is possible to reduce the amount of lubricant and coolant contained in the wastewater generated in the cleaning process, thereby making it possible to reduce the environmental burden.

[0077] <Drying Process> As described above, in this embodiment, the cleaning process can be omitted as appropriate. In this case, it is preferable to provide a drying process to remove the lubricant and coolant adhering to the inner and outer surfaces of the bottomed cylindrical body. That is, in this embodiment, it is preferable to use a lubricant in the drawing process and a coolant in the ironing process that is water-soluble and / or has a boiling point of less than 300°C. Therefore, after the can-making process (drawing process and ironing process), it is possible to remove the lubricant and coolant adhering to the inner and outer surfaces by the drying process without providing a cleaning process.

[0078] In the drying process of this embodiment, specifically, the lubricant and coolant adhering to the inner and outer surfaces of the bottomed cylindrical body can be removed, for example, by heating the body in a drying oven at approximately 150 to 300°C for 30 to 180 seconds.

[0079] <Purification step> Next, a description will be given of a purification step of purifying the wastewater discharged in the ironing step and / or washing step in the above-described method for manufacturing a bottomed tubular body in this embodiment. Note that in this embodiment, "wastewater discharged in the ironing step and / or washing step" means that it may be either "wastewater discharged in the ironing step" or "wastewater discharged in the washing step," or it may be both.

[0080] As described above, in the manufacturing method of the bottomed cylindrical body of this embodiment, the ironing process involves ironing using coolant. The cleaning process involves a main cleaning step using a detergent to remove the lubricant and coolant adhering to the surface of the bottomed cylindrical body, as well as a pre-cleaning step using water and a rinsing step using water to remove the detergent after the main cleaning step. Therefore, a large amount of wastewater is generated during the cleaning process.

[0081] Therefore, the method for manufacturing a bottomed tubular body in this embodiment may further include a purification step of purifying the wastewater, as shown in Fig. 3. In this case, for reasons described below, it is preferable that the purified wastewater be reused (recycled) as purified water in the straining step and washing step again.

[0082] That is, in the manufacturing method of the bottomed tubular body according to this embodiment, as described above, the lubricant applied in the lubricant application step is water-soluble and / or has a boiling point of less than 300° C. As described above, the coolant used in the ironing step is also water-soluble and / or has a boiling point of less than 300° C. Therefore, the oil content in the wastewater discharged in the ironing step and the washing step is also less than a predetermined value.

[0083] Therefore, the wastewater generated in the scraping step and / or the washing step can be purified by a relatively simple method, and by undergoing the purification step, it is possible to further reduce the environmental load and the cost.

[0084] As a method for purifying wastewater in the purification step, known methods can be used as appropriate. That is, purification can be performed by appropriately combining methods such as filtration, neutralization, boiling, precipitation, flotation, biological treatment, and UV sterilization. In addition, a flocculant, disinfectant, bactericide, etc. may be appropriately mixed.

[0085] As described above, the method for manufacturing a bottomed tubular body according to this embodiment can achieve the following effects. (A) Because a carbon film is formed on the processed surface of the formed workpiece in the ironing process, the coolant used in the ironing process can be water-soluble and / or have a boiling point of less than 300°C. (B) Because the hardness of the processed surface of the formed workpiece in the drawing process is set to a predetermined value or higher, it is possible to omit the step of applying a lubricant to the surface of the metal plate (flat plate) before drawing. (C) As a result of the above, it is possible to suppress heating of the cleaning agent in the cleaning process and / or shorten the cleaning time. It is also possible to omit the cleaning process. (D) As a result, it is possible to reduce the environmental impact and reduce costs.

[0086] Furthermore, if the purification step is further carried out in this embodiment, the following effects can be further achieved: (E) The wastewater discharged in the squeezing step and / or the washing step can be easily purified. (F) It becomes possible to purify and reuse (recycle) the wastewater, thereby reducing costs and the burden on the environment.

[0087] Second Embodiment Next, a method for manufacturing a bottomed tubular body according to a second embodiment will be described. The schematic diagram showing the drawing process shown in Fig. 1 is also applicable to the second embodiment. The schematic diagram showing the ironing process shown in Fig. 2 is also applicable to the second embodiment. Furthermore, Fig. 4 is a schematic diagram showing the flow of the method for manufacturing a bottomed tubular body according to the second embodiment.

[0088] <Metal Sheet> The metal sheet used as the workpiece in this embodiment is not particularly limited as long as it is suitable for general metal press working. For example, various known metal sheets such as aluminum, copper, iron, steel, titanium, and pure metals as well as alloys thereof can be used. Among these, aluminum alloy sheets are particularly suitable for forming seamless can bodies.

[0089] The thickness of the metal plate in this embodiment is not particularly limited, and may be a normal thickness used in the manufacture of seamless can bodies. For example, when an aluminum alloy plate is used for can manufacturing, the original plate thickness (thickness of the original plate) is, for example, 0.1 mm to 0.5 mm.

[0090] <Lubricant Application Step> The manufacturing method for a bottomed tubular body of this embodiment may include a lubricant application step in which a lubricant is applied to the surface of the metal plate (flat plate) before drawing. In this embodiment, the lubricant also includes oils commonly referred to as "metal processing oil" or "metal cutting oil." As is generally known, applying a known processing oil or lubricant before drawing makes it possible to process the metal plate into a desired shape, such as a bottomed tubular body, without damaging or breaking it, even when subjected to severe drawing and ironing processes in the subsequent drawing and ironing steps. However, in this embodiment, this step is not essential for reasons described below.

[0091] Examples of types of lubricants that can be used in this embodiment include the following. For example, mineral oils composed of fatty acid esters, fatty acid alcohols, or fatty acids can be used. Alternatively, water-soluble lubricants or lubricants with a boiling point of less than 300°C can also be used. The water-soluble lubricant in this embodiment is defined as a lubricant that is soluble in water. The use of a water-soluble lubricant is preferable because it makes it possible to remove lubricant components that adhere after can manufacturing without using chemicals (acids, alkalis, surfactants, etc.). In this embodiment, when washing with water in the washing process described below, for example, it is preferable that the lubricant components and coolant components are removed to an extent that defects such as uneven paint or repellency do not occur in subsequent printing processes.

[0092] Specifically, a non-washing oil commercially available as a volatile lubricant can be used as a lubricant having a boiling point of less than 300°C. The reason why a lubricant having a boiling point of less than 300°C is preferred is that the adhering lubricant components can be vaporized and removed at a relatively low temperature after the can manufacturing process. From the viewpoint of equipment costs, energy costs, etc., it is more preferable that the boiling point of the lubricant is less than 250°C.

[0093] In this step, the amount and method of application of the lubricant may be known amounts and known methods.

[0094] In this embodiment, it is preferable that the viscosity of the lubricant is less than 200 mPa·s from the viewpoint of reducing the environmental impact and costs in the cleaning process, which is the objective of the present invention. If the viscosity of the lubricant is 200 mPa·s or more, it may not be possible to sufficiently clean or remove the lubricant in the subsequent cleaning and drying processes, which is not preferable. It is more preferable that the viscosity of the lubricant is less than 100 mPa·s.

[0095] <Drawing Process> Next, the drawing process in this embodiment will be described. In the drawing process in this embodiment, it is preferable that the processed surface of the forming workpiece (for example, the drawing die or drawing punch) in the drawing process has a predetermined hardness or more. Specifically, the hardness of the processed surface needs to be Hv 1000 to 12000 in Vickers hardness. Specifically, the method for producing a bottomed tubular body in this embodiment is characterized in that the hardness of the processed surface of the drawing die is greater than Hv 1500 to 12000, and the hardness of the processed surface of the drawing punch is Hv 1000 to 12000. The reasons for this are as follows.

[0096] That is, an example of a metal sheet drawing process will be explained using FIG. 1. Ｄ and drawing punch P Ｄ With the metal plate 10 interposed between the drawing punch P Ｄ The drawing process is performed by the drawing die D to manufacture a shallow drawn cup M. Ｄ and drawing punch P Ｄ Since a strong impact load acts on the bearing, it is necessary for it to have high durability and abrasion resistance to withstand mass production.

[0097] In this embodiment, in order to reduce the environmental impact and costs of the cleaning process, it is possible to omit the process of applying processing oil or lubricant to the surface of the metal plate (flat plate) before drawing. In this case, in order to prevent the metal plate from being scratched or broken by the forming parts, it is necessary to impart high hardness or slipperiness to the mold.

[0098] As a result of trial and error conducted by the inventors from the above viewpoint, in this embodiment, it has been found that, when the hardness of the processed surface of the formed workpiece in drawing is such that the hardness of the processed surface of the drawing die is greater than 1500 to 12000 Hv and the hardness of the processed surface of the drawing punch is 1000 to 12000 Hv in Vickers hardness, there are no problems in terms of durability, wear resistance, damage to the metal plate, etc., even when severe drawing and ironing processes are performed.

[0099] In this embodiment, the forming workpiece (mold) in the drawing step may be manufactured from a base material made of a known material, as long as the processed surface has the above-mentioned hardness, or may be manufactured by forming a surface treatment film L (see FIG. 2) on the processed surface of such a base material.

[0100] Specific examples of the material for the substrate in the above-mentioned mold include cemented carbide obtained by sintering a mixture of tungsten carbide (WC) and a metal binder such as cobalt; and cermet obtained by sintering a mixture of a metal carbide such as titanium carbide (TiC) or a titanium compound such as titanium carbonitride (TiNC) and a metal binder such as nickel or cobalt; and the like.

[0101] As the surface treatment film L formed on the substrate, for example, a carbon film, a ceramic film, a fluororesin film, etc. can be preferably used.

[0102] Examples of the carbon film include a diamond film having a Vickers hardness of about Hv 8000 to 12000 and a DLC film having a Vickers hardness of about Hv 3000 to 7000. There are no particular limitations on the method for forming these carbon films, and for example, chemical vapor deposition (CVD) or physical vapor deposition (PVD) can be used.

[0103] The ceramic film may be made of silicon carbide (SiC) or silicon nitride (Si ３ N ４ ), alumina (Al ２ O ３ ), zirconia (ZrO ２ ) and the like.

[0104] In this embodiment, as a combination of types of forming members used in the drawing step, the same material or surface treatment film L may be used for both the drawing die and the drawing punch, or different materials or surface treatment films L may be used. For example, both the drawing die and the drawing punch may be made of cemented carbide, or one of the drawing die or the drawing punch may be made of cemented carbide. Alternatively, a carbon film may be formed on the working surface of both the drawing die and the drawing punch, or a carbon film may be formed on the working surface of one of the drawing die or the drawing punch. That is, in FIG. 2, the drawing die D Ｄ The surface treatment film L is formed on the processing surface of the drawing punch P Ｄ Although the surface treatment film L is not formed on the processed surface of the substrate, the present invention is not limited to this.

[0105] In this embodiment, it is preferable that a carbon film be formed on the working surface of at least one of the male and female dies used during drawing. For example, when a drawing die is used as the female die and a drawing punch is used as the male die, it is preferable that a carbon film be formed on the working surface of at least one of them.

[0106] More specifically, a DLC film may be formed on the working surfaces of both the drawing die and the drawing punch, or a diamond film may be formed on one of the drawing die and the drawing punch and a DLC film may be formed on the other.

[0107] In particular, from the viewpoint of controlling the dimensions between dies and suppressing damage caused by breakage between dies, if the surface treatment film of one of the drawing die and the drawing punch is a diamond film, it is more preferable that the other is a surface treatment film other than a diamond film. In this case, it is particularly preferable that a diamond film is formed on the drawing die, which is subjected to a higher processing load. Note that the diamond film only needs to be formed on the above-mentioned processing surface of the die part, but it may also be formed on other parts.

[0108] The thickness of the diamond film is preferably 5 μm to 30 μm. If the thickness is less than 5 μm, the resulting diamond film is prone to cracking and peeling, which is not preferred. On the other hand, if the thickness exceeds 30 μm, the internal stress of the diamond film increases, making it prone to peeling, which is not preferred.

[0109] On the other hand, when the surface treatment film of one of the drawing die and the drawing punch is a diamond film, the thickness of the surface treatment film formed on the other is preferably about 0.1 to 10 μm, and is particularly preferably set to be thinner than the thickness of the diamond film.This is due to the following reasons.That is, for example, if the thickness of the surface treatment film formed on the drawing punch is thinner than the thickness of the diamond film formed on the drawing die, the dimensional error due to film formation can be reduced in the first place because it is a thin film.In addition, since the Vickers hardness of the surface treatment film is softer than that of the diamond film, it can be easily polished using known diamond abrasive grains, which not only reduces processing costs but also allows the target mold dimensions to be finished with high precision.

[0110] <Ironing Step> Next, the ironing step in this embodiment will be described. The ironing step in this embodiment is characterized in that the hardness of the processed surface of the formed workpiece (for example, the ironing die or ironing punch) in the ironing step is Hv 1500 to 12000.

[0111] The ironing step of this embodiment will be described in more detail with reference to the drawings. As shown in FIGS. 2(a) and 2(b), for example, an ironing die D having a diamond film 20 formed on its processing surface is used. Ｉ and an ironing punch P having a surface treatment film 30 different from a diamond film formed on the processing surface. Ｉ With the coolant C in between, the die D Ｉ and Punch P Ｉ The process includes a step of ironing a shallow drawn cup M with the processed surface.

[0112] At that time, the above-mentioned ironing die D Ｉ Toshigoki Punch P ＩThe coolant C is required to have high durability and abrasion resistance to a degree that can withstand mass production. In this embodiment, as will be described later, the oil concentration contained in the coolant C is required to be less than 4.0% by volume, or the coolant C is required to be a water-soluble coolant or a coolant with a boiling point of less than 300°C. Therefore, in order to avoid damage or breakage of the workpiece (metal plate 10 or shallow-drawn cup M), the ironing die D Ｉ Toshigoki Punch P Ｉ The hardness of the processed surface must be Hv 1500 to 12000.

[0113] In the above, in particular, the ironing die D Ｉ Toshigoki Punch P Ｉ It is preferable that a carbon film is formed on any of the processed surfaces. Examples of the carbon film include a diamond film having a Vickers hardness of about Hv 8000 to 12000 and a DLC film having a Vickers hardness of about Hv 3000 to 7000. There are no particular limitations on the method for forming these carbon films, and for example, chemical vapor deposition (CVD) or physical vapor deposition (PVD) can be used.

[0114] In this embodiment, it is particularly preferable that the diamond film is formed on the processing surface of either the male or female mold of the die. That is, as shown in FIG. 2, a diamond film 20 having high hardness is formed on the ironing die D. Ｉ is formed on the processed surface of the ironing punch P Ｉ A surface treatment film 30 different from the diamond film may be formed on the processed surface of the substrate, or vice versa (not shown).

[0115] In general, the ironing die is subjected to a heavier processing load than the ironing punch, so it is particularly preferable to form the diamond film 20 on the processing surface of the ironing die.

[0116] The thickness of the diamond film 20 is preferably 5 μm to 30 μm. If the thickness is less than 5 μm, the resulting diamond film is prone to cracking and peeling, which is not preferred. On the other hand, if the thickness exceeds 30 μm, the internal stress of the diamond film increases, making it prone to peeling, which is also not preferred.

[0117] On the other hand, the thickness of the surface treatment film 30, which is different from the diamond film 20, is preferably about 0.1 to 10 μm, and is particularly preferably set to be thinner than the thickness of the diamond film 20. This is for the following reason: For example, if the thickness of the surface treatment film 30 is made thinner than the thickness of the diamond film 20, the dimensional error due to film formation can be reduced in the first place because it is a thin film.

[0118] In this embodiment, the surface roughness Ra (JIS B-0601-1994) of the diamond film 20 is preferably 0.12 μm or less, from the viewpoint of imparting high sliding properties to the mold. Furthermore, if Ra is 0.08 μm or less, the appearance of the workpiece (e.g., a can body) can be made to have a mirror finish or a smooth surface close to a mirror finish, which is more preferable. In this case, the coefficient of friction μ between the diamond film 20 and the workpiece during press working is preferably lower than 0.1.

[0119] Next, the coolant used in the ironing process of this embodiment will be described. The coolant used in this embodiment may contain oil as one of its components, but it is preferable that it can be easily cleaned in a subsequent cleaning process, or that it can be removed by drying even if a cleaning process is not performed. Therefore, the coolant in this embodiment preferably satisfies at least one of the following: (a) it contains less than 4.0% by volume of oil, (b) it is a water-soluble coolant, or (c) it is a coolant with a boiling point of less than 300°C.

[0120] (a) In the case of a coolant containing less than 4.0% by volume of oil, examples of the oil include oils contained in general water-soluble metalworking oil compositions. The oil may be a natural oil or a synthetic oil.

[0121] Examples of natural oils include mineral oils such as paraffinic, naphthenic, and aromatic oils. Fatty acid glycerides can also be mentioned as natural oils. Examples of synthetic oils include hydrocarbons such as polyolefins, esters such as fatty acid esters, ethers such as polyalkylene glycols, fluorine-containing oils such as perfluorocarbons, phosphorus-containing oils such as phosphate esters, and silicon-containing oils such as silicate esters. The oils listed above may be used alone or in combination of two or more.

[0122] Specific examples include water-soluble metalworking fluids of Class A1 (emulsion type) or Class A2 (soluble type) specified in JIS K 2241. In addition, although not specified in the JIS standard, water-soluble metalworking fluids known as synthetic types (metalworking fluids that do not contain mineral oil but contain chemically synthesized oil) can also be used.

[0123] In this embodiment, the concentration of the oil in the coolant is preferably less than 4.0% by volume. In this case, a stock solution containing an oil content of 4.0% by volume or more may be first prepared and stored until use, and then diluted with a solvent such as water to prepare a coolant with an oil concentration of less than 4.0% by volume. In other words, the oil concentration in the coolant needs to be less than 4.0% by volume when in use.

[0124] Next, in the coolant used in this embodiment, (b) a water-soluble coolant is defined as a coolant that is soluble in water. The use of a water-soluble coolant is preferable because it makes it possible to remove coolant components that adhere after can manufacturing without using chemicals (acids, alkalis, surfactants, etc.). In this embodiment, it is preferable that lubricant components and coolant components are removed to an extent that does not cause defects such as uneven paint or repellency in subsequent printing processes, for example, when washing with water in the washing process described below.

[0125] In this embodiment, the coolant (c) having a boiling point of less than 300°C may be, for example, a commercially available volatile lubricant that does not require cleaning. A coolant with a boiling point of less than 300°C is preferred because it allows the adhering coolant components to be vaporized and removed at a relatively low temperature after the can manufacturing process. From the viewpoints of equipment costs, energy costs, and the like, it is even more preferable for the boiling point of the coolant to be less than 250°C.

[0126] The coolant used in this embodiment may be a mixture of the above-mentioned coolants (a), (b), and (c), or may be a coolant that combines the properties of two or more of (a), (b), and (c).

[0127] The coolant in this embodiment may contain additives as long as they do not impair at least one of the following characteristics: (a) an oil content of less than 4.0% by volume, (b) water solubility, and (c) a boiling point of less than 300° C. For example, the coolant may contain water, surfactants, rust inhibitors, extreme pressure additives, coupling agents, non-ferrous metal corrosion inhibitors, preservatives, rust inhibitors, antifoaming agents, chelating agents, coloring agents, fragrances, etc.

[0128] In particular, the coolant of this embodiment preferably contains an antiseptic and / or anti-rust agent. This is for the following reason: Water-soluble coolants contain many substances that serve as nutrient sources for microorganisms such as bacteria and mold. This causes problems such as the coolant being prone to spoilage after dilution and rust being likely to occur at points of machining equipment that come into contact with the coolant. Note that in this embodiment, "antiseptic and / or anti-rust agent" means that the coolant may contain either an "antiseptic" or a "rust inhibitor," or may contain both. Furthermore, it also means that a substance having either "antiseptic" or "anti-rust" properties may be used, or a substance having both "antiseptic" and "anti-rust" properties may be used.

[0129] As coolant decay progresses, not only does it lose its lubricating and cooling functions, but it also produces a foul odor. Furthermore, if rust develops, it can cause problems such as scratches on the workpiece. Furthermore, the occurrence of decay and rust increases the frequency of coolant changes, creating cost issues. Furthermore, mold and rust can cause pipe blockages in the circulation system, such as in pumps.

[0130] Any known substance may be used as the antiseptic and / or antirust agent as long as it does not impair at least one of the following characteristics of the coolant: (a) an oil content of less than 4.0% by volume, (b) water solubility, and (c) a boiling point of less than 300° C. For example, formaldehyde-releasing or phenolic substances, or amine-based substances may be added as appropriate.

[0131] As described above, in the manufacturing method of this embodiment, if the coolant used during ironing is at least one of (a) an oil content of less than 4.0 volume %, (b) a water-soluble coolant, or (c) a coolant with a boiling point of less than 300°C, it is possible to suppress molding defects during can manufacturing, and as a result, it is possible to improve molding stability.

[0132] Furthermore, since the present embodiment uses the above-described coolant, cleaning can be performed using chemicals or water with low environmental impact in the cleaning process described below. Alternatively, the cleaning process itself can be omitted, thereby reducing the burden on the environment. Furthermore, since wastewater treatment after cleaning is simplified, when wastewater is recycled and circulated, the recycling rate can be improved, thereby reducing costs and the burden on the environment.

[0133] The ironing process of this embodiment preferably includes an ironing step in which the metal material is ironed to form a can body portion at an ironing rate (rate of reduction in plate thickness) of 10% or more. The ironing step may be performed multiple times, and the ironing rate may be varied for each step. For example, the ironing rate in the initial ironing step may be set to 10% or more, and the ironing rate in the final ironing step may be set to 30% or more. The ironing rate in this embodiment is expressed by the following formula, where t0 is the plate thickness before ironing, and t1 is the plate thickness after ironing (at a portion 60 mm from the can bottom): Ironing rate (%) = 100 × (t0 - t1) / t0

[0134] <Cleaning Step> Next, the cleaning step in this embodiment will be described. The cleaning step in this embodiment is a step of bringing a cleaner into contact with the bottomed tubular body obtained in the drawing step and ironing step described above, and removing the lubricant and coolant adhering to the inner and outer surfaces of the bottomed tubular body. Note that the cleaning step is not an essential step in this embodiment, and can be omitted as appropriate.

[0135] The method for bringing the cleaning agent into contact with the bottomed cylindrical body can be appropriately selected from known methods. For example, the bottomed cylindrical body may be immersed in the cleaning agent, or the cleaning agent may be sprayed onto the bottomed cylindrical body by spraying or showering.

[0136] As the cleaning agent used in this embodiment, a known alkaline cleaning agent, acid cleaning agent, or neutral cleaning agent can be used, or water can also be used.

[0137] Examples of alkaline cleaners include aqueous solutions of inorganic compounds such as sodium carbonate, potassium carbonate, sodium bicarbonate, sodium hydroxide, and potassium hydroxide. Examples of acid cleaners include aqueous solutions of inorganic acids such as sulfuric acid, nitric acid, hydrochloric acid, and hydrofluoric acid.

[0138] After the cleaning treatment using an alkaline cleaner or an acid cleaner, it is preferred to carry out a water-rinsing treatment to remove any remaining cleaner on the metal sheet surface, as is well known, and then remove moisture from the metal sheet surface by a method such as air blowing or hot air drying.

[0139] When an alkaline cleaner or an acid cleaner is used, the concentration of the cleaning component in the cleaner is preferably 2.0 to 5.0% by weight from the viewpoint of maintaining cleaning performance while reducing costs and environmental impact.

[0140] In the cleaning step of this embodiment, the temperature of the cleaning agent used is preferably less than 70° C. That is, in this embodiment, it is possible to omit the step of applying processing oil or lubricant to the surface of the metal plate (flat plate) before drawing, and at least one of (a) an oil content of less than 4.0 vol%, (b) a water-soluble coolant, or (c) a coolant with a boiling point of less than 300° C. is used as the coolant in the ironing step. Therefore, even if the temperature of the cleaning agent is less than 70° C., it is possible to sufficiently remove oil from the inner surface and the outer surface of the bottomed cylindrical body.

[0141] On the other hand, the lower limit of the temperature of the cleaning agent is preferably room temperature (e.g., 20°C). Generally, when cleaning processing oil or the like in metal press working, the cleaning agent is heated before use to enhance cleaning performance. However, heating the cleaning agent consumes a considerable amount of energy resources. Therefore, in this embodiment, from the viewpoint of cost reduction and reduction of environmental load, the cleaning agent can be used at room temperature as long as its cleaning performance is not reduced.

[0142] Furthermore, in this embodiment, from the viewpoint of cost reduction and environmental load reduction, the cleaning time in the cleaning step is preferably 45 seconds or less. That is, in this embodiment, since both the lubricant used in the drawing step and the coolant used in the ironing step are water-soluble and / or have boiling points below 300°C, the inner and outer surfaces of the bottomed cylindrical body can be sufficiently cleaned even if the cleaning time is 45 seconds or less. While there is no particular lower limit to the cleaning time, a lower limit of, for example, more than 10 seconds is preferred as a cleaning time that allows cleaning without practical problems and does not cause problems in wastewater treatability. Furthermore, when the cleaning method involves spraying the cleaning agent by spray or shower, the amount of the cleaning agent sprayed per can is preferably 60 to 70 ml / second.

[0143] In the cleaning process of this embodiment, the lubricant and coolant adhering to the inner and outer surfaces of the bottomed cylindrical body are removed by the cleaning agent. Therefore, the weight of the bottomed cylindrical body changes before and after cleaning, but the weight change is within 100 mg / m ２ It is preferable that it is less than 10 ...

[0144] That is, in this embodiment, it is possible to reduce the amount of lubricant or coolant adhering to the inner and outer surfaces of the bottomed cylindrical body after the can-making process (drawing process and ironing process).

[0145] Therefore, the weight change of the bottomed cylindrical body before and after cleaning was 100 mg / m ２ By setting the amount of lubricant and coolant contained in the wastewater generated in the cleaning process to less than this, it is possible to reduce the amount of lubricant and coolant contained in the wastewater generated in the cleaning process, thereby making it possible to reduce the environmental burden.

[0146] <Drying Step> As described above, in the present embodiment, the cleaning step can be omitted as appropriate. In that case, it is preferable to provide a drying step in order to remove the lubricant and coolant adhering to the inner and outer surfaces of the bottomed cylindrical body.

[0147] That is, in this embodiment, it is possible to omit the step of applying processing oil or lubricant to the surface of the metal plate (flat plate) before drawing, and at least one of the following coolants is used in the ironing step: (a) an oil content of less than 4.0 volume %, (b) a water-soluble coolant, or (c) a coolant with a boiling point of less than 300° C. Among these, when processing oil or lubricant is not applied to the surface of the metal plate (flat plate) before drawing, and (c) a coolant with a boiling point of less than 300° C. is used as the coolant in the ironing step, it is possible to remove the lubricant and coolant adhering to the inner and outer surfaces of the bottomed cylindrical body by the drying step, even if a cleaning step is not performed after the can making process (drawing step and ironing step).

[0148] In the drying process of this embodiment, specifically, the lubricant and coolant adhering to the inner and outer surfaces of the bottomed cylindrical body can be removed, for example, by heating the body in a drying oven at approximately 150 to 300°C for 30 to 180 seconds.

[0149] <Purification Step> Next, the purification step in this embodiment will be described. The method for manufacturing a bottomed tubular body in this embodiment may include a purification step of purifying the wastewater discharged in the above-mentioned ironing step and / or washing step, as shown in Fig. 3 .

[0150] As described above, in the manufacturing method of the bottomed cylindrical body of this embodiment, the ironing process involves ironing using a coolant, and the cleaning process involves removing coolant components adhering to the surface of the bottomed cylindrical body using a detergent. Therefore, a large amount of wastewater is generated in both processes.

[0151] Therefore, the method for manufacturing a bottomed tubular body in this embodiment may further include a purification step of purifying the wastewater, as shown in Fig. 3. In this case, for reasons described below, it is preferable that the purified wastewater be reused (recycled) as purified water in the straining step and washing step again.

[0152] As described above, in the method for manufacturing a bottomed cylindrical body according to this embodiment, it is possible to omit the step of applying processing oil or lubricant to the surface of the metal plate (flat plate) before drawing. Also, as described above, at least one of (a) an oil content of less than 4.0% by volume, (b) a water-soluble coolant, or (c) a coolant with a boiling point of less than 300°C is used as the coolant in the ironing step.

[0153] Therefore, the wastewater generated in the scraping step and / or the washing step can be purified by a relatively simple method, and by undergoing the above-mentioned purification step, it is possible to further reduce the environmental load and the cost.

[0154] As a method for purifying wastewater in the purification step, known methods can be used as appropriate. That is, purification can be performed by appropriately combining methods such as filtration, neutralization, boiling, precipitation, flotation, biological treatment, and UV sterilization. In addition, a flocculant, disinfectant, bactericide, etc. may be appropriately mixed.

[0155] As described above, the manufacturing method for a bottomed tubular body according to this embodiment can achieve the following effects. (A) In order to ensure that the hardness of the processed surface of the formed member in the drawing process is at least a predetermined value, the process of applying a lubricant to the surface of the metal plate (flat plate) before drawing can be omitted. (B) In order to ensure that the hardness of the processed surface of the formed member in the ironing process is at least a predetermined value, a coolant that satisfies at least one of the following conditions can be used in the ironing process: (a) an oil content of less than 4.0% by volume, (b) a water-soluble coolant, or (c) a coolant with a boiling point of less than 300°C. (C) As a result of the above, the concentration of cleaning components in the cleaning agent in the cleaning process can be reduced, heating of the cleaning agent can be suppressed, and / or the cleaning time can be shortened. It is also possible to omit the cleaning process. (D) As a result, it is possible to reduce environmental impact and reduce costs.

[0156] Furthermore, if the purification step is further carried out in this embodiment, the following effects can be further achieved: (E) The wastewater discharged in the squeezing step and / or the washing step can be easily purified. (F) It becomes possible to purify and reuse (recycle) the wastewater, thereby reducing costs and the burden on the environment.

[0157] The present invention will be described in more detail below using examples, but the present invention is not limited to the following examples.

[0158] Example 1 A drawn and ironed can (DI can) with an internal volume of 350 mL was manufactured by the following method. First, an aluminum alloy plate (JIS H 4000 3104 material, 0.28 mm) was prepared. Next, a water-soluble lubricant was applied to both sides of the aluminum alloy plate at a concentration of 1.0 to 1.3 g / m as a lubricant during drawing. ２ It was applied.

[0159] Next, the aluminum alloy plate was punched out into a disk shape with a diameter of 160 mm using a drawing machine, and then immediately subjected to drawing to form a cup shape with a diameter of 90 mm. The surface hardness of the formed member during the drawing process was Hv 1500.

[0160] The obtained cup body was transported to a body maker (can body manufacturing machine) and re-drawn to a shape with a diameter of 66 mm, and then ironed using coolant to a shape with a diameter of 66 mm and a height of 130 mm.

[0161] The ironing die used in this experiment had a diamond film formed on its surface with an average thickness of approximately 10 μm. The surface hardness of the diamond film was Hv 10,000. The ironing punch used had a diamond-like carbon film formed on its surface with a thickness of 0.5 μm. The surface hardness of the diamond-like carbon film was Hv 3,000.

[0162] The ironing rate during the ironing process is shown in Table 1. A water-soluble coolant was used during the ironing process, and the coolant contained known surfactants, rust inhibitors, extreme pressure additives, and preservatives.

[0163] The resulting DI can was washed to remove lubricant and coolant components adhering to the inner and outer surfaces. Sulfuric acid (concentration: 3.0% by volume) was used as the washing agent. The temperature of the washing agent was 20°C, and the washing time was 30 seconds.

[0164] Example 2 The same procedure as in Example 1 was carried out, except that lubricants having boiling points shown in Table 1 were used as lubricants during drawing. The results are shown in Table 1.

[0165] Example 3 The same procedure as in Example 1 was carried out, except that the surface hardness of the formed member during drawing was set as shown in Table 1. The results are shown in Table 1.

[0166] Example 4 The same procedure as in Example 1 was carried out, except that the working surface hardness of the drawing die during drawing was set as shown in Table 1. The results are shown in Table 1.

[0167] Example 5 The same procedure as in Example 1 was carried out, except that the working surface hardness of the drawing punch during drawing was set as shown in Table 1. The results are shown in Table 1.

[0168] (Example 6) The ironing die used in the ironing process had a diamond-like carbon film formed on its surface with an average thickness of 0.5 μm. The surface hardness of the diamond-like carbon film was Hv3000. The rest of the procedure was the same as in Example 1. The results are shown in Table 1.

[0169] Example 7 The ironing punch used in the ironing process had a diamond film formed on its surface with an average thickness of approximately 10 μm. The surface hardness of the diamond film was Hv 10,000. The rest of the procedure was the same as in Example 1. The results are shown in Table 1.

[0170] (Example 8) The coolant used during ironing had a boiling point shown in Table 1. Other than that, the same procedure as in Example 1 was carried out. The results are shown in Table 1.

[0171] Example 9 The same procedure as in Example 1 was carried out except that pure water was used as the cleaning agent during cleaning. The results are shown in Table 1.

[0172] Example 10 The same procedure as in Example 1 was carried out, except that drying (at 300° C. for 30 seconds) was carried out instead of the cleaning step after drawing and ironing. The results are shown in Table 1.

[0173] (Example 11) The coolant used during ironing had a boiling point shown in Table 1. Otherwise, the same procedure as in Example 2 was carried out. The results are shown in Table 1.

[0174] Example 12 The same procedure as in Example 2 was carried out except that pure water was used as the cleaning agent during cleaning. The results are shown in Table 1.

[0175] Example 13 The same procedure as in Example 2 was carried out, except that drying (at 300° C. for 30 seconds) was carried out instead of the washing step after drawing and ironing. The results are shown in Table 1.

[0176] Example 14 The same procedure as in Example 8 was carried out except that pure water was used as the cleaning agent during cleaning. The results are shown in Table 1.

[0177] Example 15 The same procedure as in Example 8 was carried out, except that drying (at 300° C. for 30 seconds) was carried out instead of the washing step after drawing and ironing. The results are shown in Table 1.

[0178] Example 16 The same procedure as in Example 11 was carried out except that pure water was used as the cleaning agent during cleaning. The results are shown in Table 1.

[0179] Example 17 The same procedure as in Example 11 was carried out, except that drying (at 300° C. for 30 seconds) was carried out instead of the washing step after drawing and ironing. The results are shown in Table 1.

[0180] Example 18 After the washing step following drawing and ironing, drying (300°C for 30 seconds) was further carried out. Otherwise, the same procedure as in Example 14 was carried out. The results are shown in Table 1.

[0181] Example 19 After the washing step following drawing and ironing, drying (300°C for 30 seconds) was further carried out. Otherwise, the same procedure as in Example 12 was carried out. The results are shown in Table 1.

[0182] Example 20 The same procedure as in Example 3 was carried out except that no lubricant was used during drawing and that the ironing rate during ironing was set to the value shown in Table 1. The results are shown in Table 1.

[0183] Comparative Example 1 The same procedure as in Example 1 was carried out except that a water-insoluble lubricant was applied as a lubricant during drawing. The results are shown in Table 1.

[0184] Comparative Example 2 The same procedure as in Example 1 was carried out except that a lubricant having a boiling point shown in Table 1 was used as the lubricant during drawing. The results are shown in Table 1.

[0185] Comparative Example 3 The same procedure as in Example 1 was carried out except that the working surface hardness of the drawing die during drawing was set as shown in Table 1, but the body broke during the drawing process. The results are shown in Table 1.

[0186] Comparative Example 4 The ironing die and ironing punch used in the ironing process were made of cemented carbide (Hv 1000).Other than that, the same procedure as in Example 1 was carried out.The results are shown in Table 1.

[0187] Comparative Example 5 The same procedure as in Example 1 was carried out except that the coolant used during ironing was a water-insoluble coolant. The results are shown in Table 1.

[0188] Comparative Example 6 The coolant used during the ironing process had a boiling point shown in Table 1, and the process was carried out in the same manner as in Example 1, except that drying (300°C for 30 seconds) was carried out instead of the cleaning step after the drawing and ironing process. The results are shown in Table 1.

[0189] Comparative Example 7 The same procedures as in Example 1 were carried out except that a water-insoluble coolant was used during the ironing process and drying (300°C for 30 seconds) was carried out instead of the washing step after the drawing and ironing process. The results are shown in Table 1.

[0190] Comparative Example 8 The same procedure as in Example 1 was carried out except that no lubricant was used during the drawing process, but the barrel broke during the drawing process. The results are shown in Table 1.

[0191] [Evaluation] The DI cans obtained by the above method were evaluated by the following methods. The results are shown in Table 1.

[0192] [Ironing processability] The following three items were visually observed: (i) the presence or absence of breakage during ironing, (ii) bleed-through (black streaks) at the opening of the obtained DI cans and discoloration on the inside and outside surfaces of the can body, and (iii) scratches on the outside surface of the can body. Cans that were excellent and had no problems in any of the above three items were rated as ⊚, those that had problems in any of the above items but were suitable for practical use were rated as ◯, and those that had problems in any of the above items and were not suitable for practical use were rated as x.

[0193] [Printability] After cleaning the resulting DI cans, an aqueous paint was applied to the can surface, followed by baking using a known method, and the unevenness of the paint was evaluated. A mark of ○ was given to a can with no visible unevenness in the paint, and a mark of × was given to a can with unevenness due to paint repellency or the like. Incidentally, the occurrence of unevenness in the paint can be considered to indicate that the lubricant and / or coolant used in the drawing or ironing process remains.

[0194] [Wastewater treatability] The above cleaning solution was used to spray clean a DI can, and the wastewater was rinsed with water. The wastewater was then placed in a beaker and measured for chemical oxygen demand (COD) using a known method. If the COD was less than 200 ppm, it was judged as ○ (good wastewater treatability), and if it was 200 ppm or more, it was judged as × (poor wastewater treatability). The results are shown in Table 1.

[0195]

[0196] Example 21 A drawn and ironed can (DI can) having an internal volume of 350 mL was manufactured by the following method. First, an aluminum alloy plate (JIS H 4000 3104 material, 0.28 mm) was prepared. No lubricant was applied to either side of the aluminum alloy plate.

[0197] Next, the aluminum alloy plate was punched out into a disk shape with a diameter of 160 mm using a drawing machine, and then immediately subjected to drawing to form a cup body with a diameter of 90 mm. The processed surface hardness of the formed member during drawing was as shown in Table 1.

[0198] The obtained cup body was transported to a body maker (can body manufacturing machine) and re-drawn to a shape with a diameter of 66 mm, and then ironed using coolant to a shape with a diameter of 66 mm and a height of 130 mm.

[0199] The ironing die used in this experiment had a diamond film with an average thickness of about 10 μm formed on its surface. The surface hardness of the diamond film was as shown in Table 1. The ironing punch used had a diamond-like carbon film with a thickness of 0.5 μm formed on its surface. The surface hardness of the diamond-like carbon film was as shown in Table 1.

[0200] The ironing rate during ironing was as shown in Table 1. The oil content in the coolant was as shown in Table 1. Known surfactants, rust inhibitors, extreme pressure additives, and preservatives were added to the coolant.

[0201] The obtained DI can was washed to remove lubricant and coolant components adhering to the inner and outer surfaces. The washing agent used was sulfuric acid (concentration: 3.0%). The temperature of the washing agent was 50°C, and the washing time was 30 seconds.

[0202] Example 22 The same procedure as in Example 21 was carried out, except that the ironing surface hardness of the ironing die during ironing was set as shown in Table 2. The results are shown in Table 2.

[0203] Example 23 The same procedure as in Example 21 was carried out, except that the ironing surface hardness of the ironing die during ironing was set as shown in Table 2. The results are shown in Table 2.

[0204] Example 24 The same procedure as in Example 21 was carried out, except that the ironing punch had a surface hardness as shown in Table 2 during ironing. The results are shown in Table 2.

[0205] (Example 25) The oil content of the coolant used during ironing was as shown in Table 2. Other than that, the same procedure as in Example 21 was carried out. The results are shown in Table 2.

[0206] (Example 26) The coolant used during ironing had a boiling point shown in Table 2. Otherwise, the same procedure as in Example 21 was carried out. The results are shown in Table 2.

[0207] Example 27 The same procedure as in Example 21 was carried out except that pure water was used as the cleaning agent during cleaning. The results are shown in Table 2.

[0208] Example 28 The same procedure as in Example 21 was carried out, except that the coolant used during the ironing process had a boiling point shown in Table 2, and drying (300°C for 30 seconds) was carried out instead of the cleaning step after the drawing and ironing process. The results are shown in Table 2.

[0209] Example 29 The same procedure as in Example 27 was carried out, except that the working surface hardness of the punch and die in the drawing step and the ironing step was set as shown in Table 2. The results are shown in Table 2.

[0210] Example 30 The same procedure as in Example 27 was carried out, except that the working surface hardness of the punch and die in the drawing step and the ironing step was set as shown in Table 2. The results are shown in Table 2.

[0211] Example 31 The same procedure as in Example 28 was carried out, except that the working surface hardness of the punch and die in the drawing step and the ironing step was set as shown in Table 2. The results are shown in Table 2.

[0212] Example 32 The same procedure as in Example 21 was carried out, except that the working surface hardness of the punch and die in the drawing step and the ironing step was set as shown in Table 2. The results are shown in Table 2.

[0213] (Example 33) The same procedure as in Example 27 was carried out, except that a water-soluble lubricant was applied before the drawing process and the working surface hardness of the drawing punch and drawing die in the drawing process was set as shown in Table 2. The results are shown in Table 2.

[0214] Example 34 The same procedure as in Example 21 was carried out, except that the working surface hardness of the drawing punch in the drawing step was set as shown in Table 2. The results are shown in Table 2.

[0215] Example 35 The same procedure as in Example 34 was carried out except that a water-soluble lubricant was applied before the drawing process. The results are shown in Table 2.

[0216] Example 36 The same procedure as in Example 21 was carried out, except that the hardness of the processed surface of the punch in the drawing step and the ironing step was set as shown in Table 2. The results are shown in Table 2.

[0217] Example 37 The same procedure as in Example 34 was carried out, except that the hardness of the processed surface of the punch in the ironing step was set as shown in Table 2. The results are shown in Table 2.

[0218] Comparative Example 9 The same procedure as in Example 21 was carried out except that the working surface hardness of the drawing die during drawing was set as shown in Table 2, but the body broke during the drawing process. The results are shown in Table 2.

[0219] Comparative Example 10 The same procedure as in Example 21 was carried out except that the working surface hardness of the drawing die and drawing punch during drawing was set as shown in Table 2, but the barrel broke during the drawing process. The results are shown in Table 2.

[0220] Comparative Example 11 The same procedure as in Example 21 was carried out, except that the surface hardness of the ironing die and ironing punch during ironing was set as shown in Table 2. The results are shown in Table 2.

[0221] Comparative Example 12 The same procedure as in Comparative Example 11 was carried out except that a water-soluble lubricant was applied before the drawing process. The results are shown in Table 2.

[0222] Comparative Example 13 The same procedures as in Example 21 were carried out, except that drying (at 300° C. for 30 seconds) was carried out instead of the washing step after drawing and ironing. The results are shown in Table 2.

[0223] (Comparative Example 14) The processed surface hardness of the punch and die in the drawing step and the ironing step was as shown in Table 2, and the oil content of the coolant used during the ironing step was as shown in Table 2. Other than that, the same procedure as in Example 27 was carried out. The results are shown in Table 2.

[0224] Comparative Example 15 The oil content of the coolant used during ironing was as shown in Table 2. Other than that, the same procedure as in Example 21 was carried out. The results are shown in Table 2.

[0225] Comparative Example 16 The same procedure as in Comparative Example 13 was carried out except that a water-soluble lubricant was applied before the drawing process. The results are shown in Table 2.

[0226] [Evaluation] The DI cans obtained by the above method were evaluated by the following methods. The results are shown in Table 1.

[0227] [Ironing processability] The following three items were visually observed: (i) the presence or absence of breakage during ironing, (ii) bleed-through (black streaks) at the opening of the obtained DI can, and (iii) scratches on the outer surface of the can body. Cans with no problems in any of the above four items and a mirror-like surface were rated as ⊚, those with no problems in any of the above items and excellent properties were rated as ◯, those with problems in any of the above items but suitable for practical use were rated as △, and those with problems in any of the above items and unsuitable for practical use were rated as ×.

[0228] [Printability] After cleaning the resulting DI cans, an aqueous paint was applied to the can surface, followed by baking using a known method, and the unevenness of the paint was evaluated. A mark of ○ was given to a can with no visible unevenness in the paint, and a mark of × was given to a can with unevenness due to paint repellency or the like. Incidentally, the occurrence of unevenness in the paint can be considered to indicate that the lubricant and / or coolant used in the drawing or ironing process remains.

[0229] [Wastewater treatability] The above cleaning solution was used to spray clean a DI can, and the wastewater was rinsed with water. The wastewater was then placed in a beaker and measured for chemical oxygen demand (COD) using a known method. If the COD was less than 200 ppm, it was judged as ○ (good wastewater treatability), and if it was 200 ppm or more, it was judged as × (poor wastewater treatability). The results are shown in Table 2.

[0230]

[0231] According to the manufacturing method of the bottomed tubular body of the first embodiment, it is possible to obtain a bottomed tubular body with an ironing rate similar to or better than that of the conventional method, even when the coolant used in the ironing step is water-soluble and / or has a boiling point of less than 300° C. Furthermore, according to the first embodiment, it is possible to further provide a lubricant application step in which a lubricant is applied to the surface of the metal sheet (flat plate) before drawing, and it is possible to obtain workability similar to or better than that of the conventional method, even when the lubricant is water-soluble and / or has a boiling point of less than 300° C.

[0232] In the first embodiment, water-soluble lubricants and coolants, and lubricants and coolants with boiling points below 300°C, are used in the drawing and ironing processes. This makes it possible to use water or hot water in the washing process without using detergents. Alternatively, the lubricants, coolants, etc. adhering to the can body can be removed by drying after can manufacturing without providing a washing process. It is also clear that the wastewater generated in the ironing and washing processes can be reused (recycled) in the ironing and washing processes after a purification process.

[0233] According to the second embodiment of the manufacturing method for a bottomed cylindrical body, it is possible to obtain a bottomed cylindrical body with an ironing rate similar to or higher than that of conventional products, even when the coolant used in the ironing process satisfies at least one of the following conditions: (a) the oil concentration is less than 4.0% by volume, (b) the coolant is water-soluble, or (c) the boiling point is less than 300°C.

[0234] In the second embodiment, because the coolant is used, cleaning can be performed using water or hot water without using a cleaning agent in the cleaning process. Alternatively, the lubricant, coolant, etc. adhering to the can body can be removed by drying after can manufacturing without providing a cleaning process. It is also clear that the wastewater generated in the ironing and cleaning processes can be reused (recycled) in the ironing and cleaning processes again after a purification process.

[0235] The present invention can be suitably used in the field of metal press working, which requires consideration for the environment while maintaining workability and forming stability.

[0236] D Ｄ Drawing die P Ｄ Drawing punch D Ｉ Stroking Die P Ｉ Ironing punch C Coolant M Shallow-drawn cup 10 Metal plate 20 Diamond film 30 Surface treatment film

Claims

1. A method for manufacturing a bottomed cylindrical body, comprising: a drawing step of drawing a metal plate using a forming member having a processing surface hardness exceeding Hv1500 to 12000; and a ironing step of ironing a workpiece through a coolant using a forming member having a carbon film on the processing surface to form a bottomed cylindrical body, wherein the coolant is a water-soluble coolant and / or a coolant having a boiling point of less than 300°C. A method for manufacturing a bottomed cylindrical body, characterized by this.

2. The method for manufacturing a bottomed cylindrical body according to claim 1, wherein the bottomed cylindrical body is a seamless can body.

3. The method for manufacturing a bottomed cylindrical body according to claim 1 or 2, wherein the metal plate is an aluminum alloy.

4. The method for manufacturing a bottomed cylindrical body according to any one of claims 1 to 3, wherein the carbon film is a diamond film.

5. Before the drawing step of drawing the metal plate, the method includes a lubricant application step of applying a water-soluble lubricant and / or a lubricant having a boiling point of less than 300°C to the metal plate, and the hardness of the processing surface of the forming member in the drawing step is Hv1500 to 12000. The method for manufacturing a bottomed cylindrical body according to any one of claims 1 to 4.

6. The method for manufacturing a bottomed cylindrical body according to any one of claims 1 to 5, wherein the coolant has an antiseptic and / or a rust inhibitor.

7. The method for manufacturing a bottomed cylindrical body according to any one of claims 1 to 6, further including a cleaning step of removing the lubricant and / or the coolant adhering to the surface of the bottomed cylindrical body.

8. The method for manufacturing a bottomed cylindrical body according to any one of claims 1 to 7, further including a purification step of purifying the wastewater discharged in the ironing step and / or the cleaning step.

9. A method for manufacturing a bottomed cylindrical body, comprising: a drawing step of drawing a metal plate using a drawing die having a processing surface hardness exceeding Hv1500 to 12000 and a drawing punch having a hardness of Hv1000 to 12000; and a ironing step of ironing a workpiece through a coolant using a forming member having a processing surface hardness of Hv1500 to 12000 to form a bottomed cylindrical body, wherein the coolant satisfies at least one of (a) the concentration of the contained oil component is less than 4.0% by volume, (b) a water-soluble coolant, or (c) a boiling point of less than 300°C. A method for manufacturing a bottomed cylindrical body, characterized by this.

10. The method for manufacturing a bottomed cylindrical body according to claim 9, wherein the bottomed cylindrical body is a seamless can body.

11. The method for manufacturing a bottomed cylindrical body according to claim 9 or 10, wherein the metal plate is an aluminum alloy.

12. The method for manufacturing a bottomed cylindrical body according to any one of claims 9 to 11, wherein a carbon film is formed on the processed surface of the forming member in the drawing process and / or on the processed surface of the forming member in the ironing process.

13. The method for manufacturing a bottomed cylindrical body according to any one of claims 9 to 12, including a lubricant application step of applying a lubricant to the surface of the metal plate before the drawing process, and the hardness of the processed surface of the drawing die in the drawing process is Hv1000 to 12000.

14. The method for manufacturing a bottomed cylindrical body according to any one of claims 9 to 13, further including a purification step of purifying the wastewater discharged in the ironing process or in the cleaning process after the ironing process.

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