KR102284465B1 - Method for producing stainless container - Google Patents

Abstract

The present invention relates to a method for manufacturing a stainless steel container capable of suppressing the occurrence of micro-scale cracks in an R-processing unit during molding of a stainless steel container. The method for manufacturing a stainless steel container according to the present invention comprises: a cutting process for cutting a stainless steel plate to a certain size; a press forming process for forming an enclosure having side walls and a bottom surface by inserting the cut stainless steel plate into a press machine; a trimming process for trimming the enclosure through mechanical work; a surface treatment process for treating the entire surface of the enclosure or at least the surface of the R-processing unit; and a follow-up process for performing follow-up processes such as quality inspection when the surface treatment process is completed.

Description

Manufacturing method of stainless steel container {METHOD FOR PRODUCING STAINLESS CONTAINER}

The present invention relates to a method for manufacturing a stainless steel container, and more particularly, to a method for manufacturing a stainless steel container capable of suppressing the occurrence of microcracks in the R-processed portion during molding of the stainless steel container.

Kitchen containers such as rice cookers, rice cookers, frying pans, pots, cups, and cups used for general food cooking have been manufactured by forming plates such as stainless steel and aluminum alloy by pressing or casting them in a mold.

Among them, stainless steel containers made of stainless steel plates are not rusted, are harmless to the human body, are hygienically safe, and have almost no shape deformation or discoloration. Microcracks may occur in the rounded corners that lead to the lower end), and these microcracks usually cause corrosion and rust. In addition, when the stainless steel is forcibly stretched, it is difficult to form due to the property that a tensile force is generated that is pulled to each other and is restored to its original position after forming.

US 10-0702490 B1

It is an object of the present invention to provide a method for manufacturing a stainless steel container capable of suppressing the occurrence of microcracks in the R-processed portion during molding of the stainless steel container.

Other objects and advantages of the present invention will be set forth below and will be learned by way of example of the present invention. Furthermore, the objects and advantages of the present invention may be realized by means and combinations indicated in the claims.

According to an aspect of the present invention, a cutting process of cutting a stainless steel sheet to a predetermined size; a press forming process of inserting a cut stainless steel sheet into a press machine to form a housing having sidewalls and a bottom surface; Trimming process of trimming the enclosure through mechanical work; a surface treatment step of performing surface treatment on the entire surface of the housing or at least only the R-processed portion; And when the surface treatment step is completed, a method for manufacturing a stainless steel container using a stainless steel sheet as a material comprising a subsequent process of performing a subsequent process, including quality inspection, as a material, wherein the press forming process includes first pressing the cut stainless steel plate. The first press forming process in which a steel sheet is formed into the housing through the first press forming process, and after a certain time elapses that the housing formed through the primary press forming process can be deformed by the tensile force of the stainless steel itself, the housing is put into the press again Including a secondary press forming step of placing and performing a second press pressurization, wherein the surface treatment step is 32 to 42 parts by weight of nitric acid, 32 to 42 parts by weight of phosphoric acid, 37 to 47 parts by weight of glycerol, 20 to 25 parts by weight of hydrogen peroxide A primary polishing process of performing polishing using a polishing liquid consisting of parts and distilled water, and 32 to 42 parts by weight of nitric acid, 32 to 42 parts by weight of phosphoric acid, 37 to 47 parts by weight of glycerol, 20 to 25 parts by weight of hydrogen peroxide, A secondary polishing process of performing electrolytic polishing for 5 to 10 minutes using an electrolyte consisting of 1 to 3 parts by weight of a surfactant and distilled water, 17 to 22 parts by weight of nitric acid, 18 to 23 parts by weight of sulfuric acid, 10 parts by weight of gluconic acid to 20 parts by weight, and a step of impregnating the housing in an acid mixture consisting of the remaining distilled water, and in the secondary press forming process, the elapsed time of the deformation process can be adjusted according to the slope of the sidewall of the housing, Electrolytic polishing in the secondary polishing process is characterized in that it is performed for 5 to 10 minutes at a current density of 30 ~ 40A/dm2 and a temperature of 70 ~ 80 ℃.

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According to the method for manufacturing a stainless container of the present invention, there is an effect of suppressing the occurrence of microcracks in the R-processed portion during molding of the stainless container.

1 is a flowchart for explaining a method for manufacturing a stainless steel container according to the present invention;
Figure 2 is a flowchart for explaining the press forming process according to Figure 1,
Figure 3 is a flowchart for explaining the surface treatment process according to Figure 1,
4 is a flowchart for explaining the pattern forming process according to the present invention,
5 is a view showing an example of surface defects of the R-processed portion in the stainless steel container.

Hereinafter, specific embodiments of the present invention will be described in detail with reference to the drawings. However, the spirit of the present invention is not limited to the embodiments presented, and those skilled in the art who understand the spirit of the present invention may add, change, delete, etc. other components within the scope of the same spirit, through addition, change, deletion, etc. Other embodiments included within the scope of the invention may be easily proposed, but this will also be included within the scope of the invention.

In addition, components having the same function within the scope of the same idea shown in the drawings of each embodiment will be described using the same reference numerals.

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings showing preferred embodiments.

In describing the present invention, if it is determined that a detailed description of a related known function or configuration may unnecessarily obscure the gist of the present invention, a detailed description thereof will be omitted.

1 is a flow chart for explaining a method of manufacturing a stainless container according to the present invention, Figure 2 is a flow chart for explaining the press forming process according to Figure 1, Figure 3 is for explaining the surface treatment process according to Figure 1 It is a flow chart, Figure 4 is a flow chart for explaining the pattern forming process according to the present invention, Figure 5 is a view showing an example of the surface defects of the R-processed portion in the stainless steel container.

First, referring to FIG. 1 , the method for manufacturing a stainless steel container using a stainless steel sheet according to the present invention includes a cutting step (S10); press forming process (S20); trimming process (S30); surface treatment process (S40); and a subsequent process (S50).

The cutting process (S10) is a process of cutting (cutting) the stainless steel plate of the original plate to a predetermined size. The size of the cut stainless steel sheet is determined according to the standard of the stainless steel container to be manufactured, and the planar shape may be any shape such as a circle, a square, or an oval.

The press forming process (S20) is a process of forming a housing having a side wall and a bottom surface by putting a cut stainless steel sheet into a press machine.

Referring to FIG. 5 , when the flat-shaped cut stainless steel sheet is processed into the housing 10, cracks in the R processing part 11, which is the connection part between the part that will be the bottom of the stainless steel container and the part that will be the side wall (perimeter) (12) or pinhole 13 may be generated, and later, these cracks 12 or pinhole 13 may cause corrosion and rust.

In this step, anti-rust oil may be applied to reduce frictional resistance when press-molding a flat plate-shaped cut stainless steel sheet into an enclosure to suppress cracks and the like.

The trimming process (S30) is a process of trimming the housing through mechanical work, removing unnecessary parts, and substantially matching the dimensions of the product.

The surface treatment step ( S40 ) is a step of performing surface treatment on the entire surface of the housing 10 or at least only the R processing portion 11 .

The subsequent process ( S50 ) is a process of performing subsequent processes including quality inspection and packaging when the surface treatment step is completed.

Referring to FIG. 2 , the press forming process ( S20 ) includes a primary press forming process ( S22 ) in which the cut stainless steel sheet is first press-pressed to form the steel plate into the housing 10 , and the primary press Secondary press molding in which the housing 10 molded through the molding process can be deformed by the tensile force of the stainless steel itself elapses after a certain period of time has elapsed It may include a process (S24).

When forming the housing 10, when a certain period of time elapses, the primary press-molded state cannot be maintained due to the characteristics of the stainless steel in which a tensile force is generated. As a result, the shape (refer to FIG. 5) of the housing 10 is deformed. In this deformation process, after a sufficient amount of time has elapsed for the stainless steel to generate sufficient tensile force, the housing 10 is placed in the press again to perform press-press molding a second time. When this is done, the shape deformed in the deformation process is stretched again, and the reduced portion is offset, and the tensile force is not generated again on the side wall 14 and the bottom surface 16 after the second press forming process (S24).

At this time, the closer the inclination of the side wall 14 is to the vertical, the more tensile force is generated in the housing 10 to increase the shape deformation rate. desirable.

Referring to FIG. 3 , the surface treatment process ( S40 ) may include a primary polishing process ( S42 ), a secondary polishing process ( S44 ), and an impregnation process ( S46 ).

In the primary polishing process (S42), chemical polishing is performed using a polishing liquid consisting of 32 to 42 parts by weight of nitric acid, 32 to 42 parts by weight of phosphoric acid, 37 to 47 parts by weight of glycerol, 20 to 25 parts by weight of hydrogen peroxide, and the remaining distilled water. is a process that

The secondary polishing step (S44) is an electrolyte solution consisting of 32 to 42 parts by weight of nitric acid, 32 to 42 parts by weight of phosphoric acid, 37 to 47 parts by weight of glycerol, 20 to 25 parts by weight of hydrogen peroxide, 1 to 3 parts by weight of surfactant, and the remainder of distilled water. It is a process of performing electrolytic polishing for 5 to 10 minutes using At this time, the electropolishing time may be changed according to the magnitude of the current applied to the electrolyte and the temperature of the electrolyte.

For example, the electrolytic polishing treatment is preferably performed for 5 to 10 minutes at a current density of 30 to 40A/dm 2 and a temperature of 70 to 80°C.

If the current density is less than 30A/dm2 or the electropolishing treatment temperature is less than 70℃, it may be difficult to properly exert the polishing effect on the surface. Conversely, when the current density exceeds 40A/dm 2 or the electropolishing treatment temperature exceeds 80° C., it is advantageous in terms of polishing the surface, but it is not preferable because the effect against the increase in cost is insignificant.

In addition, if the electropolishing treatment time is less than 5 minutes, it may be difficult to properly exhibit the effect of surface polishing because sufficient polishing is not performed. Conversely, if the electropolishing treatment time exceeds 10 minutes, it is not economical because it may act as a factor that increases only the manufacturing cost without further increasing the effect.

In addition, after leaving the electropolished housing 10 in piranha for 1 to 2 hours, ultrasonic cleaning with distilled water for 5 to 10 minutes, and washing with acetone for 5 to 10 minutes. can Here, the surfactant may exert a gloss-imparting effect, and sodium lauryl sulfate may be used as the surfactant.

The impregnation process (S46) is a process of impregnating the housing 10 in an acid mixture consisting of 17 to 22 parts by weight of nitric acid, 18 to 23 parts by weight of sulfuric acid, 10 to 20 parts by weight of gluconic acid, and the remainder of distilled water.

This impregnation process (S46) improves the effect of surface treatment such as rust removal effect or oxide film formation.

Referring to FIG. 4 , before the secondary polishing process ( S46 ), a pattern forming process ( S60 ) of forming a decorative pattern on the surface of the housing may be further included.

Such a pattern forming process (S60) can improve the aesthetics of the stainless steel container by forming various patterns on the surface of the stainless steel container. At this time, various methods can be used as a method for forming the pattern, but in the present invention, an etching method that can easily form even a pattern of a sophisticated shape at a low cost is used in consideration of the characteristics of the material called stainless. .

Referring to FIG. 2 , the pattern forming process ( S60 ) includes a design process ( S62 ) of drawing a pattern of a desired shape on the surface of the housing 10 , and an etching solution for the pattern drawn on the surface of the housing 10 . It may include an etching process (S64) of etching and a drying process (S66) of drying the etched housing 10 by putting it in an oven.

In this case, a solution in which nitric acid, hydrochloric acid, and methanol are mixed may be used as the etching solution.

In the drying process (S66), the etched housing 10 is placed in an oven and dried for a predetermined time (about 10 minutes) to evaporate the solution remaining on the surface of the stainless steel sheet.

Thereafter, by performing the secondary polishing process (S46) as described above with respect to the dried housing 10, it is possible to improve wear resistance and improve resistance to corrosion.

In the above, the configuration and features of the present invention have been described based on the embodiments according to the present invention, but the present invention is not limited thereto, and it is understood that various changes or modifications can be made within the spirit and scope of the present invention. It is intended that such changes or modifications will be apparent to those skilled in the art, and therefore fall within the scope of the appended claims.

S10: Cutting process
S20: Press forming process
S30: Trimming process
S40: Surface treatment process
S50: follow-up process
S60: Pattern forming process

Claims (8)

A cutting process of cutting a stainless steel sheet to a certain size; a press forming process of inserting a cut stainless steel sheet into a press machine to form a housing having side walls and a bottom surface; Trimming process of trimming the enclosure through mechanical work; a surface treatment step of performing surface treatment on the entire surface of the housing or at least only the R-processed portion; And when the surface treatment step is completed, a method for manufacturing a stainless steel container made of a stainless steel sheet comprising a subsequent process of performing a subsequent process including quality inspection,
The press forming process is
A first press forming process in which a steel sheet is formed into the housing by first pressing the cut stainless steel sheet;
After a certain period of time has elapsed for the housing molded through the primary press forming process to be deformed by the tensile force of the stainless steel itself, the secondary press forming process is performed by placing the housing in the press again to perform secondary press pressurization. do,
The surface treatment process is
A primary polishing step of performing polishing using a polishing liquid consisting of 32 to 42 parts by weight of nitric acid, 32 to 42 parts by weight of phosphoric acid, 37 to 47 parts by weight of glycerol, 20 to 25 parts by weight of hydrogen peroxide, and the remainder of distilled water;
Using an electrolyte solution consisting of 32 to 42 parts by weight of nitric acid, 32 to 42 parts by weight of phosphoric acid, 37 to 47 parts by weight of glycerol, 20 to 25 parts by weight of hydrogen peroxide, 1 to 3 parts by weight of a surfactant, and the remainder of distilled water for 5 to 10 minutes A secondary polishing process of performing electrolytic polishing, and
17 to 22 parts by weight of nitric acid, 18 to 23 parts by weight of sulfuric acid, 10 to 20 parts by weight of gluconic acid, and a step of impregnating the housing with an acid mixture consisting of the remaining distilled water,
In the secondary press forming process, it is possible to adjust the elapsed time of the deformation process according to the inclination of the side wall of the housing,
The electrolytic polishing treatment in the secondary polishing process is a method of manufacturing a stainless container, characterized in that it is carried out for 5 to 10 minutes at a current density of 30 ~ 40A / dm2 and a temperature of 70 ~ 80 ℃.
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