JP2589445B2 - Molded products such as bills having fine irregularities and a method of manufacturing the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a handprint or the like formed by transferring fine irregularities such as a fingerprint or a footprint (a handprint or a footprint).
And methods for producing molded articles such as bills,
An object of the present invention is to propose a method of manufacturing a metal molded product in which a pattern such as a fine fingerprint or a palm print which appears on a handprint or the like is faithfully transferred.

[0002]

2. Description of the Related Art Conventionally, bills, footprints, and the like have generally been produced by embedding a prototype in a sand mold or by a precision casting method represented by lost wax. However, production of bills and the like by such a method has various problems as described below.

(1) Because of poor transfer characteristics, it is impossible to faithfully reproduce minute irregularities such as fingerprints. (2) It is difficult to repair the fingerprint when defects such as nests, wrinkles, pinholes, etc., are specific to the cast product. (3) Since large-sized ones increase the pouring weight, molds are liable to crack when ceramics are used as the molds. (4) In the case of cast products, dimensional changes occur due to heat shrinkage. (5) In many cases, production is complicated and mass production is difficult. (6) The product weight increases.

[0004] Regarding this point, the plate thickness is 0.3 to 5.
In order to manufacture bills, etc. using a superplastic material (duplex stainless steel) with a thickness of about 0 mm, it is necessary to apply such superplastic material to a female mold made of ceramics. Therefore, it is difficult to use a metal mold, and ceramics are used for that purpose.) Polymerization at a temperature of about 980 ° C, a processing time of about 60 minutes, and a gas pressure of about 8 kgf / cm ² However, in such a method, there is a limit to increasing the gas pressure because the mold may be damaged, and fine irregularities such as fingerprints are formed on the surface of the material. It could not be faithfully reproduced.

[0005]

SUMMARY OF THE INVENTION It is an object of the present invention to overcome the above-mentioned problems of the prior art, and in particular to a bill which is advantageous for reliably printing a fine fingerprint or footprint on a metal material surface. Providing metal products such as footprints
The present invention proposes an advantageous manufacturing method for the above.

[0006]

In order to solve the above-mentioned problems, in the present invention, various experiments and examinations were conducted in order to obtain metal handprints and footprints on which delicate fingerprints, footprints and the like were transferred.
As a result, it has been found that in order to manufacture such handprints and footprints, it is extremely important to select a superplastic metal material which is a particularly optimum component and to form it under specific conditions.

[0007]

[0008]

That is , the present invention provides a method for producing C ≦ 0.1 wt%, Si ≦
2.0 wt%, Mn ≦ 2.0 wt%, Ni: 4-10 wt%, Cr: 15-30
wt%, N: 0.05 ~ 0.30wt%, B: 0.001 ~ 0.01wt%,
O: A material containing ≦ 0.005 wt%, the balance being Fe and unavoidable impurities and having a thickness of 2.0 mm or less, is polymerized into a mold having ultra-fine irregularities in a temperature range of 800 to 500 ° C. for 30 minutes. After holding the above and performing rough forming under a pressure of 5 kgf / cm ² or more, furthermore, in the same temperature range and 50 ° C.
Hold at high temperature for 30 minutes or more, and perform fine molding under pressure of 10 kgf / cm ² or more. is there.

Further, the present invention relates to a method for producing a polymer having C ≦ 0.1 wt%, Si ≦ 2.0
wt%, Mn ≦ 2.0 wt%, Ni: 4-10 wt%, Cr: 15-30 wt%
%, N: 0.05 to 0.30 wt%, B: 0.001 to 0.01 wt%, O:
≦ 0.005 wt%, and further contains at least one of Cu, W, V, Mo, Ti and Nb in an amount of 5 wt% or less, with the balance being
A material consisting of Fe and unavoidable impurities with a thickness of 2.0 mm or less is
Maintain in a temperature range of 1050 ° C for 30 minutes or more and perform rough forming under a pressure of 5 kgf / cm ² or more, and then hold in the same temperature range and 50 ° C or more higher than the temperature during rough forming for 30 minutes or more. Then 10
This is a method for producing a molded article such as a handprint having fine irregularities, characterized by performing superplastic molding in two stages of fine molding under a pressure of kgf / cm ² or more.

[0011]

According to the present invention, in manufacturing a bill or the like using a superplastic metal material, the composition of the superplastic metal material, the thickness of the superplastic metal material, and the two-step superplastic forming of coarse forming and fine forming. The processing conditions are defined as described above, and by satisfying such conditions, a portion of the material having a large deformation (e.g., a bottom portion) and a portion of a small deformation amount (e.g. The balance of the amount of deformation of the shoulder portion can be maintained, and as a result, fine irregularities such as fingerprints appearing on the prototype can be transferred almost as they are.

In the present invention, the thickness of the superplastic material is 2 mm.
The reason is as follows, because the use of such a material makes it possible to reproduce fine irregularities.

In the production of bills and the like, superplastic forming is processed in two stages. The reason is as follows.
First, a large uneven pattern and a fine uneven pattern can be accurately transferred, respectively.Second, when a female mold made of a ceramic suitable for use in producing this type of molded product is used, the female mold is used. This is because a high pressure (gas pressure), which is advantageous for reproducing fine irregularities, can be applied as necessary without fear of causing breakage.

Next, the reasons for limiting the component composition of the material applied to the method of the present invention will be described. C: 0.1 wt% or less (hereinafter, wt% is simply indicated by "%") If C is added in a large amount, carbides precipitate during superplastic forming, which causes deterioration of superplastic performance. Therefore, in the present invention, the content of C is limited to 0.1% or less. Si: 2.0% or less Si is an element added as a deoxidizing agent, but if its content exceeds 2.0%, there is a disadvantage that the material is hardened. Therefore, in the present invention, the content of Si is limited to 2.0% or less.

Mn: 2.0% or less Mn is an element added for improving workability. However, if its content exceeds 2.0%, there is a disadvantage that hot workability is deteriorated. Therefore, in the present invention, the content of Mn is set to 2.0%
Limited to the following. Ni: 4 to 10% Ni is a main component of the duplex stainless steel, and it is necessary to maintain a phase ratio between ferrite and austenite. Therefore, in the present invention, the content of Ni is limited to the range of 4 to 10%.

Cr: 15 to 30% Cr is an element to be added from the viewpoint of corrosion resistance. If the content is less than 15%, the corrosion resistance is not sufficient, and if it exceeds 30%, embrittlement becomes remarkable. Therefore, in the present invention, the content of Cr is limited to the range of 15 to 30%. N: 0.05 to 0.30% N is an element added from the viewpoint of corrosion resistance. However, if it is less than 0.05%, the corrosion resistance is not sufficient, and if it exceeds 0.30%, the strength becomes too large and processing becomes difficult. Therefore, in the present invention, the content of N is limited to the range of 0.05 to 0.30%.

B: 0.001 to 0.01% B is a particularly important element in the present invention. Although this element is generally known to improve hot workability, the present inventors have found that this element improves fine superplastic deformability in superplastic forming,
In particular, good deformability is shown in the range of 0.001 to 0.01%. However, addition beyond this range will degrade the cleanliness of the steel and will also degrade superplastic performance. Therefore, in the present invention, the content of B is 0.001 to 0.
Limited to 01% range.

In the present invention, in order to improve the corrosion resistance of steel, at least one element of Cu, W, V, Mo, Ti, and Nb in addition to the above elements can be added up to 5% in total. However, if the added amount exceeds 5%, there is a disadvantage that workability is deteriorated. For this reason, in the present invention, when the above elements are added, the content is limited to 5% or less.

Next, the manufacturing conditions in the present invention will be described. The point of the present invention is that the superplastic forming is divided into two stages, and the gas pressure at that time is set to a pressure corresponding to each stage, and is set to a higher pressure than the conventional case of the same forming plate thickness. is there.

In the present invention, first, as a first step, in order to avoid imposing a significant burden on the mold, the superplastic material is superposed on the mold in a temperature range of 800 to 500 ° C.
The superplastic forming corresponding to the rough forming is performed at a gas pressure of 5 kgf / cm ² or more while maintaining the temperature range of 30 minutes or more. In other words, at this stage, the temperature and gas pressure are slightly lowered, and the superplastic material (plate)
(For example, in the production of a bill, at this stage, it is shaped into a palm or a finger).

As a second step, in the present invention, a gas pressure of 10 kgf / cm ² or more is maintained in the same temperature range as the first step and at a temperature of 50 ° C. or more higher than the temperature at the time of rough molding for 30 minutes or more. And superplastic forming corresponding to fine forming. At this stage, it is a process for activating diffusion, which is a condition for transferring fine irregularities such as fingerprints appearing in the prototype, to eliminate the σ phase of the duplex stainless steel, and to increase the viscous flow capability. The temperature range is a temperature higher than the normal superplastic forming temperature of the duplex stainless steel, and although the superplastic performance is slightly inferior, fine irregularities formed on the prototype are faithfully transferred by this second step.

Through the above-described processing, it is possible to manufacture a molding material according to the purpose while reducing the load of pressure on the ceramic mold. FIG. 1 is a photograph of a handprint obtained by applying the manufacturing method of the present invention.

[0023]

EXAMPLE 10 kg of a duplex stainless steel having the composition shown in Table 1 was melted in an air induction furnace, subjected to hot rolling, annealing, and cold rolling to finish a sheet of 0.5 to 3.0 mm. The sheet was superplastically formed under the conditions shown in Table 2 and was subjected to superplastic forming as shown in FIG.
Made a good bill. The evaluation of the quality of the obtained bill is also shown in Table 2. The female mold used for producing the bill was made of ceramics.

[0024]

[Table 1]

[0025]

[Table 2]

In the evaluations in Table 2, は indicates that the fine irregularities could be faithfully transferred, Δ indicates that there were some defective portions, and X indicates that the fine irregularities were completely transferred. This indicates that it was not possible. When the bill was manufactured according to the present invention, the mold was not damaged at all and the product quality was all good.

[0027]

As described above, according to the present invention, it is possible to manufacture a very precise molded product such as a bill without causing breakage of the molding die.

[Brief description of the drawings]

FIG. 1 is a front view of a bill manufactured according to the method of the present invention.

[Description of Signs] 1 Superplastic forming plate 2 Handprint

Claims (2)

(57) [Claims] [Claim 1] C ≦ 0.1 wt%, Si ≦ 2.0 wt%, Mn ≦ 2.0 wt%, Ni: 4 to 10 wt%, Cr: 15 to 30 wt%, N: 0.05 to 0.30 wt%, B: 0.001 to 0.01 wt%, O: A material containing ≤0.005 wt%, the balance being Fe and unavoidable impurities and having a thickness of 2.0 mm or less is polymerized into a mold having ultra-fine irregularities.
Keep in the temperature range of 800 to 1,050 ° C for 30 minutes or more, 5kgf / cm ²
After rough forming under the above pressure, furthermore, hold at the same temperature range and at a temperature higher than 50 ° C. higher than the temperature at the time of rough forming for 30 minutes or more, and finely mold under a pressure of 10 kgf / cm ² or more, A method for producing a molded article such as a handprint having fine irregularities, wherein superplastic molding is performed in two stages. 2. C ≦ 0.1 wt%, Si ≦ 2.0 wt%, Mn ≦ 2.0 wt%, Ni: 4 to 10 wt%, Cr: 15 to 30 wt%, N: 0.05 to 0.30 wt%, B: 0.001 to 0.01 wt%, O: ≦ 0.005 wt%, further contains at least one of Cu, W, V, Mo, Ti and Nb in an amount of 5 wt% or less, with the balance being 2.0 mm in thickness consisting of Fe and unavoidable impurities. The following materials were polymerized into a mold with very fine irregularities,
After performing rough forming under a pressure of 5 kgf / cm ² or more while maintaining the temperature for at least
A method of manufacturing a molded article such as a handprint having fine irregularities characterized by performing a two-stage superplastic molding in which the composition is finely molded under a pressure of 10 kgf / cm ² or more while being held at a temperature of 30 ° C. or higher for 30 minutes or more. .