JP2003293093A - Method of producing stainless steel formed article having excellent shape precision - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of easily producing a stainless steel formed article having an excellent shape precision by press forming and the subsequent machining with stainless steel having excellent machinability as the stock. <P>SOLUTION: Stainless steel containing, by mass, ≤0.5% C, ≤1.0% Si, ≤1.0% Mn, 10 to 30% Cr, ≤0.60% Ni, 0.5 to 6.0% Cu, ≥0.005% Sn or In and ≤1.0% Al, and in which a second phase essentially consisting of Cu, and containing ≥10% Sn or In is dispersed into a matrix in the ratio of ≥0.2 vol.% is press- formed, and is thereafter subjected to machining. The stainless steel can be subjected to the press forming as heated. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is made of ferritic and martensitic stainless steels whose machinability has been improved by adding non-toxic Cu, by press molding and finish cutting, and mechanical parts, electronic electrical parts, The present invention relates to a method for manufacturing a stainless steel molded product having excellent shape accuracy, which can easily manufacture a metal molded component such as a hard disk hub that requires strict dimensional accuracy.

[0002]

2. Description of the Related Art Due to the remarkable development of the precision machinery industry and the increasing demand for household appliances, furniture and the like, stainless steel has come to be used even in the parts which have not been used in the past. Among such machine parts, there are some that require strict dimensional accuracy, such as parts that are rotated at high speed and parts that require built-in accuracy.
Processing by cutting from bulk material (total cutting)
Has been done. In such applications, S is used as a free-cutting element such as SUS430F specified in JIS G4303.
Is added and Se is added like 51430 (corresponding to Type430Se in AISI standard) defined in SAE,
Ferritic stainless steels with improved machinability have been used. Further, as martensitic stainless steel, a stainless steel with improved machinability by adding Pb as a free-cutting element such as SUS410F2 or SUS410F2 specified in JIS G4303, or adding S such as SUS416 or SUS420F. Has been used.

[0003]

However, the cutting process takes a long time for forming, requires a lot of processing energy, and the ratio of the used material to the input material is low, which not only causes an increase in manufacturing cost. However, there has been a problem that the total energy required for manufacturing the parts is increased and, as a result, the load on the global environment is increased. In addition, S-containing steel, which is a conventional steel for cutting, has a significantly reduced corrosion resistance, and Pb and Se-containing steel contains harmful elements, which is a problem in terms of environmental measures.

[0004] So far, as a method which does not use cutting steel, the problem is solved by press forming using ordinary stainless steel or press forming to a shape close to a target and then performing light finishing cutting. Tried. However, in the press working, due to the plastic anisotropy of the plate material, the plastic flow has directionality, and the target dimensional accuracy cannot be obtained. Further, when the press product is subjected to finish cutting, there is a problem that the stress and strain balance after press molding is broken and the dimensional accuracy further deteriorates. Also, when using ordinary stainless steel as the material,
During the final cutting after press molding, the bite was worn and the productivity was significantly reduced. Therefore, Pb which becomes an environmental problem
The conventional free-cutting stainless steel excluding the steels using Se and Se as free-cutting elements was used as the raw material, but the inclusions containing S etc. used as free-cutting elements were the starting points,
There was a problem that the target product shape could not be formed due to cracking during press forming.

By the way, the inventors of the present invention, as a means for significantly improving machinability without adversely affecting the environment,
Introduced a ferritic and martensitic stainless steel in which a predetermined amount of a second phase mainly composed of Cu containing a certain amount or more of Sn or In was precipitated (Japanese Patent Application No. 2001-2).
05349). The present invention has been devised to solve the above problems, using the stainless steel excellent in machinability introduced above as a raw material, and easily shape accuracy by press molding and subsequent cutting. It is an object of the present invention to provide a method for manufacturing an excellent stainless steel molded product.

[0006]

In order to achieve the object, the method for producing a stainless steel molded product excellent in shape accuracy according to the present invention has a mass% of C: 0.5% or less and Si: 1.0. %
Hereinafter, Mn: 1.0% or less, Cr: 10.0 to 30.0
%, Ni: 0.60% or less, Cu: 0.5 to 6.0%,
Sn or In: 0.005-0.8%, Al: 1.0
%, And a second phase mainly composed of Cu containing 10% or more of Sn or In dispersed in a matrix at a ratio of 0.2% by volume or more is subjected to cutting after press forming. Characterize.

This stainless steel also contains, in mass%,
S: less than 0.15%, Nb: 0.01 to 1.0%, T
i: 0.01 to 1.0%, Mo: 3.0% or less, Zr:
One or more of 1.0% or less, V: 1.0% or less, B: 0.05% or less, and rare earth element (REM): 0.05% or less can be contained. Further, such a stainless steel has a temperature A of 500 ° C. or higher after hot rolling until it becomes a final product, and is defined by the following formula (1).
One aging treatment in which the material is heated and held for 1 hour or more in the temperature range of C or less
A material that has been applied more than once to promote the precipitation of the second phase mainly composed of Cu containing 10% or more of Sn or In is preferable. Further, it is preferable that the press molding is performed in a state of being heated to a temperature range equal to or lower than AC defined by the following formula (1). AC = 35Cr + 75Si + 60Mo + 170Nb + 620Ti + 750Al-250C-280N -120Ni-70Mn-20 (Cu + Sn + In) +500 (1) In the present specification, Cu The second phase mainly composed of will be hereinafter referred to as "Cu-rich phase". Further, “%” indicating the content of each element in steel means “mass%” unless otherwise specified.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Stainless steel is generally poor in machinability and is regarded as one of difficult-to-cut materials. The causes of poor machinability include low thermal conductivity, high degree of work hardening, and easy adhesion. The present inventors have found that ε-C affects the lubrication and heat conduction between the tool and the work material.
Focusing on the action of the Cu-rich phase such as u, it was found that machinability is improved when Cu is added to stainless steel and a part thereof is finely and uniformly precipitated as the Cu-rich phase. . The improvement of machinability due to the Cu-rich phase is due to lubrication due to the Cu-rich phase on the tool scooping surface at the time of cutting, and wear due to the heat conduction effect to reduce the cutting resistance and prolong the tool life, resulting in the machinability. It is thought that the property will be improved. Especially in ferritic stainless steels and annealed martensitic stainless steels, the crystal structure is body-centered cubic bcc.
Precipitation of the rich phase has an even greater effect on machinability improvement as compared with the case of precipitating the Cu rich phase in austenitic stainless steel having the same crystal structure as the Cu rich phase.

The reason why the dispersed precipitation of the Cu-rich phase is different between the austenite type, the martensite type and the ferrite type is presumed as follows. When a face-centered cubic Cu-rich phase is precipitated in a martensitic or ferritic stainless steel matrix having a body-centered cubic crystal structure, C
The u-rich phase reduces the crystal conformity and enables the accumulation of large dislocations. Further, by adding 0.005% or more of Sn or In, which is the basis of the present invention, 10% or more of Sn or In is concentrated in the Cu-rich phase, and a Cu-Sn alloy or Cu-In alloy having a low melting point is obtained. Form. As described above, Cu has a high accumulation of dislocations and a low melting point.
Since the rich phase is dispersed as foreign matter in the matrix, the machinability, which is a fracture phenomenon, is improved, and the foreign matter having a low melting point has a lubricating action with the cutting tool, so that the tool life is significantly improved. It has been confirmed that machinability is improved by dispersing and precipitating such a Cu-rich phase in which Sn or In is concentrated in the matrix at a ratio of 0.2 vol% or more.

The cutting process is a process with a very high strain rate, that is, a fracture phenomenon. Press forming is a plastic deformation phenomenon in which the strain rate is three to four orders of magnitude lower than that in cutting. As described above, the Cu-rich phase has an action of accumulating dislocations at the time of high-speed deformation, effectively acts as a crack starting point, and contributes to improvement of machinability. However, in the case of low-speed strain processing such as press working, the dislocation can pass through the Cu-rich phase and does not accumulate the dislocation. Cu
Since the rich phase is an alloy phase mainly composed of Cu having a low yield point, the rich point has a low yield point. Therefore, when the main phase is dispersed, the shape fixability is improved. Therefore, if the Cu-rich phase is dispersed, the shape fixability is improved, and it is possible to obtain a product having a predetermined dimensional accuracy even if the amount of subsequent cutting is reduced.

If a ferritic and martensitic stainless steel having excellent machinability is used as a material and press-formed into a shape close to a target shape in advance, and then cutting is performed, the cutting amount is significantly higher than that of the conventional method. Stainless steel products with excellent shape accuracy can be easily manufactured with very little processing. Moreover, since the Cu-rich phase in which Sn or In is concentrated does not become a starting point of cracking, it does not hinder workability during press molding.

During press forming, it is preferable to keep the stainless steel material at a high temperature. When press-molding at normal temperature, due to the anisotropy of the material, even if the shape of the part is symmetrical, plastic flow may differ, and the dimensional accuracy may deteriorate. So, if you heat and process the material,
The yield strength is reduced to improve the shape fixability, the deformation resistance is reduced to facilitate plastic flow, the anisotropy is reduced to improve the workability, and the dimensional accuracy is improved. A higher heating temperature is more effective for improving workability, but if it is too high, the parent phase transforms, the solid solubility with respect to Cu and Sn increases, the Cu-rich phase forms a solid solution, and the machinability decreases. .

By the way, the present invention relates to a method for producing a stainless steel molded article having excellent dimensional accuracy. Since the dimensional accuracy of a molded product differs depending on the size and shape, it is difficult to define this as an absolute value. Molded articles used for rotating parts and molded articles requiring flatness are point-symmetrical or several-time symmetric systems, and these are collectively expressed as a dimensional accuracy index and defined as the d value. This d value was defined by the following equation (2), where X is a measured value of height, outer diameter, etc. at a symmetrical position at a distance r from the center point. ΔX / r = (X _max −X _min ) / r (2) When the component is manufactured by the total shaving process, the d value becomes 5.0 × 10 ⁻⁴ or less, so the present invention In this case, the target is 5.0 × 10 ⁻⁴ or less.

First, the alloy components, content, Cu-rich phase, etc. contained in the stainless steel material of the present invention will be described below. C: 0.5% or less Excessive C content causes reduction in manufacturability and corrosion resistance, so in the present invention, the upper limit of C content is set to 0.5%. It should be noted that C has a function of generating Cr carbide which is effective as a precipitation site of the Cu-rich phase and uniformly dispersing the fine Cu-rich phase throughout the matrix. In order to exhibit such an effect, in a ferrite system, 0.0
It is preferable that the content is 01% or more.

Si: 1.0% or less An alloy component effective for improving the corrosion resistance. But 1.0
If Si is contained in an excessive amount exceeding%, manufacturability deteriorates. Mn: 1.0% or less It has the effect of improving manufacturability and fixing harmful S in steel as MnS. MnS is an alloy component that is effective in forming a fine Cu-rich phase because it works effectively in improving machinability and also acts as a nucleus for Cu-rich phase formation. However, when an excessive amount of Mn exceeding 1.0% is included, the corrosion resistance tends to deteriorate.

Cr: 10.0 to 30.0% Cr is an alloy component required to maintain the original corrosion resistance of stainless steel, and to ensure the required corrosion resistance, 10.
Add 0% or more of Cr. However, if an excessive amount of Cr exceeding 30.0% is contained, the manufacturability and workability are adversely affected. Ni: 0.60% or less It is a component that is inevitably mixed from the raw materials in the industrial manufacturing process of stainless steel. In the present invention, 0.60% is set as the upper limit value of the level mixed in a normal production line.

Cu: 0.5-6.0% This is the most important alloying component in the stainless steel of the present invention, and 0.2% by volume is required for exhibiting good machinability.
It is necessary that the Cu-rich phase is precipitated in the matrix at the above ratio. In order to precipitate a Cu-rich phase of 0.2 volume% or more in the stainless steel having the composition of each alloy component specified as described above, the Cu content is 0.5%.
That is all. However, an excess amount of C exceeding 6.0%
Addition of u adversely affects manufacturability, workability, corrosion resistance and the like. The Cu-rich phase precipitated in the matrix is not particularly limited by the size of the precipitate, but it is preferable that the Cu-rich phase is uniformly dispersed on the surface and inside. C
The uniform dispersion of the u-rich phase stably improves the machinability.

Sn or In: 0.005-0.8% Like Cu, it is the most important alloy component in the present invention,
In order to develop good machinability, it is necessary to be contained in the Cu-rich phase in a proportion of 10% or more. When either or both of Sn and In are contained in the Cu-rich phase at this ratio, the Cu-rich phase itself has a low melting point, so that the machinability is remarkably improved. In order to realize this lowering of the melting point, the content of Sn or In in the entire alloy needs to be 0.005% or more. However, if the melting point is excessively lowered due to the increase in the content, the hot rolling property is significantly deteriorated due to the embrittlement of the liquid film, so the upper limit value is 0.8%.

Al: 1.0% or less It has a function of improving the corrosion resistance and precipitates as a compound effective as a nuclear site of a fine Cu-rich phase.
However, excessive addition of Al deteriorates manufacturability and workability, so the upper limit was set to 1.0%. S: 0.15% or less An element that forms MnS that is effective in improving machinability. It also has a function of forming Cu-rich phase nuclear sites by the formation of sulfides. However, if the S content exceeds 0.15%, the hot workability and ductility are significantly reduced. Therefore, in the present invention, the upper limit of the S content is set to 0.15%.
Set to.

Nb: 0.01 to 1.0% The Cu-rich phase has a strong tendency to precipitate around Nb-based precipitates among various precipitates. Therefore, in order to uniformly precipitate and disperse the Cu-rich phase, a structure in which Nb carbides, nitrides, carbonitrides, and the like are finely precipitated as necessary is preferable. However, the addition of an excessive amount of Nb adversely affects the manufacturability and workability. Therefore, when Nb is added, the Nb content is selected within the range of 0.01 to 1.0%. Ti: 0.02 to 1.0% This is an alloy component added as needed and, like Nb, is an alloy component that forms a carbonitride effective as a precipitation site of a Cu-rich phase. However, the addition of an excessive amount of Ti deteriorates manufacturability and workability and causes defects on the product surface. Therefore, when adding Ti, T
The i content is selected within the range of 0.02 to 1.0%.

Mo: 3.0% or less An alloy component added as necessary, which improves corrosion resistance and precipitates as an intermetallic compound such as Fe ₂ Mo that is effective as a nuclear site of a fine Cu-rich phase. . However, excessive Mo content exceeding 3.0% adversely affects manufacturability and workability. Zr: 1.0% or less It is an alloy component added as necessary, and is deposited as a carbonitride effective as a nuclear site of a fine Cu-rich phase. However, excessive addition of Zr adversely affects the manufacturability and workability, so that the upper limit of the content is regulated to 1.0% when Zr is added.

V: 1.0% or less It is an alloy component added as necessary and, like Zr, it precipitates as a carbonitride effective as a nuclear site of a fine Cu-rich phase. However, excessive addition of Zr adversely affects the manufacturability and workability, so that the upper limit of the content is regulated to 1.0% when Zr is added.

B: 0.05% or less An alloy component added as necessary, which improves hot workability and also becomes a precipitate and is dispersed in the matrix. The B precipitate also acts as a Cu-rich phase precipitation site. However, since excessive addition of B will reduce hot workability, the upper limit of the content is regulated to 0.05% when B is added. Rare earth element (REM): 0.05% or less It is an alloy component added as necessary, and improves the hot workability in the same manner as B by adding an appropriate amount. Further, it becomes a precipitate effective for the precipitation of the Cu-rich phase and is dispersed in the matrix. However, if added excessively, the hot workability deteriorates, so when adding a rare earth element, the upper limit of the content is restricted to 0.05%.

Heat treatment temperature: 500 ° C. or higher, AC or lower In order to obtain excellent machinability due to precipitation of a Cu-rich phase, aging treatment at a temperature of 500 ° C. or higher is effective. The lower the aging temperature, the more solid solution Cu in the matrix
The amount decreases and the amount of precipitation of the Cu-rich phase increases. However, if the aging treatment temperature is too low, the diffusion rate becomes slow, so that the precipitation amount tends to decrease rather. When the influence of the aging temperature on the precipitation of the Cu-rich phase effective for machinability was investigated from various experiments, it was 500 to 900 ° C.
Most effective for machinability when aging in the temperature range of
It was found that the rich phase precipitates at a ratio of 0.2 vol% or more.

However, when the AC temperature defined by the equation (1) is exceeded, the mother phase transforms into an austenite phase, and Cu or S
The solid solubility with respect to n and In becomes large, and the Cu rich phase decreases. AC = 35Cr + 75Si + 60Mo + 170Nb + 620Ti + 750Al-250C-280N -120Ni-70Mn-20 (Cu + Sn + In) +500 ・ ・ ・ (1) Therefore, the upper limit temperature of 900 ℃ is a rough guideline. ,
The strict upper limit temperature is equal to or lower than the AC point. Precipitation of the Cu-rich phase is easy to form carbonitrides or precipitates Nb, Ti, Mo
It is also promoted by the addition of elements such as, or by increasing the S content to form sulfides. Carbonitrides and sulfides,
It acts as a precipitation site and uniformly disperses the Cu-rich phase in the matrix to efficiently improve the machinability and the manufacturability at the time of manufacturing a molded product. The aging treatment is preferably performed for 1 hour or more, and may be performed at any stage from the end of hot rolling to the production of a product.

Press forming temperature: AC or less When a material is heated and processed, the yield strength is lowered and the shape fixability is improved, and the deformation resistance is reduced to facilitate plastic flow and the anisotropy is lowered, Workability is improved. Also in the stainless steel of the present invention, excellent dimensional accuracy can be obtained by press-molding in a state in which anisotropy is reduced by heating. The higher the heating temperature is, the more effective it is. However, if the heating temperature is higher than AC shown in equation (1),
Since the parent phase is transformed and the solid solubility with respect to Cu or Sn is increased, the Cu-rich phase is solid-solved and reduced, and the machinability is deteriorated. In addition, if heating is performed in excess of AC and press-molding, distortion in the product increases due to phase transformation due to cooling after pressing, and the desired dimensional accuracy cannot be obtained. Therefore, the upper limit is the AC point.

The purpose is achieved if the soaking time is 0 seconds or more, but soaking may be maintained for a longer time. However, if the heating is performed for an excessively long time, the size of the Cu-rich phase that expresses the machinability becomes small, and the amount thereof becomes small, so that the machinability effect is diminished. Further, since a large amount of oxide scale is generated during heating and holding to cause meat pressure loss, the upper limit of the soaking time is 10
It is preferable to make the minutes. The heating method is sufficient if it is a method capable of obtaining a uniform temperature distribution at the processed portion. Electrical heating or induction heating is desirable. A method of heating the entire mold in a heating furnace may be used as long as the material is uniformly heated to a target temperature. As described above, Sn or I
Stainless steel in which a Cu-rich phase in which n is concentrated is deposited has excellent shape fixability after press forming. Therefore,
Needless to say, it is not always necessary to perform hot press forming, and if cold cutting is performed and then ordinary cutting is performed, a machinability is excellent and a molded product with good dimensional accuracy can be obtained.

[0028]

EXAMPLES Example 1: Stainless steels A and B having the chemical composition shown in Table 1 were melted and forged in a vacuum melting furnace, and were then heated at 1230 ° C. for 1 hour.
After heating for an hour, hot rolling is performed, followed by aging treatment at 750 ° C for 12 hours, then pickling, and plate thickness 2 mm, width 40 m.
m steel strip was produced. After forming into a predetermined shape by press molding, the dimensional accuracy index d value was obtained. Furthermore, the same processed product,
About 0.1 mm depth from the surface layer was finished by rotary cutting, and d value was similarly measured. Figure 1 shows the shape and dimensional accuracy measurement position of the processed product. The processed product was a hat-shaped hat with an outer diameter of φ35 mm, and the dimensional accuracy was evaluated at eight points equally divided by an internal angle of 45 ° on the circumference of 16 mm from the center position.

[0029]

Table 2 shows the measurement results of the dimensional accuracy of the press-formed product and the cut-finished product. In the as-press-molded A1 and B1, the d value exceeds 5.0 × 10 ⁻⁴ , and sufficient dimensional accuracy is not obtained. However, only 0.
With A2, which was only cut to a depth of 1 mm, the d value was 5.0 x 1
It was 0 ^-4 , indicating good dimensional accuracy. On the other hand, B2
Although the dimensional accuracy is improved, the dimensional accuracy is not sufficient because the Cu and Sn contents are small.

[0031]

Example 2 Using stainless steels C to L having the chemical composition shown in Table 3, the thickness was 2 m in the same manner as in Example 1.
A steel strip having a width of m and a width of 40 mm was produced. This was press-molded to produce 1000 products having the shape shown in FIG. Table 4 shows the press molding results. In the steel types C to K, which are the steels of the present invention, there was no cracking in 1000 pieces and good press formability was exhibited. On the other hand, in the conventional stainless steel L used as a comparative product and using S as a free-cutting element, work cracking occurred in 263 pressed products and the yield was remarkably reduced.

[0033]

[0034]

For the steel types C to K, which had good press formability, each processed product was subjected to finish cutting at a depth of about 0.1 mm in the same manner as in Example 1. It should be noted that each processed product of the same material was cut using a new blade. Finish cutting 10
For the 00th product, the dimensional accuracy was measured at the same position as in Example 1. The results are shown in Table 5. All d values were 5.0 × 10 ⁻⁴ or less, indicating excellent dimensional accuracy.

[0036]

Example 3: Stainless steels M to U having the chemical components shown in Table 6 and commercially available steels were melted and forged in a vacuum melting furnace, and 12
After heating at 30 ° C for 1 hour, hot rolling, then 750 ° C
After aging treatment for 12 hours, pickled and plate thickness 2m
A steel strip having a width of m and a width of 37 mm was produced. Press molding was performed using a pressing device as shown in FIG. That is, a steel strip is continuously supplied and heated by energizing while sandwiching it between electrodes arranged before and after the press die, and immediately after reaching a predetermined temperature, as shown in FIG.
It was press-formed into the shape shown in, and subsequently cooled in the atmosphere. About the processed product which was not cracked at the stage of press molding, after cooling, about 0.1 m from the surface layer as in Example 1.
It was cut to a depth of m. Then, the d value was measured in the same manner as in Example 1 to evaluate the dimensional accuracy. Press temperature and workability,
Table 7 shows the measurement results of the relationship of dimensional accuracy after cutting.

[0038]

[0039]

Test N pressed at temperatures above the AC point
o. In M3, a work crack was generated at the punch shoulder. Similarly, the test No. with a large Cu content was used. P1 and Sn contents are 0.
Test No. over 8% Also in S1, work cracks were generated in the punch shoulder during press molding. Other tests N
o. Then, the press formability was good. The conventional free-cutting steels SUS430F and SUS41 used for comparison were used.
0F had a work crack in the punch shoulder during pressing. Test No. that caused work cracking The dimensional accuracy of the press-molded products excluding M3, P1, and S1 which were subjected to the cutting process were d values of 5.0 × 10 ⁻⁴ or less, indicating good dimensional accuracy.

[0041]

As described above, Sn or In
According to the method of the present invention in which a Cu-rich phase enriched in Cu is deposited and stainless steel having improved press formability and machinability is used as a material, the cutting amount after press forming can be reduced and the cutting can be easily performed. Therefore, it has dimensional accuracy equal to or better than that of a product machined from a bulk material. In addition, since the amount of shaving is reduced, the material yield is improved and processing can be performed in a short time, compared with the case where a molded product is manufactured by total shaving, so that the manufacturing cost can be significantly reduced.

[Brief description of drawings]

FIG. 1 is a diagram for explaining the shape of a processed product and the measurement position for dimensional accuracy.

FIG. 2 is a diagram illustrating an outline of an apparatus for press-molding in a heated state.

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) C22C 38/42 C22C 38/42 38/54 38/54 (72) Inventor Naoto Hiramatsu Nomura, Shinnanyo-shi, Yamaguchi Prefecture 4976 Minamimachi Nisshin Steel Co., Ltd. Stainless Business Division

Claims (4)

[Claims] 1. In mass%, C: 0.5% or less, Si:
1.0% or less, Mn: 1.0% or less, Cr: 10.0 to
30.0%, Ni: 0.60% or less, Cu: 0.5 to
6.0%, Sn or In: 0.005-0.8%, A
l: 1.0% or less, and a second phase mainly composed of Cu containing 10% or more of Sn or In dispersed in a matrix in a proportion of 0.2% by volume or more, after press molding, A method for manufacturing a stainless steel molded product excellent in shape accuracy, which is characterized by cutting. 2. Stainless steel, further comprising S:
Less than 0.15%, Nb: 0.01 to 1.0%, Ti:
0.01-1.0%, Mo: 3.0% or less, Zr: 1.
The shape accuracy according to claim 1, which includes one or more of 0% or less, V: 1.0% or less, B: 0.05% or less, and a rare earth element (REM): 0.05% or less. An excellent method for manufacturing stainless steel molded products. 3. A stainless steel having the composition according to claim 1 or 2, at a temperature of 500 ° C. or higher after hot rolling until it becomes a final product, and having an AC of not more than AC defined by the following formula (1). The aging treatment in which the material is heated and held in the temperature range for 1 hour or more is performed once or more to promote the precipitation of the second phase mainly containing Cu containing 10% or more of Sn or In, and then the forming and cutting are performed. 2. A method for producing a stainless steel molded product having excellent shape accuracy according to 2. AC = 35Cr + 75Si + 60Mo + 170Nb + 620Ti + 750Al-250C-280N -120Ni-70Mn-20 (Cu + Sn + In) +500 ・ ・ ・ (1) 4. The press molding is performed in a state of being heated in a temperature range of AC or lower defined by the following formula (1).
3. The method for producing a stainless steel molded product according to any one of 3 above, which is excellent in shape accuracy. AC = 35Cr + 75Si + 60Mo + 170Nb + 620Ti + 750Al-250C-280N -120Ni-70Mn-20 (Cu + Sn + In) +500 ・ ・ ・ (1)