Method for manufacturing a shaped body, intermediate body, and shaped body

Abstract

To provide a shaped body manufacturing method that can manufacture a shaped body having excellent creep characteristics.SOLUTION: This method for manufacturing a shaped body includes: a fabrication step for fabricating an intermediate through powder bed fusion using a powder comprising a gamma prime precipitation-strengthened-type Ni-based alloy; and a heat treatment step for heat-treating the intermediate. The Ni-based alloy contains, in terms of mass percentage, 7.0-17.0% of Cr, 7.0-12.0% of Co, 5.0-8.0% of Al+Ti, 2.0-12.0% of W, 1.5-4.4% of Nb+Ta, 2.3% or less of Mo, 0.3% or less of C, 2.0% or less of Hf, and 0.2% or less of Zr. In the fabrication step, when applying a laser onto a layer formed of powder along a plurality of scanning lines parallel to each other, a value found by dividing the interval between the scanning lines by a laser spot diameter is 0.6-1.1.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a method for manufacturing a shaped body, and intermediates and shaped bodies obtained at intermediate and final stages of the method.

Background Art

[0002] Conventionally, a method is known in which an intermediate is produced by powder bed fusion using a powder composed of a Ni-based alloy, and a shaped body is produced by heat-treating this intermediate (see, for example, Patent Document 1). A shaped body made of a Ni-based alloy manufactured by such a manufacturing method is used as a high-temperature component such as a gas turbine engine.

[0003] As the Ni-based alloy constituting the powder, a gamma prime precipitation-strengthened Ni-based alloy may be used. A gamma prime precipitation-strengthened Ni-based alloy is a Ni-based alloy whose composition is prepared so that a gamma prime (Ni3(Al,Ti)) phase for strength strengthening precipitates by heat treatment.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] When using a powder composed of a gamma prime precipitation-strengthened Ni-based alloy as described above, it is difficult to manufacture a shaped body having excellent creep characteristics by ordinary powder bed fusion.

[0006] Therefore, an object of the present invention is to provide a method for manufacturing a shaped body capable of manufacturing a shaped body having excellent creep characteristics, and a shaped body obtained by this method for manufacturing a shaped body.

Means for Solving the Problems

[0007] In order to solve the above problems, as a result of intensive research by the inventors of the present invention, in powder bed fusion in which a laser is irradiated along a plurality of scanning lines parallel to each other on a layer made of powder, it has been found that there is a correlation between the value obtained by dividing the interval between those scanning lines by the laser spot diameter and the creep characteristics of the shaped body. The present invention has been made from such a viewpoint.

[0008] That is, the method for manufacturing a shaped body of the present invention includes a manufacturing step of producing an intermediate by powder bed fusion using a powder made of a gamma prime precipitation-strengthened Ni-based alloy, and a heat treatment step of heat-treating the intermediate. The Ni-based alloy contains, by mass percentage, 7.0 to 17.0% Cr, 7.0 to 12.0% Co, 5.0 to 8.0% Al + Ti, 2.0 to 12.0% W, 1.5 to 4.4% Nb + Ta, 2.3% or less Mo, 0.3% or less C, 2.0% or less Hf, and 0.2% or less Zr. In the manufacturing step, when irradiating a laser along a plurality of scanning lines parallel to each other on the layer made of the powder, the value obtained by dividing the interval between the plurality of scanning lines by the laser spot diameter is set to 0.6 or more and 1.1 or less.

[0009] According to the above configuration, a shaped body having excellent creep characteristics can be manufactured.

[0010] The intermediate of the present invention is an intermediate made of a Ni-based alloy and having columnar crystal grains with a dendritic crystal structure. The Ni-based alloy contains, by mass percentage, 7.0 to 17.0% Cr, 7.0 to 12.0% Co, 5.0 to 8.0% Al + Ti, 2.0 to 12.0% W, 1.5 to 4.4% Nb + Ta, 2.3% or less Mo, 0.3% or less C, 2.0% or less Hf, and 0.2% or less Zr. The interval between the branches of the primary dendrites of the dendritic crystal structure is less than 3 μm, and the orientation ratio of the {100} plane in the cross-section orthogonal to the longitudinal direction of the columnar crystal grains is 30% or more.

[0011] The intermediate produced by powder bed fusion has columnar crystal grains with dendritic crystals. In the shaped body produced by casting, the interval between the branches of the primary dendrites of the dendritic crystal structure is greater than about 40 μm, while in the intermediate produced by powder bed fusion using a laser as a heat source, the interval between the branches of the primary dendrites of the dendritic crystal structure is less than 3 μm. Further, if the value obtained by dividing the interval between a plurality of scanning lines by the laser spot diameter in powder bed fusion is 0.6 or more and 1.1 or less, the orientation ratio of the {100} plane on a specific cross-section (a cross-section orthogonal to the longitudinal direction of the columnar crystal grains) is 30% or more.

[0012] The shaped body of the present invention is a shaped body made of a Ni-based alloy and having columnar crystal grains with a non-dendritic crystal structure. The Ni-based alloy contains, by mass percentage, 7.0 to 17.0% of Cr, 7.0 to 12.0% of Co, 5.0 to 8.0% of Al + Ti, 2.0 to 12.0% of W, 1.5 to 4.4% of Nb + Ta, 2.3% or less of Mo, 0.3% or less of C, 2.0% or less of Hf, and 0.2% or less of Zr. The crystal grain aspect ratio, which is the value obtained by dividing the sum of the ratios of the major axis length to the minor axis length when approximating the shape of each columnar crystal grain within the observation range on a cross-section parallel to the longitudinal direction of the columnar crystal grains to an ellipse of the same area by the number of columnar crystal grains within the observation range, is 2.70 or more.

[0013] When the intermediate as described above is heat-treated, although the dendritic crystal structure disappears, the crystal grain aspect ratio of the shaped body becomes 2.70 or more. That is, the shaped body having this configuration is a shaped body with excellent creep characteristics.

Effect of the Invention

[0014] According to the present invention, a shaped body with excellent creep characteristics can be manufactured.

Brief Description of the Drawings

[0015]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Mode for Carrying Out the Invention

[0016] The method for manufacturing a shaped body according to an embodiment of the present invention includes a manufacturing step of producing an intermediate body by powder bed fusion and a heat treatment step of heat-treating the produced intermediate body. Hereinafter, each step will be described in detail.

[0017] <Manufacturing Step> In powder bed fusion, a powder made of a gamma prime precipitation-strengthened Ni-based alloy is used. In powder bed fusion, the heat source for melting the powder may be an electron beam in some cases, but in this embodiment, the heat source is a laser.

[0018] In powder bed fusion, as shown in FIG. 1, a layer 3 made of powder is formed on the platform 1, and a laser is irradiated along a plurality of scanning lines 4 parallel to each other on the layer 3. The laser is irradiated so as to be focused near the surface of the layer 3. The position, shape, and length of each scanning line 4 are determined by the cross-sectional shape of the intermediate body (the same shape as the final shaped body) to be produced. For example, the scanning line 4 may be a straight line or a curve.

[0019] FIG. 1 is an example of fabricating a prismatic intermediate. In FIG. 1, the scanning directions of the laser for adjacent scanning lines 4 are opposite to each other, but the scanning directions of the laser for all the scanning lines 4 may be the same direction.

[0020] By irradiating layer 3 with a laser, part or all of layer 3 is melted and solidified. Thereafter, the platform 1 is lowered by the thickness of layer 3, a new layer (hereinafter, the uppermost layer) 3 made of powder is formed on the immediately preceding layer (hereinafter, the immediately preceding layer) 3, and the uppermost layer 3 is irradiated with a laser along a plurality of scanning lines 4 parallel to each other. Note that the bed 2 includes the already fabricated part where the uppermost layer 3 is formed on the immediately preceding layer 3 and the unmelted powder.

[0021] In the uppermost layer 3 and the immediately preceding layer 3, the directions of the scanning lines 4 may be the same or different. When the directions of the scanning lines 4 in the uppermost layer 3 and the immediately preceding layer 3 are different, the angle of the scanning line 4 in the uppermost layer 3 with respect to the scanning line 4 in the immediately preceding layer 3 (hereinafter, the scanning rotation angle) can be determined as appropriate. For example, in FIG. 1, the scanning rotation angle is 90 degrees.

[0022] By repeating the above operations and finally removing the unmelted powder from the bed 2, an intermediate is fabricated. Such an intermediate has columnar crystal grains of dendritic crystals. Also, the spacing between the branches of the primary dendritic crystals in the dendritic crystal structure is as small as less than 3 μm. The longitudinal direction of the columnar crystal grains is the stacking direction (the vertical direction in FIG. 1) during the fabrication of the intermediate.

[0023] The particle size distribution of the powder used in powder bed fusion is, for example, 5 to 75 μm, but desirably 15 to 63 μm. The thickness of each layer 3 is, for example, 20 to 60 μm.

[0024] The Ni-based alloy that constitutes the powder contains, as essential components other than Ni, in mass percentage (the same hereinafter), 7.0 to 17.0% of Cr, 7.0 to 12.0% of Co, 5.0 to 8.0% of Al + Ti, 2.0 to 12.0% of W, and 1.5 to 4.4% of Nb + Ta. Examples of such Ni-based alloys include IN738 (IN is an abbreviation of Inconel (registered trademark), the same hereinafter), IN738LC, CM247LC, Mar-M247, etc. Regarding Nb and Ta, the Ni-based alloy may not contain either Nb or Ta.

[0025] The content of each essential component is more preferably Cr: 7.0 to 10.0%, Co: 8.0 to 11.0, Al + Ti: 5.0 to 7.5%, W: 8.0 to 11.0%, and Nb + Ta: 2.0 to 4.0%.

[0026] The Ni-based alloy may contain at least one of Mo of 2.3% or less (preferably 0.2 to 1.0%), C of 0.3% or less (preferably 0.01 to 0.2%), Hf of 2.0% or less (preferably 0.5 to 2.0%), and Zr of 0.2% or less as other optional components. The remainder other than the above-described components of the Ni-based alloy is Ni and inevitable impurities.

[0027] In this embodiment, when irradiating the laser on each layer 3, the value (L / D) obtained by dividing the interval L between the scanning lines 4 by the laser spot diameter D is set to be 0.6 or more and 1.1 or less. The laser spot diameter D is the beam diameter at the position where the intensity of the laser has dropped from the peak value to 1 / e 2 (in other words, the position where it becomes about 13.5% of the peak value). Among the powder bed fusion apparatuses using a laser, there are those in which the laser spot diameter can be set by the device user and those in which it cannot be set.

[0028] The laser spot diameter D is, for example, 0.02 to 0.20 mm, but preferably 0.05 to 0.15 mm. The interval L between the scanning lines 4 is, for example, 0.05 mm to 0.08 mm. Desirably, L / D is 0.6 or more and 0.9 or less.

[0029] The laser scanning speed is, for example, 500 to 3000 mm / s, preferably 600 to 2000 mm / s, and more preferably 700 to 1500 mm / s. The laser output is, for example, 100 to 400 W, preferably 130 to 350 W, and more preferably 150 to 300 W.

[0030] By setting the value (L / D) obtained by dividing the interval L between the scanning lines 4 when irradiating the laser on each layer 3 as described above by the laser spot diameter D to be 0.6 or more and 1.1 or less, the orientation ratio of the {100} plane in the cross-section (hereinafter referred to as the specific cross-section) orthogonal to the longitudinal direction of the columnar crystal grains of the intermediate body becomes 30% or more (35% or more depending on the conditions).

[0031] Here, the "orientation ratio of the {100} plane" is, as shown in FIG. 2, the area ratio of the crystal grains in which the angle difference between the normal direction of the measurement surface (the upward direction in FIG. 2) and the normal direction of the {100} plane of the crystal grains in the measurement surface is within 15 degrees, calculated by the EBSD (Electron Backscatter Diffraction) method. For reference, in a cast body of a Ni-based alloy, generally, when a creep load is applied in a direction perpendicular to the {100} plane, the creep rupture life becomes longer.

[0032] <Heat treatment process> The heat treatment performed in the heat treatment process includes, for example, HIP (Hot Isostatic Pressing) treatment, solution treatment, and aging treatment as shown in FIG. 3. However, the HIP treatment may be omitted, or both the HIP treatment and the solution treatment may be omitted.

[0033] In the HIP treatment, the intermediate body is put into a furnace filled with an inert gas, and the furnace is heated and pressurized for a predetermined time. Examples of the inert gas include argon. The heating and pressurizing time is, for example, 0.5 to 6 hours, preferably 1 to 5 hours. The heating temperature is, for example, 1150 to 1300 °C, preferably 1180 to 1260 °C. The pressure during pressurization is, for example, 80 to 160 MPa, preferably 90 to 150 MPa.

[0034] In the solution treatment, the intermediate is heated in air or vacuum or an inert gas atmosphere for a predetermined time and then cooled. The cooling method may be any of air cooling (including gas fan cooling), water cooling, and oil cooling. The heating time is, for example, 0.5 to 6 hours, preferably 1 to 4 hours. The heating temperature is, for example, 1150 to 1300 °C.

[0035] In the aging treatment, the intermediate is heated in air or vacuum or an inert gas atmosphere for a relatively long predetermined time and then cooled. The cooling method may be any of air cooling (including gas fan cooling), water cooling, oil cooling, and furnace cooling. In the aging treatment, heating and cooling may be repeated. The heating time for one time is preferably, for example, 1 to 48 hours. The heating temperature is, for example, 700 to 1200 °C.

[0036] Through the above manufacturing process and heat treatment process, a formed body is manufactured. Since the dendritic crystal structure disappears due to the heat treatment, the formed body has columnar crystal grains with a non-dendritic crystal structure.

[0037] In the obtained formed body, the crystal grain aspect ratio is 2.70 or more. The crystal grain aspect ratio is the value obtained by dividing the sum of the ratios of the major axis length to the minor axis length when the shape of each columnar crystal grain within the observation range on a cross-section parallel to the longitudinal direction of the columnar crystal grain (a cross-section perpendicular to the specific cross-section described above) is approximated to an ellipse of the same area by the number of columnar crystal grains within the observation range. That is, the crystal grain aspect ratio is obtained from the following formula. Note that the crystal grain aspect ratio may be 5.00 or less, or may be 4.00 or less.

[0038]

Equation

[0039] The formed body obtained by the manufacturing method of the present embodiment is a formed body excellent in creep characteristics.

Example

[0040] Hereinafter, the present invention will be described with reference to examples, but the present invention is not limited to the following examples.

[0041] (Example 1) An intermediate body having a rectangular parallelepiped shape (10 mm × 10 mm × 60 mm) long in the stacking direction was produced by powder bed fusion using a powder having alloy components equivalent to CM247LC. The particle size distribution of the powder was 16 to 45 μm. Further, when analyzing the alloy components of the powder, the contents of components other than Ni were Cr: 8.0%, Co: 9.1%, Al: 5.5%, Ti: 0.7%, W: 9.5%, Nb: 0%, Ta: 3.1%, Mo: 0.5%, C: 0.06%, Hf: 1.5%, Zr: 0.01% (the contents of inevitable impurities are omitted).

[0042] As the powder bed fusion apparatus, EOS M290 manufactured by EOS was used. In this apparatus, the laser spot diameter D is set to 0.08 mm on the manufacturer side. The thickness of each layer when manufacturing the formed body was 40 μm, the interval between scanning lines when irradiating the laser on each layer was 0.05 mm, the laser scanning speed was 1000 mm / s, the laser output was 180 W, and the scanning rotation angle was 90 degrees.

[0043] The above intermediate body was subjected to HIP treatment, solution treatment, and aging treatment to obtain a formed body. In the HIP treatment, argon was used as the inert gas, the heating and pressurization time was 4 hours, the heating temperature was 1250°C, and the pressure during pressurization was 140 MPa. In the solution treatment, the intermediate body was heated in an argon atmosphere and then cooled, the heating time was 2 hours, and the heating temperature was 1250°C. In the aging treatment, the intermediate body was heated and cooled twice in an argon atmosphere. In the first heating, the heating time was 4 hours and the heating temperature was 1080°C, and in the second heating, the heating time was 20 hours and the heating temperature was 870°C.

[0044] (Example 2) A shaped body was manufactured in the same manner as in Example 1, except that the interval between scanning lines when irradiating each layer with a laser was set to 0.06 mm.

[0045] (Example 3) A shaped body was manufactured in the same manner as in Example 2, except that the scanning rotation angle was set to 67 degrees.

[0046] (Example 4) A shaped body was manufactured in the same manner as in Example 1, except that the interval between scanning lines when irradiating each layer with a laser was set to 0.07 mm.

[0047] (Example 5) A shaped body was manufactured in the same manner as in Example 1, except that the interval between scanning lines when irradiating each layer with a laser was set to 0.08 mm.

[0048] (Comparative Example 1) A shaped body was manufactured in the same manner as in Example 1, except that the interval between scanning lines when irradiating each layer with a laser was set to 0.04 mm.

[0049] (Comparative Example 2) A shaped body was manufactured in the same manner as in Example 1, except that the interval between scanning lines when irradiating each layer with a laser was set to 0.09 mm.

[0050] (Comparative Example 3) A shaped body was manufactured in the same manner as in Example 1, except that the interval between scanning lines when irradiating each layer with a laser was set to 0.10 mm.

[0051] The manufacturing conditions of the shaped bodies of Examples 1 to 5 and Comparative Examples 1 to 3 are shown in Table 1. Table 1 also shows the value (L / D) when the interval L between scanning lines is divided by the laser spot diameter D.

[0052]

Table 1

[0053] (Calculation of the orientation ratio of the intermediate) The intermediates of Examples 1 to 5 and Comparative Examples 1 to 3 were cut along a plane orthogonal to the longitudinal direction (lamination direction), and the orientation ratio of the {100} plane on the cut surface was calculated. For this calculation, as the EBSD apparatus, SEM-SU5000 manufactured by Hitachi, Ltd. and Pegasus Digiview5 manufactured by EDAX / TSL were used, and as the analysis software, OIM Data Collection / OIM Analysis ver.8 manufactured by EDAX / TSL was used.

[0054] Regarding the measurement of the orientation ratio of the {100} plane, more specifically, as a pre-treatment, the cut surface was mechanically polished using waterproof abrasive paper and diamond abrasive grains, and then polished using colloidal silica. This pre-treatment is for reducing measurement defects and ensuring measurement accuracy, and is generally used for EBSD measurement. Next, Kikuchi lines were measured at a step size of 3 μm for a region of 900 μm × 900 μm on the cut surface, and analyzed using analysis software to obtain the orientation ratio of the {100} plane.

[0055] (Calculation of the grain aspect ratio of the shaped body) The shaped bodies of Examples 1 to 5 and Comparative Examples 1 to 3 were cut along a plane parallel to the longitudinal direction (lamination direction), and the grain aspect ratio within the observation range on the cut surface was calculated. For this calculation, the same EBSD apparatus and analysis software as those used for the calculation of the orientation ratio were used.

[0056] Regarding the measurement of the grain aspect ratio, the same pre-treatment as that used for the measurement of the orientation ratio was used. Next, Kikuchi lines were measured at a step size of 6 μm for a region of 1800 μm × 1800 μm on the cut surface, and analyzed using analysis software to obtain the grain aspect ratio. In calculating the grain aspect ratio, the measurement points where the azimuth difference between adjacent measurement points was 15° or more were regarded as grain boundaries.

[0057] Table 2 shows the orientation ratios of the intermediates of Examples 1 to 5 and Comparative Examples 1 to 3, and the grain aspect ratios of the shaped bodies of Examples 1 to 5 and Comparative Examples 1 to 3.

[0058]

Table 2

[0059] As is clear from Table 2, in the formed bodies of Examples 1 to 5 in which the interval between scanning lines when irradiating the laser on each layer was adjusted so that L / D was 0.6 or more and 1.1 or less, the crystal grain aspect ratio was 2.70 or more. On the other hand, in the formed bodies of Comparative Examples 1 to 3 in which L / D was less than 0.6 or more than 1.1, the crystal grain aspect ratio was less than 2.70.

[0060] The above difference in crystal grain aspect ratio is presumed to be due to the orientation ratio of the intermediate body. That is, the orientation ratio of the intermediate bodies of Examples 1 to 5 was 30% or more, while the orientation ratio of the formed bodies of Comparative Examples 1 to 3 was less than 30%. In particular, in Examples 1 to 4 in which L / D was 0.6 or more and 0.9 or less, the orientation ratio of the intermediate body was 35% or more, and the crystal grain aspect ratio of the formed body was 2.90 or more.

[0061] When HIP treatment is performed as the heat treatment, since the crystal orientation in the formed body is different from that of the intermediate body and becomes random, the orientation ratio of the formed body becomes a low value.

[0062] (Creep rupture test) From the formed bodies of Examples 1 to 5 and Comparative Examples 1 to 3, bar-shaped test pieces as shown in FIG. 4 were cut out, and this test piece was pulled in the longitudinal direction, and the time until the test piece broke was measured. The temperature of the test piece was 980 °C, and the tensile stress was 90 MPa.

[0063] Table 3 shows the results of the creep rupture test. Further, FIG. 5 shows the relationship between the orientation ratio of the intermediate bodies of Examples 1 to 5 and Comparative Examples 1 to 3 and the rupture time in the creep rupture test.

[0064]

Table 3

[0065] As is clear from Table 3 and FIG. 5, in Comparative Examples 1 to 3 where L / D was less than 0.6 or more than 1.1, the breaking time was short, less than 1800 hours. On the other hand, in Examples 1 to 5 where L / D was 0.6 or more and 1.1 or less, the breaking time was long, more than 1800 hours. In particular, in Examples 1 to 4 where L / D was 0.6 or more and 0.9 or less, the breaking time was considerably long, more than 2500 hours. In Example 1, the breaking time was remarkably long, more than 3500 hours. However, it is presumed that this is because breakage occurred at a position different from other examples and comparative examples only in this Example 1.

[0066] Further, FIG. 6 shows the relationship between the crystal grain aspect ratio of the shaped bodies of Examples 1 to 5 and Comparative Examples 1 to 3 and the breaking time in the creep rupture test. From FIG. 6, it can be seen that the longer the crystal grain aspect ratio of the shaped body, the longer the breaking time.

Explanation of Signs

[0067] 1 Platform 2 Bed 3 Layer 4 Scanning line

Claims

1. A manufacturing process of producing an intermediate by powder bed fusion using a powder made of a gamma prime precipitation strengthened Ni-based alloy, and a heat treatment process of heat-treating the intermediate, wherein the Ni-based alloy contains, by mass percentage, 7.0 to 10.0% of Cr, 8.0 to 11.0% of Co, 5.0 to 7.5% of Al + Ti, 8.0 to 11.0% of W, 2.0 to 4.0% of Nb + Ta, 0.2 to 1.0% of Mo, 0.01 to 0.2% of C, 0.5 to 2.0% of Hf, 0.2% or less of Zr, the balance being composed of Ni and unavoidable impurities, in the manufacturing process, when irradiating a laser along a plurality of scanning lines parallel to each other on a layer made of the powder, the value obtained by dividing the interval between the plurality of scanning lines by the laser spot diameter is 0.6 or more and 1.1 or less, A method for manufacturing a shaped body.

2. An intermediate having columnar crystal grains with a dendritic crystal structure, made of a Ni-based alloy, wherein the Ni-based alloy contains, by mass percentage, 7.0 to 10.0% of Cr, 8.0 to 11.0% of Co, 5.0 to 7.5% of Al + Ti, 8.0 to 11.0% of W, 2.0 to 4.0% of Nb + Ta, 0.2 to 1.0% of Mo, 0.01 to 0.2% of C, 0.5 to 2.0% of Hf, 0.2% or less of Zr, the balance being composed of Ni and unavoidable impurities, the interval between the branches of the primary dendrites of the dendritic crystal structure is less than 3 μm, and the orientation ratio of the {100} plane in the cross-section orthogonal to the longitudinal direction of the columnar crystal grains is 30% or more. An intermediate.

3. A shaped body having columnar crystal grains with a non-dendritic crystal structure, made of a Ni-based alloy, wherein the Ni-based alloy contains, by mass percentage, 7.0 to 10.0% of Cr, 8.0 to 11.0% of Co, 5.0 to 7.5% of Al + Ti, 8.0 to 11.0% of W, 2.0 to 4.0% of Nb + Ta, 0.2 to 1.0% of Mo, 0.01 to 0.2% of C, 0.5 to 2.0% of Hf, 0.2% or less of Zr, the balance being composed of Ni and unavoidable impurities, the grain aspect ratio, which is the value obtained by dividing the sum of the ratios of the minor axis length to the major axis length when approximating the shape of each columnar crystal grain within the observation range on the cross-section parallel to the longitudinal direction of the columnar crystal grains to an ellipse of the same area by the number of columnar crystal grains within the observation range, is 2.70 or more. A shaped body.

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