JP5616845B2 - Method for producing Co-based alloy for living body - Google Patents

Description

  The present invention relates to a method for producing a Co-based alloy for a living body that has a good balance between strength and ductility as well as high corrosion resistance and can be suitably used as a material for artificial bones, particularly artificial joints. .

  Background Art Co-based alloys for living bodies have been conventionally used as materials for artificial bones, particularly artificial joints, and ASTM standard F799 is known as this living body Co-based alloy. However, although this ASTM-F799 has a rough chemical composition range and mechanical properties, and a rough manufacturing method as characteristics to be satisfied by a bio-based Co-based alloy for artificial bone, the specific provisions are as follows. It has not been.

  The main characteristics required of an artificial bone, particularly an artificial joint, are strength and ductility. First, it is necessary to have a good balance between both strength and ductility. Among them, in the knee joint and hip joint, there is a site where the biomedical metal material (Co-based casting alloy for biomedical use) and the biomedical polyethylene rub against each other. In addition, there is a demand for characteristics that are not worn by biomedical polyethylene. As a matter of course, since there is a problem that the artificial joint itself is enlarged, strength is necessary as a basic characteristic.

  In addition, there is a need to process a three-dimensional complicated shape in a metal material for a living body used particularly for a knee joint or the like.

  As a prior art regarding such a metal material for a living body used for an artificial bone, particularly a Co-based alloy for a living body, for example, there are proposals described in Patent Documents 1 to 3 below.

  Patent Document 1 discloses a biocompatible Co-based alloy that can obtain sufficient ductility by making the ε phase, which is an HCP phase, substantially a single phase, and a method for producing the alloy. However, since it is necessary to perform heat treatment for 24 hours at 800 ° C., sufficient ductility can be secured, but the maximum strength remains at about 800 MPa, and the strength is insufficient for use as a material for artificial bones, particularly artificial joints. It is.

  Patent Document 2 describes a Co-based alloy for living organisms and a method for producing the alloy. This alloy is obtained by quench-casting using a water-cooled copper mold, forging the resulting ingot, and adjusting the average crystal grain size to a structure of 50 μm or less. In the case of Co-29Cr-6Mo alloy, a strength close to 1200 MPa can be obtained. In addition, the Co-based alloy to which Ni is added in an amount of 16 to 24% can obtain a fracture elongation close to 0.5 with a true strain with a strength of about 1000 MPa, while the Co-based alloy to which Ni is not added has a true strain. The elongation at break up to about 0.2 is obtained (strength is 1200 MPa).

  However, addition of Ni is not preferable from the viewpoint of biocompatibility, and even if it is added, it should be made the minimum necessary amount, and a large amount of Ni of 16 to 24% is added from the viewpoint of biocompatibility. It is not particularly preferable. Further, the strength and ductility obtained when Ni is not added can be obtained by adopting a method of casting using a special mold, and a significant increase in cost cannot be avoided.

  In addition, the present inventors can obtain a strength and ductility equivalent to or higher than those of conventional biomedical Co-based alloys without adopting both a large amount of Ni addition and a casting method using a special mold. A bio-based Co-based alloy and a method for producing the same are proposed.

  The biomedical Co alloy has Cr: 26 to 30% by mass, Mo: 5 to 8% by mass, C: 0.20% by mass or less (not including 0% by mass), and N: 0.05 to 0.25% by mass. Is a bio-based Co-based alloy in which the balance is substantially made of Co, the average value of the crystal grain size is 1.5 to 15 μm, and the ratio of the FCC phase is 90% or more in area ratio . In addition, three types of manufacturing methods are proposed as methods for setting the average value of the crystal grain size to 1.5 to 15 μm and the ratio (area ratio) of the FCC phase to 90% or more for a Co-based alloy having a predetermined component composition. doing.

  The manufacturing method is as follows: a Co-based alloy having a predetermined component composition is heated to 950 to 1250 ° C., forged at a forging temperature of 870 ° C. or higher, and forged strain to be applied: 30% or higher. Air cooling for a second, followed by water cooling immediately, a Co-based alloy having a predetermined component composition is heated to 950 to 1250 ° C., forging launch temperature: 870 ° C. or higher, and forging strain to be applied: 30% or higher. After forging, a method of cooling at a cooling rate of 1 to 50 ° C./s, a Co-based alloy having a predetermined component composition is heated to a temperature of 1250 ° C. or higher, and a total of 30 at a temperature of 1000 ° C. or higher at the heating temperature or lower. % Forging that applies processing strain of at least%, starting cooling within 0.5 to 20 seconds after completion of the forging, and cooling to 300 ° C. or less at a cooling rate of 30 ° C./s or more, 3 Seed method.

  However, even if any of these methods is used to produce a biomedical Co alloy, in order to finally process it into a three-dimensional complicated shape, it is necessary to perform cutting after deburring. As described above, when cutting is performed to process a high-strength material, a lot of time and cost are consumed as a result, and the subsequent cutting processing has a large burden for producing a bio-based Co-based alloy. It was.

JP 2004-269994 A JP 2002-363675 A JP 2009-46758 A

  The present invention has been made as a solution to the above-described conventional problems, and has a high balance of corrosion resistance as well as a high balance between strength and ductility, and can be suitably used as a material for artificial bones. It is possible to forge the base alloy to a shape close to the final three-dimensional complicated finished shape, and reduce the labor of subsequent cutting or eliminate the need for the cutting itself. It is an object of the present invention to provide a manufacturing method.

  The invention according to claim 1 is mass%, Cr: 26-30%, Mo: 5-8%, C: 0.20% or less (not including 0%), N: 0.05-0.25. %, And the balance is made of Co and inevitable impurities, and the Co-based alloy having the above component composition is heated at 950 ° C. to 1250 ° C. Yes, forging is performed at a temperature of 850 ° C. to 1050 ° C. with a processing strain of 30% or more in total, and cooling is started within 5 seconds after the completion of the forging, and 300 ° C. or less at a cooling rate of 30 ° C./s or more. After the first step of cooling until the first step is completed, after removing the burrs and surplus on the surface of the Co-based alloy, it is heated at 850 to 1050 ° C. for 5 to 60 minutes, and then below this heating temperature And a total processing of 15% or less at a temperature of 850 to 1000 ° C. And forging is performed, and cooling is started within 20 seconds after the end of the forging, and the second step of cooling to 300 ° C. or less at a cooling rate of 30 ° C./s or more. This is a method for producing a bio-based Co-based alloy.

  The invention according to claim 2 is characterized in that the bio-based Co-based alloy contains Si: 0.5 to 1.0% and / or Mn: 0.5 to 1.0% by mass. 1. A method for producing a living body Co-based alloy according to 1.

  According to the method for producing a bio-based Co-based alloy of the present invention, a bio-based Co-based alloy that has a good balance between strength and ductility as well as high corrosion resistance and can be suitably used as a material for artificial bones. It is possible to forge to a shape that is close to the final three-dimensional complex finished shape, reducing the time and cost of post-cutting work that consumes a lot of time and cost, or making the cutting process itself unnecessary. it can.

  Hereinafter, the present invention will be described in more detail based on embodiments.

  Co-based alloys have been characterized as having a good balance between strength and ductility as well as high corrosion resistance, and so far have been used favorably as materials for artificial bones, especially artificial joints. However, in order to machine the final three-dimensional complex shape, cutting that consumes a great deal of time and cost is indispensable. For this reason, the present inventors have conducted extensive research in order to develop a method for producing a bio-based Co-based alloy that does not require this cutting process or at least reduces the labor of the cutting process.

  As a result, forging, which has conventionally been performed in only one step, is divided into two steps, and by appropriately defining the manufacturing conditions of the first step and the second step, post-cutting processing that consumes a great deal of time and cost. It has been found that it can be eliminated, or at least the labor of cutting can be reduced, and the present invention has been completed.

(Component composition)
First, the reason for limiting the component range (content) of each element added to the bio-based Co-based alloy will be described. In addition, although all units are described as%, all the mass% is included unless otherwise specified, including descriptions in other specifications.

Cr: 26-30%
Cr is an essential element for ensuring corrosion resistance. However, if its content is less than 26%, corrosion resistance deteriorates, and conversely if it exceeds 30%, workability deteriorates. Therefore, the Cr content range is set to 26-30%.

Mo: 5-8%
Mo is also an element necessary for ensuring corrosion resistance, and is also an element contributing to improvement of wear resistance. However, if the content is less than 5%, the corrosion resistance deteriorates, and conversely if it exceeds 8%, the workability deteriorates. Therefore, the range of the Mo content is set to 5 to 8%.

C: 0.20% or less (excluding 0%)
C is an element to be added depending on the necessity and degree of wear resistance, but when the C content exceeds 0.20%, ductility may be lowered due to the formed carbide. Also, due to the lowering of the melting point, when the temperature is raised to around 1250 ° C. by heating during forging, a part of the alloy may melt and forging may not be possible. Therefore, the content of C is set to 0.20% or less. In addition, the upper limit with preferable content of C is 0.10%.

N: 0.05-0.25%
N is an interstitial element similar to C, but has an effect of stabilizing the FCC phase (face-centered cubic crystal) and an effect of increasing ductility. However, if the addition amount (content) of N is less than 0.05%, the addition effect of N (FCC phase stabilization effect) is not significant. On the other hand, if it exceeds 0.25%, there is a concern that the phenomenon of reducing ductility such as nitride formation may occur. Therefore, the content range of N is set to 0.05 to 0.25%. From the viewpoint of stabilizing the FCC phase, the N content is preferably 0.10% or more, and more preferably 0.15% or more.

  The above are the essential contained elements specified in the present invention, and the balance is Co and inevitable impurities. Examples of unavoidable impurities include O, Ni, Fe, and the like, but if the O content exceeds 100 ppm, there is an effect of reducing elongation and drawing. By controlling the O content to 100 ppm or less, elongation and drawing can be improved even with the same strength. Therefore, the O content is desirably 100 ppm or less. In order to reduce the O content to 100 ppm or less, the alloy may be melted by vacuum melting. When it is not necessary to control the oxygen concentration, an air melting method can be adopted as a melting method.

  In addition, it is also effective to positively contain the following elements in the biomedical Co-based alloy, and the characteristics of the biomedical Co-based alloy are further improved depending on the type of chemical component (element) contained. .

Si: 0.5 to 1.0% and / or Mn: 0.5 to 1.0%
Si and Mn strengthen the solid solution of the Co-based alloy for biomedical use, increase the strength, and have the effect of somewhat suppressing grain growth during hot working and in air cooling immediately thereafter. The effect is not remarkable when the content is less than 0.5%, and when the content exceeds 1.0%, the F799 alloy becomes out of specification. Therefore, Si: 0.5 to 1.0% and / or Mn: 0.5 to 1.0%.

(Production conditions)
Next, a method for producing a living body Co-based alloy using the Co-based alloy having the component composition described above will be described. Usually, when a bio-based Co-based alloy is manufactured by forging, it is performed by forging once, the average value of the crystal grain size is 1.5 to 15 μm, and the ratio of the FCC phase is 90% or more in area ratio. Thus, a bio-based Co-based alloy having a good balance between strength and ductility could be manufactured. In the manufacturing method of the present invention, forging is performed in two steps. By performing forging in two steps in this way, it is possible to make the living body Co-based alloy into a shape close to the final three-dimensional complicated finished shape only by forging.

  In the first step, the crystal grain size is made smaller, and in the second step, the average value of the crystal grain size is set to a final size of 1.5 to 15 μm. The reason why the crystal grain size is made smaller in the first step is as described below. That is, in the second step, since a large processing strain cannot be applied, recrystallization does not occur and the crystal grain size cannot be made fine. However, the coarsening of the crystal grains is inevitably caused by the heating in the second step. Therefore, if the crystal grain size is reduced in advance in the first step where a large processing strain can be applied and then passed to the next second step, the average value of the crystal grain size in the second step is the final size. It is because it becomes possible to set it as 1.5-15 micrometers.

  More specifically, in the method for producing a bio-based Co-based alloy of the present invention, the Co-based alloy having the above-mentioned predetermined component composition is heated at 950 ° C. to 1250 ° C., and is below this heating temperature and 850 ° C. to 1050 ° C. Forging is performed at a temperature of 0 ° C. by adding processing strain of 30% or more in total, and cooling is started within 5 seconds after completion of the forging, and cooling is performed at a cooling rate of 30 ° C./s or more until 300 ° C. or less. After completion of the first step and the first step, after removing burrs and surplus on the surface of the Co-based alloy, heating is performed at 850 to 1050 ° C. for 5 to 60 minutes, and thereafter, the heating temperature is equal to or lower than 850 to 1000. Forging is performed by adding a processing strain of 15% or less in total at a temperature of 0 ° C., cooling is started within 20 seconds after the completion of this forging, and cooling is performed until the temperature becomes 300 ° C. or less at a cooling rate of 30 ° C./s or more. It consists of two steps. Hereinafter, the manufacturing conditions will be described in more detail in the first step and the second step.

-1st process First, although Co base alloy of a predetermined component composition is heated before forging, the heating temperature shall be 950 to 1250 degreeC. The reason why the lower limit of the heating temperature before forging is 950 ° C. is that if the temperature is lower than 950 ° C., a sufficient FCC phase cannot be obtained, and the deformation resistance becomes too high for forging. On the other hand, the reason for setting the upper limit of the heating temperature before forging to 1250 ° C. is that if the heating temperature exceeds 1250 ° C., there is a risk of partial melting depending on the carbon concentration of the Co-based alloy. This is because the waiting time takes too long.

  Subsequently, forging is performed at a temperature of 850 ° C. to 1050 ° C. with a processing strain of 30% or more in total and the lower limit of the forging temperature is 850 ° C. The forging temperature is 850 ° C. This is because an ε phase that deteriorates ductility is generated at a temperature lower than ℃. On the other hand, the reason why the upper limit of the forging temperature is 1050 ° C. is that when the forging temperature exceeds 1050 ° C., the crystal grain size becomes coarse.

  The total processing strain applied during forging is 30% or more in order to add strain to the FCC phase, promote dynamic and static recrystallization, and promote refinement of the crystal grain size. is there. When the processing strain is less than 30% in total, recrystallization becomes insufficient, the crystal grain size becomes coarse, and the average crystal grain size exceeds 15 μm. From the viewpoint of refinement of the crystal grain size, it is desirable that the applied processing strain be 50% or more.

  Cooling is started within 5 seconds after the end of this forging. When the cooling start exceeds 5 seconds after completion of forging, the crystal grain size becomes coarse.

  The cooling rate at the time of this cooling is preferably 30 ° C./s or more, and it is desirable to carry out by water cooling. When the cooling rate is less than 30 ° C./s, for example, when cooling is performed by air cooling, the crystal grain size becomes coarse and an ε phase is generated.

  Moreover, cooling is implemented until it becomes 300 degrees C or less. If cooling is stopped before reaching 300 ° C., an ε phase may be generated.

・ Second step After the first step, the second step is started after removing burrs and surplus slightly formed on the surface of the Co-based alloy by punching or laser processing. The Co-based alloy is heated before the heating. The heating temperature is 850 to 1050 ° C., and the heating time is 5 to 60 minutes. The reason why the lower limit of the heating temperature before forging is 850 ° C. is that if the heating temperature is less than 850 ° C., an ε phase may be generated. On the other hand, the reason why the upper limit of the heating temperature before forging is set to 1050 ° C. is that the crystal grain size becomes coarse.

  The reason why the lower limit of the heating time before forging is set to 5 minutes is that if the heating time is less than that, it is impossible to ensure soaking of the material. On the other hand, the reason for setting the upper limit of the heating time before forging to 60 minutes is that when the heating time exceeds 60 minutes, the crystal grain size becomes coarse.

  Subsequently, forging is performed at a temperature of 850 to 1000 ° C. at a temperature of 850 to 1000 ° C. with a processing strain of 15% or less in total, but the lower limit of the forging temperature is 850 ° C. The forging temperature is 850 ° C. This is because it is impossible to ensure the soaking of the material if it is less than 1. On the other hand, the reason why the upper limit of the forging temperature is 1000 ° C. is that when the forging temperature exceeds 1000 ° C., the crystal grain size becomes coarse.

  In addition, the total processing strain applied during forging is 15% or less. If the total processing strain exceeds 15%, the amount of strain that generates burrs is generated. This is because it is necessary to take it.

  Cooling is started within 20 seconds after this forging is completed. When the start of cooling exceeds 20 seconds after the end of forging, the crystal grain size becomes coarse.

  The cooling rate at the time of this cooling is preferably 30 ° C./s or more, and it is desirable to carry out by water cooling. When the cooling rate is less than 30 ° C./s, for example, when cooling is performed by air cooling, the crystal grain size becomes coarse and an ε phase is generated.

  Moreover, cooling is implemented until it becomes 300 degrees C or less. If cooling is stopped before reaching 300 ° C., an ε phase may be generated.

  By producing a bio-based Co-based alloy under the above conditions, the average value of the crystal grain size is 1.5 to 15 μm, the ratio of the FCC phase is 90% or more in area ratio, and the final three-dimensional complex It can be a shape close to the finished shape. Thus, by setting the average value of the crystal grain size to 1.5 to 15 μm and the ratio of the FCC phase to 90% or more in area ratio, a bio-based Co-based alloy having a good balance between strength and ductility is manufactured. The reason why this can be done is as described below.

(Average value of crystal grain size)
When the average value of the crystal grain size is less than 1.5 μm, the strength is increased, but the ductility is lowered. On the other hand, if the average value of the crystal grain size exceeds 15 μm, the strength required for the artificial bone cannot be maintained. Therefore, the average value of the crystal grain size may be 1.5 to 15 μm. From the viewpoint of ductility, the average value of the crystal grain size is preferably 3.0 μm or more, more preferably 5.0 μm or more, and further preferably 7.0 μm or more. From the viewpoint of strength, the average value of the crystal grain size is desirably 13 μm or less, and more desirably 10 μm or less.

(Percentage of FCC phase)
The FCC phase is a phase rich in ductility and has an effect of improving ductility. If the ratio of the FCC phase is less than 90% in terms of area ratio, the ductility is lowered and becomes insufficient. Therefore, the ratio of the FCC phase may be 90% or more in terms of area ratio. From the viewpoint of ductility, the FCC ratio is desirably 93% or more in terms of area ratio. The FCC phase is a phase having a face-centered cubic lattice crystal structure.

  EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited by the following examples, and the present invention is implemented with appropriate modifications within a range that can meet the gist of the present invention. These are all included in the technical scope of the present invention.

  First, a Co-based alloy having the composition shown in Table 1 was melted by vacuum melting to obtain a melted material. This melted material was once hot forged to φ26 mm and cut to a length of 180 mm to obtain a Co-based alloy material (sample) for testing.

  The forging of the 1st process was implemented on the conditions shown in Table 2 using these samples. More specifically, forging was carried out using each of the produced samples in the order of high-frequency heating → forging → cooling. Table 2 shows the heating temperature, forging temperature, forging strain (working strain), post-forging retention time (time to start cooling), cooling type, and cooling rate.

  Next, forging in the second step was performed under the conditions shown in Table 3 using each sample for which forging in the first step was completed. More specifically, after removing burrs and surplus on the surface of each sample for which forging was completed in the first step, forging was performed through the sequence of high-frequency heating → forging → cooling. Table 3 shows the heating temperature, heating time, forging temperature, forging strain (working strain), post-forging holding time (time to start cooling), cooling type, and cooling rate.

  Thus, a test piece was collected from each Co-based alloy obtained through the first step and the second step, and the following measurement of crystal grain size, tensile test, and confirmation of the occurrence of burrs were performed. In addition, although it was reference, the test piece was extract | collected even after completion | finish of the 1st process, and the measurement of the crystal grain size and the tensile test were implemented. The test results are shown in Table 3, and the results after the first step are shown in Table 3, respectively.

<Measurement method of crystal grain size>
The crystal grain size was measured using an image quality map of EBSP measurement shown below. This is because the Co-based alloy has very high corrosion resistance and has a fine crystal grain size, and thus it is difficult to observe the structure with an optical microscope. On the structure photograph of the image quality map, the particle size was measured by the linear crossing method, five or more points were measured, and the average slice length was taken as the measured particle size (average particle size).

The apparatus and measurement conditions used for this measurement are as follows.
・ Device: SEM JEOL JSM 5410
EBSP Measurement Analysis System TSL OIM
Analysis software OIMA Analysis
Measurement conditions: measurement area 50 μm × 50 μm to 500 μm × 500 μm
・ Measurement interval: 0.1 to 0.4 μm

<Measurement method of FCC rate>
In the EBSP measurement, it is automatically determined for each measurement point of 0.1 to 0.4 μm as an FCC phase, an ε phase (HCP phase), or other phases (almost no current time). When it is shown in the figure, it can be displayed separately for FCC and HCP as a kind of photograph. In this example, the number of FCC measurement points was divided by the total number of measurement points to obtain the FCC rate (area ratio), that is, the FCC phase ratio.

<Tensile test method>
A tensile test piece having a parallel portion of φ6.5 mm × 25 mm is manufactured, and a tensile test is performed by using the tensile test piece. YS: Yield stress (0.2% proof stress), TS: Tensile strength (tensile strength), Elongation (EL), Drawing (RA) was measured. At this time, the tensile speed was 0.5% / min up to 0.2% proof stress, and the tensile speed was 10% / min from the 0.2% proof stress until breaking. Shimadzu 200KN hydraulic universal testing machine was used as the tensile testing machine.

  In this example, YS: Yield stress (0.2% yield strength) is 800 MPa or more, TS: Tensile strength (tensile strength) is 1150 MPa or more, EL: Elongation is 12% or more, and RA: Drawing is 12% or more. Is a bio-based Co-based alloy having a good balance between strength and ductility.

  No. 1, No. 1 6, no. 9 is an invention example in which the component composition of the Co-based alloy satisfies the requirements of the present invention and the manufacturing conditions also satisfy the requirements of the present invention. As a result, a Co-based alloy having a good balance between strength and ductility could be produced without generating burrs.

  In contrast, no. No. 2 is a comparative example in which the start of cooling in the first step exceeded 5 seconds after completion of forging, No. 2 No. 3 is a comparative example in which the heating temperature in the second step exceeded 1050 ° C. and the forging temperature exceeded 1000 ° C., No. 3 4 is a comparative example in which the forging temperature in the first step exceeded 1050 ° C. No. 5-1 is a comparative example in which the processing strain in the second step exceeded 15%, No. 5-1. 5-2 is a comparative example in which the start of cooling in the second step exceeds 20 seconds after the end of forging. No. 5-1. As for 5-2, since the 1st process is the same conditions, in Table 2, it is No. Shown as 5.

  Furthermore, no. 10-1 and no. 10-2 is a comparative example in which the cooling rate was less than 30 ° C./s because the cooling in the first step was performed by air cooling. No. In No. 10-2, the cooling in the second step was also performed by air cooling, so the cooling rate in the second step was also less than 30 ° C./s. Incidentally, no. 10-1 and no. In No. 10-2, the forging temperature in the first step exceeds 1050 ° C., and the cooling start in the first step also exceeds 5 seconds after the end of forging, and these conditions do not satisfy the conditions of the present invention. No. 10-1 and no. No. 10-2 is No. 1 in Table 2 because the first step is under the same conditions. Shown as 10.

  As a result, no. 2-4, no. 5-2, no. 10-1, no. 10-2, YS: Yield stress (0.2% proof stress), TS: Tensile strength (tensile strength), EL: Elongation, RA: It is not possible to satisfy the pass judgment condition in any one or more of the items, A Co-based alloy having a good balance between strength and ductility could not be produced. No. In 5-1, burrs were generated in the Co-based alloy obtained by forging.

  No. 2, no. 4, no. 10 (No. 10-1, No. 10-2), the manufacturing conditions of the first step are not preferable, so the crystal grain size after the first step is coarsened. 10-1, no. In 10-2, the ratio of the FCC phase is less than 90% in area ratio.

  No. No. 7 is a comparative example in which the C content is too high, No. 7 8 is a comparative example in which the content of N is too large. Thus, since there was too much content of C and N, the crack generate | occur | produced at the time of the forge of a 1st process, and it could not progress to a 2nd process.

Claims (2)

In mass%, Cr: 26-30%, Mo: 5-8%, C: 0.20% or less (excluding 0%), N: 0.05-0.25%, the balance being Co And a method for producing a bio-based Co-based alloy comprising inevitable impurities,
After the Co-based alloy having the above component composition is heated at 950 ° C. to 1250 ° C., forging is performed at a temperature not higher than this heating temperature and at a temperature of 850 ° C. to 1050 ° C. with a working strain of 30% or more in total. A first step of starting cooling within 5 seconds after the end of forging, and cooling to 300 ° C. or lower at a cooling rate of 30 ° C./s or higher;
After completion of the first step, after removing burrs and surplus on the surface of the Co-based alloy, heating is performed at 850 to 1050 ° C. for 5 to 60 minutes, and then the heating temperature is equal to or lower than 850 to 1000 ° C. Forging is performed by applying a processing strain of 15% or less, and cooling is started within 20 seconds after the forging is completed, and cooling is performed until the temperature becomes 300 ° C. or less at a cooling rate of 30 ° C./s or more. A method for producing a bio-based Co-based alloy.   The bio-based Co-based alloy according to claim 1, wherein the bio-based Co-based alloy contains Si: 0.5 to 1.0% and / or Mn: 0.5 to 1.0% by mass. Manufacturing method.