Metal injection molding stainless steel powder, steel material preparation method and alloy steel material

Abstract

The embodiment of the invention discloses metal injection molding stainless steel powder, a steel material preparation method and an alloy steel material. The stainless steel powder comprises the following components in percentage by mass: 0 to 0.20 percent of C, 0 to 0.25 percent of Si, 0 to 0.04 percent of S, 0 to 0.03 percent of P, 0 to 1.00 percent of Mn, 0 to 0.55 percent of Ni, 0 to 0.50 percent of Cr, 0 to 0.20 percent of Mo, 0 to 0.35 percent of Cu, 0 to 0.05 percent of O, 0 to 0.05 percent of N and the balance of Fe and impurities. The alloy steel material is prepared from the stainless steel powder and the adhesive through the steps of granulation, injection molding, degreasing, sintering, cooling and the like. The manganese element in a certain content range is added into the stainless steel powder, meanwhile, excessive release of the carbon element in a blank can be avoided through a certain cooling rate in the preparation process, the content of the carbon element in the blank is kept within a certain horizontal range, and the carbon element and the manganese element have a strengthening effect on an alloy steel material; therefore, the prepared alloy steel material has stronger rigidity and higher hardness.

Description

Technical Field

[0001] The embodiments of the present application relate to the field of steel material preparation, and specifically to a metal injection molding stainless steel powder, a steel material preparation method and an alloy steel material. Background Art

[0002] Metal Injection Molding (MIM) is an emerging technology that combines traditional powder metallurgy process with existing plastic injection molding technology. It not only has the characteristics of high material utilization rate of powder metallurgy products, but also has the advantages of high production efficiency of injection molding, uniform product structure, close to net shape, and high dimensional accuracy. It is now widely used in a variety of material systems such as high specific gravity, hard alloy, stainless steel, low alloy steel, magnetic materials, etc., and its products have also been used in many industries such as computers, mechanical automation, automobiles and ships, and medical equipment.

[0003] However, the finished products made by the existing process are still insufficient in hardness and rigidity, and a better process is urgently needed to improve the hardness and rigidity of the finished products. Summary of the invention

[0004] The embodiments of the present application provide a metal injection molding stainless steel powder, a steel material preparation method and an alloy steel material, which can improve the rigidity and hardness of the alloy steel material.

[0005] In a first aspect, an embodiment of the present application provides a metal injection molding stainless steel powder, comprising the following components in mass fractions:

[0006] C: 0~0.20%, Si: 0~0.25%, S: 0~0.04%, P: 0~0.03%, Mn: 0~1.00%, Ni: 0~0.55%, Cr: 0~0.50%, Mo: 0~0.20%, Cu: 0~0.35%, O: 0~0.05%, N: 0~0.05%, and the balance is Fe and impurities, and the impurity content is less than 0.01%.

[0007] Optionally, the mass fraction of Mn is 0.70-1.00%.

[0008] Optionally, the mass fraction of Mn is 0.80-1.00%.

[0009] Optionally, the mass fraction of Mn is 0.90-1.00%.

[0010] Optionally, the mass fraction of Mn is 1.00%.

[0011] A second aspect of the embodiment of the present application provides a method for preparing a steel material, comprising the following steps:

[0012] Granulation: The metal injection molding stainless steel powder described in the first aspect is mixed with a binder to obtain a granular feed; the mass fraction of the stainless steel powder is 88-92%, and the mass fraction of the binder is 8-12%;

[0013] Injection molding: injecting the granular feed into a mold to obtain a blank;

[0014] Degreasing: Degreasing the blank, the degreasing temperature is 100-140° C., the nitrogen temperature is 100-150° C., and the degreasing time is 180-360 min;

[0015] Sintering: Sintering the degreased blank at a sintering temperature of room temperature to 600°C, introducing nitrogen, with a nitrogen pressure of 2-7Kpa, a heating time of 180-360min, and a heat preservation time of 30-90min; performing atmosphere reduction on the sintered blank, with a heating rate of 3-5°C, a heating time of 180-320min, and a heat preservation time of 60-180min; performing partial pressure sintering on the blank after atmosphere reduction, sintering the partial pressure sintering to the highest temperature of 1320-1360°C, and keeping the temperature at the highest temperature for 180-480min;

[0016] Cooling: The blank that has completed partial pressure sintering is cooled to room temperature to obtain an alloy steel material, wherein the cooling rate is 10 to 200°C / min.

[0017] Optionally, the mass fraction of Mn in the stainless steel powder is 0.70-1.00%, and the cooling rate in the cooling step is 10-50° C. / min.

[0018] Optionally, the mass fraction of Mn in the stainless steel powder is 0.80-1.00%, and the cooling rate in the cooling step is 50-100° C. / min.

[0019] Optionally, the mass fraction of Mn in the stainless steel powder is 0.90-1.00%, and the cooling rate in the cooling step is 100-150° C. / min.

[0020] Optionally, the mass fraction of Mn in the stainless steel powder is 1.00%, and the cooling rate in the cooling step is 150-200° C. / min.

[0021] A third aspect of the embodiment of the present application provides an alloy steel material, which is prepared according to the method described in the second aspect. The hardness of the alloy steel material is 55-80 HRB, and the Mn content in the alloy steel material is 0.2-0.85%.

[0022] It can be seen from the above technical solutions that the embodiments of the present application have the following advantages:

[0023] The stainless steel powder includes the following components by mass fraction: C: 0-0.20%, Si: 0-0.25%, S: 0-0.04%, P: 0-0.03%, Mn: 0-1.00%, Ni: 0-0.55%, Cr: 0-0.50%, Mo: 0-0.20%, Cu: 0-0.35%, O: 0-0.05%, N: 0-0.05%, and the balance is Fe and impurities. The stainless steel powder of the above components and the binder are subjected to granulation, injection molding, degreasing, sintering, cooling and other steps to prepare the alloy steel material. Since the stainless steel powder is added with a certain content range of manganese, the manganese element has a strengthening effect on the alloy steel material, so the prepared alloy steel material can have high rigidity and high hardness. At the same time, a certain cooling rate during the preparation process can avoid excessive release of carbon elements in the blank, so that the carbon content in the blank is maintained within a certain level range to strengthen the alloy stainless steel material, and further improve the rigidity and hardness of the alloy stainless steel material. DETAILED DESCRIPTION

[0024] The embodiments of the present application provide a metal injection molding stainless steel powder, a steel material preparation method and an alloy steel material, which can improve the rigidity and hardness of the alloy steel material.

[0025] The metal injection molding stainless steel powder in the embodiment of the present application is described below:

[0026] The metal injection molding stainless steel powder comprises the following components by mass fraction:

[0027] C: 0~0.20%, Si: 0~0.25%, S: 0~0.04%, P: 0~0.03%, Mn: 0~1.00%, Ni: 0~0.55%, Cr: 0~0.50%, Mo: 0~0.20%, Cu: 0~0.35%, O: 0~0.05%, N: 0~0.05%, and the balance is Fe and impurities, and the impurity content is less than 0.01%.

[0028] The stainless steel powder including the above-mentioned components in mass fraction can be used to prepare an alloy steel material with high rigidity and high hardness.

[0029] Preferably, the mass fraction of Mn is 0.70-1.00%.

[0030] In another preferred embodiment, the mass fraction of Mn is 0.80-1.00%.

[0031] In another preferred embodiment, the mass fraction of Mn is 0.90-1.00%.

[0032] In another preferred embodiment, the mass fraction of Mn is 1.00%.

[0033] Since manganese within a certain content range has a strengthening effect on alloy steel materials, the stainless steel powder contains manganese within the above mass fraction range, which can make the alloy steel material prepared using this stainless steel powder have stronger rigidity and higher hardness, meeting industrialization needs.

[0034] The following is a description of the steel material preparation method in the embodiment of the present application:

[0035] The steel material preparation method comprises the following steps:

[0036] Granulation: The stainless steel powder is prepared according to the mass fraction and ratio of each element in the stainless steel powder as described above, and the stainless steel powder is mixed and granulated with a binder to obtain a granular feed; the mass fraction of the stainless steel powder is 88-92%, and the mass fraction of the binder is 8-12%;

[0037] Injection molding: injecting the granular feed into a mold to obtain a blank;

[0038] Degreasing: Degreasing the blank, the degreasing temperature is 100-140°C, the nitrogen temperature is 100-150°C, and the degreasing time is 180-360min;

[0039] Sintering: Sinter the degreased blank at a sintering temperature of room temperature to 600°C, introduce nitrogen, the nitrogen pressure is 2-7Kpa, the heating time is 180-360min, and the holding time is 30-90min; perform atmosphere reduction on the sintered blank, the heating rate of atmosphere reduction is 3-5°C, the heating time is 180-320min, and the holding time is 60-180min; perform partial pressure sintering on the blank after atmosphere reduction, the partial pressure sintering is performed to the highest temperature, which is 1320-1360°C, and the highest temperature is kept for 180-480min;

[0040] Cooling: The blank that has completed partial pressure sintering is cooled to room temperature to obtain an alloy steel material, wherein the cooling rate is 10 to 200°C / min.

[0041] Among them, the stainless steel powder and the adhesive can be mixed and granulated using an internal mixer to obtain a granular feed. In the injection molding step, the granular feed can be loaded into the injection machine barrel and heated to a specified temperature (generally the melting temperature of the adhesive, between 170-195°C) to make it fluid, and then injected into a customized mold under appropriate pressure to form a green blank.

[0042] During degreasing, a degreasing furnace can be used to degrease the blank to remove the adhesive remaining in the blank. In the embodiment of the present application, the blank is degreased based on the above parameters, and the degreasing rate of the blank can reach more than 6.8%.

[0043] The degreased blank can be sintered in a sintering furnace. During the atmosphere reduction, a reducing atmosphere such as nitrogen or a mixture of nitrogen and hydrogen can be introduced. During the partial pressure sintering, argon can be introduced to protect the blank from oxidation at high temperature.

[0044] In a preferred embodiment, the mass fraction of Mn in the stainless steel powder is 0.70-1.00%, and the cooling rate in the cooling step is 10-50° C. / min.

[0045] In another preferred embodiment, the mass fraction of Mn in the stainless steel powder is 0.80-1.00%, and the cooling rate in the cooling step is 50-100° C. / min.

[0046] In another preferred embodiment, the mass fraction of Mn in the stainless steel powder is 0.90-1.00%, and the cooling rate in the cooling step is 100-150° C. / min.

[0047] In another preferred embodiment, the mass fraction of Mn in the stainless steel powder is 1.00%, and the cooling rate in the cooling step is 150-200° C. / min.

[0048] Since carbon within a certain content range has a strengthening effect on alloy steel materials, and the carbon element of the blank will be continuously released under high temperature conditions, resulting in a gradual decrease in the carbon content in the blank, rapid cooling can reduce the release of carbon elements in the blank, thereby ensuring that the carbon content in the blank remains within a certain level range. Therefore, rapid cooling of the blank after partial pressure sintering at the above cooling rate can avoid excessive release of carbon elements in the blank, so that the carbon content in the blank is maintained within a certain level range to strengthen the alloy stainless steel material, thereby improving the rigidity and hardness of the alloy stainless steel material.

[0049] The alloy steel material in the embodiment of the present application is described below:

[0050] The alloy steel material is prepared according to the steel material preparation method described above. The hardness of the alloy steel material is 55-80 HRB, and the content of Mn in the alloy steel material is 0.2-0.85%.

[0051] The embodiment of the present application provides a stainless steel powder, an alloy steel material prepared using the stainless steel powder, and a method for preparing the alloy steel material. The stainless steel powder includes the following components by mass fraction: C: 0-0.20%, Si: 0-0.25%, S: 0-0.04%, P: 0-0.03%, Mn: 0-1.00%, Ni: 0-0.55%, Cr: 0-0.50%, Mo: 0-0.20%, Cu: 0-0.35%, O: 0-0.05%, N: 0-0.05%, and the remainder is Fe and impurities. The stainless steel powder of the above components and the adhesive are subjected to granulation, injection molding, degreasing, sintering, cooling and other steps to prepare the alloy steel material. Since a certain content range of manganese is added to the stainless steel powder, the manganese element has a strengthening effect on the alloy steel material, so the prepared alloy steel material can have high rigidity and high hardness. At the same time, a certain cooling rate during the preparation process can prevent excessive release of carbon elements in the blank, so that the carbon content in the blank is maintained within a certain level range to strengthen the alloy stainless steel material and further improve the rigidity and hardness of the alloy stainless steel material.

[0052] In order to further illustrate the embodiments of the present application in detail, a metal injection molding stainless steel powder, a steel material preparation method and an alloy steel material provided by the present invention are described in detail below in combination with the embodiments, but it should not be understood as limiting the scope of protection of the present invention.

[0053] Example 1

[0054] Weighing: Weigh each component according to the mass fraction of the following components to obtain stainless steel powder:

[0055] C: 0.20%, Si: 0.25%, S: 0.04%, P: 0.03%, Mn: 0.70%, Ni: 0.55%, Cr: 0.50%, Mo: 0.20%, Cu: 0.35%, O: 0.05%, N: 0.05%, and the balance is Fe.

[0056] Granulation: using an internal mixer to mix and granulate the stainless steel powder and the adhesive to obtain a granular feed; the mass fraction of the stainless steel powder is 88-92%, and the mass fraction of the adhesive is 8-12%;

[0057] Injection molding: injecting the granular feed into a mold to obtain a blank;

[0058] Degreasing: Degreasing the blank, the degreasing temperature is 100-140°C, the nitrogen temperature is 100-150°C, and the degreasing time is 180-360min;

[0059] Sintering: Sinter the degreased blank at a sintering temperature of room temperature to 600°C, introduce nitrogen, the nitrogen pressure is 2-7Kpa, the heating time is 180-360min, and the holding time is 30-90min; perform atmosphere reduction on the sintered blank, the heating rate of atmosphere reduction is 3-5°C, the heating time is 180-320min, and the holding time is 60-180min; perform partial pressure sintering on the blank after atmosphere reduction, the partial pressure sintering is performed to the highest temperature, which is 1320-1360°C, and the highest temperature is kept for 180-480min;

[0060] Cooling: The blank that has completed partial pressure sintering is cooled to room temperature to obtain an alloy steel material, wherein the cooling rate is 10 to 50°C / min.

[0061] Test: The alloy steel material was tested for product performance and key component Mn content, and its hardness was 55-60HRB, and the Mn element content was 0.2-0.3%.

[0062] Example 2

[0063] Weighing: Weigh each component according to the mass fraction of the following components to obtain stainless steel powder:

[0064] C: 0.20%, Si: 0.25%, S: 0.04%, P: 0.03%, Mn: 0.80%, Ni: 0.55%, Cr: 0.50%, Mo: 0.20%, Cu: 0.35%, O: 0.05%, N: 0.05%, and the balance is Fe.

[0065] Granulation: using an internal mixer to mix and granulate the stainless steel powder and the adhesive to obtain a granular feed; the mass fraction of the stainless steel powder is 88-92%, and the mass fraction of the adhesive is 8-12%;

[0066] Injection molding: injecting the granular feed into a mold to obtain a blank;

[0067] Degreasing: Degreasing the blank, the degreasing temperature is 100-140°C, the nitrogen temperature is 100-150°C, and the degreasing time is 180-360min;

[0068] Sintering: Sinter the degreased blank at a sintering temperature of room temperature to 600°C, introduce nitrogen, the nitrogen pressure is 2-7Kpa, the heating time is 180-360min, and the holding time is 30-90min; perform atmosphere reduction on the sintered blank, the heating rate of atmosphere reduction is 3-5°C, the heating time is 180-320min, and the holding time is 60-180min; perform partial pressure sintering on the blank after atmosphere reduction, the partial pressure sintering is performed to the highest temperature, which is 1320-1360°C, and the highest temperature is kept for 180-480min;

[0069] Cooling: The blank that has completed partial pressure sintering is cooled to room temperature to obtain an alloy steel material, wherein the cooling rate is 50 to 100°C / min.

[0070] Test: The alloy steel material was tested for product performance and key component Mn content, and its hardness was 60-65HRB, and the Mn element content was 0.35-0.45%.

[0071] Example 3

[0072] Weighing: Weigh each component according to the mass fraction of the following components to obtain stainless steel powder:

[0073] C: 0.20%, Si: 0.25%, S: 0.04%, P: 0.03%, Mn: 0.90%, Ni: 0.55%, Cr: 0.50%, Mo: 0.20%, Cu: 0.35%, O: 0.05%, N: 0.05%, and the balance is Fe.

[0074] Granulation: using an internal mixer to mix and granulate the stainless steel powder and the adhesive to obtain a granular feed; the mass fraction of the stainless steel powder is 88-92%, and the mass fraction of the adhesive is 8-12%;

[0075] Injection molding: injecting the granular feed into a mold to obtain a blank;

[0076] Degreasing: Degreasing the blank, the degreasing temperature is 100-140°C, the nitrogen temperature is 100-150°C, and the degreasing time is 180-360min;

[0077] Sintering: Sinter the degreased blank at a sintering temperature of room temperature to 600°C, introduce nitrogen, the nitrogen pressure is 2-7Kpa, the heating time is 180-360min, and the holding time is 30-90min; perform atmosphere reduction on the sintered blank, the heating rate of atmosphere reduction is 3-5°C, the heating time is 180-320min, and the holding time is 60-180min; perform partial pressure sintering on the blank after atmosphere reduction, the partial pressure sintering is performed to the highest temperature, which is 1320-1360°C, and the highest temperature is kept for 180-480min;

[0078] Cooling: The blank that has completed partial pressure sintering is cooled to room temperature to obtain an alloy steel material, wherein the cooling rate is 100 to 150°C / min.

[0079] Test: The alloy steel material was tested for product performance and key component Mn content, and its hardness was 65-70HRB, and the Mn element content was 0.55-0.65%.

[0080] Example 4

[0081] Weighing: Weigh each component according to the mass fraction of the following components to obtain stainless steel powder:

[0082] C: 0.20%, Si: 0.25%, S: 0.04%, P: 0.03%, Mn: 1.00%, Ni: 0.55%, Cr: 0.50%, Mo: 0.20%, Cu: 0.35%, O: 0.05%, N: 0.05%, and the balance is Fe.

[0083] Granulation: using an internal mixer to mix and granulate the stainless steel powder and the adhesive to obtain a granular feed; the mass fraction of the stainless steel powder is 88-92%, and the mass fraction of the adhesive is 8-12%;

[0084] Injection molding: injecting the granular feed into a mold to obtain a blank;

[0085] Degreasing: Degreasing the blank, the degreasing temperature is 100-140°C, the nitrogen temperature is 100-150°C, and the degreasing time is 180-360min;

[0086] Sintering: Sinter the degreased blank at a sintering temperature of room temperature to 600°C, introduce nitrogen, the nitrogen pressure is 2-7Kpa, the heating time is 180-360min, and the holding time is 30-90min; perform atmosphere reduction on the sintered blank, the heating rate of atmosphere reduction is 3-5°C, the heating time is 180-320min, and the holding time is 60-180min; perform partial pressure sintering on the blank after atmosphere reduction, the partial pressure sintering is performed to the highest temperature, which is 1320-1360°C, and the highest temperature is kept for 180-480min;

[0087] Cooling: The blank that has completed partial pressure sintering is cooled to room temperature to obtain an alloy steel material, wherein the cooling rate is 150-200°C / min.

[0088] Test: The alloy steel material was tested for product performance and key component Mn content, and its hardness was 70-80HRB, and the Mn element content was 0.75-0.85%.

[0089] It can be seen from the above-mentioned multiple embodiments that adding a certain range of manganese elements to the stainless steel powder can strengthen the alloy steel material and improve the rigidity and hardness of the alloy steel material. In the above-mentioned multiple embodiments, when the manganese content is 1.00%, the hardness of the alloy steel material is the highest, and the manganese content is also relatively high. In addition, the cooling rate within a certain range can also improve the rigidity and hardness of the alloy steel material. In the above-mentioned multiple embodiments, when the cooling rate is 150-200℃ / min, the hardness of the alloy steel material is the highest, and the manganese content is also relatively high.

[0090] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A metal injection molding stainless steel powder, characterized in that: The following components are included in mass fraction: C: 0~0.20%, Si: 0~0.25%, S: 0~0.04%, P: 0~0.03%, Mn: 0~1.00%, Ni: 0~0.55%, Cr: 0~0.50%, Mo: 0~0.20%, Cu: 0~0.35%, O: 0~0.05%, N: 0~0.05%, and the balance is Fe and impurities, and the impurity content is less than 0.01%.

2. The metal injection molding stainless steel powder according to claim 1, characterized in that The mass fraction of Mn is 0.70-1.00%.

3. The metal injection molding stainless steel powder according to claim 1, characterized in that The mass fraction of Mn is 0.80-1.00%.

4. The metal injection molding stainless steel powder according to claim 1, characterized in that The mass fraction of Mn is 0.90-1.00%.

5. The metal injection molding stainless steel powder according to claim 1, characterized in that The mass fraction of Mn is 1.00%.

6. A method for preparing a steel material, characterized in that: The following steps are involved: Granulation: The metal injection molding stainless steel powder according to any one of claims 1 to 5 is mixed and granulated with a binder to obtain a granular feed; the mass fraction of the stainless steel powder is 88-92%, and the mass fraction of the binder is 8-12%; Injection molding: injecting the granular feed into a mold to obtain a blank; Degreasing: Degreasing the blank, the degreasing temperature is 100-140° C., the nitrogen temperature is 100-150° C., and the degreasing time is 180-360 min; Sintering: Sintering the degreased blank at a sintering temperature of room temperature to 600°C, introducing nitrogen, with a nitrogen pressure of 2-7Kpa, a heating time of 180-360min, and a heat preservation time of 30-90min; performing atmosphere reduction on the sintered blank, with a heating rate of 3-5°C, a heating time of 180-320min, and a heat preservation time of 60-180min; performing partial pressure sintering on the blank after atmosphere reduction, sintering the partial pressure sintering to the highest temperature of 1320-1360°C, and keeping the temperature at the highest temperature for 180-480min; Cooling: The blank that has completed partial pressure sintering is cooled to room temperature to obtain an alloy steel material, wherein the cooling rate is 10 to 200°C / min.

7. The method according to claim 6, characterized in that The mass fraction of Mn in the stainless steel powder is 0.70-1.00%, and the cooling rate in the cooling step is 10-50° C. / min.

8. The method according to claim 6, characterized in that The mass fraction of Mn in the stainless steel powder is 0.80-1.00%, and the cooling rate in the cooling step is 50-100° C. / min.

9. The method according to claim 6, characterized in that The mass fraction of Mn in the stainless steel powder is 0.90-1.00%, and the cooling rate in the cooling step is 100-150° C. / min.

10. The method according to claim 6, characterized in that The mass fraction of Mn in the stainless steel powder is 1.00%, and the cooling rate in the cooling step is 150-200° C. / min.

11. An alloy steel material, characterized in that: The alloy steel material is prepared according to the method according to any one of claims 6 to 10, the hardness of the alloy steel material is 55-80 HRB, and the content of Mn in the alloy steel material is 0.2-0.85%.