A method of generating porous spherical iron system alloyed powder by a reduction reaction, and its powder and sintered compact

Abstract

A method for preparing a porous spherical iron-based alloy powder, wherein the powder and the sintered body are prepared by first mixing an iron oxide powder with a metal-containing powder to form a mixed powder; subjecting the mixed powder to a spray granulation process such that The mixed powder forms a spherical spray granulated powder; the spherical spray granulated powder is placed in a reduced environment and heated to a reduction temperature of less than 700 DEG C to obtain a porous spherical iron-based alloy powder. The iron-based alloy powder prepared by the method has the advantages of low cost, high fluidity, high compressibility and excellent sintering property.

Description

technical field

[0001] The invention relates to a method for preparing iron-based alloy powder, the powder and a sintered body, especially a method for preparing porous spherical iron-based alloy powder, the powder and a sintered body. Background technique

[0002] Powder Metallurgy (Powder Metallurgy) is one of the common manufacturing technologies for metal materials. Among them, the powder with iron as the main raw material has the widest application range. According to the preparation method, it can be roughly divided into pre-alloyed powder, diffusion alloy powder, and mixed powder. Or a mixture of the above powders, etc.

[0003] The average particle size of the above-mentioned various forms of powder is about 70 μm, which belongs to coarse powder and has a large particle gap. The large particle gap will make the size of the pores in the sintered product larger, and the large pores will lead to poor mechanical properties. In addition, compared with the fine powder, th...

Examples

Embodiment 1

[0036] Embodiment 1~2: be to adopt the mixed powder of composition 1, wherein the average particle diameter of ferric oxide powder is 0.3 μm, 316L stainless steel powder contains the chromium of 17wt%, the nickel of 10.4wt%, the molybdenum of 2.2wt%, 1.6 Wt% manganese, 0.6wt% silicon, and its average particle size is 8 μm, and the average particle size of molybdenum powder is 3 μm. After adding binder, plasticizer and water to this mixed powder, it is obtained after the spray granulation process Spherical spray granulation powder, no hollow large holes through section inspection. The spray granulated powder was reduced for 3 hours at the reduction temperature of 600°C and 650°C respectively, and the obtained porous spherical iron-based alloy powder had a specific surface area of ​​4.55m 2 / g and 3.20m 2 / g, the green density is above 70%, and the compressibility is good, while the sintered density reaches 98.9% and 97.9% respectively. figure 2 It is an electron microscope p...

Embodiment 3

[0037] Example 3: using the mixed powder of composition 2, at a reduction temperature of 600°C, after 3 hours of reduction, the obtained porous spherical iron-based alloy powder has a specific surface area of ​​2.56m 2 / g, the green density is above 70%, the compressibility is good, and the sintered density reaches 94.6%. It can be clearly seen from a high-magnification electron microscope that the porous spherical iron-based alloy powder is in a good spherical shape and has a large number of holes.

Embodiment 4

[0038] Example 4: The mixed powder of composition 3 is used, and the reduction is carried out for 3 hours at a reduction temperature of 700 ° C. The obtained porous spherical iron-based alloy powder has a specific surface area of ​​1.26m 2 / g, while the sintered density reaches 95.6%. The porous spherical iron-based alloy powder is in a good spherical shape and has a large number of holes.

[0039] Comparative examples 1 and 2: the iron-based alloy powder obtained by using the mixed powder of composition 1 and reducing it at the reduction temperature of 750°C and 800°C for 3 hours, the specific surface area is only 0.20m 2 / g and 0.08m 2 / g, the green density is 79.2% and 79.4%, respectively, higher than the examples, but the sintered density is only 91.5% and 89.7%. Although the iron-based alloy powder is slightly spherical, it has almost no holes, so the specific surface area is small and the sintering driving force is low.

technical field

[0001] The invention relates to a method for preparing iron-based alloy powder, the powder and a sintered body, especially a method for preparing porous spherical iron-based alloy powder, the powder and a sintered body. Background technique

[0002] Powder Metallurgy (Powder Metallurgy) is one of the common manufacturing technologies for metal materials. Among them, the powder with iron as the main raw material has the widest application range. According to the preparation method, it can be roughly divided into pre-alloyed powder, diffusion alloy powder, and mixed powder. Or a mixture of the above powders, etc.

[0003] The average particle size of the above-mentioned various forms of powder is about 70 μm, which belongs to coarse powder and has a large particle gap. The large particle gap will make the size of the pores in the sintered product larger, and the large pores will lead to poor mechanical properties. In addition, compared with the fine powder, th...

Examples

Embodiment 1

[0036] Embodiment 1~2: be to adopt the mixed powder of composition 1, wherein the average particle diameter of ferric oxide powder is 0.3 μm, 316L stainless steel powder contains the chromium of 17wt%, the nickel of 10.4wt%, the molybdenum of 2.2wt%, 1.6 Wt% manganese, 0.6wt% silicon, and its average particle size is 8 μm, and the average particle size of molybdenum powder is 3 μm. After adding binder, plasticizer and water to this mixed powder, it is obtained after the spray granulation process Spherical spray granulation powder, no hollow large holes through section inspection. The spray granulated powder was reduced for 3 hours at the reduction temperature of 600°C and 650°C respectively, and the obtained porous spherical iron-based alloy powder had a specific surface area of ​​4.55m 2 / g and 3.20m 2 / g, the green density is above 70%, and the compressibility is good, while the sintered density reaches 98.9% and 97.9% respectively. figure 2 It is an electron microscope p...

Embodiment 3

[0037] Example 3: using the mixed powder of composition 2, at a reduction temperature of 600°C, after 3 hours of reduction, the obtained porous spherical iron-based alloy powder has a specific surface area of ​​2.56m 2 / g, the green density is above 70%, the compressibility is good, and the sintered density reaches 94.6%. It can be clearly seen from a high-magnification electron microscope that the porous spherical iron-based alloy powder is in a good spherical shape and has a large number of holes.

Embodiment 4

[0038] Example 4: The mixed powder of composition 3 is used, and the reduction is carried out for 3 hours at a reduction temperature of 700 ° C. The obtained porous spherical iron-based alloy powder has a specific surface area of ​​1.26m 2 / g, while the sintered density reaches 95.6%. The porous spherical iron-based alloy powder is in a good spherical shape and has a large number of holes.

[0039] Comparative examples 1 and 2: the iron-based alloy powder obtained by using the mixed powder of composition 1 and reducing it at the reduction temperature of 750°C and 800°C for 3 hours, the specific surface area is only 0.20m 2 / g and 0.08m 2 / g, the green density is 79.2% and 79.4%, respectively, higher than the examples, but the sintered density is only 91.5% and 89.7%. Although the iron-based alloy powder is slightly spherical, it has almost no holes, so the specific surface area is small and the sintering driving force is low.

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