Annular magnetic hub for powder metallurgy and preparation method thereof

[0034] Example 1

[0035] Refer to attached figure 1 , 2 Preparation of the present invention. figure 1 , 2 An embodiment of a powder metallurgy circular magnetic hub prepared by the present invention is given. The powder metallurgy annular magnetic hub is characterized in that it is composed of a ring 1, the inner diameter of the ring 1 is 204.75mm, the outer diameter of the ring 1 is 213mm, and the height of the ring 1 is 24mm. There are rectangular magnetic teeth 2 with a rectangular cross section on the inner wall of the inner wall, the width of the rectangular magnetic teeth 2 is 3 mm, the distance between adjacent rectangular magnetic teeth 2 is 10.8 mm, and there are 46 rectangular magnetic teeth 2 in total. The inner wall of the ring 1 between the teeth 2 is provided with a groove 3 with a depth of 0.2 mm and a width of 2 mm; the composition of the ring 1 and its rectangular magnetic teeth 2 is as follows: the weight of pure iron powder is 100 Part, the weight of lubricant is 0.8 part.

[0036] The pure iron powder, wherein iron content ≥ 98.36%, carbon content 0.05-0.10%, silicon content 0.05-0.12%, manganese content 0.10-0.30%, phosphorus content 0.03-0.05%, sulfur content 0.03-0.05%, hydrochloric acid The insoluble matter content is 0.10-0.30%, and FHY80.27 iron powder produced by Shandong Laigang Group Powder Metallurgy Co., Ltd. is used.

[0037] Described lubricant is zinc stearate.

[0038]A preparation method of the powder metallurgy annular magnetic hub of embodiment 1 as above, comprising the following production steps:

[0039] (1), making molds: image 3 , 4 , 5, 6 gives a special mold map. The mold includes a mold cover 6, a mandrel 4, an upper die punch 5 and a mold base. The inner diameter of the mold cavity of the mold casing 6 is determined by multiplying the outer diameter of the ring 1 by the expansion coefficient, the height is 4 times the height of the ring 1, the inner surface finish is 0.8, and the material is Cr 12 m 0 V, the surface hardness is HRC61-63, placed on the formwork, mainly to determine the shape of the powder metallurgy circular magnetic hub; the outer diameter of the mandrel 4 is similar to the inner diameter of the ring 1, according to the inner diameter of the ring 1 multiplied Determined by the expansion coefficient, the surface finish is 0.8, and the material is Cr 12 m 0 V, the surface hardness is HRC61-63, and the outer wall of the mandrel 4 is provided with a convex groove that meshes with the rectangular magnetic teeth 2 and the groove 3 on the inner wall of the powder metallurgy ring magnetic hub, so that the powder metallurgy ring The ring 1 of the magnetic hub and the rectangular magnetic teeth 2 and the groove 3 on the inner wall are finalized; The dies 5 are the same, but in opposite directions, and the inner wall is provided with the same convex corrugation as the rectangular magnetic tooth 2 and the groove 3 on the inner wall of the ring 1; the die frame is three layers of floating, and the bottom layer is a flat plate, which is used as a horizontal workbench .

[0040] (2) Mixing: Use pure iron powder as raw material, weigh 100 parts, add 0.8 parts of lubricant, use double-cone mixer, mix for 45 minutes, make it evenly mixed, pure iron powder is Shandong Laigang FHY80.27 iron powder produced by Group Powder Metallurgy Co., Ltd.

[0041] (3) Press forming: use YZ79-315 press, three upper and two lower mold frames to press, put the mixed pure iron powder into the mold cavity, and use the upper and lower punches to simultaneously press the pure iron powder in the mold cavity from the upper and lower directions. Iron powder is stamped, and the stamping force is 8 tons/cm 3 , Finally, under the action of the drawing force of the mold base, the formed blank is ejected with the lower die 5 .

[0042] (4) Sintering: use a mesh belt furnace for sintering, and lay horizontal refractory porcelain plates in the sintering furnace. The side length of each refractory porcelain plate is 5cm larger than the outer diameter of the powder metallurgy circular magnetic hub, and the blank is placed vertically On the refractory porcelain plate, the sintering temperature is 1130°C, sintering at high temperature for 45 minutes, and cooling with the furnace. During this sintering process, the added lubricant evaporates.

[0043] (5) Finishing processing: YZ79-500 press is used, two upper and two lower mold bases are used for pressing, and the precision of the shaped product is guaranteed through high-precision molds.

[0044] The powder metallurgy annular magnetic hub formed by the above ratio and preparation process is randomly sampled in one furnace, and after testing, its technical indicators are as follows:

[0045] Average Density: 6.10

[0046] Average sintering hardness: HB60.

[0047] Example 2

[0048] The shape and manufacturing process steps of the powder metallurgy magnetic hub are the same as those in Example 1. However, improvements have been made in the ratio and where there is a limited interval: the composition of the ring 1 and its rectangular magnetic teeth 2 is as follows: the weight of pure iron powder is 100 parts, and the weight of lubricant is 1 part.

[0049] The depth of the groove 3 provided on the inner wall of the ring 1 between adjacent magnetic teeth 2 is changed to 0.1mm, and the width is changed to 3mm. After mixing, molding, pressing, sintering, cooling, and finishing, it is processed into products. In the mixing step, use pure iron powder as raw material, weigh 100 parts by weight, add 1 part of lubricant, and use a double-cone mixer for 50 minutes of mixing. In the sintering step, the sintering temperature is 1133°C, sintering at high temperature for 60 minutes, and cooling with the furnace. During this sintering process, the added lubricant evaporates.

[0050] The magnetic hubs prepared according to the above ratio and process are randomly sampled in a furnace, and 100 are randomly sampled. After testing, the technical indicators are as follows:

[0051] Average Density: 6.15

[0052] Average sintering hardness: HB55.

[0053] Example 3

[0054] The shape and preparation process of the powder metallurgy magnetic hub are the same as in Example 1, but improvements have been made in the ratio and where there are interval limits: the composition of the ring 1 and its rectangular magnetic teeth 2 is: pure iron powder The weight is 100 parts, and the weight of the lubricant is 0.5 parts.

[0055] The depth of the groove 3 provided on the inner wall of the ring 1 between adjacent magnetic teeth 2 is changed to 0.15mm, and the width is changed to 3mm. After mixing, molding, pressing, sintering, cooling, and finishing, it is processed into products. In the mixing step, pure iron powder is used as a raw material, weighing 100 parts, plus 0.5 part of lubricant, using a double-cone mixer, and mixing for 40 minutes. In the sintering step, the sintering temperature is 1127°C, sintering at high temperature for 40 minutes, and cooling with the furnace. During this sintering process, the added lubricant evaporates.

[0056] The magnetic hubs prepared according to the above ratio and process are randomly sampled in a furnace, and 100 are randomly sampled. After testing, the technical indicators are as follows:

[0057] Average Density: 6.01

[0058] Average sintering hardness: HB50.