A MIM feed material and preparation method thereof

Abstract

This invention relates to the field of metal injection molding technology, specifically disclosing a metal injection molding (MIM) feedstock and its preparation method. The MIM feedstock comprises the following components in parts by weight: 85-90 parts of metal powder; 10-15 parts of binder; the binder is a compound of modified polyoxymethylene, lubricant, and dispersant; the modified polyoxymethylene is prepared by mixing polyoxymethylene, garlic oil, ginger oil, and Acer truncatum seed oil. This invention has the advantage of improving the strength of metal products.

Description

Technical Field

[0001] The invention relates to the field of metal injection molding, in particular to a MIM feed material and a preparation method thereof. Background Art

[0002] Metal injection molding (MIM) is a method of mixing metal powder and a binder under certain conditions, extruding and granulating the mixture into a feed material, and then injecting the feed material into a mold to form a product of the desired shape.

[0003] The process is roughly divided into four steps: granulation, injection, degreasing, and sintering. First, the metal powder is mixed with the binder through the granulation step, and the metal powder is evenly coated with the binder. Then, the injection step is used to form a shaped green embryo. The green embryo is degreased to remove most of the binder to form a brown embryo, and the brown embryo is sintered to obtain a metal product.

[0004] During the sintering process, the remaining binder serving as the skeleton will be completely removed, allowing the metal powders to bond to each other, thus forming a dense whole. However, there is no pressure from the mold during the sintering process, and under the action of the binder, there will be gaps between the metal powders. Although the brown embryo will shrink by about 20% during the sintering process, it still cannot reach a very dense state, resulting in generally low strength of metal products, which makes it difficult to meet application scenarios that require high strength of metal products. Therefore, there is still room for improvement. Summary of the invention

[0005] In order to improve the strength of metal products, the present application provides a MIM feed and a preparation method thereof.

[0006] In the first aspect, the present application provides a MIM feeding, which adopts the following technical solution:

[0007] A MIM feedstock comprises the following components in parts by weight:

[0008] 85-90 parts of metal powder;

[0009] 10-15 parts of binder;

[0010] The binder is a compound of modified polyoxymethylene, a lubricant and a dispersant;

[0011] The modified polyoxymethylene is prepared by mixing polyoxymethylene, garlic oil, ginger oil and Acer truncatum seed oil.

[0012] By adopting the above technical scheme, polyformaldehyde is modified by adding garlic oil, ginger oil and maple seed oil into polyformaldehyde, and the modified polyformaldehyde is used as the skeleton material of the adhesive. During the sintering process, it can help promote the aggregation of metal powders, thereby improving the density of the sintered metal products, effectively improving the strength of the metal products, and enabling the metal products to better meet the needs of application scenarios with high strength requirements.

[0013] Preferably, the mass ratio of the modified polyoxymethylene, lubricant and dispersant is 6-9:3-4:1-2.

[0014] By adopting the above technical solution and specifically selecting the mass ratio of modified polyoxymethylene, lubricant and dispersant in the binder, the fluidity of the feed after hot melting is better, so that the metal powder can fill the mold well, the quality of the injection step is better, the formed green embryo is less likely to have defects, and the product qualification rate is effectively improved.

[0015] Preferably, the lubricant is stearic acid.

[0016] By adopting the above technical solution and specifically selecting stearic acid, the lubrication effect is better, the fluidity of the feed after hot melting is better improved, and the quality of the obtained green embryo is higher.

[0017] Preferably, the dispersant is dioctyl ester.

[0018] By adopting the above technical solution and specifically selecting dioctyl ester, the obtained feed material has better quality, good fluidity, uniform dispersion of metal powder, better green embryo quality, and thus better quality of the sintered metal.

[0019] Preferably, in the modified polyoxymethylene, the mass ratio of polyoxymethylene, garlic oil, ginger oil and Acer truncatum seed oil is 100:2-3:4-5:3-4.

[0020] By adopting the above technical scheme and specifically selecting the mass ratio of polyformaldehyde, garlic oil, ginger oil and maple seed oil in the modified polyformaldehyde, the modification effect of polyformaldehyde is better, the heat-oxidative aging resistance of polyformaldehyde is better, and the modified polyformaldehyde can better improve the density of metal products after sintering, thereby improving the strength of metal products.

[0021] Preferably, the preparation method of the modified polyoxymethylene is as follows:

[0022] Step 1), polyoxymethylene, garlic oil, ginger oil and Acer truncatum seed oil are put into a mixing device and mixed evenly to obtain a premix; step 2), the premix is ​​extruded and granulated to obtain modified polyoxymethylene.

[0023] By adopting the above technical solution, the modified polyoxymethylene has better effect and quality, and can better promote the aggregation of metal powder during the sintering process, thereby effectively improving the strength of metal products.

[0024] In a second aspect, the present application provides a method for preparing a MIM feed material, using the following technical solution:

[0025] A method for preparing the above-mentioned MIM feed material comprises the following steps:

[0026] Step 01), mixing metal powder and a binder, heating until the binder is melted, and mixing and dispersing the mixture uniformly to obtain a mixture;

[0027] Step 02), the mixture is extruded and granulated to obtain MIM feed.

[0028] By adopting the above technical solution, the metal powder in the feed is evenly dispersed, the quality of the obtained feed is better, and after the feed is injected and sintered, the quality of the obtained metal product is better.

[0029] Preferably, in the step 1), the metal powder and the binder are mixed, heated to 195-205° C., and mixed and dispersed uniformly at 195-205° C.

[0030] By adopting the above technical solution and specifically selecting 195-205°C, the metal powder is evenly dispersed, which effectively reduces the defects of pores, gaps, etc. in the sintered metal products, and the product qualification rate is high.

[0031] In summary, this application has the following beneficial effects:

[0032] 1. Since the present application modifies polyformaldehyde by adding garlic oil, ginger oil and maple seed oil into polyformaldehyde, and adopts modified polyformaldehyde as the skeleton material of the adhesive, it can help promote the aggregation of metal powder during the sintering process, thereby improving the density of the sintered metal product, effectively improving the strength of the metal product, and making the metal product better meet the needs of application scenarios with high strength requirements.

[0033] 2. In the present application, it is preferred to specifically select the mass ratio of modified polyoxymethylene, lubricant and dispersant in the binder so that the fluidity of the feed after hot melting is better, so that the metal powder can fill the mold well, the quality of the injection step is better, the formed green embryo is not prone to defects, and the product qualification rate is effectively improved.

[0034] 3. In the present application, it is preferred to specifically select the mass ratio of polyformaldehyde, garlic oil, ginger oil and Acer truncatum seed oil in the modified polyformaldehyde so that the modification effect of the polyformaldehyde is better, the heat-oxidative aging resistance of the polyformaldehyde is better, and the modified polyformaldehyde can better improve the density of the metal product after sintering, and the effect of improving the strength of the metal product is better. DETAILED DESCRIPTION

[0035] The present application is further described in detail below with reference to the embodiments.

[0036] Example 1

[0037] A MIM feedstock is made of metal powder and a binder.

[0038] The metal powder is stainless steel powder purchased from Nangong Xindun Alloy Welding Material Spraying Co., Ltd., with a brand of 316L and a particle size of 500 mesh.

[0039] The binder is a compound of modified polyoxymethylene, a lubricant and a dispersant.

[0040] The lubricant is stearic acid, which was purchased from Jinan Xinshuangyue Chemical Co., Ltd., CAS No.: 57-11-4.

[0041] Among them, the dispersant is dioctyl ester, which was purchased from Shandong Baifeng New Material Technology Co., Ltd., CAS No.: 117-81-7.

[0042] The modified polyoxymethylene is prepared by mixing polyoxymethylene, garlic oil, ginger oil and Acer truncatum seed oil.

[0043] Polyoxymethylene was purchased from Polyplastics of Japan, brand: M90LV.

[0044] Garlic oil was purchased from Shaanxi Chenming Biotechnology Co., Ltd.

[0045] Ginger oil was purchased from Hubei Xinghengye Technology Co., Ltd.

[0046] Acer truncatum seed oil was purchased from Wuhan Lanabai Pharmaceutical Chemical Co., Ltd.

[0047] The preparation method of modified polyoxymethylene is as follows:

[0048] Step 1), 100kg of polyoxymethylene, 2kg of garlic oil, 4kg of ginger oil, and 3kg of Acer truncatum seed oil are put into an internal mixer, the speed is 45r / min, the pressure is 10MPa, the mixing temperature is increased to 170°C, the mixing temperature is kept at 170°C for 2min, and the material is discharged to obtain a premix.

[0049] Step 2), the premix is ​​put into a twin-screw extruder for extrusion granulation, the processing temperatures of the twin-screw extruder zones I-XI are sequentially set to: 160°C, 165°C, 165°C, 180°C, 180°C, 200°C, 200°C, 200°C, 195°C, 195°C, the main screw speed is 400rpm, the water tank temperature is 25°C during the cooling process, and underwater granulation is performed to obtain modified polyoxymethylene.

[0050] The method for preparing the MIM feedstock comprises the following steps:

[0051] Step 01), put 85kg of metal powder, 9kg of modified polyoxymethylene, 4kg of lubricant and 2kg of dispersant into an internal mixer, rotate at 45r / min, press the plunger at 10MPa, heat the mixing to 195°C, continue mixing at a constant temperature of 195°C for 8min, discharge the material, and obtain a mixture.

[0052] Step 02), the mixture is put into a twin-screw extruder for extrusion granulation, and the processing temperatures of the twin-screw extruder zones I-XI are set to: 160°C, 165°C, 165°C, 180°C, 180°C, 200°C, 200°C, 200°C, 195°C, 195°C, the main screw speed is 400rpm, the water tank temperature is 25°C during the cooling process, and underwater granulation is performed to obtain MIM feed.

[0053] Example 2

[0054] A MIM feedstock is made of metal powder and a binder.

[0055] The metal powder is stainless steel powder purchased from Nangong Xindun Alloy Welding Material Spraying Co., Ltd., with a brand of 316L and a particle size of 500 mesh.

[0056] The binder is a compound of modified polyoxymethylene, a lubricant and a dispersant.

[0057] The lubricant is stearic acid, which was purchased from Jinan Xinshuangyue Chemical Co., Ltd., CAS No.: 57-11-4.

[0058] Among them, the dispersant is dioctyl ester, which was purchased from Shandong Baifeng New Material Technology Co., Ltd., CAS No.: 117-81-7.

[0059] The modified polyoxymethylene is prepared by mixing polyoxymethylene, garlic oil, ginger oil and Acer truncatum seed oil.

[0060] Polyoxymethylene was purchased from Polyplastics of Japan, brand: M90LV.

[0061] Garlic oil was purchased from Shaanxi Chenming Biotechnology Co., Ltd.

[0062] Ginger oil was purchased from Hubei Xinghengye Technology Co., Ltd.

[0063] Acer truncatum seed oil was purchased from Wuhan Lanabai Pharmaceutical Chemical Co., Ltd.

[0064] The preparation method of modified polyoxymethylene is as follows:

[0065] Step 1), 100 kg of polyoxymethylene, 2.5 kg of garlic oil, 4.5 kg of ginger oil, and 3.5 kg of Acer truncatum seed oil are put into an internal mixer, the speed is 45 r / min, the pressure is 10 MPa, the mixing temperature is increased to 172.5 ° C, the temperature is kept at 172.5 ° C for 2.5 min, and the material is discharged to obtain a premix.

[0066] Step 2), the premix is ​​put into a twin-screw extruder for extrusion granulation, the processing temperatures of the twin-screw extruder zones I-XI are sequentially set to: 160°C, 165°C, 165°C, 180°C, 180°C, 200°C, 200°C, 200°C, 195°C, 195°C, the main screw speed is 400rpm, the water tank temperature is 25°C during the cooling process, and underwater granulation is performed to obtain modified polyoxymethylene.

[0067] The method for preparing the MIM feedstock comprises the following steps:

[0068] Step 01), put 87.5kg metal powder, 7.5kg modified polyoxymethylene, 3.5kg lubricant and 1.5kg dispersant into an internal mixer, with a speed of 45r / min and a pressure of 10MPa. Heat the mixing to 200°C, keep mixing at a constant temperature of 200°C for 9min, discharge the material, and obtain a mixture.

[0069] Step 02), the mixture is put into a twin-screw extruder for extrusion granulation, and the processing temperatures of the twin-screw extruder zones I-XI are set to: 160°C, 165°C, 165°C, 180°C, 180°C, 200°C, 200°C, 200°C, 195°C, 195°C, the main screw speed is 400rpm, the water tank temperature is 25°C during the cooling process, and underwater granulation is performed to obtain MIM feed.

[0070] Example 3

[0071] A MIM feedstock is made of metal powder and a binder.

[0072] The metal powder is stainless steel powder purchased from Nangong Xindun Alloy Welding Material Spraying Co., Ltd., with a brand of 316L and a particle size of 500 mesh.

[0073] The binder is a compound of modified polyoxymethylene, a lubricant and a dispersant.

[0074] The lubricant is stearic acid, which was purchased from Jinan Xinshuangyue Chemical Co., Ltd., CAS No.: 57-11-4.

[0075] Among them, the dispersant is dioctyl ester, which was purchased from Shandong Baifeng New Material Technology Co., Ltd., CAS No.: 117-81-7.

[0076] The modified polyoxymethylene is prepared by mixing polyoxymethylene, garlic oil, ginger oil and Acer truncatum seed oil.

[0077] Polyoxymethylene was purchased from Polyplastics of Japan, brand: M90LV.

[0078] Garlic oil was purchased from Shaanxi Chenming Biotechnology Co., Ltd.

[0079] Ginger oil was purchased from Hubei Xinghengye Technology Co., Ltd.

[0080] Acer truncatum seed oil was purchased from Wuhan Lanabai Pharmaceutical Chemical Co., Ltd.

[0081] The preparation method of modified polyoxymethylene is as follows:

[0082] Step 1), 100kg of polyoxymethylene, 3kg of garlic oil, 5kg of ginger oil, and 4kg of Acer truncatum seed oil are put into an internal mixer, the speed is 45r / min, the pressure is 10MPa, the mixing temperature is increased to 175°C, the mixing temperature is kept at 175°C for 3min, and the material is discharged to obtain a premix.

[0083] Step 2), the premix is ​​put into a twin-screw extruder for extrusion granulation, the processing temperatures of the twin-screw extruder zones I-XI are sequentially set to: 160°C, 165°C, 165°C, 180°C, 180°C, 200°C, 200°C, 200°C, 195°C, 195°C, the main screw speed is 400rpm, the water tank temperature is 25°C during the cooling process, and underwater granulation is performed to obtain modified polyoxymethylene.

[0084] The method for preparing the MIM feedstock comprises the following steps:

[0085] Step 01), put 90kg of metal powder, 6kg of modified polyoxymethylene, 3kg of lubricant and 1kg of dispersant into an internal mixer, rotate at 45r / min, press the plunger at 10MPa, heat the mixer to 205°C, continue mixing at a constant temperature of 205°C for 10min, discharge the mixer to obtain a mixture.

[0086] Step 02), the mixture is put into a twin-screw extruder for extrusion granulation, and the processing temperatures of the twin-screw extruder zones I-XI are set to: 160°C, 165°C, 165°C, 180°C, 180°C, 200°C, 200°C, 200°C, 195°C, 195°C, the main screw speed is 400rpm, the water tank temperature is 25°C during the cooling process, and underwater granulation is performed to obtain MIM feed.

[0087] Comparative Example 1

[0088] A MIM feedstock is made of metal powder and a binder.

[0089] The metal powder is stainless steel powder purchased from Nangong Xindun Alloy Welding Material Spraying Co., Ltd., with a brand of 316L and a particle size of 500 mesh.

[0090] The binder is a compound of modified polyoxymethylene, a lubricant and a dispersant.

[0091] The lubricant is stearic acid, which was purchased from Jinan Xinshuangyue Chemical Co., Ltd., CAS No.: 57-11-4.

[0092] Among them, the dispersant is dioctyl ester, which was purchased from Shandong Baifeng New Material Technology Co., Ltd., CAS No.: 117-81-7.

[0093] The modified polyoxymethylene is prepared by mixing polyoxymethylene, white oil, ginger oil and maple seed oil.

[0094] Polyoxymethylene was purchased from Polyplastics of Japan, brand: M90LV.

[0095] White oil was purchased from Shandong Zhuyou Lubrication Technology Co., Ltd.

[0096] Ginger oil was purchased from Hubei Xinghengye Technology Co., Ltd.

[0097] Acer truncatum seed oil was purchased from Wuhan Lanabai Pharmaceutical Chemical Co., Ltd.

[0098] The preparation method of modified polyoxymethylene is as follows:

[0099] Step 1), 100kg of polyoxymethylene, 2.5kg of white oil, 4.5kg of ginger oil, and 3.5kg of Acer truncatum seed oil are put into an internal mixer, the speed is 45r / min, the pressure is 10MPa, the mixing temperature is increased to 172.5°C, the temperature is kept at 172.5°C for 2.5min, and the material is discharged to obtain a premix.

[0100] Step 2), the premix is ​​put into a twin-screw extruder for extrusion granulation, the processing temperatures of the twin-screw extruder zones I-XI are sequentially set to: 160°C, 165°C, 165°C, 180°C, 180°C, 200°C, 200°C, 200°C, 195°C, 195°C, the main screw speed is 400rpm, the water tank temperature is 25°C during the cooling process, and underwater granulation is performed to obtain modified polyoxymethylene.

[0101] The method for preparing the MIM feedstock comprises the following steps:

[0102] Step 01), put 87.5kg metal powder, 7.5kg modified polyoxymethylene, 3.5kg lubricant and 1.5kg dispersant into an internal mixer, with a speed of 45r / min and a pressure of 10MPa. Heat the mixing to 200°C, keep mixing at a constant temperature of 200°C for 9min, discharge the material, and obtain a mixture.

[0103] Step 02), the mixture is put into a twin-screw extruder for extrusion granulation, and the processing temperatures of the twin-screw extruder zones I-XI are set to: 160°C, 165°C, 165°C, 180°C, 180°C, 200°C, 200°C, 200°C, 195°C, 195°C, the main screw speed is 400rpm, the water tank temperature is 25°C during the cooling process, and underwater granulation is performed to obtain MIM feed.

[0104] Comparative Example 2

[0105] A MIM feedstock is made of metal powder and a binder.

[0106] The metal powder is stainless steel powder purchased from Nangong Xindun Alloy Welding Material Spraying Co., Ltd., with a brand of 316L and a particle size of 500 mesh.

[0107] The binder is a compound of modified polyoxymethylene, a lubricant and a dispersant.

[0108] The lubricant is stearic acid, which was purchased from Jinan Xinshuangyue Chemical Co., Ltd., CAS No.: 57-11-4.

[0109] Among them, the dispersant is dioctyl ester, which was purchased from Shandong Baifeng New Material Technology Co., Ltd., CAS No.: 117-81-7.

[0110] The modified polyoxymethylene is prepared by mixing polyoxymethylene, garlic oil, castor oil and maple seed oil.

[0111] Polyoxymethylene was purchased from Polyplastics of Japan, brand: M90LV.

[0112] Garlic oil was purchased from Shaanxi Chenming Biotechnology Co., Ltd.

[0113] Castor oil was purchased from Jining Sanshi Biotechnology Co., Ltd.

[0114] Acer truncatum seed oil was purchased from Wuhan Lanabai Pharmaceutical Chemical Co., Ltd.

[0115] The preparation method of modified polyoxymethylene is as follows:

[0116] Step 1), 100 kg of polyoxymethylene, 2.5 kg of garlic oil, 4.5 kg of castor oil, and 3.5 kg of Acer truncatum seed oil are put into an internal mixer, the speed is 45 r / min, the pressure is 10 MPa, the mixing temperature is increased to 172.5 ° C, the temperature is kept at 172.5 ° C for 2.5 min, and the material is discharged to obtain a premix.

[0117] Step 2), the premix is ​​put into a twin-screw extruder for extrusion granulation, the processing temperatures of the twin-screw extruder zones I-XI are sequentially set to: 160°C, 165°C, 165°C, 180°C, 180°C, 200°C, 200°C, 200°C, 195°C, 195°C, the main screw speed is 400rpm, the water tank temperature is 25°C during the cooling process, and underwater granulation is performed to obtain modified polyoxymethylene.

[0118] The method for preparing the MIM feedstock comprises the following steps:

[0119] Step 01), put 87.5kg metal powder, 7.5kg modified polyoxymethylene, 3.5kg lubricant and 1.5kg dispersant into an internal mixer, with a speed of 45r / min and a pressure of 10MPa. Heat the mixing to 200°C, keep mixing at a constant temperature of 200°C for 9min, discharge the material, and obtain a mixture.

[0120] Step 02), the mixture is put into a twin-screw extruder for extrusion granulation, and the processing temperatures of the twin-screw extruder zones I-XI are set to: 160°C, 165°C, 165°C, 180°C, 180°C, 200°C, 200°C, 200°C, 195°C, 195°C, the main screw speed is 400rpm, the water tank temperature is 25°C during the cooling process, and underwater granulation is performed to obtain MIM feed.

[0121] Comparative Example 3

[0122] A MIM feedstock is made of metal powder and a binder.

[0123] The metal powder is stainless steel powder purchased from Nangong Xindun Alloy Welding Material Spraying Co., Ltd., with a brand of 316L and a particle size of 500 mesh.

[0124] The binder is a compound of modified polyoxymethylene, a lubricant and a dispersant.

[0125] The lubricant is stearic acid, which was purchased from Jinan Xinshuangyue Chemical Co., Ltd., CAS No.: 57-11-4.

[0126] Among them, the dispersant is dioctyl ester, which was purchased from Shandong Baifeng New Material Technology Co., Ltd., CAS No.: 117-81-7.

[0127] The modified polyoxymethylene is prepared by mixing polyoxymethylene, garlic oil, ginger oil and tung oil.

[0128] Polyoxymethylene was purchased from Polyplastics of Japan, brand: M90LV.

[0129] Garlic oil was purchased from Shaanxi Chenming Biotechnology Co., Ltd.

[0130] Ginger oil was purchased from Hubei Xinghengye Technology Co., Ltd.

[0131] Tung oil was purchased from Shandong Baihua Chemical Co., Ltd.

[0132] The preparation method of modified polyoxymethylene is as follows:

[0133] Step 1), 100kg of polyoxymethylene, 2.5kg of garlic oil, 4.5kg of ginger oil, and 3.5kg of tung oil are put into an internal mixer at a speed of 45r / min and a pressure of 10MPa, and the mixing temperature is raised to 172.5°C, and the mixing temperature is kept at 172.5°C for 2.5min, and the material is discharged to obtain a premix.

[0134] Step 2), the premix is ​​put into a twin-screw extruder for extrusion granulation, the processing temperatures of the twin-screw extruder zones I-XI are sequentially set to: 160°C, 165°C, 165°C, 180°C, 180°C, 200°C, 200°C, 200°C, 195°C, 195°C, the main screw speed is 400rpm, the water tank temperature is 25°C during the cooling process, and underwater granulation is performed to obtain modified polyoxymethylene.

[0135] The method for preparing the MIM feedstock comprises the following steps:

[0136] Step 01), put 87.5kg metal powder, 7.5kg modified polyoxymethylene, 3.5kg lubricant and 1.5kg dispersant into an internal mixer, with a speed of 45r / min and a pressure of 10MPa. Heat the mixing to 200°C, keep mixing at a constant temperature of 200°C for 9min, discharge the material, and obtain a mixture.

[0137] Step 02), the mixture is put into a twin-screw extruder for extrusion granulation, and the processing temperatures of the twin-screw extruder zones I-XI are set to: 160°C, 165°C, 165°C, 180°C, 180°C, 200°C, 200°C, 200°C, 195°C, 195°C, the main screw speed is 400rpm, the water tank temperature is 25°C during the cooling process, and underwater granulation is performed to obtain MIM feed.

[0138] Comparative Example 4

[0139] A MIM feedstock is made of metal powder and a binder.

[0140] The metal powder is stainless steel powder purchased from Nangong Xindun Alloy Welding Material Spraying Co., Ltd., with a brand of 316L and a particle size of 500 mesh.

[0141] The binder is a compound of modified polyoxymethylene, a lubricant and a dispersant.

[0142] The lubricant is stearic acid, which was purchased from Jinan Xinshuangyue Chemical Co., Ltd., CAS No.: 57-11-4.

[0143] Among them, the dispersant is dioctyl ester, which was purchased from Shandong Baifeng New Material Technology Co., Ltd., CAS No.: 117-81-7.

[0144] The modified polyoxymethylene is prepared by mixing polyoxymethylene, white oil, castor oil and tung oil.

[0145] Polyoxymethylene was purchased from Polyplastics of Japan, brand: M90LV.

[0146] White oil was purchased from Shandong Zhuyou Lubrication Technology Co., Ltd.

[0147] Castor oil was purchased from Jining Sanshi Biotechnology Co., Ltd.

[0148] Tung oil was purchased from Shandong Baihua Chemical Co., Ltd.

[0149] The preparation method of modified polyoxymethylene is as follows:

[0150] Step 1), 100 kg of polyoxymethylene, 2.5 kg of white oil, 4.5 kg of castor oil and 3.5 kg of tung oil are put into an internal mixer at a speed of 45 r / min and a pressure of 10 MPa, and the mixing temperature is raised to 172.5 ° C., and the mixing temperature is kept at 172.5 ° C for 2.5 min, and the material is discharged to obtain a premix.

[0151] Step 2), the premix is ​​put into a twin-screw extruder for extrusion granulation, the processing temperatures of the twin-screw extruder zones I-XI are sequentially set to: 160°C, 165°C, 165°C, 180°C, 180°C, 200°C, 200°C, 200°C, 195°C, 195°C, the main screw speed is 400rpm, the water tank temperature is 25°C during the cooling process, and underwater granulation is performed to obtain modified polyoxymethylene.

[0152] The method for preparing the MIM feedstock comprises the following steps:

[0153] Step 01), put 87.5kg metal powder, 7.5kg modified polyoxymethylene, 3.5kg lubricant and 1.5kg dispersant into an internal mixer, with a speed of 45r / min and a pressure of 10MPa. Heat the mixing to 200°C, keep mixing at a constant temperature of 200°C for 9min, discharge the material, and obtain a mixture.

[0154] Step 02), the mixture is put into a twin-screw extruder for extrusion granulation, and the processing temperatures of the twin-screw extruder zones I-XI are set to: 160°C, 165°C, 165°C, 180°C, 180°C, 200°C, 200°C, 200°C, 195°C, 195°C, the main screw speed is 400rpm, the water tank temperature is 25°C during the cooling process, and underwater granulation is performed to obtain MIM feed.

[0155] Experiment 1

[0156] According to GB / T228.1-2021 "Tensile test of metallic materials Part 1: Room temperature test method", the tensile strength of the test samples prepared by the MIM feed of each embodiment and comparative example is tested.

[0157] The sample to be tested is made of plate with a thickness of 2mm.

[0158] The preparation method of the test sample is as follows:

[0159] Step 001), feed the MIM material into an injection molding machine, inject it into a mold through the injection molding machine, cool and demould to obtain a green embryo.

[0160] Step 002), heating the raw embryo to 110°C, keeping the temperature constant for 1 hour, completing defatting, and obtaining brown embryo.

[0161] Step 003), put the brown embryo into a sintering furnace, introduce nitrogen to exhaust the air, heat to 800°C, keep the temperature constant for 80 minutes, increase the temperature to 950°C, keep the temperature constant for 120 minutes, cool down to 700°C, keep the temperature constant for 20 minutes, cool to room temperature, and obtain a primary sintered embryo.

[0162] Step 004), put the primary sintered embryo into a sintering furnace, introduce nitrogen to exhaust the air, heat to 800°C, keep the temperature constant for 120 minutes, increase the temperature to 1100°C, keep the temperature constant for 60 minutes, increase the temperature to 1350°C, keep the temperature constant for 240 minutes, reduce the temperature to 800°C, keep the temperature constant for 30 minutes, cool to room temperature, and obtain the test sample.

[0163] The specific detection method of Experiment 1 is shown in Table 1.

[0164] Table 1

[0165] Tensile strength(MPa) Example 1 623 Example 2 626 Example 3 625 Comparative Example 1 608 Comparative Example 2 596 Comparative Example 3 601 Comparative Example 4 591

[0166] According to the data comparison in Table 1, the tensile strength of the test samples prepared in each embodiment is higher than that of each comparative example. It can be seen that the density of the test samples prepared by the MIM feed of each embodiment is higher, so that the strength of the test samples is higher. It can be seen that adding modified polyformaldehyde modified by garlic oil, ginger oil and Acer truncatum seed oil to the MIM feed can effectively improve the density of the metal product during the sintering process, so that the strength of the metal product is higher, thereby better meeting the application scenarios with higher strength requirements and having higher economic value.

[0167] This specific embodiment is merely an explanation of the present application and is not a limitation of the present application. After reading this specification, those skilled in the art may make modifications to the present embodiment without any creative contribution as needed. However, as long as it is within the scope of the claims of the present application, it shall be protected by the patent law.

Claims

1. A MIM feed, characterized in that: The composition includes the following components in parts by weight: 85-90 parts of metal powder; 10-15 parts of binder; The binder is a compound of modified polyoxymethylene, a lubricant and a dispersant; The modified polyoxymethylene is prepared by mixing polyoxymethylene, garlic oil, ginger oil and Acer truncatum seed oil; In the modified polyoxymethylene, the mass ratio of polyoxymethylene, garlic oil, ginger oil and Acer truncatum seed oil is 100:2-3:4-5:3-4.

2. A MIM feed material according to claim 1, characterized in that: The mass ratio of the modified polyoxymethylene, lubricant and dispersant is 6-9:3-4:1-2.

3. A MIM feed material according to claim 2, characterized in that: The lubricant is stearic acid.

4. A MIM feed material according to claim 2, characterized in that: The dispersant is dioctyl ester.

5. A MIM feed material according to claim 1, characterized in that: The preparation method of the modified polyoxymethylene is as follows: Step 1), polyoxymethylene, garlic oil, ginger oil, and Acer truncatum seed oil are put into a mixing device and mixed evenly to prepare a premix; Step 2), the premix is ​​extruded and granulated to obtain modified polyoxymethylene.

6. A method for preparing a MIM feed material according to any one of claims 1 to 5, characterized in that: The following steps are involved: Step 01), mixing metal powder and binder, heating until the binder is melted, and mixing and dispersing uniformly to obtain a mixture; Step 02), the mixture is extruded and granulated to obtain MIM feed.

7. The method for preparing a MIM feed material according to claim 6, characterized in that: In the step 01), the metal powder and the binder are mixed, heated to 195-205° C., and mixed and dispersed uniformly at 195-205° C.