A kind of heating riser material for water glass investment mold and preparation method thereof

Abstract

The invention relates to the technical field of casting, and proposes a heating riser material for water glass investment mold and a preparation method thereof. The heating riser material for water glass investment mold comprises the following raw materials in parts by weight: 5-10 parts of aluminum powder, 5-10 parts of flux, 15-25 parts of oxidant, 20-30 parts of quartz sand, 10-15 parts of magnesia powder, 15-25 parts of reinforcing fiber, 3-5 parts of rare earth oxide, and 10-15 parts of binder. Through the above technical scheme, the problems of poor high temperature resistance and low compressive strength of the heating riser in the related technology are solved.

Description

Technical Field

[0001] The invention relates to the technical field of casting, and in particular to a heating riser material for water glass investment mold and a preparation method thereof. Background Art

[0002] Generally, in the water glass investment process, due to the limitation of the traditional shell burning and roasting process, the products produced generally have a low yield rate. Especially for thick and large products, the average yield rate is 40%~50%. It is impossible to meet the cost control requirements of production. In the traditional method of increasing the process output, the process yield rate of the product can only be increased by increasing the number of components per casting or adding secondary shrinkage compensation during casting. This will increase the weight of each group, increase the labor intensity of workers, and indirectly affect the production efficiency of the product. In order to improve the product yield rate, a heating riser is generally added to the investment mold so that it can quickly ignite and burn after the molten steel is poured, and release heat to increase the temperature of the molten steel in the riser, prolong the solidification time of the molten metal, extend the shrinkage compensation time, and improve the shrinkage compensation efficiency of the riser for the casting. However, due to the low high temperature resistance and compressive strength of ordinary risers, it cannot meet the shrinkage compensation requirements of castings. Therefore, it is necessary to develop a high temperature resistant heating riser material suitable for water glass investment molds to improve the yield rate of castings. Summary of the invention

[0003] The invention provides a heating riser material for water glass investment mold and a preparation method thereof, which solves the problems of low high temperature resistance and low compressive strength of the heating riser material in the related art.

[0004] The technical solution of the present invention is as follows:

[0005] The invention provides a heating riser material for water glass investment mold, comprising the following raw materials in parts by weight: 5-10 parts of aluminum powder, 5-10 parts of flux, 15-25 parts of oxidant, 20-30 parts of quartz sand, 10-15 parts of magnesia powder, 15-25 parts of reinforcing fiber, 3-5 parts of rare earth oxide and 10-15 parts of binder.

[0006] As a further technical solution, the reinforcing fiber is wollastonite whisker.

[0007] In the present invention, by adding wollastonite whiskers, the high temperature resistance and compressive strength of the heating riser material are further improved.

[0008] As a further technical solution, the rare earth oxide includes one or both of hafnium oxide and niobium oxide.

[0009] As a further technical solution, the rare earth oxide is hafnium oxide.

[0010] In the present invention, by limiting the rare earth oxide to hafnium oxide, the high temperature resistance and compressive strength of the heating riser are further improved.

[0011] As a further technical solution, the oxidant includes one or more of potassium permanganate, ferrosoferric oxide, and potassium nitrate.

[0012] As a further technical solution, the wollastonite whiskers are modified with polysuccinimide before use.

[0013] In the present invention, polysuccinimide is added to the reinforcing fiber to modify the wollastonite whisker, thereby further improving the high temperature resistance and compressive strength of the heating riser material.

[0014] As a further technical solution, the added amount of the polysuccinimide is 2% to 6% of the mass of the wollastonite whiskers.

[0015] As a further technical solution, the modification method comprises the following steps:

[0016] After mixing wollastonite whiskers and polysuccinimide, wollastonite whiskers modified by polysuccinimide are obtained.

[0017] As a further technical solution, the modification temperature is 25-30°C and the modification time is 5-9h.

[0018] As a further technical solution, the binder includes one or both of phenolic resin and epoxy resin.

[0019] As a further technical solution, the flux includes one or more of potassium fluoroaluminate, sodium carbonate, and boric acid.

[0020] The present invention also provides a method for preparing a heating riser material for a water glass investment mold, comprising the following steps:

[0021] S1, mixing the raw materials uniformly to obtain a mixed material;

[0022] S2, filling the mixed material into a riser mold, pressing and molding, demoulding, and drying to obtain a heating riser for water glass investment mold.

[0023] The working principle and beneficial effects of the present invention are:

[0024] In the present invention, aluminum powder is added as a heat-generating agent, and quartz sand and magnesia powder are added as high-temperature resistant materials to improve the high-temperature resistance of the heating riser. The addition of rare earth oxides and reinforcing fibers can further improve the high-temperature stability and high-temperature compressive strength of the heating riser, thereby solving the problems of poor high-temperature resistance and low compressive strength of the heating riser. DETAILED DESCRIPTION

[0025] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0026] In the following embodiments and comparative examples:

[0027] Wollastonite whisker, particle size: 8μm, diameter: 160μm; phenolic resin, model: 2130; epoxy resin, model: WSR6101; quartz sand, particle size: 200 mesh; magnesia powder, particle size: 325 mesh; polysuccinimide, MW 5000-15000.

[0028] Example 1

[0029] A method for preparing a heating riser material for a water glass investment mold comprises the following steps:

[0030] S1, 5 parts of aluminum powder, 5 parts of potassium fluoroaluminate, 15 parts of potassium permanganate, 20 parts of quartz sand, 10 parts of magnesia powder, 15 parts of wollastonite whiskers, 3 parts of hafnium oxide, and 10 parts of phenolic resin are uniformly mixed to obtain a mixture;

[0031] S2, filling the mixed material into a riser mold, pressing and molding, demoulding, and drying to obtain a heating riser material for water glass investment mold.

[0032] Example 2

[0033] A method for preparing a heating riser material for a water glass investment mold comprises the following steps:

[0034] S1, 7 parts of aluminum powder, 7 parts of sodium carbonate, 20 parts of ferrosoferric oxide, 25 parts of quartz sand, 12 parts of magnesia powder, 20 parts of wollastonite whiskers, 4 parts of hafnium oxide, and 12 parts of phenolic resin are uniformly mixed to obtain a mixture;

[0035] S2, filling the mixed material into a riser mold, pressing and molding, demoulding, and drying to obtain a heating riser material for water glass investment mold.

[0036] Example 3

[0037] A method for preparing a heating riser material for a water glass investment mold comprises the following steps:

[0038] S1, 10 parts of aluminum powder, 10 parts of boric acid, 25 parts of potassium nitrate, 30 parts of quartz sand, 15 parts of magnesia powder, 25 parts of wollastonite whiskers, 5 parts of niobium oxide, and 15 parts of epoxy resin are uniformly mixed to obtain a mixture;

[0039] S2, filling the mixed material into a riser mold, pressing and molding, demoulding, and drying to obtain a heating riser material for water glass investment mold.

[0040] Example 4

[0041] The present embodiment is different from the embodiment 1 only in that the preparation method of the modified wollastonite whisker is as follows: 40 g of wollastonite whisker and 2.8 g of polysuccinimide are added to 400 mL of water and mixed evenly, then stirred at 25° C. for 9 h, filtered and dried to obtain the modified wollastonite whisker.

[0042] Example 5

[0043] The only difference between this embodiment and embodiment 4 is that the added amount of polysuccinimide is 0.4 g.

[0044] Example 6

[0045] The only difference between this embodiment and embodiment 4 is that the added amount of polysuccinimide is 0.8 g.

[0046] Example 7

[0047] The only difference between this embodiment and embodiment 4 is that the added amount of polysuccinimide is 1.6 g.

[0048] Example 8

[0049] The only difference between this embodiment and embodiment 4 is that the added amount of polysuccinimide is 2.4 g.

[0050] Example 9

[0051] The only difference between this embodiment and embodiment 1 is that hafnium oxide is replaced by an equal amount of niobium oxide.

[0052] Comparative Example 1

[0053] The only difference between this comparative example and Example 1 is that the wollastonite whiskers are replaced with an equal amount of hafnium oxide.

[0054] Comparative Example 2

[0055] The only difference between this comparative example and Example 1 is that hafnium oxide is replaced by an equal amount of wollastonite whiskers.

[0056] Comparative Example 3

[0057] The only difference between this comparative example and Example 1 is that hafnium oxide is replaced by an equal amount of zirconium oxide.

[0058] The heat-resistant and compressive strength tests were performed on the heat-generating riser materials prepared in Examples 1 to 9 and Comparative Examples 1 to 3, respectively.

[0059] High temperature resistance: According to the determination method in JB / T 13040-2017 "Heating and Insulating Riser Sleeves for Casting", the maximum heating temperature of the heating riser material was tested, wherein the dimensions of the heating risers prepared in Examples 1 to 9 and Comparative Examples 1 to 3 are: the inner diameter du of the bottom of the riser is 118 mm, the outer diameter Du of the bottom of the riser is 154.5 mm, the inner diameter do of the top of the riser is 112 mm, the outer diameter Do of the top of the riser is 148 mm, the internal height h of the riser is 130 mm, and the external height H of the riser is 150 mm;

[0060] Compressive strength: According to the determination method in GB / T 2684-2009 "Test methods for foundry sand and mixtures", the compressive strength of the exothermic riser material is tested;

[0061] The test results are recorded in Table 1.

[0062] Table 1 Performance test results of exothermic riser materials

[0063]

[0064] Compared with Example 1, Comparative Example 1 did not add wollastonite whiskers, Comparative Example 2 did not add hafnium oxide, and Comparative Example 3 replaced hafnium oxide with zirconium oxide. As a result, the maximum heating temperature and compressive strength of the heating risers in Comparative Examples 1 to 3 were lower than those in Example 1, indicating that the compounding of wollastonite whiskers and rare earth oxides can improve the high temperature resistance and compressive strength of the heating risers.

[0065] Compared with Example 1, Example 9 replaces hafnium oxide with an equal amount of niobium oxide. As a result, the maximum heating temperature and compressive strength of the heating riser in Example 9 are lower than those in Example 1, indicating that the compounding of wollastonite whiskers and hafnium oxide can further improve the high temperature resistance and compressive strength of the heating riser.

[0066] Compared with Example 1, the wollastonite whiskers in Example 4 were modified with polysuccinimide. As a result, the maximum heating temperature and compressive strength of the heating riser in Example 4 were higher than those in Example 1, indicating that the high temperature resistance and compressive strength of the heating riser can be further improved by modifying the wollastonite whiskers with polysuccinimide.

[0067] Compared with Example 4, Examples 5 to 8 change the amount of polysuccinimide added, and it is found that the maximum heating temperature and compressive strength of the heating risers in Examples 6 to 8 are higher than those in Examples 4 and 5, indicating that when the amount of polysuccinimide added is 2% to 6% of the mass of wollastonite whiskers, the high temperature resistance and compressive strength of the heating riser can be further improved; by comparing Examples 6 to 8, it is found that the maximum heating temperature and compressive strength of the heating riser in Example 7 are higher than those in Examples 6 and 8, indicating that when the amount of polysuccinimide added is 4% of the mass of wollastonite whiskers, the obtained heating riser has the highest high temperature resistance and compressive strength.

[0068] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A heating riser material for water glass investment mold, characterized in that: The invention is composed of the following raw materials in parts by weight: 5-10 parts of aluminum powder, 5-10 parts of flux, 15-25 parts of oxidant, 20-30 parts of quartz sand, 10-15 parts of magnesia powder, 15-25 parts of reinforcing fiber, 3-5 parts of rare earth oxide, and 10-15 parts of binder; The reinforcing fibers are wollastonite whiskers; The wollastonite whiskers are modified with polysuccinimide before use; The amount of polysuccinimide added is 2% to 6% of the mass of wollastonite whiskers; The rare earth oxide includes one or both of hafnium oxide and niobium oxide; The flux includes one or more of potassium fluoroaluminate, sodium carbonate and boric acid.

2. The exothermic riser material for water glass investment mold according to claim 1, characterized in that: The rare earth oxide is hafnium oxide.

3. The exothermic riser material for water glass investment mold according to claim 1, characterized in that: The modification method comprises the following steps: After mixing wollastonite whiskers and polysuccinimide, wollastonite whiskers modified by polysuccinimide are obtained.

4. The exothermic riser material for water glass investment mold according to claim 1, characterized in that: The binder includes one or both of phenolic resin and epoxy resin.

5. The method for preparing a heating riser material for water glass investment mold according to any one of claims 1 to 4, characterized in that: The following steps are involved: S1, mixing the raw materials uniformly to obtain a mixed material; S2, filling the mixed material into a riser mold, pressing and molding, demoulding, and drying to obtain a heating riser material for water glass investment mold.

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