阅读说明：本技术 一种型内铸造孕育块以及球墨铸铁的孕育方法 (in-mold casting inoculation block and inoculation method of nodular cast iron ) 是由 辛照龙 于 2019-10-22 设计创作，主要内容包括：本发明公开了一种型内铸造孕育块以及球墨铸铁的孕育方法。该型内铸造孕育块的原料包括75硅铁和粘结剂,75硅铁和粘结剂的重量比为100：(2-3),75硅铁的粒度为5-10mm,粘结剂包括以下原料：硼酸,聚乙烯醇,羧甲基纤维素,碳化硅晶须,水。本发明制备型内铸造孕育块的工艺简单,成本低,制得的孕育块成型强度高、溶解速度均匀、孕育效果好,生产的球墨铸铁铸件力学性能好、废品率低。(The invention discloses an type in-mold casting inoculation block and an inoculation method of nodular cast iron, wherein the raw materials of the in-mold casting inoculation block comprise 75 ferrosilicon and a binder, the weight ratio of the 75 ferrosilicon to the binder is 100 (2-3), the granularity of the 75 ferrosilicon is 5-10mm, and the binder comprises boric acid, polyvinyl alcohol, carboxymethyl cellulose, silicon carbide whiskers and water.)

1, type in-mold casting inoculation block, which is characterized in that the raw material of the type in-mold casting inoculation block comprises 75 ferrosilicon and a binder, wherein the weight ratio of the 75 ferrosilicon to the binder is 100 (2-3);

the granularity of the 75 ferrosilicon is 5-10 mm;

the adhesive comprises the following raw materials: boric acid, polyvinyl alcohol, carboxymethyl cellulose, silicon carbide whiskers and water; the average polymerization degree of the polyvinyl alcohol is 500-800, and the alcoholysis degree is 78-88%; the diameter of the silicon carbide whisker is 200-300nm, and the length-diameter ratio is 30-50.

2. The in-mold cast inoculant block as claimed in claim 1, wherein said binder comprises the following raw materials in weight percent: 2-3% of boric acid, 4-6% of polyvinyl alcohol, 0.3-0.5% of carboxymethyl cellulose, 0.5-1% of silicon carbide whisker and the balance of water.

3. The in-mold cast inoculant block as claimed in claim 1 or 2, wherein said binder comprises the following raw materials in weight percent: 2.5% of boric acid, 5% of polyvinyl alcohol, 0.35% of carboxymethyl cellulose, 0.8% of silicon carbide whisker and the balance of water.

4. The in-mold cast inoculant block of any one of claims 1 to 3 to , wherein the binder is prepared by the following method:

s1, adding boric acid into water with the weight of 20-25 times of that of the boric acid to be completely dissolved to obtain a boric acid solution;

and S2, dissolving the polyvinyl alcohol in the rest water, adding the carboxymethyl cellulose and the silicon carbide whiskers, stirring and dispersing, then adding the boric acid solution, and uniformly mixing to obtain the water-based organic silicon fertilizer.

5. The in-mold cast inoculant block of any one of claims 1 to 4 to , wherein the weight ratio of the 75 Si-Fe to the binder is 100: 2.5.

6. The in-mold casting inoculation block according to any one of claims 1 to 5 to , wherein the preparation method comprises weighing 75 ferrosilicon and binder by weight, mixing uniformly, press-molding under 30 to 50MPa, and oven-drying at 60 to 70 ℃.

The inoculation method of spheroidal graphite cast irons, which is characterized by comprising the steps of placing the in-mold casting inoculation block of in claims 1-6 on a foamed ceramic filter, then placing the foamed ceramic filter into a roasted mold shell pouring cup, and pouring molten iron.

8. The inoculation method for spheroidal graphite cast iron according to claim 7, wherein the weight of the in-mold casting inoculation block is 0.5 to 0.6 percent of the weight of the molten iron.

9. The inoculation method for spheroidal graphite cast iron according to claim 7 or 8, wherein the ceramic foam filter pore density is 30-35 ppi.

10. The inoculation method of nodular cast iron as claimed in any of claims 7-9, wherein the molten iron pouring temperature is 1420-.

Technical Field

The invention relates to the technical field of casting, in particular to an in-mold casting inoculation block and an inoculation method of nodular cast iron.

Background

The inoculation treatment can effectively improve the processing performance of castings and is a key link for producing thin-wall and high-strength castings, and the in-mold inoculation is characterized in that a blocky inoculant is directly put into a casting mold, so that the inoculation effect can be improved to the maximum extent, and the consumption of alloy is reduced, so that -range application is obtained.

Disclosure of Invention

Based on the technical problems in the background art, the invention provides an type in-mold casting inoculation block and an inoculation method of nodular cast iron, the process for preparing the inoculation block is simple, the cost is low, the prepared inoculation block has high molding strength, uniform dissolution speed and good inoculation effect, and the produced nodular cast iron casting has good mechanical property and low rejection rate.

The in-mold casting inoculation block provided by the invention comprises raw materials of 75 ferrosilicon and a binder, wherein the weight ratio of the 75 ferrosilicon to the binder is 100 (2-3);

the granularity of the 75 ferrosilicon is 5-10 mm;

the adhesive comprises the following raw materials: boric acid, polyvinyl alcohol, carboxymethyl cellulose, silicon carbide whiskers and water; the average polymerization degree of the polyvinyl alcohol is 500-800, and the alcoholysis degree is 78-88%; the diameter of the silicon carbide whisker is 200-300nm, and the length-diameter ratio is 30-50.

Preferably, the binder comprises the following raw materials in percentage by weight: 2-3% of boric acid, 4-6% of polyvinyl alcohol, 0.3-0.5% of carboxymethyl cellulose, 0.5-1% of silicon carbide whisker and the balance of water.

More preferably, the binder comprises the following raw materials in percentage by weight: 2.5% of boric acid, 5% of polyvinyl alcohol, 0.35% of carboxymethyl cellulose, 0.8% of silicon carbide whisker and the balance of water.

Preferably, the preparation method of the binder is as follows:

s1, adding boric acid into water with the weight of 20-25 times of that of the boric acid to be completely dissolved to obtain a boric acid solution;

and S2, dissolving the polyvinyl alcohol in the rest water, adding the carboxymethyl cellulose and the silicon carbide whiskers, stirring and dispersing, then adding the boric acid solution, and uniformly mixing to obtain the water-based organic silicon fertilizer.

Preferably, the weight ratio of the 75 ferrosilicon to the binder is 100: 2.5.

preferably, the preparation method of the in-mold casting inoculation block comprises the following steps: weighing 75 ferrosilicon and a binder by weight, uniformly mixing, pressing and molding under the pressure of 30-50MPa, and drying at the temperature of 60-70 ℃ to obtain the ferrosilicon/binder.

The inoculation method of nodular cast iron comprises the steps of placing the in-mold casting inoculation block on a foamed ceramic filter, then placing the foamed ceramic filter into a roasted mould shell pouring cup, and pouring molten iron.

Preferably, the weight of the in-mold casting inoculation block is 0.5-0.6% of the weight of molten iron.

Preferably, the ceramic foam filter has a pore density of 30 to 35 ppi.

Preferably, the pouring temperature of the molten iron is 1420-.

The invention has the following beneficial effects:

the binder adopted by the mold-in casting inoculation block is prepared from boric acid, polyvinyl alcohol, carboxymethyl cellulose and silicon carbide whiskers, wherein the boric acid and the polyvinyl alcohol are respectively used as an inorganic binder and an organic binder and have good binding performance, the boric acid can enable the polyvinyl alcohol to be crosslinked to improve the binding strength of the binder, the carboxymethyl cellulose can be used as a tackifier, the step is carried out to improve the binding strength and improve the dispersion uniformity of the binder, the silicon carbide whiskers can form a three-dimensional network structure to play a role of a framework to strengthen and toughen the binder and improve the impact resistance of the mold, the average polymerization degree and alcoholysis degree of the polyvinyl alcohol are too high, a carbon layer is easily formed on the contact surface of metal liquid and the inoculant in the casting process, the inoculation reaction is hindered from fully proceeding, the average polymerization degree and alcoholysis degree are too low, the binding property is insufficient, the prepared mold inoculation block has insufficient strength, the inoculation is not uniform, the silicon carbide whiskers are thinned, the strength is high, the formed three-dimensional rigid network framework has high stability, the mold-in-mold inoculation block is not easy to break, the mold inoculation block is not easy to obtain the uniform inoculation along with the high mold-in-casting process, the mold inoculation block, the mold-in-mold casting process, the mold inoculation block, the mold inoculation is not only, the mold inoculation is not easy to obtain the mold inoculation block, the mold inoculation.

The inoculation method of the nodular cast iron adopts a mode of combining the in-mold casting inoculation block and the foamed ceramic filter, and the foamed ceramic filter with proper porosity is selected, so that slag inclusion generated during inoculation treatment of the bonding molding inoculation block can be effectively removed, defects in castings are reduced, the mechanical property of the castings is improved, and the rejection rate is greatly reduced.

In conclusion, the process for preparing the in-mold casting inoculation block is simple, the cost is low, the prepared inoculation block is high in molding strength, uniform in dissolving speed and good in inoculation effect, and the produced nodular cast iron casting is good in mechanical property and low in rejection rate.

Detailed Description

The technical solution of the present invention will be described in detail below with reference to specific examples.