SU876265A1 - Method of making castings - Google Patents

Description

(54) METHOD OF MANUFACTURING CASTINGS

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The invention relates to foundry, in particular, to methods for producing castings from high manganese steels.

A known method of manufacturing castings from steel 110G13L, containing,%: 0.9 - 1.4 C, 11.5 - 15.0 Mp 0.4-1.0 Si using refrigerators 1.

. However, this method does not provide stable production of high-quality casting.

The closest to the proposed technical essence and the achieved effect is a method of manufacturing castings from steel 110G13L with a reduced wall thickness of 3-14 mm in two-stack forms, on the top of which there is a ferrostatic pressure of 0.1-0.36 kgf / cm , on the lower 0.36-0.7 kgf / cm, inclusive of the operation of manufacturing a mold according to the model with a facing layer of one composition with a heat storage capacity of more than 40 kcal / m grad.h

Using a known method leads to the formation of cracks and cracks. Castings have a large pro-. cent of marriage, as shown by investigators, to 25-27%.

High heat storage capacity (40 kcal / m hail / h) leads to premature hardening of the metal in parts of the sprue

5 systems located in the lower form, i.e. more distant from the gating part than similar elements in the upper form. As a result, in the bottom i i nui form in insufficient quantities

  liquid metal enters to compensate for the shrinkage of the castings, which leads to the formation of shrink holes in them. In addition, due to the intensive cooling of the castings, the formation of combustible cracks in them is observed.

The purpose of the invention is to increase the yield of suitable casting.

The goal is achieved by the fact that upon receipt of castings with a reduced thickness of 3-14 mm from high manganese steel 110G13L in two-pillar vertical sand molds, the top of which is ferrostatic when casting metal

25 pressure equal to 0.1-0.36 kgf / cm, and the lower pressure 0.36-0.7 kgf / cm, including the manufacture of molds with a facing layer, assembly and casting of molds, the cladding of the upper molds is done by blending heat storage capacity of 22-29 kcal / mgrad is lower and 30-40 kkap / m deg-h, and the metal is cast at 1420-. . In the manufacture of castings, when a facing mixture of the same composition with low heat storage capacity (less than 22 kcal / m-degree) is used for all forms of the stack, due to the long-term presence of the metal in the liquid state on the castings L is formed. High manganese steels are hypersensitive to pouring temperature. Wash down the molten metal must be West in the temperature range 1420-1440C. At a temperature of casting steel above 1440C, the formation of a columnar structure of the nozzle and shrinkage looseness in castings is observed, which significantly reduces the physical and mechanical properties. For example, increasing the pouring temperature from 1400 to lower the impact strength of the alloy from 15 to 9 kgm / cm. The low temperature of the filling (less than 1420 ° С) ensures the obtaining of a fine-grained metal macrostructure with high physicomechanical properties of the metal. However, this reduces the fluidity of the molten metal, which contributes to the formation in the castings of a significant amount of scrap and casting defects on the floor, geometry, gas shells. The optimum temperature range for the filling ranges from 1420 to 1440 ° C, ensuring both the quality of the casting and its high physicomechanical properties.

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Caustic Magnesite Powder

Table 1

70 60 50 70 60 50 86 19

4 5

3 2 5 3 2

2 2 2 2

55 5 5 7 4 30 40

20 30 40 - 70 Example 1. Received 300 casting of pan attachments with a reduced thickness of 3-14 mm from 110G13L steel. Metal casting was carried out at 1430s. The upper and lower half-molds were made using facing mixtures, its heat-storage capacity was 22 and 30 kcal / m rad-h, respectively, compositions 1 and 4 in the table. 1 and 2. Of the 150 castings obtained in the upper half-forms of the stack, 8 had defects, which accounted for 5.3% of the rejects. The same reject rate was observed in castings produced in the lower molds. PRI mme R 2. Received 300 castings of pan attachments with a reduced thickness of 3-14 mm from steel 110G13L. Metal forms were poured at 1430 ° C .. The upper and lower half-forms of the stack were made using facing mixtures with a heat storage capacity of 26 and 34 kcal / mx X, respectively, compositions No. 2, 5 in the table. 1.2. Of the 150 castings obtained in the upper half of the stack, 5 had defects, which accounted for 3.3% of the rejects. The same reject rate was observed in castings produced in the lower molds. Example 3. Received 300 castings of pan attachments with a reduced thickness of 3-14 mm from steel grinder 110G13L. The metal was molded with metal at 1430 Co. The upper and lower hemoform stacks were made using facing mixtures with a heat storage capacity of 29 and 4 kcal / m deg. respectively, compounds 3 and 6 in the table, 1 and 2.

table 2

Claims (1)

Claim A method of manufacturing castings, mainly with a reduced thickness of 3 to 14 mm, from high manganese steels in double-stacked vertical sand forms, the upper of which is affected by a ferrostatic pressure of 0.1-0.36 kgf / cm ² ; and on the bottom - 0.36-0.7 kgf / cm ² ·, including the manufacture of molds with a facing layer of the same composition according to the broaching model, assembly and pouring, characterized in that, in order to increase the yield of casting, the lining of the upper molds is carried out with a mixture with a heat storage capacity of 22-29 kcal / mgrad h ^{, li} , of the lower ones - 30-40 kcal / m ?grad · h *, and pouring is carried out at 1420 1430 C.