SU500870A1 - Composition for the manufacture of gasified models - Google Patents

Description

one

The invention relates to a foundry, in particular to model compositions based on expanded polystyrene, used to make gasified models.

Known model compositions based on polystyrene foam containing various additives that help gasify the model and improve the quality of castings, but do not solve the problem of controlling surface carburization during casting of small thin-walled castings.

The aim of the invention is to regulate the steps of the surface angle of the steel and steel castings.

This is achieved by the fact that the model composition as a special additive contains carburizing inhibitors in an amount of 0.5-30 wt. hours per 100 weight. including penny-polystyrene. At the same time, as a carburizing inhibitor, 0.5-15 wt.% Can be introduced. including iron oxide or 5-27 weight. including calcium carbonate, or 0.5-3 wt. including potassium carbonate, or 0.5-2 wt. tc antioxide antimony.

Examples of the introduction of carburizing inhibitors in polystyrene foam grade PSV-L are presented in Table. one.

The material for making casting models is prepared as follows.

The original polystyrene beads are decorated to a saturation of 0.02-0.025 g / cm. The sublimate grains are sieved to break up and separate lumps, peremyvaya polyvipylybutyral is dipped with a 2-3% alcohol solution, mixed thoroughly, sprinkled with powdered inhibitors (Fe2O3, CaCO3, Sb2O5) and re-mixed.

Water: A carbonic acid inhibitor is used to add K2COz by the method of treating Graiul with a 2-5% solution of this inhibitor. The drying of the granules is carried out with warm air while stirring them simultaneously. After drying and technological curing for 8-24 hours, the graule is suitable for sintering models from them in molds.

Examples of the effect of inhibitors on the carbon concentration in the surface layer of the obtained castings are given in ta.bl according to the results of microstructural studies of thin sections of steel 20L ejection samples. 2

table 2

From these examples, it can be seen that the reduction of nQBepxHocTiHoro in the carburizing of castings from steel 20L is observed in all cases of the introduction of inhibitors: in this case, the less significant one is IB example 3, the larger one in example 1 and the surface carburization of example 2 is completely eliminated.

At the same time, the inhibitors of examples 2-3 in the castings of steel 45L contributed to the alignment of steel; the structures of the castings throughout the cross section and in the core completely eliminated the appearance of surface and volume carburizing of the castings.

Inhibitors of Example 2 are the cheapest and most common materials. However, an increase in the concentration of these additives by more than 10% sometimes leads to a deterioration in the quality of sintering of models and their mechanical strength.

The positive effect of SbgOg on the structure of steel castings in terms of carburization is limited by the toxicity of antimony compounds.

Inhibitors can also be used in various combinations with each other.

Thus, the use of polystyrene foam models with various inhibitor options and the choice of the optimal number of inhibitors to achieve a positive effect of controlling the surface carburization of low-carbon steel castings and leveling their structure without applying subsequent heat treatment is caused in each particular case by the cast steel and the co-constructive patterns. The application of the proposed model composition allows for a 10–15% increase in the range of castings that are converted to production by casting on gasified models by increasing the range of steel thin-walled parts of a complex profile. These parts are manufactured by well-known methods by complex machining of long-rolled steel billets or by casting on produced models, because when casting them on gasified models, the carbon content in the varied

the layer of castings significantly exceeds the permissible limits, which leads to an unrecoverable marriage even with their subsequent heat treatment. 56

Claims (1)

1. The unit for gasification is 0.5-15 wt. including oxides of chewable models including polystyrene foam. and special additives, different from 5 3. Composition - pop. 1, characterized in that, in order to regulate the degree of the fact that, as an inhibitor of carburizing and surface carburizing of castings, it contains 5-27 wt. including carbon dioxide As a special additive, the composition of co-calcium and 0.5-3 wt. including potassium carbonate, keeps carburide inhibitors in co-4. The composition according to claim. 1, a and y. Lichene 0.5-30 weight. h. “and 100 weight. including foam in that it contains 0.5-2 wt. part of thioxide 500870 the fact that as an inhibitor of carbonaceous antimony.