Cast iron products
Iron casting – these are castings from various cast iron obtained by casting in a cold-temperature system, sandy-clay mixtures, according to burned-out models, centrifugal casting. Cast iron is an iron alloy with a carbon content. Its composition may, in addition to them, include manganese, phosphorus, silicon, sulfur and other components.
We plan to produce both casting for mechanical engineering, machine tool building, and decorative art casting. Smelting of metal is carried out in imported induction furnaces with a capacity of 250, 400, 750 kg. This type of furnace provides low waste of elements, low gas content and uniformity of chemical composition throughout the volume of the metal due to its mixing and additional filters in the induction field.
Main grades of cast iron alloys
SCh – gray cast iron GOST 1412-85: SCH10, SCH15, SCH18, SCH20, SCH21, SCH24, SCH25, SCH30, SCH35.
VCh – high-strength cast iron GOST 7293-85: VCh 35, VCh 40, VCh 50, VCh 60, VCh 70, VCh 80, VCh 100.
Iron casting – manufacturing methods:
Casting of cast iron in cold-hardening mixtures (CTC) is casting of cast iron using artificial resin. Instead of tamping the mixture (as in casting into the ground), the mixture is poured into a flask and waiting for the resin to harden. It usually cures at room temperature within 20 minutes. CTC casting significantly improves the quality of the raw surfaces of the steel casting compared to other sand casting technologies. Usually, wood, metal or MDF plastic is used to make model equipment. To cure the resins, the core boxes are purged with various tertiary amines. Casting technology in cold-rolled steel ensures high quality of the casting surface, absence of gas defects and blockages in the casting.
Casting of cast iron on the burned-out and lost-wax patterns – first, a copy of the future product is made from a special material with the necessary allowances for shrinkage and subsequent machining. For lost-wax models, paraffin, stearin, wax or their mixtures are used, and for burned-out models, materials are used that burn in air or in an oxygen environment with low formation of smoke and dry residues (as professionals say, with low ash content). Then, on the resulting model – no matter whether it is burned out or melted – ceramic powders with a silicate binder are applied in several layers (up to nineteen), drying the model after each layer is applied. As a result, a strong heat-resistant crust forms around the model, into which molten iron will then be poured. But before filling, the model must be deleted somehow. If the model is lost wax, then the crust, together with the model, is transferred to a hot water bath, where the paraffin-stearin substance, the melting point of which is 61-75 ° C, melts and successfully leaves the crust. They do things differently with burned-out models – the mold is placed in a furnace and kept for a long period of time at a high temperature either in air or with oxygen supply – for a more complete and faster combustion of the model (that’s why the model is called burned out). To remove combustion products, the mold is blown with compressed air. If the environment allows, then before pouring the mold is allowed to cool to room temperature, and the ash residues are washed out with a stream of water or blown out with air. But such removal of dry residues is not always possible: when it cools, a web of cracks may appear on the crust. Various complex products (pumps, grates, wheels) are cast using burned-out or lost-wax models,
Casting iron into the ground – the cheapest and easiest casting method. Models are made from various materials: wood, plaster, metal. The most popular material is wood. First, a model of the future casting is made from wood in a model workshop. It should be slightly larger than the casting, taking into account the shrinkage of the metal during cooling. The model (as well as the future form) is split and consists of two halves. In the ground preparation department of the foundry, a molding mixture is prepared from the earth and various additives. If the casting must have an internal hole or cavity, then another mixture must be prepared – for the rods. The purpose of the bars is to fill in those places in the form that correspond to holes or cavities in the part. The disadvantage of casting cast iron into the ground: expensive machining: allowances are given at least 7 mm (sometimes up to 40 mm),
Cast iron dishes:
Designed for cooking both in stationary and in the field. The main method of casting cast iron dishes is pouring molten metal (SCH-10, SCH15) into metal molds – a chill mold.