Molding process at the Foundry!
For a long time Ukraine was famous for its achievements in the galleys of lithic metals, and the foundry belongs to the traditional Ukrainian crafts and handicrafts of the Ukrainians.
Foundry production is called the process of making shaped molds (casting) by pouring molten metal into an empty form, creating a form and shaping future details. After the hardening of the metal, the forks come out of the form – harvesting or a detail.
With all the various viscosities of impurities formed during the long period of development of its technological process, the scheme of the technological process of casting has not changed more than 70 centuries of its development and includes the main stages: melting of metal, making molds, pouring liquid metal into molds, removing the hardened casting from the mold.
Today we will talk with Serhii Oleksiyovych Kolodny, who has been working at the Foundry of the Poltava Turbomechanical Plant since August 2003. He graduated from the Poltava Vocational College of Oil and Gas of the National University “Poltava Polytechnic named after Yuriy Kondratyuk”, by education a technician-technologist, by profession a driller of gas and oil wells. At the enterprise, he works as a foreman of the rod section and part-time foreman of the steel casting section.
Forming is the main part of foundry production, without which we will not get the expected screw in production.
The composition of molding mixtures is chosen depending on the alloy of the casting, first of all, on the temperature of its pouring, tendency to oxidation, as well as on what forms (dry or raw) this alloy is poured into.
Molding is the process of forming molds, molds are made to produce castings. Castings are both with rods and without rods.
Rod mixtures have higher requirements than molding ones in terms of gas permeability, strength, ductility and fire resistance. In the process of pouring forms, they are in more difficult conditions, experiencing more thermal and mechanical effects of liquid metal.
The composition and properties of rod mixtures are chosen depending on the position of the rods in the mold, their configuration and the type of alloy being poured.
The rod is inserted into the mold in the mold, then the cavity between the mold and the rod is filled with metal and we have a casting.
The molding of the Omega2 line is the so-called HTS (cold-hardening composition). During the molding process, the regenerated material (sand with the addition of hardener and resin) is mixed, and the reaction of the two substances results in solidification of the mold. This process takes 10-12 minutes. After filling the model with loose material, a form is obtained, which hardens and turns into a solid material.
After leaving the model, the forms are painted with a special non-stick coating and dried. After that, if the form is formed using rods, the rod is inserted, it is attached from one line to the assembly table, and the assembly of the top and bottom is already there.
The core is made of sand and resin, after which the core boxes are filled with carbon dioxide, frozen, and also from the loose composition it turns out to be as hard as a stone. Rods have various modifications and shapes, sizes and weights.
For ease of forming and to obtain accurate castings in terms of dimensions, the model should have the following qualities:
- it should not be destroyed or change its shape during the formation and compaction of the earth around it, have strength
- it is easy to remove from the mold without damaging its walls, have forming cones
- corresponding slopes on the (side) walls
- have a clean, smooth surface so that the earth does not stick to it
- be light, so that when extracting it from the ground, you do not strain the muscles of the hands, as this causes the model to shake and the parts of the form to fall off
- be slightly larger than the original, so that the product cast on it after shrinkage corresponds to the dimensions of the drawing.
The enterprise has press forming machines based on pneumatics and working under the influence of compressed air. They mechanize one of the most time-consuming processes – compaction of the molding mixture.
This is such an interesting process that the forming section goes through. Every day, the guys prepare molds for nightly metal castings. As a result, the «Nicmas» Concern receives high-quality castings that will become parts in the future.