MIV d.d. is one of the most known foundries in Europe and worldwide, whose tradition dates back to the year 1939. The yearly foundry capacity is 8 000 tons of castings, with the possibility to increase capacity.
Medium frequency furnace
Iron basic melt is performed in the up-to-date medium frequency furnace with 2 melting pots of total power 2.75 kW. An hourly furnace capacity is 5 tons (gross) with the system for filtering of the solid particles and gases (CO₂, NO₂, CO, SO₂).
In one melting pot, the basic pot is melted and the power up to 2500 kWh is used, while the melted metal is taken from the pot containing the melted metal, and used for casting at manual moulding, accumulated in ASEA receptor (for casting at the machine casting) or in an AUTOMAT (for casting at the automatic moulding line AFA-30). In the melt temperature maintenace temperature, the power of up to 250 kWh is used. ASEA is a channel induction furnace, 5 tons capacity, with an inductor, of the single power up to 250 kW for maintenance and warming-up and reheating of the melt temperature. The basic melt for nodular cast iron is accumulated, reheated and homogenized into ASEA receptor.
In the foundry, there are 3 production lines:
- Manual moulding
- Machine moulding
- Automatic line
Individual casting production in CO2 technology. The castings whose weight is up to 8 tons, DN 2500, can be produced, while the monthly production is up to 250 tons.
The moulds and cores are made in CO2 technology. The following raw materials are used:
- Dry quartz sand
- Binder sodium silicate – sigel (commercial name)
- Vezivo natrijev silikat - sigel (komercijalni naziv)
- CO₂ gas as a fixing agent
- One pair of machines F – 40 with the flasks up to 800x800 mm at which the castings up to 100 kg are made. In one shift, ca. 100 moulds are produced.
- One pair of machines FKT with the flasks up to 1200x700 mm at which the castings up to 50 kg are made. In one shift, ca. 90 moulds are produced.
- Three pair of machines F – 20 with the flasks up to 500x400 mm at which the castings up to 20 kg are made. In one shift, ca. 220 moulds are produced.
- One pair of machines WF - 20 with the flasks up to 630x500 mm at which the castings up to 35 kg are made. In one shift, ca. 200 moulds are produced.
At the line, about 500 casts per shift are made. The casting weight is up to 50 kg, the flask dimensions are 730x690 mm. Casting is performed by means of the CASTING AUTOMAT, i.e. the channel induction furnace whose capacity is 2.5 tons. It is used for making of the castings from nodular cast iron as per the Inmold process (it is a channel induction furnace whose capacity is 2.5 tons. Within the Foundry, there is a laboratory where the continuous analysis and material check-ups are performed, in order to achieve as high product quality as possible.
- Sand laboratory
- Chemical laboratory
- Chemical melt analysis and mechanical property testing of Y-specimes
Check-up of the moulding and core mixture is performed in the Mould&Core Mixture Laboratory, where strength, throughput and moisture of the bentonite and CO2 mixtures are tested.
Chemical analysis of the melt and mechanical properties of the nodular cast iron
For checkup of the basic melt, LECO inspecting device C and S and DTA are used, which inspect C and Si by means of the rapid process. The final checkup of the chemical composition is performed at the spectrometer – quantometer ARL-3460 which inspects 24 elements. Mechanical properties are inspected at the inspection specimens made from the Y-testing specimen. The following properties are inspected:
- Tensile strength Rm = N/mm2
- Elongation A5 = %
- Yield point Rp = N/mm2