In this episode, you will see how cast iron castings are made.
Cast iron, an iron-carbon alloy, is a material without which it is difficult to imagine the development of modern industry - from construction to automotive. The unquestionable advantages of this material are its strength, corrosion resistance, vibration dampening ability and ease of casting. We decided to take a look at this technology by visiting the Konec Foundry, which has been in operation for 130 years. There we will see how fittings, manholes, pipes and other cast iron products are made. Watch out, it's going to be hot!
To start with, we take a look at the furnace control room. Here, the loading of batch materials is managed by computer. Programmed commands are passed on to the warehouse, where there are daily bins for iron and steel scrap, pig iron, coke, fluxes and various additives. These materials land in a loading trolley with a scale. All the parameters that have been set in the computer are checked, and then the trolley dumps the contents into the skip.
At KZO, melting takes place in two shaft furnaces, known as cast iron furnaces. They have a capacity of 8 tonnes per hour and the temperature they achieve by burning coke is over 1,500 degrees Celsius. The charge enters the furnace through a batch window located at the top. Melting takes place in a so-called boiler, equipped with nozzles supplying hot air enriched with oxygen.
The melted cast iron flows down a drain into a ladle, from which it is distributed to all casting lines. This is done by means of a trolley with a turntable.
KZO has three automatic moulding lines, two boxless lines with vertical mould division of 675mm x 550mm and 950mm x 700mm, and a box line with horizontal mould division of 1000mm x 800mm. The lines allow castings to be made in a wide weight range from 0.5kg to 150kg.
Model plates are required for this. One is mounted on a piston and the other on a tilt arm. In the blasting chamber, the mass is injected under high pressure into the space between the plates and pressed with the piston. This creates so-called packets, which the piston pushes out to transfer to the pouring zone. The pouring machine fills them with cast iron at a temperature of around 1,400 degrees Celsius. Sewer components, furnace castings, agricultural castings and automotive castings are produced in this way.
It is different in horizontal moulding. This is the line for the heaviest castings. Special boxes measuring 100x80x40 cm are used for this. Here we have two plate carriers, on which the casting model is placed. It is backfilled with moulding compound and compacted with cylinders from a multi-piston head.
The moulds - once separated from the model - are put together and transported to the pouring area. The flooded moulds have to cool down and only then do they travel to the shaking grid, where the products are knocked out of the mass. The mass is recycled in a 150 t/h mass processing station. After refreshing, it is returned to the production lines. The castings, meanwhile, are transported by a system of vibrating conveyors to a cooling tunnel. Once they have cooled completely, their surface is smoothed in an eight-tube belt shotblasting machine. If necessary, the castings are cleaned manually or in a hanger-type shotblasting machine.
For some products, machining is necessary. Manholes and street gullies are machined on a two-spindle milling machine. The castings are then sent to the paint shop. They are immersed in an 8-tonne bath and then dried at 60 degrees Celsius. Ready! The products from the Konec Casting Plant leave for their recipients after packing. Maybe not warm anymore, but straight from the oven!