In recent years by implementing the first phase of reconstruction project, the plant's annual capacity has been increased to 430,000 tons that in the next phase of the development plan will reach 860 thousand tons per year. Raw materials of the plant are supplied by sponge iron, briquettes, Ferro alloys, iron scrap and additives. The plant's products are steel ingots in section of 100 * 100, 130 * 130, 150 * 150 and 160 * 160 mm square with a length of 4 to 12 meters.
The plant is currently using a 60-ton electric arc furnace, a LF ladle furnace and a station for continuous casting according to common standards produces ingots of 160 * 160 and 150 * 150 and 130 * 130 and 100 * 100 mm with a length of 4- 8 meters. These plants' raw materials are generally scrapped and sponge iron and ingots produced in the plants are used as raw materials of fittings and wire, and beam rolling plants.
Steel plant is composed of 3 major sectors and 4 minor sectors:
1. Electric arc furnace
Steel production begins with an electric arc furnace. In the first step, scrap is charged into the furnace by a special basket filled in scrap yard, and by lowering graphite electrodes and establishing the arc melting process begins. Sponge iron, alloy materials and lime are added to melting by materials' feed system through the funnel at the top of the furnace. By complete melting scrap its volume is reduced and enough space to recharge the scrap is made. At this step, the cover of the furnace is removed and scrap iron is recharged into the furnace. With the completion of the melting operation, the furnace temperature is raised up to about 1640 ° C until in order to be ready to be discharged. In this step, which is called "composition modification", some metallurgical operations such as de-phosphorus, de-carbonization and the addition of alloying elements are performed and the melt is ready to enter ladle furnace. The melt is ready and high-temperature is discharged through the valve embedded in ladle furnace nose at the bottom of the furnace.
2. Ladle furnace
Secondary steelmaking operation is a crucial step in steelmaking. In this step, the chemical composition and melt temperature are set and ready to send to casting. Adding or removing alloying elements to the melt are done in the ladle furnace and additionally the melt temperature is set. The melt ladle is transferred by a crane and ladle car to the bottom of the ladle furnace. By lowering graphite electrodes and placing the arc, needed energy to set the temperature is provided and alloy materials are added to the melt after weighing in materials system installed on the furnace cover. By pumping nitrogen gas (N) from the bottom of the ladle melt composition and temperature are set.
3. Continuous casting
Molten steel is added to continuous cast through secondary steelmaking workshop as feeding. The ladle is moved by a crane and placed on a turret that put the ladle under casting conditions. By opening the valve at the bottom of the ladle, the molten steel is entered the tundish. Tundish acts as a mediator between the mold and ladle. When tundish was filled nozzles are opened and steel is poured into copper molds under the tundish with the cold water. Steel strand after leaving the mold should have thick enough skin that can tolerate liquid steel weight within it. The strand is removed from the mold with the help of several rollers. Rollers conduct steel in an arc path until the strand becomes horizontal. Cold and solid steel is cut into needed dimensions.
Minor sectors include:
• Scrap unit: iron scrap and sponge supply, processing and sending to an arc furnace
• Water supply: preparation and needed water of cooling systems of the complex
• Oxygen: oxygen and nitrogen supply required by the plant by air analysis
• Duster: Purification and separation of suspended particle and toxic vapor of output gas