Issues to Consider in the Production Process of Ductile Castings

In the traditional production process of ductile iron castings, it is generally adopted 10 Approximately a certain percentage of carbon-containing scrap steel is used as a charge material. This article discusses only the key issues that require special attention when producing ductile iron castings in an induction furnace after increasing the scrap-to-carbon ratio. Based on production experience, the following points are presented for your reference.

( 1 ）The scrap steel used for producing ductile iron castings should be carbon-based. It must not contain elements that hinder graphitization, such as chromium, and should also be free from anti-spheroidizing alloying elements. The thickness of the scrap steel should be within 30 About %, it can be laid flat inside the oven.

( 2 ) Carburizing agent: high-quality coke with low sulfur content and specific size. 60 ~ 80 mm , high strength and does not shatter when heated red-hot. Scrap electrode blocks—ideally of a certain length for easy immersion into molten iron.

( 3 ) Pig iron is primarily used to adjust the carbon content of molten iron. Tungsten carbide is preferred for this purpose. 4 High-carbon, low-sulfur pig iron. The higher the silicon content in the pig iron, the better—this allows for reduced use of ferrosilicon when producing ductile castings.

( 4 ) The spheroidizing agent and inoculant are used according to traditional processes, with adjustments made based on the specific conditions of each plant.

The ductile iron casting melting process flow: Coke blocks, scrap steel, and electrode blocks are heated; the coke and electrode blocks are then removed; samples are taken to analyze carbon content; finally, pig iron return material is sampled for analysis. Yes And Mn Heating manganese iron - Silicon-iron steelmaking involves inoculation and spheroidal casting. Here are the precautions to keep in mind during the smelting process:

( 1 ) Coke blocks are installed at the bottom of the furnace to ensure they remain immersed in the molten iron for an extended period. The consumption rate of coke blocks is approximately equivalent to that of scrap steel. 5 ％. Scrap Steel Melting 50 About %, the top of the coke is covered with thick, flaky scrap steel. 60 ~ 80 mm The waste electrode blocks can also be used as a substitute for coke, serving as a carburizing agent installed at the furnace bottom. With their lower sulfur content, they are more conducive to producing high-quality ductile iron castings.

( 2 ) The utilization rate of scrap steel is primarily determined by carbon-increasing efficiency. Manufacturers that have begun producing ductile iron castings using this method, 30 Around % is preferable. After improving carbon-increasing efficiency, the utilization rate of scrap steel has gradually risen. However, if carbon-increasing efficiency remains low, excessive use of scrap steel can negatively impact the carbon and silicon equivalents in the final product.

( 3 After the scrap steel is melted, insert the electrode rods and gradually increase the furnace temperature to enhance carbon-increasing efficiency. However, excessively high furnace temperatures will lead to increased energy consumption and negatively impact the furnace lining.

( 4 Once the estimated carbon content reaches a sufficiently high level, select the coke lumps and electrode rods, and then take samples for carbon content analysis.