It is an important ingredient in the production of grey iron. It is added to the smelting processes to increase carbon levels and improve the properties of the cast material. Carbon additives are available in a variety of forms, which are differentiated by their chemical indexes (fixed carbon, sulfur, nitrogen, ash and volatile matter). The type of cast-iron produced by foundries determines the types of carbon additives used. The most common carbon addition is graphite, which can be mixed with the melting melt to produce a flake structure of graphite that controls microstructure and mechanical characteristics.
Gray iron has a typical microstructure consisting of graphite flake in pearlitic matrix. The free carbon found in these graphite flakes acts as a lubricant and allows the castings to be machined. The flakes, however, also serve as stress increasers which makes the metal quite brittle. Despite its cost, gray iron cast is a good choice for those who want a durable, flexible and affordable material. It is especially well-suited for vibration damping and machining applications.
Graphitic flakes in the shape of graphite are an essential part of gray iron cast because they affect its physical properties. These include its strength, ductility, and wear resistance. The carbon in the graphite flakes replaces some of iron ions and reduces the tensile strengths and ductility. The graphite flakes and lubrication compensate for this brittleness.
The metallurgical characteristics of gray cast iron are largely dependent on the amount and size of free carbon in graphite flakes. For a foundry metalurgist to control these properties, they must adjust the carbon-equivalent (CE) and the silicon carbon ratio in the graphite containing charge. The carbon distribution and morphology in the graphite flake play an important role in microstructure, mechanical performance, and processability.
To maximize the benefits of carbon additive, foundries must ensure that the material meets all specifications. Among other things, it must be low in sulfur and nitrogen and have a high fixed carbon content to ensure optimal results. It's also important that particle size, grading and consistency are maintained to prevent contamination.
A foundry can achieve desired castings by using the right carbon additive without sacrificing either quality or productivity. In a preferred procedure, an effective amount of commercial silicon carbide mixed with graphite is added to a blend of coking and non-coking coals before being burned in a byproduct coke oven. This produces an improved coke for use in a gray cast iron foundry's cupola, and it also improves cast metal quality. It can lead to a reduction in the amount of scrap and more castings that are defect-free. This method will also reduce the cost of energy while increasing casting production. For more information on our range of carbon recarburizers and additives, contact Superior Graphite.
English
Write a Message