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2023.2.27
To clarify, “gray cast iron” is graphite flake-infused cast iron. The name “gray cast iron” comes from the color of the resulting cracks when the material breaks. Iron, carbon, silicon, manganese, sulfur, and phosphorus make up the bulk of the ingredients. Almost all other cast irons are compared to it. Almost 80% of the world’s cast iron comes from its factories. Cast iron comes in a variety of colors and finishes, including this grey variety. The flake graphite form of carbon is present in cast iron. There is a grayish crack there. It offers high wear resistance, excellent casting qualities, and outstanding cutting abilities. Used in the production of boxes, frames, and similar items. Since the graphite in gray cast iron is flaky, the effective bearing surface is tiny, and the graphite tip is easy to produce stress concentration, gray cast iron has inferior strength, plasticity, and toughness compared to other cast iron. Nonetheless, it is highly resistant to wear and has a low notch sensitivity and great shock absorption. Today, we are going to find out, is there a particular reason that a cast iron platform needs to be made of gray iron.
1. The ability to withstand wear and absorb stress is a major plus. Cast iron’s wear resistance is high thanks to the graphite in the material, which makes it an ideal medium for lubrication and oil storage. In a similar vein, gray cast iron has superior shock absorption over steel because of the presence of graphite.
2. The results of the method are satisfactory. Owing to its near-eutectic composition, gray cast iron is ideal for casting complex or thin-walled castings because of its low melting temperature, superior fluidity, and low shrinkage rate. The ease with which graphite forms chips during cutting makes gray cast iron a superior machinable material to steel.
3. A connection between hardness and tensile strength:
The tensile strength and hardness of gray cast iron are proportional to one another. When the oxygen partial pressure is less than 196 nmol per square meter, the empirical formula is as follows: a. HB=RH (FL00+0.4380b)……(B1); and when it is greater than 796 nmol per square meter, HB=RH (44+0.7240b)……(B2) (B2). The formula’s RH value, which represents the relative hardness, is mostly determined by the nature of the raw material, the melting procedure, the treatment, and the casting’s rate of cooling.
4. Benefits of casting machine beds in a resin sand mold:
For casting gray cast iron and nodular cast iron with minimal or no riser, a resin sand mold with good rigidity and high strength at the beginning of the casting process is essential.
-Full mold casting is made with a polystyrene foam pattern and a furan resin self-hardening mold. It’s important to note that the foam plastic mold vanishes into thin air as the molten metal is poured into it due to the extreme heat of the molten metal. As the metal cools and solidifies, it takes on the exact shape of the mold it was cast in, taking the place of the original foam plastic.
When compared to the conventional sand mold, lost foam casting is superior for producing a single part or a small run of car panels, a machine tool bed, etc. In addition to avoiding the high costs associated with wooden molds, this method is simpler to use, takes less time to complete, boosts production efficiency, and provides better results overall thanks to its superior dimensional precision, reduced machining tolerances, and high-quality finished products.
The material requirements for a cast iron platform are low. Gray cast iron is commonly used because high-performance materials cannot fully fulfill the role of materials and waste costs. Iron, carbon, silicon, manganese, sulfur, and phosphorus are the primary ingredients in gray cast iron. Almost all other cast irons are compared to it. More than 80% of the world’s cast iron comes from its factories. Gray cast iron gets its name from the dark gray appearance of its fractures. Grey cast iron boasts high wear resistance and shock absorption in addition to good ca stability and machinability.
Gray iron castings can benefit from surface quenching when high hardness and wear resistance are required, as is the case with machine tool guide rails and the inside walls of cylinder sleeves in internal combustion engines.
While its tensile strength is low due to its high carbon content and rather open structure, its compressive strength is exceptional. Gray cast iron’s “HT plus tensile strength grade” designations denote various strengths. Each of the six types of gray cast iron (HT100, HT150, HT200, HT250, HT300, and HT350) has its own specific properties and uses. Each has its own unique tensile strength. Machine tool bases, cast iron platform plates, oil press pistons, bearing seats, reducer housings, and so on all benefit from the material’s excellent wear resistance, vibration resistance, ease of processing, and retention accuracy after aging treatment or heat treatment.