Gray casting iron (GB/T9439-1988)
Gray cast iron, commonly known as cast iron, is a metal alloy consisting predominantly of iron with carbon and silicon as the main alloying elements. Gray cast iron has a comparatively high strength and wear resistance, and is used in a wide variety of applications.
Gray cast iron is an alloy of iron, carbon and silicon and is one of the earliest metals to be used in manufacturing. It consists of primarily iron, as well as small amounts of carbon and silicon. The carbon, in combination with the iron, gives the metal its gray color, as well as its high strength and wear resistance.
The Chinese national standard, GB/T9439-1988, defines three grades of gray cast iron according to their mechanical properties. Grade I includes grades A and B, grade II includes grades C, D and E, and grade III includes grade F. Each grade is further broken down into categories, which specify the required properties of the cast iron.
Grade I cast iron is suitable for general-purpose use and is used mainly in machine parts and gears. It provides good wear resistance, reasonable strength and fair malleability. Grade II cast iron is designed for service where higher strength is important and offers superior wear resistance, malleability and strength, although it does not have the same physical properties as grade I. Grade III cast iron is used for applications where high resistance to fracture and wear are essential, such as dies and cutting blades.
The three grades of gray cast iron are commonly divided into two types based on the carbon content. Type A iron has a carbon content of 2.0-3.3%, and type B has a carbon content of 3.3-3.5%. The type of cast iron used depends on the application and desired properties of the finished product.
Gray cast iron has a low cost and is ideal for mass-producing complex parts. Due to its high strength and wear resistance, it has a wide range of applications, including engine blocks and cylinder heads, gears, valves, machine tools, pumps and heavy equipment.
Gray cast iron is a versatile material that is used in a variety of industries and applications. Its strength, wear resistance and low cost make it an ideal choice for many products and applications. With the right grade, it can provide superior performance with minimal post-processing. The Chinese national standard, GB/T9439-1988, can help to ensure that the correct grade of gray cast iron is used for each application.
