Abstract
GB 9439-88 is a national standard for gray cast iron parts. Gray cast iron is a type of cast iron which has an even surface and a dense microstructure with excellent mechanical properties and wear resistance. This standard specifies the requirements, test methods, acceptance criteria, marking, packaging and transportation of gray cast iron parts. It also includes resin sand molds and surface spraying requirements used to make gray cast iron parts. GB 9439-88 shall be used to assess gray cast iron parts and to ensure reliable quality of gray cast iron parts.
Introduction
Graycast iron is a type of cast iron derived from pig iron, characterized by its grayish color and relatively lower melting point. Due to its high strength, wear resistance and relatively low cost, gray cast iron is widely used in many industries. It is used to create components such as engine blocks, cylinder heads, construction parts, casting pumps and valves, marine components, and much more.
Gray cast iron has excellent machinability, good vibration damping characteristics, and resistance to shock. It is also suited for a variety of surface coating applications, including enameling and painting. Its high strength make it an ideal material for parts with complex shapes or for parts required to bear high loads, such as engine blocks and cylinder heads.
The requirements for gray cast iron parts stated in GB9439-88 are divided into three categories: chemical composition, mechanical properties and surface quality. The chemical composition requirements include requirements for the acid insolubleash, graphite powder, and other elements of the alloy. Furthermore, the GB9439-88 standard specifies the mechanical properties of gray cast iron, including tensile strength, hardness, elongation, and Brinell hardness. Lastly, the surface quality requirements include the maximum permissible surface roughness and surface imperfections such as porosity, sand, and casting marksetc.
GB9439-88 also includes requirements for molds used to make gray cast iron parts. It stipulates that the molds must be made of either resin sand or steel, depending on the application. Resin sand molds must be inspected and cleaned regularly to ensure quality of the gray cast iron parts. Additionally, the surface of the gray cast iron parts must be treated to prevent the scuffing and rolling wear of the parts. Generally, the recommended surface treatment is to spray a layer of anti-wear paint.
Conclusion
GB9439-88 is a national standard that specifies the requirements, test methods, acceptance criteria, marking, packaging and transportation of gray cast iron parts. It includes requirements for molds and surface treatment, enabling the production of gray cast iron parts of consistent quality. Compliance with the GB9439-88 standard is essential to ensure safe and reliable gray cast iron parts.
