Detailed Explanation of the Characteristics and Structural Advantages of Gray Iron Castings

　　Laser surface treatment and casting surface alloying technologies for gray iron components can create metallurgically bonded alloy layers on the surfaces of ordinary castings, endowing them with enhanced, multifunctional properties—and have already yielded remarkable results. Strengthening and refining are emerging as key development directions for gray cast iron parts in China. The goals of thinning, lightweighting, and strengthening gray iron components are aimed at meeting industry demands for energy efficiency and promoting the recyclability of engineering materials, aligning perfectly with the principles of the "Human Sustainable Development Strategy."

　 Gray iron castings that have undergone inoculation treatment exhibit characteristics such as refined graphite, uniform microstructure, and low sensitivity to wall thickness variations. Historically, the advancement of inoculation technology has undoubtedly relied heavily on the development of new inoculants. However, in recent years, improvements in inoculation methods—particularly late-stage inoculation—have drawn significant attention. As a result, in the future, alongside the development of innovative inoculants, research efforts may shift toward exploring entirely new methodologies. Alloying remains one of the key strategies for enhancing the performance of gray cast iron components.

With the advancement of technology, alloying or micro-alloying of gray cast iron components will play a crucial role. Leveraging local resources, we will continue developing new varieties of alloyed gray cast iron parts, while employing cutting-edge methods to deepen our understanding of existing alloyed gray cast iron products.

　　"Thin-walled, high-strength castings are emerging as a growing trend in the engineering field, with their technological applications becoming increasingly mature and rapidly expanding. In the foreseeable future, 3- to 5-mm-thick, high-strength ductile iron castings will appear extensively in general-purpose mechanical and electrical products. Compared to aluminum alloy castings, gray iron castings have the key advantages of lower costs and superior casting performance. Currently, one of the main factors hindering the growth and development of gray iron castings is the challenge of achieving lightweight designs—this, however, is set to inject fresh vitality into the gray iron casting industry. As such, developing advanced production technologies for high-strength, thin-walled gray iron components has become the critical solution to these challenges. Moreover, it’s essential to continuously innovate new varieties of gray iron castings while strengthening the research and application of large-section, thin-walled gray iron casting techniques in their as-cast state. Ultimately, ensuring that the strength and machinability of these castings remain intact—even as wall thicknesses are reduced—depends fundamentally on enhancing the overall mechanical properties of gray iron materials."

　　Structural advantages of gray iron castings:

　　1. The surface is smooth, resulting in a smaller machining allowance compared to cast steel. Additionally, any minor imperfections in surface finish have minimal adverse effects on fatigue performance.

　　2. It has high vibration damping and is commonly used as a base for vibration bearings.

　　3. Not permitted for parts intended for long-term operation at 250°C.

　　4. The performance of different sections is consistent, making it suitable for thick castings with varying cross-sections that demand high quality.

　　5. Highly sensitive to cooling rates, thin sections are prone to white cracks and fissures, while thicker sections often develop Ryukyu pine structures. Consequently, when the wall thickness of gray cast iron exceeds its critical value, its mechanical properties significantly deteriorate as the thickness increases.