关键词: 行走轮, 球墨铸铁, 正火工艺, 力学性能, 微合金化

Abstract: A normalizing process experiment was conducted on a large travel wheel made of nodular cast iron containing 0.460% Cu, and the effect of normalizing temperature (850 ℃ and 880 ℃) on the microstructure and mechanical properties of the travel wheel flange and spoke was studied. The results show that the large nodular cast iron travel wheel containing Cu can only obtain partial pearlite after low-temperature normalizing at 850 ℃, and there is still 25% to 30%(volume fraction) fragmented ferrite, resulting in the strength of the wheel flange not meeting the requirements. After normalizing at 880 ℃ (fan blown cooling) and tempering at 550 ℃, the mechanical properties of the flange and spoke can meet the requirements. More pearlite forms when normalized at 880 ℃ than that at 850 ℃. This is because as the normalizing temperature increases, the carbon content in austenite increases, the stability of undercooled austenite increases, and the C-curves shift to the right, making it easier to obtain pearlite during cooling. For the tested large nodular cast iron travel wheels, a higher normalizing temperature such as 880 ℃ is preferred.

Key words: travel wheel, nodular cast iron, normalizing process, mechanical properties, microalloying