论文部分内容阅读
我厂G6300,6300,295曲轴,均采用稀土镁铜钼合金球铁整体铸造,是典型大断面(230～330mm)球铁件。由于凝固时冷速缓慢,必然引起球化和孕育衰退,造成石墨粗大,球数减少,尤其在厚壁中心和冒口附近造成石墨畸变,严重时形成聚集厚片状和碎块状石墨,组织粗大,偏析严重;在最终凝固的共晶团边界上富集Mo、Mn、P元素,形成难以分解的合金碳化物和化合物,在石墨周围则富集Si和Cu,促进石墨周围析出铁素体。清华大学和佛山球铁研究所提高大断面球铁件性能的主要经验是,严格控制成分,应用微量元素和长效孕育剂和长效球化剂,及进行二次孕育处理。
I plant G6300,6300,295 crankshaft, are made of rare earth magnesium-copper-molybdenum alloy ductile iron casting, is a typical large section (230 ~ 330mm) ductile iron pieces. Due to the slow cooling rate during solidification, inevitability of spheroidization and inoculation decline will lead to coarse graphite and reduced number of balls, especially in the vicinity of thick-walled centers and risers. In severe cases, thick aggregates of flake-like and crumb-shaped graphite, Coarse, serious segregation; enrich the Mo, Mn, P elements in the final solidified eutectic groups to form alloy carbides and compounds that are difficult to decompose, enrich Si and Cu around the graphite to promote precipitation of ferrite around the graphite . Tsinghua University and Foshan Ductile Iron Research Institute to improve the performance of large-section nodular iron pieces of the main experience is that the strict control of the composition, the application of trace elements and long-lasting inoculant and long-acting nodulizer, and secondary inoculation.