Abstract: Banding structure of φ100 mm rolled products produced by 300 mm X 340 mm cast bloom of gear steel SAE8620H （0. 19C, 0. 48Cr, 0. 48Ni, 0. 18Mo, 0.32 Al） with 3 process conditions- hot rolled , completed annealed treatment-heating at 930 °C 1 h furnace cooling to 650 °C 1 h air cooling, and isothermal annealed treatment-heating at 930 °C 1 h outside furnace quick cooling to 650 °C 1 h air cooling has been tested. Results showed that the rating of banding structure of completed annealed rolled-products was higher than that of hot rolled ； and the rating of banding structure of isothermal annealed rolled-products was lower than that of hot rolled by 1. 0 ~ 1. 5 , due to quick cooling from 930 °C to 650 °C to inhibit proeutectoid ferrite precipitation that obviously improved the banding structure of steel.

Key words: Low Carbon Gear Steel, Isothermal Annealing, Banding Structure

摘要： 试验了由300mm×340mm连铸坯生产的SAE8620H齿轮钢(%:0.19C、0.48Cr、0.48Ni、0.18Mo、0.032Al)φ100mm轧材在热轧、完全退火(930℃1 h炉冷至650℃1 h空冷)以及等温退火(930℃1 h出炉快冷至650℃1 h空冷)3种状态下的的带状组织。结果表明,完全退火后轧材带状级别较热轧态高;因930～650℃快冷抑制先共析铁素体的析出,等温退火轧材带状级别较热轧态低1.0～1.5,显著改善了钢的带状组织。

关键词: 低碳齿轮钢, 等温退火, 带状组织