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针对曲轴用非调质钢C38N2轧制过程中出现的带状组织,采用高温扩散退火和控制冷却速率等热处理工艺研究消除带状组织的效果。结果表明:试样在1230℃保温120 min随炉冷却时,带状组织基本消除,呈现均匀的铁素体和珠光体组织,但试样表面氧化严重,且存在脱碳现象。试样在1230℃保温1 min,并从1050℃到500℃以0.2~0.5℃/s冷却然后空冷至室温,不存在带状组织;以0.5~2℃/s冷却时,随着冷却速度增大,带状组织变得严重;而以2~5℃/s冷却时,带状组织又逐渐消失,但组织内出现贝氏体和马氏体组织。
Aiming at the ribbon structure appearing in the C38N2 rolling process of non-quenched and tempered steel for crankshaft, the effect of eliminating the banded structure was studied by the heat treatment process such as high temperature diffusion annealing and controlled cooling rate. The results show that when the sample is cooled at 1230 ℃ for 120 min, the banded structure is basically eliminated and the uniform ferrite and pearlite structure appears. However, the sample surface is seriously oxidized and decarburization occurs. The samples were incubated at 1230 ℃ for 1 min and cooled from 1050 ℃ to 500 ℃ at 0.2 ~ 0.5 ℃ / s and then air-cooled to room temperature. There was no banded structure. When cooling at 0.5 ~ 2 ℃ / s, Large and banded tissues became severe. When cooled at 2 ~ 5 ℃ / s, the banded tissues gradually disappeared, but bainite and martensite appeared in the tissues.