变形工艺对50CrVA高强钢组织与冲击性能的影响

Influence of Deformation Process on Microstructure and Impact Properties of 50CrVA High Strength Steel

对50CrVA高强钢生产过程中精轧段变形工艺进行了微调,细化了微观组织及片层间距,改善了塑性韧性和冷加工性能。结果表明:使用传统轧制工艺(精轧段变形量为29%)生产的50CrVA高强钢平均冲击功AKV为8.13J;使用改进的控轧工艺(精轧段变形量为49.6%)生产的50CrVA钢平均冲击功AKV为17.7J,比传统工艺轧制的提高了117.71%,而两者力学性能相差较小,组织都为F+P;使用传统变形工艺生产的50CrVA钢晶粒度平均为10.1级,珠光体片层间距平均为268.75 nm,其冲击断口出现了大量的韧窝,韧窝尺寸较大且较深;使用改进的控轧工艺生产的材料晶粒度平均为11.1级,珠光体片层间距平均为222.25 nm,其冲击断口也出现大量的韧窝断口,大部分韧窝尺寸较小且较浅。

The finish rolling process of 50CrVA high strength steel was adjusted,the microstructure and lamellar spacing were refined,and the plasticity,toughness and cold workability were improved.The results show that the average impact work AKVof 50CrVA high strength steel produced by traditional rolling process(29%deformation of finishing rolling section)is 8.13 J.The average impact work AKVof 50CrVA steel produced by the improved controlled rolling process(49.6%deformation in finishing rolling section)is 17.7 J,which is 117.71%higher than that of traditional rolling process,but the difference of mechanical properties between them is small,and the microstructures are F+P.The average grain size of 50CrVA steel produced by traditional deformation process is 10.1 grade,and the average lamellar spacing of pearlite is 268.75 nm.A large number of dimples appear in the impact fracture,and the dimple size is large and deep.The average grain size of the materials produced by the improved controlled rolling process is 11.11 grade,and the average lamellar spacing of pearlite is 222.25 nm.A large number of dimples also appear in the impact fracture,and most of the dimples are small and shallow.