硅对GD钢下贝氏体组织形态及力学性能的影响

EFFECT OF SILICON ON THE MICROSTRUCTURE AND MECHANICAL PROPERTY OF LOWER BAINITE IN GD STEEL

本文研究了不同硅含量的高强韧低合金冷模具钢(代号GD钢)经马氏体—下贝氏体复相处理后下贝氏体的组织形态、亚结构和数量,讨论了GD钢的成分、组织和性能之间的关系。结果表明,GD钢的硅含量对下贝氏体的相变过程和显微结构起决定性的作用。当GD钢的硅含量达到1.82％时,复相组织中下贝氏体呈准下贝氏体形态,且复相组织表现出最佳的强韧性配合。

The morphology of micros tructure, amount and substructure of lower bainite in different Si-containing GD steel after isothermal heat-treatment have been investigated. The relationships between the composition, micros tructure and mechanical properties are discussed in detail. The experimental results show that the Si cement of GD steel are responsible for the phase transformation and microstructure of lower bainite. As the Si content in GD steel is 1.82 %, the lower bainite in duplex microstructure appears as meta-lower banite, and the duplex microstructure exhibits a best strength-toughness combination.