【摘要】 通过对Mn-Cu-Nb-B系列低碳贝氏体钢的等温转变及连续冷却转变组织的研究,发现该系列微合金钢在500~700℃可发生多种类型中温组织转变.冷却速度和终冷温度对最终组织类型和性能有很大影响,终冷温度控制在630℃,可得到准多边形铁素体、粒状贝氏体和细小M/A组元的混合组织,该类型组织屈服强度可达到600MPa,且具有较好的塑性和低温冲击性能.在了解低碳贝氏体钢组织转变特点的基础上,利用冷却制度控制中温转变组织类型能优化低碳贝氏体钢的性能.更多还原

【Abstract】 Based on the isothermal treatment and continuous cooling test of an Mn-Cu-Nb-B low carbon bainitic steel,it was found that several types of intermediate transformation could be formed in the range of 500～700?℃. Cooling rate and finish cooling temperature have much effect on the final microstructure and mechanical properties of the steel. When the finish cooling temperature was selected around 630?℃,a proper combination of quasipolygonal ferrite,granular bainite and fine M/A could be obtained. The yield stress of this type of microstructure could reach 600 MPa,with a better plasticity and low-temperature impact toughness. A proper control cooling process influences the intermediate transformation products,in this way the mechanical properties of a low carbon bainitic steel can be fairly optimized.更多还原