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通过TMCP试验,研究了不同Nb含量低碳FB钢的微观组织和扩孔性能。试验结果表明,随着终轧温度或卷取温度的降低,试验钢强度提高,而扩孔性能降低。随着Nb含量的增加,试验钢的抗拉强度与扩孔性能明显改善。当终轧温度控制在860℃,冷却中间温度在710℃,卷取温度在450℃时,Nb的质量分数约为0.02%的试验钢的铁素体晶粒尺寸细化到6.3μm,抗拉强度达到570 MPa,扩孔率为91%左右,获得了良好的综合性能。
Through TMCP test, the microstructure and hole expanding performance of low carbon steel with different Nb contents were studied. The test results show that, as the finishing temperature or coiling temperature decreases, the strength of the test steel increases, while the hole expanding performance decreases. With the increase of Nb content, the tensile strength and hole expanding performance of the test steel are obviously improved. When the finishing temperature is controlled at 860 ℃, the cooling intermediate temperature is 710 ℃ and the coiling temperature is 450 ℃, the ferrite grain size of the test steel with the mass fraction of Nb about 0.02% is refined to 6.3μm, The strength reaches 570 MPa and the hole expanding rate is about 91%, obtaining a good overall performance.