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利用透射电镜、X射线和化学相分析等方法研究热连轧轧后冷却和卷取过程中板卷组织和性能的变化。发现:晶粒细化为主要强化项,位错亚结构次之;铌的加入主要抑制奥氏体的再结晶。用X 射线线形分析法来估算位错亚结构的变化,提出了位错亚结构强化项用 K_DR_Z(?)~(-1/2)来表示,代替了位错强化项σ_d 和亚晶强化项CK_Sl~(-1/2),式中:K_D 为位错亚结构强化系数;R_z为强化取向因子,(?)为平均位错胞尺寸(即相干散射区尺寸)。进一步提出了估算屈服强度新的表达式:σ_y=σ_i+σ_s+[σ_p~2+(K_DR_Z(?)~(-1/2)]~(1/2)+K_(yd)~(-1/2)
The changes of coil structure and properties during cooling and coiling after hot tandem rolling were investigated by transmission electron microscopy, X-ray and chemical phase analysis. It is found that the grain refinement is the main strengthening item, followed by the dislocation sub-structure. The addition of niobium mainly suppresses the recrystallization of austenite. X-ray linear analysis was used to estimate the change of dislocation sub-structure. It was proposed that the dislocation substructure enhancement term was expressed by K_DR_Z (?) -1 (1/2) instead of the dislocation enhancement σ_d and subgrain enhancement CK_Sl ~ (-1/2), where: K_D is the dislocation substructure strengthening factor; R_z is the strengthening orientation factor, () is the average dislocation cell size (ie, the size of the coherent scattering region). Furthermore, a new expression for estimating the yield strength is proposed: σ_y = σ_i + σ_s + [σ_p ~ 2 + (K_DR_Z (?) -1/2)] ~ (1/2) + K_ (yd) 2)