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通过扩展Avrami相变动力学模型、开发线性混合热膨胀模型、应用有限元单胞法,考虑了相变诱导塑性(TRIP)、相变膨胀、热膨胀等机制,建立了热力耦合有限元单胞模型。用该模型研究了X65管线钢分别在0、±50、±100、±150、±200 MPa拉、压单轴外载作用下,以1℃/s的冷速从540℃冷却至480℃的控冷过程,标定了TRIP系数,定量分析了TRIP效应对应变、应力的影响。结果表明:本模型适用于研究X65管线钢中由Greenwood-Johnson机制产生的TRIP效应,TRIP系数为5.35×10-5;控冷结束,拉应力外载产生的tεrip占ε的比例最低22%,最高79%;拉、压外载作用下,TRIP效应产生的最高残余拉、压应力分别为346 MPa和-103 MPa的。
By expanding the Avrami phase transition kinetic model and developing a linear mixed thermal expansion model, the finite element cellular method is used to establish the thermal-coupled finite element model based on the mechanism of phase transition induced plasticity (TRIP), phase transformation expansion and thermal expansion. The model was used to study the cooling effect of X65 pipeline steel from 540 ℃ to 480 ℃ under the condition of 0, ± 50, ± 100, ± 150, ± 200 MPa and uniaxial load respectively Controlled cooling process, calibrated TRIP coefficient, quantitative analysis of the TRIP effect of strain, stress. The results show that this model is suitable for studying the TRIP effect caused by Greenwood-Johnson mechanism in X65 pipeline steel with a TRIP coefficient of 5.35 × 10-5. When controlled cooling ends, the ratio of tεrip to ε outside the tensile stress is 22% Up to 79%. The maximum residual tensile and compressive stresses caused by TRIP under tension and compression loading are 346 MPa and -103 MPa, respectively.