论文标题:X80高强管线钢焊接性的模拟研究
Research on the Weldability Simulation of X80 Pipeline Steel
论文作者
论文导师 李午申,论文学位 硕士,论文专业 材料加工工程
论文单位 天津大学,点击次数 16,论文页数 75页File Size4360K
2006-02-01论文免费下载 http://paper.dic123.com/lunwen_106402422/
X80 pipelinesteel; weldability; thermal simulation; numerical simulateion
高压、大管径、高钢级管线钢是石油、天然气输送管道发展的必然趋势。X80管线钢是控轧控冷的微合金钢,具有高强度和良好的抗延性断裂能力,是输气管道中的高钢级管材。本课题即以X80管线钢为对象,以热动力学、金属物理学和力学等基本理论为基础,计算其焊接接头的温度场、应力场。采用物理模拟和定量预测手段,分析X80管线钢在不同焊接工艺中所形成接头的组织和性能,实现对焊接接头的组织和性能的预测,得出保证X80管线钢焊接接头强韧化的最优焊接条件,为X80管线钢在管道上的实际应用提供理论依据。 利用SYSWELD焊接有限元分析软件,采用双椭球焊接热源模型,模拟了X80管线钢焊接过程,获得了不同工艺参数下焊接粗晶区的焊接热循环曲线,并分析讨论了工艺因素对t8/5和tH热循环参数的影响。同时,也应用SYSWELD软件模拟了X80管线钢多层焊过程,数值模拟考虑了材料热物理性能与温度的非线性关系,以及相变潜热对温度场的影响,实现焊接温度场、组织状态场和应力应变场三场耦合计算。通过模拟获得了焊接应力分布的变化和残余应力的分布结果。 此外,利用热模拟方法对X80管线钢焊接性进行了测定、分析和探讨;对焊接接头HAZ的组织和性能做了预测;并以韧性优化作为焊接工艺参数的优化目标,采用MATLAB软件,对X80管线钢的焊接工艺参数进行了优化。
High-pressure, large-diameter and high-strength pipes are inevitable trend for the oil and natural gas transporting pipeline. X80 pipeline steel, microalloyed steel produced by TMCP process with high strength and good crack- resistance prosperity, is the main material of transporting pipeline. In this paper, physical simulation and quantitative predication of CGHAZ for X80 pipeline steel were preformed in order to study its mechanical properties, which will provide theoretical knowledge for its practical application. At the same time, On the basis of heat transfer, metal physics and mechanics, the distribution of temperature, microstructure and stress could be calculated in order to optimize chemical composition and welding condition and predict microstructure and mechanical properties. SYSWELD software and double ellipsoid heat source were adopted to perform FEM simulation. Thermal cycle has been gained to reveal the relationship between weld condition and t8/5, tH. Three field of temperature, microstructure and stress were coupled considering the nonlinear relationship between material properties and temperature, and the interaction among temperature, microstructure and stress. Thermal simulating technology was used to study weld HAZ of pipeline steel X80. Based on the results of thermal simulation, the quantitative relationship between welding condition and properties of HAZ has been established. By optimization method and MATLAB, the most suitable weld condition which could lead to highest toughness of X80 pipeline steels has been determined.
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