【作者】 丛志宇；

【导师】 丁桦；

【作者基本信息】 东北大学 ， 材料工程， 2008， 硕士

【摘要】 当前,随着国民经济的高速发展,对石油、天然气的需求急剧增加,对管线钢的需求也相应地急剧增加。在激烈的市场竞争下,世界上各油气公司普遍接受采用更高强度级别管线钢,以便可以采用高压输送油气而降低成本。因此,近年来高压输送和厚壁、高强度的管线已经成为管线建设的一个新的发展趋势。在管线建设的这种新的发展趋势中,针状铁素体管线钢由于具有优良的强韧性能、焊接性能、抗硫化氢开裂性能而具有广阔的应用前景。控制轧制与控制冷却技术在现代钢铁产品生产过程中发挥着重大作用。本文将控制轧制与控制冷却技术应用于微合金管线钢的生产过程中,探讨微合金管线钢热变形过程中组织细化与性能变化的规律,为实际工业生产提供理论基础和工艺依据。主要研究以下内容：1.利用单道次压缩实验,研究X70管线钢热变形过程中的动态回复及动态再结晶等软化行为,得出不同变形温度、变形速率以及变形量下实验钢的真应力-真应变曲线；同时获得不同热模拟变形条件对材料显微组织结构的影响规律。2.利用多道次热模拟方法,以X70管线钢为研究对象,在热模拟机上分别进行不同变形量、变形速率、终轧温度、终冷温度和冷却速度对X70管线钢的奥氏体-铁素体相变行为以及显微组织影响的实验研究。3.基于多道次热模拟实验研究结果,利用某钢厂2150生产线进行实际控制轧制和控制冷却,在热轧中对X70管线钢采用多道次控轧和适当冷却速度控冷的TMCP工艺。探讨控轧控冷条件对X70管线钢显微组织、力学性能的影响规律,从而在不改变现有管线钢化学成分的情况下,仅仅通过优化的TMCP工艺,实现管线钢的柔性化轧制。更多还原

【Abstract】 The demands for pipeline steels are being increased dramatically with the national economy development. Driven by cost considerations, gas and oil transportation companies have readily adopted higher strength pipeline steels with thicker gauges to permit gas and oil transportation at higher pressures. As a result, recent construction of pipelines has shown a trend towards higher operation pressure with greater wall thickness and higher strength pipe. At the same time, acicular ferrite pipeline steels are becoming accepted as the prevalence for this new construction because of their high strength, excellent tough-ness, good weldability and satisfied hydrogen sulfide resistance.The controlled rolling and controlled cooling technology is very important in modern steel products. This paper, apply controlled rolling and controlled cooling technology on the production of micro-alloyed pipeline steel. The experimental aims were to clarify the characteristics of the change of microstructures and mechanical properties at various deformation conditions and to offer theoretical foundation and technological basis for industrial manufacture. The main contents are given as follows:1. The dynamic recovery and dynamic recrystallization of X70 during hot deformation were investigated by single pass compression test. The flow stress curves and microstructures of test steel at different temperature, strain rate and strain amount were obtained.2. By multi-pass thermal simulation test, the effects of the strain amount, strain rate, finishing temperature, final cooling temperature and the cooling rate on austenite-ferrite transformation behavior and the microstructure were studied on the thermo-mechanical simulator for pipeline steel X70.3. Based on the investigation results of multi-pass hot simulation deformation test, the practical controlled-rolling and controlled-cooling tests were performed by using the rolling mill in ANSteel ASP 2150, the improved TMCP schedules containing a multi-pass controlled rolling coupled with moderate cooling rates were applied to hot rolling experiments. And the effects of technological parameters of controlled rolling and controlled cooling on the microstructures and mechanical properties of pipeline steel were investigated to obtain flexible rolling of pipeline only by optimized TMCP, without changing the chemical compositions of existing pipeline steels.更多还原