X70管线钢的组织控制与细化工艺研究

为了解奥氏体在连续冷却过程中的组织演变规律，更好地控制管线钢室温下的组织形态，对X70管线钢进行了静态及动态热模拟试验，绘制出了相应的连续冷却转变曲线（CCT曲线），观察其组织，分析变形和冷却速度等因素对管线钢组织的影响。同时对X70管线钢的入精轧温度、终轧温度等因素控轧控冷工艺进行模拟研究。认为提高变形后的冷却速度能获得针状铁素体组织；在同一冷却速度下，动态连续冷却转变得到的组织更细密；降低入精轧温度、终轧温度，增加冷却速度能细化组织。

RESEARCH ABOUT STRUCTURE CONTROL AND FINING PROCESS OF X70 PIPE LINE STEEL

To know the structure evolution law of austenite in procedure of continuous cooling and control bet- ter the structure morphology of pipe line steel under room temperature, the static and dynamic state thermal modeling tests are carried out for X70 pipe line steel, the corresponding continuous cooling transform curve （CCT curve） is drawn out, the structure is viewed, the influence of deformation and cooling speed on the structure of pipe line steel is analyzed. At the same time the simulating research is conducted for start finish rolling and end rolling temperatures of X70 pipe line steel in controlled - rolling controlled - cooling process. It is considered that the acicular ferrite structure can be got by increasing cooling speed after transformation; under same cooling speed the structure got in dynamic continuous cooling transformation is finer; to reduce starting finish rolling temperature and end rolling temperature and increase cooling speed can fine the struc-