CAJ | 학술논문

为解决热轧厚壁无缝钢管横向壁厚分布不均的问题，建立三维热力耦合有限元模型，对张力减径轧制过程进行了动态模拟，并结合工业试验验证仿真模型。根据仿真结果分析了轧制过程中温度、应变和摩擦力的分布，研究了单道次轧制时金属的径向和周向流动规律，并结合整个轧制过程对金属的横向流动及壁厚不均的形成过程进行了分析，研究了轧制过程中温度对金属流动行为的影响，从而总结出横向壁厚分布不均的原因。结果表明：(1)在经过单道次轧制时，金属的周向流动为从孔型顶部流向辊缝，对应孔型角±30?位置处金属的周向流动最活跃，靠近孔型顶部和辊缝位置的金属周向流动性较差。但从整个轧制过程来看，金属总的周向流动为从孔型顶部和辊缝向孔型角±30?位置处流动，从而导致孔型角±30?位置处的壁厚比孔型顶部和辊缝位置要厚。(2)温度分布对金属横向流动有重大影响。由于塑性功换热的原因，孔型角±30?位置处金属的温度比辊缝和孔型顶部处高，此处金属较软，阻力较小，孔型顶部和辊缝处金属向此处的流动性增强，导致钢管截面呈内边方形。
위해결열알후벽무봉강관횡향벽후분포불균적문제，건립삼유열력우합유한원모형，대장력감경알제과정진행료동태모의，병결합공업시험험증방진모형。근거방진결과분석료알제과정중온도、응변화마찰력적분포，연구료단도차알제시금속적경향화주향류동규률，병결합정개알제과정대금속적횡향류동급벽후불균적형성과정진행료분석，연구료알제과정중온도대금속류동행위적영향，종이총결출횡향벽후분포불균적원인。결과표명：(1)재경과단도차알제시，금속적주향류동위종공형정부류향곤봉，대응공형각±30?위치처금속적주향류동최활약，고근공형정부화곤봉위치적금속주향류동성교차。단종정개알제과정래간，금속총적주향류동위종공형정부화곤봉향공형각±30?위치처류동，종이도치공형각±30?위치처적벽후비공형정부화곤봉위치요후。(2)온도분포대금속횡향류동유중대영향。유우소성공환열적원인，공형각±30?위치처금속적온도비곤봉화공형정부처고，차처금속교연，조력교소，공형정부화곤봉처금속향차처적류동성증강，도치강관절면정내변방형。
In order to solve the transverse wall thickness variation problem of thick-walled seamless steel tubes produced by hot rolling, a coupled thermo-mechanical finite element model was established to simulate the stretch reducing hot rolling process, and industrial trials were performed to verify the model. Based on simulation results, the authors analyzed temperature, strain and friction force distributions in the rolling process, studied the radial and circumferential flow laws of metal in single pass rolling, the transverse flow law in the whole rolling process and the formation of thickness variation, discussed the influence of temperature on metal flow behavior, and finally summarized the reasons of transverse wall thickness variation. The metal circumferential flow direction is from the roller top to roller gap after rolled by a single pass. Circumferential flow of metal near the ±30? position of roller groove angle is the most active, and circumferential flow of metal near the roller top and gap positions is much weaker. However, after the whole rolling process, metal flows from the roller top and gap position to the ±30? position of roller groove angle along circumference. This causes that the thickness of the ±30? position is bigger than the roller top and gap position. Temperature has huge influence on metal transverse flow behavior. Because of plastic work, metal temperature at the ±30? position of roller groove angle increases higher than other positions, which softens and lowers the resistance of this place. So the metal fluidity of the roller top and gap positions toward the ±30? position is strengthened, leading to tube cross section appearing a hexagonal bore.