Preparation method of large-diameter seamless steel pipe

The invention is suitable for the field of seamless steel tube manufacturing, and provides a preparation method of a large-diameter seamless steel tube, which comprises the following steps: step 1, preparing a blank; step 2, heating in an annular furnace; step 3, punching and rolling; 4, continuous rolling is conducted; 5, determining the outer diameter; and 6, air cooling is carried out for temperature reduction. A large-section blank is replaced with a small-section blank, the rack and the ejector head are redesigned, and the method has great significance in completing the capacity target of a company, reducing the cost and improving the competitiveness. 本发明适用于无缝钢管制造领域，提供了一种大口径无缝钢管的制备方法，包括以下步骤：步骤1、准备坯料；步骤2、环形炉加热；步骤3、穿孔轧制；步骤4、连轧轧制；步骤5、确定外径；步骤6、空冷降温。本发明使用小断面的坯子代替大断面的坯子，重新设计机架和顶头，对于完成公司产能目标、降成本和提高竞争力具有重大意义。