低成本X70管线钢减量化工艺技术研究

Research on Reduced Process Technology of Low-Cost X70 Pipeline Steel

研究了包括控轧制度和控冷工艺在内的X70管线钢减量化工艺技术。结果表明，通过提高粗轧阶段最后1个道次和精轧阶段最后1个道次的压下率，使其分别达到20％和10％以上，可使钢板心部奥氏体晶粒得到充分细化；通过降低终冷温度和提高冷却速率等工艺参数，可得到超细化的AF＋少量M／A岛；超细化AF型X70管线钢采用JCOE工艺制管后，屈服强度提高，为降低产品生产成本提供了可能。目前，首秦公司已实现无钼无镍低成本X70管线钢减量化批量生产。

In this paper, an overview of reduced process technology for X70 plates was mtroduced, including controlled rolling and controlled cooling process. The results showed that by increasing the last pass deformation of rough rolling and finish rolling, up to 20% and 10% respectively, the austenite grain in the center layer of the plate can be refined completely. The microstructure of ultra- fine acicular ferrite containing a small amount of M/A phase was obtained by decreasing the finish cooling temperature and increasing the cooling rate. After JCOE pipe making process on X70 plates with ultra-fine acicular ferrite, the yield strength raised, which provides a possibility to reduce product cost. Currently, Shouqin Company has achieved batch production of low-cost X70 plate without molybdenum and nickel alloy.