控轧控冷对X60级管线钢显微组织及低温冲击韧性的影响  

THE EFFECT OF MICROSTRUCTURE AND LOW-TEMPERATURE IMPACT TOUGHNESS OF CONTROLLED ROLLING AND COOLING OF X60 GRADE PIPELINE STEEL

作　　者：张志慧 贾小华 Zhang Zhihui;Jia Xiaohua(Technical Department,Hebei Yanshan Iron&Steel Group Co.,Ltd.,Qianan 064400,Hebei)

机构地区：[1]河北燕山钢铁集团有限公司技术部,河北迁安064400

出　　处：《河北冶金》2023年第12期46-49,55,共5页Hebei Metallurgy

摘　　要：通过扫描电子显微镜、光学显微镜等对X60级管线钢显微组织与冲击试样断口形貌进行观察分析,研究了控轧控冷工艺对试验钢的热轧显微组织及低温冲击韧性的影响。结果表明:试验钢控轧控冷条件下冲击断口无明显裂纹源,基本呈现等轴韧窝形貌特征;其获得的针状铁素体组织较常规轧制下多边形铁素体组织更加细化、均匀,晶粒尺寸均值由20μm下降至8μm左右,其尺寸小于2μm的占比达75%以上;控轧控冷工艺较常规轧制试验钢具有更好的强度及塑韧性,尤其-10℃冲击功达到180 J以上。在生产过程中通过合理设定机架间冷却水强降温工艺与轧后层流冷却速率及卷取温度控制,实现精轧控制轧制与层流控制冷却相结合的控制工艺,可极大地改善超厚规格X60管线钢低温冲击性能。The microstructure of X60 pipeline steel and the fracture morphology of impact specimens were observed and analyzed by scanning electron microscope and optical microscope,and the effects of controlled rolling and cooling process on the hot-rolled microstructure and low-temperature impact toughness of the test steel were studied.The results show that there is no obvious crack source in the impact fracture under the condition of controlled rolling and cooling,and the morphology characteristics of equiaxed dimples are basically presented,the acicular ferrite structure obtained is more refined and uniform than that of the polygonal ferrite under conventional rolling,the average grain size decreases from 20μm to about 8μm,and the proportion of the test steel with a size of less than 2μm is more than 75%,and the controlled rolling and cooling process has better strength and toughness than the conventional rolling test steel,especially the impact energy of-10℃reaches more than 180 J.In the production process,the control process of combining precision rolling control rolling and laminar flow-controlled cooling can be realized by reasonably setting the strong cooling process of the cooling water between the stands and the laminar flow control cooling rate and coiling temperature control after rolling,which can greatly improve the low-temperature impact performance of ultra-thick X60 pipeline steel.

关 键 词：X60 管线钢 控轧控冷 多边形铁素体 针状铁素体 韧窝 低温冲击性能 

分 类 号：TG142.1[一般工业技术—材料科学与工程]