Experimental research and optimized process of heavy gauge X80 steel with excellent mechanical properties

4th International Conference on Applied Materials and Manufacturing Technology

材料科学;机械制造

Li, Shao Po^1,2,3 ; Ding, Wen Hua^1,3 ; Zhang, Hai^1,3

Shougang Research Institute of Technology, Beijing

100043, China^1

University of Science and Technology Beijing, Beijing

100083, China^2

Beijing Engineering Research Center of Energy Steel, Beijing

100043, China^3

关键词: Continuous cooling phase transformation;    Experimental research;    Final microstructures;    Heavy wall thickness;    Low temperature toughness;    Manufacturing technologies;    Slab reheating temperatures;    Ultimate tensile strength;   

Others  :  https://iopscience.iop.org/article/10.1088/1757-899X/423/1/012079/pdf
DOI  :  10.1088/1757-899X/423/1/012079

学科分类：材料科学（综合）

来源: IOP

【 摘 要 】

This paper reports on the experimental research and manufacturing technology of heavy gauge X80 pipeline steel up to 33mm in wall thickness used for gas transmission project in China. The continuous cooling phase transformation behavior of the material under deforming condition was investigated. Slab reheating temperature was controlled to inhibit austenite grain coarsening. An optimized control cooling process was developed to achieve proper desired final microstructure. The result showed that the microstructure of heavy gauge X80 was composed of uniform acicular ferrite containing amount of small precipitates with a size of below 35nm. The 5000 metric tons plates produced by this process achieved good tensile strength and excellent low temperature toughness. The yield strength and ultimate tensile strength in transverse direction reached 600MPa and 710MPa respectively, which are far higher than requirements of API-X80, such as 555MPa and 625MPa. Even with this X80 strength level and heavy wall thickness the low temperature fracture toughness achieved was excellent. Transverse Charpy impact testing resulted in absorbed average energy of 390 J @ - 60 °C with 100% shear.