Duan L.,University of Science and Technology Beijing |
Duan L.,Institute for Structural Materials of CISRI |
Liu Q.,Institute for Structural Materials of CISRI |
Jia S.,Institute for Structural Materials of CISRI |
And 3 more authors.
Cailiao Yanjiu Xuebao/Chinese Journal of Materials Research | Year: 2012
The effects of microstructure, precipitate and grain size on strength and toughness of X100 hot rolled strips steel were investigated by means of optical microscope, scanning electronic microscopy (SEM), transmission electron microscopy (TEM) and electron backscattered diffraction (EBSD) in this article. The results show that average effective grain size of X100 pipeline steel with reasonable composition design reaches to 2.38 μm after selected thermo-mechanical control process (TMCP), and there are a great quantity of dislocations and substructures in grains. Microstructure of X100 strips mainly consists of granular bainite, lath bainite with plenty of fine M/A islands dispersing in the matrix or on grain boundaries. Fine precipitation particles can pin dislocation effectively, tensile strength of tested steel are higher than 970 MPa, yield strength are higher than 800 MPa, Charpy impact energy (higher than -40°C) are higher than 250 J, and ductile brittle transition temperature is between -40°C and -60°C. © right.