Research and development of 690 MPa grade high strength steel with high toughness
REN Qi-meng;CHEN Lin;Materials and Metallurgy School,Inner Mongolia University of Science and Technology;
A high strength plate with yield strength of 690 MPa was developed based on a heavy plate mill by quenching and tempering process. The microstructure of the plate is bainite. All grains were small and uniform. The size of bainite lath is thin. The yield strength Rp0. 2,tensile strength Rm,and elongation A of the plate reached 780 MPa,864 MPa,and 18. 0%,respectively. The Charpy absorbed energy is higher than 260 J at-20℃ and also higher than 250 J at-40℃. The lowest Charpy absorbed energy can reach 238 J even at-60 ℃. Especially,the plate also has good cold-bending properties.
【CateGory Index】： TG335.5