关键词: 硼, 低温球罐用钢07MnNiMoVDR , 50 mm板, 组织, 力学性能

Abstract: The 50mm plate of steel 07MnNiMoVDR (/% : 0. 06 ~0. 08C, 0. 20 ~0.30Si, 1. 50 ~ 1. 60Mn, 0.30 ~
0. 40Ni, 0. 10 ~0. 15Cr, 0. 18 ~0. 25Mo, 0. 04 ~0. 05V 0. 02 ~0. 04Al) for cryogenic spherical tank is produced by 100 t UHP EAF-LF-300 mm x 2 000 mm CC-four-high reversing mill rolling process. The Effect of 0 ~ 0. 002 0% B on structure and mechanical properties of 50 mm plate of the steel quenched at 900 °C -tempered at 620℃ has been studied. Results show that adding boron can obviously increase hardenability of plate to get homogeneous major bainite structure ； as the boron content in steel is more than 0.001 5% , the structure coarsens with occurrence of mixing grains led to impact energy decreasing and tensile strength of steel (750 MPa) larger than the upper limit of standard (730 MPa). As the boron content in steel is controlled in 0.000 5% ~0.001 5% , the steel plate has excellent strength-toughness matching i. e. tensile strength 630 ~690 MPa and impact energy 140 ~ 275 J to meet the standard requirement.

Key words: Boron, Steel 07MnNiMoVDR for Cryogenic Spherical Tank, 50 mm Plate, Structure, Mechanical Properties