硼对低温球罐用钢07MnNiMo VDR 50mm板组织与力学性能的影响

Effect of Boron on Structure and Mechanical Properties of 50 mm Plate of Steel 07MnNiMoVDR for Cryogenic Spherical Tank

低温球罐用钢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—0．04A1）50mm板由100tUHPEAF-LF-300mm×2000mmCC-4辊可逆轧机轧制工艺生产。研究了0—0．002O％B对该钢900℃淬火-620qc回火的50mm板组织和力学性能的影响。结果表明，加硼能显著提高钢板淬透性，以钢板心部得到均匀贝氏体为主的组织；当硼含量超过0．0015％时，组织粗大并有混晶出现，冲击功下降，抗拉强度750MPa超出标准上限（730MPa）。当钢中硼含量控制在0．0005％～0．0015％时钢板有良好的强韧性匹配，抗拉强度尺。为630～690MPa，冲击功140～275J，满足标准要求。

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. 04A1） 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 N 0. 002 0% B on structure and mechanical properties of 50 mm plate of the steel quenched at 900 ℃ -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 bo- ron 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.