【摘要】 为了进一步降低硼镍复合添加的含铌低合金高强度(HSLA)H型钢的韧脆转变温度。将试验钢在910℃淬火后,分别在550、600和650℃回火2 h,通过拉伸试验和夏比冲击试验对其力学性能,特别是低温冲击韧性进行了测试,使用XRD、SEM、HRTEM以及EDS对其组织和成分进行了分析。结果表明:淬火回火处理后,试验钢具有优异的强韧性配合,其韧脆转变温度降低到-70℃以下,并且-90℃时的冲击功仍在100 J左右;回火后韧性的提高主要是基体回复、再结晶的结果;回火时析出的成分复杂的碳化物有利于抑制再结晶晶粒的长大,使组织细化,细小弥散的非连续析出碳化物对韧性影响不大。更多还原

【Abstract】 To lower ductile-brittle transition temperature(50%,FATT) of high strength low alloy(HSLA) H-beam steel,a boron-nickel added Nb-containing HSLA steel were tempered at 550,600 and 650 ℃,respectively,after quenched at 910 ℃.Microstructure and mechanical properties,especially cryogenic toughness of the experimental steel were investigated by means of SEM,XRD,HRTEM,EDS analysis,uniaxial tensile and Charpy impact tests.The results indicate that the quenched and tempered steel exhibits good combination of strength and toughness.Their FATTs are all below-70 ℃ and the impact energy tested at-90 ℃ is about 100 J.The improvement of fracture toughness is the result of recovery and recrystallization of the quenched steel during tempering.Complex carbides precipitated in the tempered steel promote grain refinement and have little influence on cryogenic toughness.更多还原