本发明提供一种抗氢致延迟开裂的高强钢及制备方法,属于高强钢技术领域。该高强钢质量百分比组成为：C：0.22～0.25％、Si：0.25～0.35％、Mn：1.2～1.4％、S：≤0.005％、P：≤0.02％、Al：0.02～0.05％、Ti：0.02～0.05％、Cr：0.11～0.2％、B：0.002～0.0035％、Nb：0.025～0.055％、N：N/(Ti+Nb)＝1/8～1/6、Fe:余量。该高强钢通过22MnB5钢添加微量Nb、N,形成Ti、Nb、N复合微合金化,使材料的组织中析出弥散分布的纳米级(<10nm)碳氮化物；该析出物可以形成氢陷阱,对氢起钉扎作用,抑制氢的扩散,使氢在基体中均匀分布,避免氢原子聚集成氢气团,从而使钢具有抗氢致延迟开裂的能力。本发明所述的钢还具有良好的力学性能,其屈服强度和韧性好于含铌量在该范围以外的同种材料。

The present invention provides a high-strength steel resistant to hydrogen-delayed cracking and a method for its preparation, which belongs to the technical field of high-strength steels. The composition of the high-strength steel in mass percentages is: C: 0.22-0.25%, Si: 0.25-0.35%, Mn: 1.2-1.4%, S: ≤0.005%, P: ≤0.02%, Al: 0.02-0.05%, Ti: 0.02-0.05%, Cr: 0.11-0.2%, B: 0.002-0.0035%, Nb : 0.025 to 0.055%, N: N/(Ti+Nb) = 1/8 to 1/6, Fe: balance. The high-strength steel is micro-alloyed with Ti, Nb and N through the addition of trace amounts of Nb and N to 22MnB5 steel, resulting in the precipitation of diffusely distributed nano-scale (<10nm) carbonitrides in the material's structure; the precipitates can form hydrogen traps, which act as nails for hydrogen, inhibit the diffusion of hydrogen, make hydrogen uniformly distributed in the matrix, and prevent hydrogen atoms from aggregating into hydrogen gas clusters, thus making the steel resistant to hydrogen-induced delayed cracking. The steel is thus resistant to hydrogen delayed cracking. The steel of the invention also has good mechanical properties, with better yield strength and toughness than materials of the same type with niobium content outside this range.