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采用固溶+时效的热处理方法研究了时效温度对HSLA(High Strength Low Alloy)高强船体钢组织性能的影响。结果表明,试验钢在450℃处出现强度峰值,这是由大量纳米级的Cu析出物(<5 nm)和少量Nb(C,N)粒子的共同强化造成。过时效状态下,基体的软化作用加强,且Cu析出粒子尺寸显著增大(10～30 nm),沉淀强化作用也逐渐减弱,钢的强度下降。时效过程中基体软化和析出相沉淀强化的共同作用决定了HSLA高强船体钢的性能变化规律。试验钢在650～670℃范围内时效不仅获得了670～780 MPa的强度,而且保证-40℃冲击功在80 J以上,体现出良好的强韧性匹配。
The effects of aging temperature on the microstructure and properties of HSLA (High Strength Low Alloy) high-strength hull steel were investigated by the heat treatment method of solution treatment and aging. The results show that the tensile strength of the test steel at 450 ℃ is caused by the co-strengthening of a large number of nanoscale Cu precipitates (<5 nm) and a small amount of Nb (C, N) particles. Under the aging condition, the softening effect of the matrix is strengthened, and the size of precipitated Cu particles is significantly increased (10 ~ 30 nm), the precipitation strengthening effect is gradually weakened, and the strength of the steel is decreased. The combination of matrix softening and precipitation precipitation strengthening during aging determines the regularity of the performance of HSLA high-strength hull steel. Experimental steel in the 650 ~ 670 ℃ aging not only obtained the strength of 670 ~ 780 MPa, but also to ensure that the -40 ℃ impact energy above 80 J, reflecting a good toughness match.