Interrelationships between room-temperature yield strength and low-temperature impact toughness are examined for low-carbon, copper-precipitation-strengthened, high-strength low-alloy (HSLA) plate steels. Three steels, designated as HSLA-80, HSLA-80/100, and HSLA-100, are compared based on plots of yield strength versus 50% shear fracture-appearance transition temperature, followed by comparison of yield strength versus energy absorbed during Charpy V-notch testing at −84 °C. Analysis of both approaches produced similar outcomes, indicating that either is acceptable for predicting the influence of microstructure on the combination of strength and toughness. Data from over 15 studies including over 160 data points are amassed into a single master plot. Strengthening for the highest-strength steels is associated with a strength-toughness vector with slope equal to −0.67 J/MPa. A grain-refinement vector is associated with a slope of approximately +0.18 J/MPa. Since austenite grain size variation was virtually nonexistent in this study, variation of effective grain size was related to the differences in crystal size and/or packet size for low-carbon martensite (finest), low-carbon bainite, and polygonal ferrite (coarsest). A detrimental effect of untempered, brittle, medium-carbon martensite islands was hypothesized. Tempering of this microconstituent during aging heat treatment reduces, but does not eliminate, the negative effect of these islands. Base microstructures of low-carbon martensite show a superior combination of strength and impact toughness, followed by low-carbon martensite with islands of stable austenite, low-carbon bainite, and polygonal ferrite. A vector approach to strength-toughness in HSLA-100 steels is used to clarify property differences from previous studies. Future developments for this class of steels should address grain refinement and changes in processing or alloying that avoid islands of medium-carbon martensite.

研究了低碳，铜沉淀强化，高强度低合金（HSLA）钢板在室温屈服强度和低温冲击韧性之间的相互关系。根据屈服强度与50％剪切断裂-出现转变温度的曲线图比较了三种分别命名为HSLA-80，HSLA-80 / 100和HSLA-100的钢，然后比较了夏比V期间的屈服强度与吸收的能量-84°C下的缺口测试。对这两种方法的分析均得出相似的结果，表明这两种方法均可用于预测微观结构对强度和韧性组合的影响。来自15多个研究的数据（包括160多个数据点）被汇总到一个主图中。强度最高的钢的强化与强度-韧性矢量的斜率等于-0.67 J / MPa有关。晶粒细化矢量的斜率约为+0.18 J / MPa。由于本研究中几乎不存在奥氏体晶粒尺寸变化，因此有效晶粒尺寸的变化与低碳马氏体（最细），低碳贝氏体和多边形铁素体（最粗）的晶体尺寸和/或晶粒尺寸的差异有关。 。假设了未回火，易碎的中碳马氏体岛的有害作用。在时效热处理过程中，这种微成分的回火可以减少但不能消除这些岛的负面影响。低碳马氏体的基本组织显示出强度和冲击韧性的极佳组合，其次是具有稳定奥氏体，低碳贝氏体和多边形铁素体岛的低碳马氏体。HSLA-100钢中强度-韧性的矢量方法用于阐明与先前研究的性能差异。这类钢的未来发展应解决晶粒细化以及加工或合金化方面的变化，这些变化应避免出现中碳马氏体孤岛。