High strength low alloy (HSLA) steels are important metallic materials especially in the defense and military sectors due to their superior mechanical properties and cost-effectiveness compared to superalloys. This study investigates monotonic tension/compression strength and fatigue strength, including both the low cyclic fatigue (LCF) and high cyclic fatigue (HCF), of a HSLA steel produced using laser powder bed fusion (LPBF) additive manufacturing (AM). The LCF tests were strain-controlled (from 0.45% to 1.2% strain amplitudes) achieving a constant strain rate of 0.0005/s, while the HCF tests were stress-controlled (from 467 MPa to 1007 MPa stress range), all carried out at room temperature. Specimens of the alloy were manufactured in two build orientations to evaluate anisotropy. Moreover, a set of rolled plate and as-cast specimens were tested to facilitate comparisons. The alloy exhibited excellent performance confirming the potential of LPBF AM to manufacture HSLA steels with significant performance gains over as-cast counterparts. Nevertheless, the rolled material exhibited the highest performances. Details pertaining to the processing along with the testing results and characterization of microstructural origins of the high strength are presented and discussed in this paper.

中文翻译：

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激光粉末床熔合超高强度低合金钢的疲劳强度

高强度低合金（HSLA）钢是重要的金属材料，特别是在国防和军事领域，因为与高温合金相比，其具有优异的机械性能和成本效益。本研究研究了使用激光粉末床熔合 (LPBF) 增材制造 (AM) 生产的 HSLA 钢的单调拉伸/压缩强度和疲劳强度，包括低循环疲劳 (LCF) 和高循环疲劳 (HCF)。LCF 测试是应变控制的（从 0.45% 到 1.2% 应变幅度），实现了 0.0005/s 的恒定应变率，而 HCF 测试是应力控制的（从 467 MPa 到 1007 MPa 应力范围），全部在室内温度。以两个构建方向制造合金样本以评估各向异性。此外，还测试了一组轧制板和铸态样品以方便比较。该合金表现出优异的性能，证实了 LPBF AM 制造 HSLA 钢的潜力，与铸态钢相比，性能显着提升。尽管如此，轧制材料表现出了最高的性能。本文介绍并讨论了有关加工的详细信息以及高强度微观结构起源的测试结果和表征。