共查询到17条相似文献,搜索用时 296 毫秒
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新型纳米强化超高强度钢的研究与进展 总被引:1,自引:0,他引:1
随着资源、能源和环境压力日益加大,超高强度钢的开发越来越受到世界各国的极大重视。传统的超高强度钢大都是依赖提高碳含量或合金元素含量而获得较高强度的马氏体或贝氏体钢,此种钢存在着焊接性能差、塑韧性低、钢材尺寸受限制和成本昂贵等问题,严重制约了经济的快速发展和现代国防的建设,因此,开发综合性能良好、成本低廉的新型超高强度钢刻不容缓。结合当前纳米科技的发展,介绍了新型纳米强化超高强度钢的设计理念,阐述了以纳米相析出强化为主、多种强化方式结合的强韧化理论,并总结了纳米析出强化超高强度钢在合金设计和工艺优化等方面的初步研究进展,最后探讨了新型纳米强化超高强度钢亟待解决的问题。 相似文献
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综述了低预热焊接的高强度舰船结构钢种的研究现状和发展途径。指出其发展途径主要是改进现役钢种、开发沉淀硬化型舰船结构钢、研究超低碳贝氏体舰船结构钢及采用新的生产工艺。 相似文献
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对船体结构钢焊接冷裂纹研究进展进行了综述。分析了扩散氢、淬硬组织和拉应力等因素在焊接冷裂纹形成过程中的作用,介绍了基于3个影响因素形成的焊接冷裂纹形成机理,总结了基于焊接材料改进、焊接工艺控制、母材焊接性改进、低匹配焊接等思路的船体结构钢焊接冷裂纹控制方法,并对焊接冷裂纹研究重点进行了展望。 相似文献
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16Co14Ni10Cr2Mo钢制飞机平尾大轴的真空淬火EI 总被引:2,自引:0,他引:2
介绍了可焊接的新型超高强度结构钢16NiCo及其制作的飞机水平安定面转动轴的真空热处理工艺。实践证明,采用真空热处理,可获得最佳的技术经济效益。 相似文献
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综述了美国舰船用钢的发展历程,总结了其成分体系、工艺技术及典型应用,分析了新一代舰船用钢的发展趋势。介绍了我国舰船用钢的主要发展历程,指出了我国舰船用钢与国际先进水平的主要差距。对于新一代极低碳复合析出强化型高强韧钢进行了探索性研究。结果发现,采用极低碳成分并结合控制轧制工艺技术,可以获得强度和韧性的良好匹配。对实验钢的显微组织和析出相进行了检测分析,对强韧化机制进行了初步的阐述。最后,概述了我国高强韧钢生产的关键技术及装备基础。我国自主开发的新一代TMCP工艺技术和装备已达到国际先进水平,表明我国新一代舰船用钢由“跟踪”向“自主研发”转变已经具备了坚实的装备和工艺基础。 相似文献
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To combine the advantage of density reduction and excellent performance, nanometer-sized B2 particles were introduced into the δ ferrite matrix of high-aluminium low-density steel by the addition of nickel (Fe–0.2C–11Mn–6Al–4/8Ni). Compared to Fe–0.2C–11Mn–6Al (0Ni) steel, the hardness and tensile strength of 4Ni and 8Ni steels are significantly improved. The improvement of tensile strength in 4Ni and 8Ni steels was primarily contributed by the precipitation strengthening or solution strengthening of B2 particles in δ ferrite. At the higher annealing temperature, the original dislocation density in δ ferrite is lower. However, dislocation multiplication during tensile deformation was more significant in the sample annealed at higher temperature, which was responsible for a higher work hardening rate. 相似文献
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Computer-aided design of transformation toughened blast resistant naval hull steels: Part I 总被引:1,自引:0,他引:1
A systematic approach to computer-aided materials design has formulated a new class of ultratough, weldable secondary hardened
plate steels combining new levels of strength and toughness while meeting processability requirements. A theoretical design
concept integrated the mechanism of precipitated nickel-stabilized dispersed austenite for transformation toughening in an
alloy strengthened by combined precipitation of M2C carbides and BCC copper both at an optimal ∼3 nm particle size for efficient strengthening. This concept was adapted to
plate steel design by employing a mixed bainitic/martensitic matrix microstructure produced by air-cooling after solution-treatment
and constraining the composition to low carbon content for weldability. With optimized levels of copper and M2C carbide formers based on a quantitative strength model, a required alloy nickel content of 6.5 wt% was predicted for optimal
austenite stability for transformation toughening at the desired strength level of 160 ksi (1,100 MPa) yield strength. A relatively
high Cu level of 3.65 wt% was employed to allow a carbon limit of 0.05 wt% for good weldability, without causing excessive
solidification microsegregation. 相似文献
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The microstructure of high-speed steels consists of a martensitic matrix with a dispersion of two sets of carbides. These carbides are usually known as primary and secondary carbides. The role of the primary carbides has been reported to be of no importance in strengthening the steels, due to their large size and large interparticle spacing. The present authors have studied the role of the primary carbides on the wear of high-speed steels and found them to be of no importance, and under certain conditions contributing to higher wear rates. It has been shown analytically and experimentally that in quenched and tempered high-speed steels, the precipitation of the secondary hardening carbide (cubic M2C type) is the main reason for the improved strength and wear resistance. This shows that the secondary hardening phenomenon of high-speed steels is a direct result of the hardening caused by the precipitation of the cubic M2C-type carbide. The present study has estimated that at peak hardness the volume fraction of secondary hardening carbides is approximately 20%. The measured strength of high-speed steels was found to be lower than the theoretically calculated strength due to non-homogeneous precipitation of the secondary hardening carbides. Areas which were observed to be free from secondary hardening carbides are real and are not artefacts. It has been shown that the strength of high-speed steel in the region of peak hardness depends primarily on the precipitation of the secondary hardening carbide and secondarily on martensitic strengthening. 相似文献
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本文结合飞机起落架的设计理念,梳理了飞机起落架用超高强度钢及高强不锈钢的应用及发展历程,重点阐述了典型超高强度不锈钢的成分、组织和力学性能以及强韧化机理。建议通过材料热力学动力学计算创新设计新的超高强度不锈钢钢种;提出新型超高强度不锈钢的组织设计,将更关注多类型或高密度的共格析出强化以及高力学稳定性残余奥氏体的强韧化作用机制;最后指出采用最新的一些加工工艺技术,如等温多向锻造工艺技术,可显著提高超高强度不锈钢的综合力学性能。 相似文献
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S. Allain M. Gouné O. Bouaziz E. Kassir P. Barges L. Jantzen 《Journal of Materials Science》2011,46(8):2764-2770
A fully lamellar ferrite/cementite nanostructure was designed in a low C steel by using a specific thermal treatment. The
strengthening of such microstructure has been investigated as a function of prestrain by rolling up to a deformation of 300%.
As in usual pearlitic structure, its work-hardening shows no saturation and its elongation to fracture remains rather constant
instead of decreasing drastically as conventional steels. The hardening by a similitude effect is thus not the privilege of
pearlitic steels. Nevertheless, its lower initial work-hardening rate at low strain compared to an equivalent pearlitic steel
and a lower hardening potential at high strain let us suspect major differences in the nature and the behaviour of ferrite
channels in relation to the morphogenesis of the microstructure. This study opens a new way to obtain low carbon ultra-high
strength steel by a nanostructuration process using severe plastic deformations. 相似文献