共查询到18条相似文献,搜索用时 211 毫秒
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采用610℃5h炉冷和800℃20 min水淬+625℃12 h空冷两种热处理工艺和0~20%拉伸预应变等试验方法,分析了 6.9%和13.6%两种奥氏体量及0~20%预应变量对中锰钢5 mm板力学性能变化的影响。利用XRD试验法测量奥氏体的体积分数,拉伸试验法测量力学性能。研究结果表明:在同一预应变量下,奥氏体体积分数为13.6%的试样与6.9%的试样相比,屈服强度低约30 MPa、抗拉强度高约40 MPa、屈强比小约0.1、总延伸率约大7个百分点、加工硬化效果更明显等。而在同一奥氏体量水平下,随预应变量增大,屈服强度、抗拉强度和屈强比都提高、总伸长率下降;且随真应变增大,加工硬化行为可分为四个阶段:减小(Ⅰ阶段)、增大(Ⅱ阶段)、几乎不变(Ⅲ阶段)、减小(Ⅳ阶段)。 相似文献
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石油、天然气输送管道通常服役环境较恶劣:管道压力大、输送介质复杂,管道的安全问题日显突出,对管线钢屈强比提出更高要求.屈强比较高是长期困扰CSP流程生产管线钢的难题,运用数理统计方法对生产管线钢的过程工艺参数进行对比分析,查找影响屈强比的关键因素,并通过采取有效措施:调整化学成分、过程工艺参数,提高固溶强化效果,使其屈... 相似文献
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摘要:为了研究大变形管线钢应变硬化行为及其表征参数之间关联性,采用TMCP工艺调控制备了9种不同贝氏体体积分数的铁素体/贝氏体(F/B)多相组织钢。通过力学性能及应变硬化行为分析,对应变硬化指数、应力比、屈强比和伸长率等大变形管线钢应变硬化能力表征参数之间的关联性及其机制、内涵和适用范围进行了研究。结果表明,F/B多相钢中,应力比Rt20/Rt10和均匀伸长率与应变硬化指数呈线性正比关系,屈强比与应变硬化指数呈非线性反比关系,应力比Rt50/Rt10在一定条件下与应变硬化指数存在线性关系,应力比Rt15/Rt05、总伸长率、应变硬化指数之间不具备明显的关系。通过应变硬化行为分析合理阐释了以上参数之间的关联机制,并阐释了其内涵和适用范围。硬化指数、均匀伸长率和应力比Rt20/Rt10应作为描述F/B多相钢塑性形变阶段应变硬化能力的主要参数,屈强比和应力比Rt50/Rt10则应作为次要参数。采用工业化生产数据对上述结论进行了验证,与所得结论吻合良好。 相似文献
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为了研究大变形管线钢应变硬化行为及其表征参数之间关联性,采用TMCP工艺调控制备了9种不同贝氏体体积分数的铁素体/贝氏体(F/B)多相组织钢。通过力学性能及应变硬化行为分析,对应变硬化指数、应力比、屈强比和伸长率等大变形管线钢应变硬化能力表征参数之间的关联性及其机制、内涵和适用范围进行了研究。结果表明,F/B多相钢中,应力比R_(t2.0)/R_(t1.0)和均匀伸长率与应变硬化指数呈线性正比关系,屈强比与应变硬化指数呈非线性反比关系,应力比R_(t5.0)/R_(t1.0)在一定条件下与应变硬化指数存在线性关系,应力比R_(t1.5)/R_(t0.5)、总伸长率、应变硬化指数之间不具备明显的关系。通过应变硬化行为分析合理阐释了以上参数之间的关联机制,并阐释了其内涵和适用范围。硬化指数、均匀伸长率和应力比R_(t2.0)/R_(t1.0)应作为描述F/B多相钢塑性形变阶段应变硬化能力的主要参数,屈强比和应力比R_(t5.0)/R_(t1.0)则应作为次要参数。采用工业化生产数据对上述结论进行了验证,与所得结论吻合良好。 相似文献
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通过循环预拉伸应变-高温退火制备Al-Cu-Li合金单晶,同时探讨循环预拉伸应变-高温退火过程中预拉伸应变量、循环应变退火次数、应变退火温度对Al-Cu-Li合金晶粒长大的影响以及晶粒长大的过程与机制.研究结果表明,通过循环预拉伸应变退火可以使得合金晶粒异常长大,并且成功制备出厘米级别的宏观粗大晶粒,其长大机理主要为应... 相似文献
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Aluminum-killed steel sheets have been subjected to plane-strain prestrain in three ways: two-pass rolling, multi-pass rolling,
and inplane, plane-strain tension. Subsequent uniaxial tensile tests were performed to evaluate the residual work-hardening
behavior. The subsequent hardening curves depended primarily on the relative direction between major strain axes in the two
deformation stages and very little on the specific prestrain procedure. These curves showed high initial yield stresses followed
by a region of low (or negative) work hardening rate. This behavior contrasted with earlier results for 70/30 brass sheet,
and a model of subsequent tensile behavior based on a strain-induced stress transient emerged.
Formerly Staff Research Scientist, General Motors Research Laboratories 相似文献
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Improving the strength-to-ductility trade-off remains the prime driving force for the development of advanced high-strength steel. Traditionally research breakthroughs are focused on the microstructure and relative phase composition. Herein, laser hardening is applied to ductile ferritic steel to introduce straight and corrugated martensitic reinforcements, effectively generating architectured steel sheets. Tensile behavior of laser-architectured samples is studied both using finite-element method simulation and mechanical testing to reveal the effect of laser-induced corrugations on strength and necking strain. The results show that with the same reinforced volume fraction of 24%, an increase in corrugation height/period leads to a gain in necking strain with a loss in yield strength and ultimate tensile stress. This beneficial effect on necking strain is due to the corrugation unbending process which introduces so-called geometric work hardening during tension. Extended simulations are carried out on various corrugation heights/periods and the evolution trends of ultimate tensile strength and necking change with different reinforced volumes. This study proposes a perspective on corrugation-reinforced architectured materials. Corrugation parameters can be chosen to tailor the mechanical behavior of laser-architectured materials. 相似文献
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The tensile behavior, serrated flow, and dynamic strain aging of Fe-(20 to 24)Mn-(0.4 to 0.6)C twinning-induced plasticity (TWIP) steel have been investigated. A mathematical approach to analyze the DSA and PLC band parameters has been developed. For Fe-(20 to 24)Mn-(0.4 to 0.6)C TWIP steel with a theoretical ordering index (TOI) between 0.1 and 0.3, DSA can occur at the very beginning of plastic deformation and provide serrations during work hardening, while for TOI less than 0.1 the occurrence of DSA is delayed and twinning-dominant work hardening remains relatively smooth. The critical strain for the onset of DSA and PLC bands in Fe-Mn-C TWIP steels decreases as C content increases, while the numbers of serrations and bands increase. As Mn content increases, the critical strain for DSA and PLC band varies irregularly, but the numbers of serrations and bands increase. For Fe-(20 to 24)Mn-(0.4 to 0.6)C TWIP steel with grain size of about 10 to 20 μm, the twinning-induced work hardening rate is about 2.5 to 3.0 GPa, while the DSA-dominant hardening rate is about 2.0 GPa on average. With increasing engineering strain from 0.01 to 0.55 at an applied strain rate of 0.001s?1, the cycle time for PLC bands in Fe-Mn-C TWIP steel increases from 6.5 to 162 seconds, while the band velocity decreases from 4.5 to 0.5 mm s?1, and the band strain increases from 0.005 to 0.08. Increasing applied strain rate leads to a linear increase of band velocity despite composition differences. In addition, the influence of the Mn and C content on the tensile properties of Fe-Mn-C TWIP steel has been also studied. As C content increases, the yield strength and tensile strength of Fe-Mn-C TWIP steel increase, but the total elongation variation against C content is dependent on Mn content. As Mn content increases, the yield strength and tensile strength decrease, while the total elongation increases, despite C content. Taking both tensile properties and serrated flow behavior into consideration, Fe-22Mn-0.4C TWIP steel shows excellent mechanical performance with a high product of tensile strength and total elongation and a slightly serrated stress–strain response. To suppress the negative effect of DSA in Fe-Mn-C TWIP steels on the stability of tensile behavior, a TOI lower than 0.1 is strongly suggested. 相似文献
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研究了室温拉伸时应变速率对高氮奥氏体不锈钢18%Cr-18%Mn-0.65%N力学性能和塑性流变行为的影响。结果表明,随应变速率的升高,试验钢的屈服强度Rp0.2升高,而抗拉强度Rm及塑性略有降低;在各应变速率下,试验钢的塑性流变行为均可以用Ludwigson模型进行描述;应变速率的升高对试验钢流变方程参数的影响如下:1)强度系数K1、应变硬化指数n1和n2减小,试验钢的加工硬化能力降低;2)真实屈服强度TYS降低;3)瞬变应变εL减小,表明升高应变速率能够促进位错多系滑移和交滑移。 相似文献
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Chongthairungruang Bunyong Uthaisangsuk Vitoon Suranuntchai Surasak Jirathearanat Suwat 《钢铁研究学报(英文版)》2011,(Z1):855-861
In sheet metal forming process of automotive components,the springback effect is significant,in particular for Advanced High Strength Steels (AHSS),for example the Dual Phase (DP) steel.Most of construction parts of modern vehicles have very complex shapes and therefore multi-step procedures are necessary to form such a part.Steel sheets,which firstly undergo pre-deformation,can show considerable change in mechanical behavior during the forming process.However,at present there are limited sufficient data concerning pre-deformation effect on the springback available.In this work,a study of influences of different pre-strain levels on the springback of steel sheet made of AHSS materials has been carried out.The sheet specimens were firstly pre-stretched on a tensile testing machine and the pre-strain values were calculated based on the engineering strain.Furthermore,the steel sheets prepared parallel,transverse,and 45° to the rolling direction have been investigated.A modified U-shape forming was used to evaluate the degree of springback of the steel sheets under various conditions.In parallel,FE simulation of the U-shape forming was performed.Both isotropic model using stress-strain responses from tensile test of specimens with different directions and anisotropic Hill’s 48 model have been applied.The experimental results are compared with the sheet metal forming FE simulations.The primarily aim is to basically understand the springback mechanism by means of the simple models.And finally,conclusions with regard to the springback modeling will be presented. 相似文献
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《钢铁研究学报(英文版)》2011,(Z1):851-854
Quenching and Partitioning (Q&P) steel is a new type ultrahigh strength steel with transformation induced plasticity (TRIP) effect. Uniaxial tensile experiments of the Q&P steel at room temperature were carried out to investigate the effects of sampling angle and strain rate on its mechanical properties. Experimental results show that the flow stress-strain curve, the hardening component n, the anisotropy coefficient through thickness r and the elongation of the Q&P steel are not sensitive to the sampling angle. However, the hardening component n and the elongation of the Q&P steel decrease with increasing the strain rate. Due to the Q&P steel with TRIP effect, when the strain rate greater, the deformation work will transform to the internal energy of specimen, and the TRIP effect of the Q&P steel will be inhibited, which results in less transformed retained austenite. X ray diffraction experiments were performed to verify it. 相似文献