共查询到16条相似文献,搜索用时 140 毫秒
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摘要:对比研究了锻态0.15C5Mn钢和0.15C5Mn2Al钢在室温下和750℃准静态拉伸条件下的力学性能,并对微观组织利用SEM和EBSD进行表征。研究结果表明,Al的加入引起了室温下的微观组织结构的不同,含铝钢在室温下的组织中存在很少量铁素体,导致含铝钢强度低;锻态0.15C5Mn钢和0.15C5Mn2Al钢在750℃下分别获得了90.5%和101%的伸长率;经750℃拉伸变形后0.15C5Mn钢获得马氏体组织,Al元素的添加扩大了双相区,使0.15C5Mn2Al钢在双相区拉伸变形,最终得到铁素体+马氏体双相组织,双相区变形使0.15C5Mn2Al钢具有较高的伸长率,降低了抗拉强度。 相似文献
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两相区退火处理含铝中锰钢的组织和力学性能 总被引:1,自引:0,他引:1
为了研究两相区退火处理对冷轧含铝中锰钢(0.2C-0.6Si-5Mn-1.2Al)(质量分数,%)微观组织和力学性能的影响规律,利用SEM、XRD及单轴拉伸等试验方法表征了不同工艺状态后的微观组织及测试了拉伸性能。结果表明,冷轧试验钢在退火过程中组织发生奥氏体逆转变,在退火温度为670 ℃、退火时间为10 min时可获得较佳的力学性能,即抗拉强度达到1 276 MPa,总伸长率达到51.8%,强塑积高达66.1 GPa·%。随着退火温度升高,残余奥氏体组织逐渐粗化且向马氏体组织转变,机械稳定性逐渐降低。残余奥氏体机械稳定性主要受残余奥氏体中碳质量分数及其晶粒尺寸的影响,而残余奥氏体中锰质量分数对其影响较小。 相似文献
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在本钢薄板坯连铸连轧生产线上进行了X00管线钢的试制。结果表明,成分为铌、钒、钛复合微合金化的低碳锰钢采用合适的控轧控冷工艺,可以保证钢的力学性能符合x60管线钢的要求。试制钢具有优良的强度和塑性配合,并具有很好的低温韧性水平。试制钢的显微组织为铁素体和珠光体,平均晶粒尺寸细小,铁素体、珠光体分布均匀,没有明显带状组织。 相似文献
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摘要:分别通过SEM、XRD、单轴拉伸试验和FLD等方法对比研究了中锰钢(MMnS780钢)与DP780钢的微观组织、力学性能及成形极限。结果表明,DP780钢获得铁素体和马氏体双相组织,具有连续屈服及较大的加工硬化能力,而MMnS780钢由细小的铁素体和奥氏体构成,具有明显屈服、相对较小的加工硬化能力和较大的均匀伸长率;不同应变状态下MMnS780钢较DP780钢具有更高的极限应变。退火组织以及细小的晶粒尺寸使MMnS780钢产生明显的屈服现象,细小组织以及亚稳奥氏体的TRIP效应使其具有较高的塑性和成形性能。 相似文献
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Dong-Woo Suh Seong-Jun Park Tae-Ho Lee Chang-Seok Oh Sung-Joon Kim 《Metallurgical and Materials Transactions A》2010,41(2):397-408
Microstructural design with an Al addition is suggested for low-carbon, manganese transformation-induced-plasticity (Mn TRIP)
steel for application in the continuous-annealing process. With an Al content of 1 mass pct, the competition between the recrystallization
of the cold-rolled microstructure and the austenite formation cannot be avoided during intercritical annealing, and the recrystallization
of the deformed matrix does not proceed effectively. The addition of 3 mass pct Al, however, allows nearly complete recrystallization
of the deformed microstructure by providing a dual-phase cold-rolled structure consisting of ferrite and martensite and by
suppressing excessive austenite formation at a higher annealing temperature. An optimized annealing condition results in the
room-temperature stability of the intercritical austenite in Mn TRIP steel containing 3 mass pct Al, permitting persistent
transformation to martensite during tensile deformation. The alloy presents an excellent strength-ductility balance combining
a tensile strength of approximately 1 GPa with a total elongation over 25 pct, which is comparable to that of Mn TRIP steel
subjected to batch-type annealing. 相似文献
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Yulong Zhang Li Wang Kip O. Findley John G. Speer 《Metallurgical and Materials Transactions A》2017,48(5):2140-2149
With an aim to elucidate the influence of temperature and grain size on austenite stability, a commercial cold-rolled 7Mn steel was annealed at 893 K (620 °C) for times varying between 3 minutes and 96 hours to develop different grain sizes. The austenite fraction after 3 minutes was 34.7 vol pct, and at longer times was around 40 pct. An elongated microstructure was retained after shorter annealing times while other conditions exhibited equiaxed ferrite and austenite grains. All conditions exhibit similar temperature dependence of mechanical properties. With increasing test temperature, the yield and tensile strength decrease gradually, while the uniform and total elongation increase, followed by an abrupt drop in strength and ductility at 393 K (120 °C). The Olson–Cohen model was applied to fit the transformed austenite fractions for strained tensile samples, measured by means of XRD. The fit results indicate that the parameters α and β decrease with increasing test temperature, consistent with increased austenite stability. The 7Mn steels exhibit a distinct temperature dependence of the work hardening rate. Optimized austenite stability provides continuous work hardening in the temperature range of 298 K to 353 K (25 °C to 80 °C). The yield and tensile strengths have a strong dependence on grain size, although grain size variations have less effect on uniform and total elongation. 相似文献
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The effect of additions of Nb, Al and Mo to Fe‐C‐Mn‐Si TRIP steel on the final microstructure and mechanical properties after simulated thermomechanical processing (TMP) has been studied. The laboratory simulations of discontinuous cooling during TMP were performed using a hot rolling mill. All samples were characterised using optical microscopy and image analysis. The volume fraction of retained austenite was ascertained using a heat tinting technique and X‐ray diffraction measurements. Room temperature mechanical properties were determined by a tensile test. From this a comprehensive understanding of the structural aspect of the bainite transformation in these types of TRIP steels has been developed. The results have shown that the final microstructures of thermomechanically processed TRIP steels comprise ~ 50 % of polygonal ferrite, 7 ‐12 % of retained austenite, non‐carbide bainitic structure and martensite. All steels exhibited a good combination of ultimate tensile strength and total elongation. The microstructure‐property examination revealed the relationship between the composition of TRIP steels and their mechanical properties. It has been shown that the addition of Mo to the C‐Si‐Mn‐Nb TRIP steel increases the ultimate tensile strength up to 1020 MPa. The stability of the retained austenite of the Nb‐Mo steel was degraded, which led to a decrease in the elongation (24 %). The results have demonstrated that the addition of Al to C‐Si‐Mn‐Nb steel leads to a good combination of strength (~ 940 MPa) and elongation (~ 30 %) due to the formation of refined acicular ferrite and granular bainite structure with ~7 ‐ 8 % of stable retained austenite. Furthermore, it has been found that the addition of Al increases the volume fraction of bainitic ferrite laths. The investigations have shown an interesting result that, in the Nb‐Mo‐Al steel, Al has a more pronounced effect on the microstructure in comparison with Mo. It has been found that the bainitic structure of the Nb‐Mo‐Al steel appears to be more granular than in the Nb‐Mo steel. Moreover, the volume fraction of the retained austenite increased (12 %) with decreasing bainitic ferrite content. The results have demonstrated that this steel has the best mechanical properties (1100 MPa and 28 % elongation). It has been concluded that the combined effect of Nb, Mo, and Al addition on the dispersion of the bainite, martensite and retained austenite in the ferrite matrix and the morphology of these phases is different than effect of Nb, Mo and Al, separately. 相似文献
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Kim Sung-joon 《钢铁研究学报(英文版)》2011,(Z1):1004-1007
The effects of bainitic treatment on microstructure and mechanical properties of 0.10C-1.5Mn-l.5Al TRIP-aided cold-rolled steels have been investigated.The samples were heated by intercritical annealing at 820℃for 2 min and quenched in banitic temperature with different hoding time for 5 to 300s,two salt bath were used for the heat treatment.Experimental results show that the yield strength and elongation increase with the increasing of bainitic holding time,while the tensile strength decrease.The volume fraction of retained austenite rise at the beginning of bainitic holding and then reduce,the carbon content of retained austenite increase during the bainitic holding.The tensile strengthen multiply elongation reaches the highest value at 120s.The mechanical stability of retained austenite fits well with strain hardening during deformation. 相似文献
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Ultrahigh carbon (UHC) steels have been investigated for their strength and ductility characteristics from 600 to 850°C. It
has been shown that such UHC steels, in the carbon range 1.3 to 1.9 pct C, are superplastic when the microstructure consisted
of fine equiaxed ferrite or austenite grains (∼1 μm) stabilized by fine spheroidized cementite particles. The flow stress-strain-rate
relations obtained at various temperatures can be quantitatively described by the additive contributions of grain boundary
(superplastic) creep and slip (lattice diffusion controlled) creep. It is predicted that superplastic characteristics should
be observed at normal forming rates for the UHC steels if the grain size can be stabilized at 0.4 μm. The UHC steels were
found to be readily rolled or forged at high strain-rates in the warm and hot range of temperatures even in the as-cast, coarse
grained, condition.
BRUNO WALSER, formerly with Department of Materials Science and Engineering, Stanford University 相似文献