L.J. Zhu
金属学报(英文版)
Because Si is a noncarbide forming element, a multiphase microstructure consisting of ferrite, bainite, and retained austenite, at room temperature, can be formed by controlling the thermomechanical process strictly. The cooling schedules must be restricted by the formation of pearlite and cementite. In the present article, a new integrated mathematical model for prediction of microstructure evolution during controlled rolling and controlled cooling is developed for a typical kind of low carbon Si-Mn TRIP steel, which consists of temperature simulation, recrystallization, and transformation models. The influence of Si contents has been thoroughly investigated. The calculated results indicate that Si retards recrystallization, restrains austenite grain growth as well as accelerates polygonal ferrite transformation.
关键词:
TRIP steel
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null
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null
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null
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null
Xiaodong WANG
,
Baoxu HUANG
,
Yonghua RONG
,
Li WANG
,
null
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null
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null
,
null
材料科学技术（英文）
Transformation induced plasticity (TRIP) steels combine high strength and excellent ductility, making them suited for application in crash-relevant parts in the automotive industry. However, the high Si contents in the conventional TRIP steel will generate surface defects on the hot rolled strip, which is difficult to process in continuous galvanizing lines. In order to solve the above problem the TRIP steel with the addition of Al replacing majority of Si was designed. In the present paper, the volume fraction of various phases in a C-Mn-Si-Al-Cr TRIP steel was determined by metallographic examination and X-ray diffraction analysis, and the multi-phase microstructures were characterized using an atomic force microscope based on their height difference. Tensile tests were performed at different temperatures ranging from -40℃ to 90℃. The results show that transition temperature MSσ in the present TRIP steel cannot be determined due to its lower volume fraction of retained austenite, different from the conventional TRIP steel. While the yield stress and tensile strength at different temperatures are higher than those of the conventional TRIP steel, which is attributed to the addition of Cr. In order to evaluate the effect of martensitic transformation on the total elongation, the sample without retained austenite obtained by quenching in liquid nitrogen was carried out under tensile test. The results indicate that the elongation of the original sample containing 9% retained austenite is about 20% higher than that of the sample quenched in liquid nitrogen, which demonstrates that the retained austenite plays an important role in improving the elongation of the TRIP steel.
关键词:
TRIP steel
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steel
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mechanical
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properties
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retaine
Y. Chen
金属学报(英文版)
The effects of finishing rolling temperature and coiling temperature on retained austen-ire were studied for hot-rolled transformation induced plasticity (TRIP) steels withdifferent carbon content. The experimental results showed that an appropriate volumefraction of retained austenite from 6% to 11% could be obtained according to the dif-ferent carbon content less than 0.20% by controlled finishing rolling and coiling forthe hot-rolled TRIP steels. It can be concluded that carbon content has a significanteffect on the fraction of retained austenite and coiling processing plays stronger roleon retaining austenite than fishing rolling processing.
关键词:
TRIP steel
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null
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null
Y. Chen
,
X. Chen
,
Q.F. Wang
金属学报(英文版)
The systematic chemical compositions including common C, Si, Mn, Al, and micro- alloying elements of Ti and Nb were designed for high volume fraction of retained austenite as much as possible. The thermo-cycle experiments were conducted by using Gleeble 2000 thermo-dynamic test machine for finding the appropriate composition. The experimental results showed that chemical composition had a significant effect on retained austenite, and the appropriate compositions were determined for commercial production of TRIP steels.
关键词:
carbon content
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null
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null
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null
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null
Weiyan LÜ
,
Lin LI
,
Li WANG
,
Yanlin HE
,
Shuigen HUANG
材料科学技术（英文）
Phase diagram information of the Fe-C, Fe-Al and Al-C systems are reviewed and the Fe-Al-C system is assessed. A FeAlC database is created by combining a set of thermodynamic parameters established by Kumar and SSOL database in Thermo-Calc software package. Ternary phase diagrams are calculated with FeAlC and the newly developed Thermo-Calc databases SSOL2 and SSOL4. The FeAlC database is the best one to describe the Fe-Al-C system. A1 and A3 values on the vertical section containing 1.5 wt pct Al are calculated with the FeAlC database in this work. To validate the thermodynamic calculation, critical temperatures Ac1 and Ac3 are determined by using dilatometer analysis. There exist some errors between the calculated values and the experimental results. So further optimization of the Fe-Al-C system regarding bcc and fcc phases is necessary. The experimental data in this work could be of some value in further optimization.
关键词:
Fe-Al-C
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null
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null
赵征志
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尹鸿祥
,
赵爱民
,
左茂方
,
曾尚武
,
党宁
材料热处理学报
采用CCT-AY-Ⅱ型钢板连续退火机模拟分析了V元素添加对TRIP800钢组织性能的影响规律.采用SEM和TEM等微观分析方法观察含钒与不含钒TRIP的微观组织,利用XRD法测量了残留奥氏体量,实验室测量了其力学性能.结果表明,随着退火温度的升高,试验钢铁素体相比例降低,贝氏体相比例升高,且含钒TRIP钢中有V(C,N)析出.820℃保温时,试验钢均获得最佳的综合力学性能.V元素的添加增加了试验TRIP钢的抗拉强度,而降低了屈服强度,有效降低了TRIP钢屈强比.且含V TRIP钢瞬时加工硬化指数前期大于无V TRIP钢,后期则小于无V TRIP钢.
关键词:
TRIP钢
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亚稳奥氏体
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两相区退火
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加工硬化
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钒微合金化
