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《钢铁研究学报(英文版)》2011,(Z1):576-580
Ultra Fast Cooling is a new technology which used to control the hot-rolling strip cooling in recent years on the international developed.It can achieve fast and accurate temperature control in the hot-rolled strip production process to obtain corresponding transformation microstructure and ideal mechanical properties.This article describes the technical principle and layout of ultra fast cooling in hot-rolled as well as cooling features.Analysis the effect of front ultra fast cooling technology in C-Mn steel and obtained consequent on the industrial produced low-cost Q345 hot rolled steel in Panzhihua Iron and Steel. 相似文献
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The improvement of hole-expansion properties for medium carbon steels by ultra fast cooling (UFC) after hot strip rolling was investigated. It was found that finely dispersed spherical cementite could be formed after ultra fast cooling, coiling and annealing treatment. Tensile strength of the steel after annealing was measured to be about 440 MPa. During hole-expansion test, cracks were observed in the edge region around the punched hole because necking or cracking took place when tangential elongation exceeded the forming limit. Cracks were mainly formed by the coalescence of micro-voids. Fine and homogeneous microstructure comprised of ferrite and spheroidized cementite could increase elongation values of the tested sheets by suppressing the combination of the adjacent micro-voids, resulting in the improved hole-expansion property. 相似文献
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Xiao-lin CHEN Guo-dong WANG Yong TIAN Bing-xing WANG GuoYUAN Zhao-dong WANG 《钢铁研究学报(英文版)》2014,21(5):481-487
Taking the element specific-heat interpolation function into account,a one-dimensional(1-D)finite element temperature field model for the on-line control of the ultra fast cooling process was developed based on the heat transfer theory.This 1-D model was successfully implemented in one 4 300mm plate production line.To improve the calculation accuracy of this model,the temperature-dependent material properties inside an element were considered during the modeling process.Furthermore,in order to satisfy the real-time requirements of the on-line model,the variable bandwidth storage method and the Cholesky decomposition method were used in the programming to storage the data and carry out the numerical solution.The on-line application of the proposed model indicated that the deviation between the calculated cooling stop temperature and the measured one was less than±15℃. 相似文献
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通过实验室热轧机组的控轧控冷试验,研究了控轧控冷参数对超高强铁素体/贝氏体双相钢组织性能的影响。结果表明,采用不同温度终轧,轧后不同方式冷却,抗拉强度几乎都在1 000MPa以上,屈强比在0.54~0.62之间,伸长率在13%~17%之间。铁素体晶粒随终轧温度降低和冷却速度加快而细化;终冷温度降低,贝氏体量增多。经800℃终轧后层流冷却至560℃左右空冷,由于铁素体晶粒细化,组织中大量的粒状贝氏体、无碳化物贝氏体、少量的孪晶马氏体以及残余奥氏体的存在使抗拉强度达1 130MPa,伸长率达16%,强塑积达到18 080MPa.%的最高值。控轧控冷获得以铁素体/贝氏体双相组织为主并含有少量残余奥氏体+马氏体的复相组织,使试验钢具有了优异的力学性能。 相似文献
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The hot deformation behaviors and the microstructural evolution of plain C-Mn steels with similar contents of C and Si but different contents of Mn have been investigated by compressive processing using Gleeble-1500 mechanical simulator.Influence of Mn and hot deformation on continuous cooling transformation of steels has been studied.The experimental results showed that deformation in austenite region accelerated transformation process,and the extent is dependent on the hot deformation and cooling conditions.The hot deformation would promote transformation process,but the increase of transformation temperature is dependent on Mn contents.The results have also shown that the effect of deformation on ferrite transformation becomes more obvious with the increase of Mn content at relatively low cooling rate. 相似文献
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结合中厚板轧后超快速冷却的工业实践,以传热学为基础,利用有限元法开发了中厚板轧后超快速冷却过程的一维温度场模型。为了同时满足在线模型的精度和实时性要求,在建模过程中采用了逐层细分法对钢板的厚向进行表面密集、心部稀疏的离散化处理;在求解过程中采用了变步长模型对时间步长进行动态调整。将该模型应用于工业现场,获得了钢板在超快速冷却条件下的水冷温降曲线和瞬时温度分布。现场应用表明,钢板终冷温度的计算值与实测平均值吻合较好,两者的偏差在±15℃以内,满足了新一代TMCP工艺的生产需求。 相似文献
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控制冷却在板带材开发生产中的应用 总被引:3,自引:0,他引:3
概述了快速冷却及直接淬火在提高板带材性能及钢种开发方面的发展应用情况,并介绍了热轧带钢的新型控制冷却技术--超快速冷却(UFC).目前,UFC的冷却速率已超过300 ℃/s.UFC技术能明显提高带钢的强度和韧性、改善材质性能.还描述了UFC装置的应用实例及在开发超级钢、多相高强钢、相变诱导塑性钢等高附加值钢铁材料方面的应用潜力.随着先进钢铁材料开发的需要,新的控制冷却技术已由传统的对轧后开冷、终冷温度的控制向基于连续冷却转变CCT曲线的相变要求而对板带整个冷却过程的微观组织相变控制方向发展. 相似文献
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Nucleation Behavior Analysis of Intragranular Acicu-lar Ferrite in a Ti-killed C-Mn Steel 总被引:1,自引:0,他引:1
By using a Gleeble 3500Dthermo-mechanical simulator,the nucleation behavior of intragranular acicular ferrites(IAF)was studied in a Ti-killed C-Mn steel.During continuous cooling transformation,the allotriomorphic ferrite(AF)and ferrite side plate(FSP)microstructures grew more rapidly with the temperature decreasing from800to 650℃,and the IAF microstructure was dominant within austenite grain with further cooling to 600℃.The diffusion bonding experiment and the effect of C,Mn and Si concentrations on the Ae3temperature by thermodynamic calculation confirm that Ti2O3itself absorbs neighboring Mn atoms to form Mn-depleted zone(MDZ),which promotes the nucleation of IAF microstructure effectively.High temperature holding tests indicate that the nucleation potential of IAF microstructure was lowered in the Ti-killed C-Mn steel when it was treated at high temperature(1 250℃)for a longer time,which is attributed to the saturated absorption degree of Mn atoms by titanium oxide. 相似文献
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热带钢超快速冷却条件下的对流换热系数研究 总被引:4,自引:0,他引:4
建立了热带钢超快速冷却过程的导热微分方程,采用有限差分方法计算了薄带钢实现超快速冷却(对于4 mm以下的薄带钢,冷却速率可达300℃/s)所需的带钢表面对流换热系数.同时,在实验室条件下采用厚度为20 mm的钢板进行了超快速冷却试验,得到了超快速冷却条件下的带钢表面对流换热系数与冷却水流量的关系.结果表明,在一定水流量范围内随着冷却水量的增加,带钢表面换热系数逐渐增加;采用所确定的换热系数对不同厚度钢板得到的温降曲线与实测值吻合较好,具有较高的精度. 相似文献
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利用热模拟技术研究了超高强度船板钢形变后控冷过程中相变行为.结果表明:随着冷速的提高,实验钢相变点Fs,Ff,Bf逐渐降低,而Bs是先升后降,仅从5 ℃/s以后才随冷速提高而降低.在冷速小于5℃/s时,其室温组织为F P B,而大于5℃/s时,其室温组织为F B(或F B M). 相似文献
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Controlled Rolling and Controlled Cooling Technology of Ultra-High Strength Steel with 700 Mpa Grade 总被引:1,自引:0,他引:1
With Gleeble-1500 system, the influences of rolling temperature, finishing tempera ture and cooling rate on the mechanical properties of two ultra-high strength steels were analyzed. The microstructure of the hot rolled specimens was observed by optical microscope, TEM and SEM. The TRIP of HSLA steels was studied. The results show that the yield stress of 700 MPa can be reached for two steels. The controlled rolling and controlled cooling technology has different effects on two sleds, but it is rational to adopt finishing temperature 800℃ for both of them. The microstructure of the steels is mainly bainite, and the influence factors ofmechanical properties are the size of bainite, and the size, distribution, composition and morphology of secondary phases. The deformation of high molybdenum steels at a high temperature with a high cooling rate would promote TRIP. 相似文献