共查询到20条相似文献,搜索用时 171 毫秒
1.
2.
The controlled cooling technology following hot rolling process is a vital factor that affects the final microstructure and mechanical properties of the hot-rolled transformation induced plasticity (TRIP) steels. In the present study, low alloy C-Si-Mn TRIP steel was successfully fabricated by hot rolling process with a 450 hot rolling mill. To maximize the volume fraction and stability of retained austenite of the steel, two different cooling methods (air-cooling and ultra-fast cooling “AC-UFC” and ultra-fast cooling, air-cooling and ultra-fast cooling “UFC-AC-UFC”) were conducted. The effects of the cooling method on the microstructure of hot-rolled TRIP steel were investigated via optical microscope, transmission electron microscope and conversion electron Mssbauer spectroscope. The mechanical properties of the steel were also evaluated by conventional tensile test. The results indicated that ferrite and bainite in the microstructure were refined with the cooling method of UFC-AC-UFC. The morphology of retained austenite was also changed from small islands distributing in bainite district (obtained with AC-UFC) to granular shape locating at the triple junction of the ferrite grain boundaries (obtained with UFC-AC-UFC). As a result, the TRIP steel with a content of retained austenite of 1152%, total elongation of 32% and product of tensile strength and total elongation of 27552 MPa·% was obtained. 相似文献
3.
Austempering of Hot Rolled SiMn TRIP Steels 总被引:2,自引:1,他引:1
The austempering after hot rolling in hot rolled Si Mn TRIP (transformation induced plasticity) steels was investigated. The mechanism of TRIP was discussed through examination of the microstructure and the mechanical properties of this kind of steel. The results showed that the strain induced transformation to martensite of retained austenite occurs in hot rolled Si Mn TRIP steels. The sample exhibited a good combination of ultimate tensile strength and total elongation when it was held at the bainite transformation temperature after hot deformation. The stability of retained austenite increases with an increase in isothermal holding time, and a further increase in the holding duration resulted in the decrease of stability. The mechanical properties were optimal when holding for 25 min, and tensile strength and total elongation reached the maximum values (774 MPa and 33%, respectively). 相似文献
4.
介绍了热轧TRIP钢TMP(形变热处理)的精轧阶段(奥氏体未再结晶区变形)、输送台冷却(γ-α两相区的相变)和卷取阶段(贝氏体转变)热轧TRIP钢组织演变的影响因素;冷轧TRIP钢临界区(γ-α区)退火和贝氏体转变区等温处理时的组织演变及其演变过程中TRIP钢残余奥氏体中碳的富集的研究进展。 相似文献
5.
借助MMS-300热模拟试验机研究了控轧温度区间、终冷温度、贝氏体区等温处理以及冷却路径对微合金化热轧TRIP钢组织演变规律的影响。结果表明,随着控轧温度区间“下调”,组织中的铁素体晶粒越来越细小,铁素体量逐渐增加,残余奥氏体量则先增加后减少。终冷温度升高时,组织中的残余奥氏体量也呈现出先增加后减少的变化趋势,而贝氏体温度范围等温时间的延长使残余奥氏体量增加。相对于“缓冷+快冷”,轧后采用“快冷+缓冷+超快冷”冷却路径更有助于铁素体晶粒的细化和奥氏体的残留。在“快冷+缓冷+超快冷”冷却路径下,当控轧温度区间为900~840℃,缓冷温度范围为710~680℃,贝氏体等温处理制度为450℃×5min时,组织中的残余奥氏体量达到最高值113%。 相似文献
6.
The effect of thermomechanical control processing(TMCP)on microstructure and mechanical properties of Fe-0.2C-1.44Si-1.32Mn hot rolled TRIP steel was investigated through experiments.Strain-induced transformation and transformation-induced plasticity behavior of retained austenite were analyzed.The results show that with multipass deformation,reduction per pass of more than critical deformation in austenite recrystallization region and total reduction of more than 58% in non-recrystallization region and high temperature section of two-phase region,austenite can be refined before γ→α transformation.It is beneficial to obtain refined ferrite grain in final microstructure.To obtain fine and uniform microstructure and excellent strength-ductility balance,a three-stage cooling process(laminar cooling-air cooling-ultra-fast cooling)after hot rolling was conducted.The ultimate tensile strength and elongation of the investigated steel can reach 663 MPa and 41%,respectively. 相似文献
7.
8.
9.
10.
热轧带钢新一代TMCP技术以超快速冷却为核心,通过冷却系统从空冷至超快冷的无级调控,利用广阔 的冷速范围及精准的温度控制,实现对带钢轧后冷却路径进行灵活的控制。有利于细晶强化、析出强化、固溶强 化、位错强化、相变强化的最佳匹配,从而使得热轧带钢产品获得优良的综合性能。新一代TMCP工艺技术具备低 成本、高效率、高均匀性、高控制精度等特征,是轧制工艺发展的重要领域之一。随着人们对带钢产品性能要求的 不断提高以及资源的日益枯竭,以超快速冷却为核心的热轧带钢新一代TMCP技术具有广阔的发展前景。 相似文献
11.
YIN Qi- long YANG Geng- wei ZHAO Gang MAO Xin- ping WANG Shui- ze LIU Yang 《钢铁研究学报》2018,30(9):754-762
The continuous cooling transformation behavior of hot rolled TRIP 600 steel produced by CSP process was investigated by means of Thermecmastor- Z thermal simulation testing machine, Formastor- F full automatic transformation instrument, OM, SEM and microhardness tester. The dynamic and static continuous cooling transformation (CCT) curves of the experimental steel were obtained. And the effect of deformation on phase transformation behavior was discussed. The results show that the temperature of austenite to ferrite and the volume fraction of ferrite gradually decrease with the increase of cooling rate. The transformation temperature range of the pro- eutectoid ferrite is 480-716??. Meanwhile, the transformation temperature range of pearlite is 519-647??, and the volume fraction of pearlite 相似文献
12.
LI Zhuang 《钢铁研究学报(英文版)》2009,16(3):43-48
Thermomechanical controlled processing (TMCP) of low carbon cold heading steel in different austenite conditions were conducted by a laboratory hot rolling mill.Effect of various processing parameters on the mechanical properties of the steel was investigated.The results showed that the mechanical properties of the low carbon cold heading steel could be significantly improved by TMCP without heat treatment.The improvement of mechanical properties can be attributed mainly to the ferrite grain refinement due to low temperature rolling.In the experiments the better ultimate tensile strength and ductility are obtained by lowering finishing cooling temperature within the temperature range from 650 ℃ to 550 ℃ since the interlamellar space in pearlite colonies become smaller.Good mechanical properties can be obtained in a proper austenite condition and thermomechanical processing parameter.The ferrite morphology has a more pronounced effect on the mechanical behavior than refinement of the microstructure.It is possible to realize the replacement of medium-carbon by low-carbon for 490 Mpa grade cold heading steel with TMCP. 相似文献
13.
Dongsheng Liu F. Fazeli M. Militzer W.J. Poole 《Metallurgical and Materials Transactions A》2007,38(4):894-909
14.
Warm deformation tests were performed using a kind of tubby heater. The microstructures and mechanical properties of an Fe-C-Mn-Si multiphase steel resulting from different warm deformation temperatures were investigated by using LOM (light optical microscopy), SEM and XRD. The results indicated that the microstructure containing polygonal ferrite, granular bainite and a significant amount of the stable retained austenite can be obtained through hot deformation and subsequent austempering. Warm deformation temperature affects the mechanical properties of the hot rolled TRIP steels. Ultimate tensile strength balance reached maximum (881 MPa) when the specimen was deformed at 250 ℃, and the total elongation and strength-ductility reached maximum (38% and 28614 MPa·%, respectively) at deforming temperature of 100 ℃. Martensite could nucleate when austenite was deformed above Ms, because mechanical driving force compensates the decrease of chemical driving force. The TRIP effect occurs in the Fe-C-Mn-Si multiphase steel at deforming temperature ranging from 15 to 350 ℃. The results of the effects of warm deformation on the mechanical properties of the Fe-C-Mn-Si multiphase steel can provide theoretical basis for the applications and the warm working of the hot rolled TRIP sheet steels in industrial manufacturing. 相似文献
15.
利用OM、SEM、XRD、EBSD和室温拉伸试验机等研究了CSP热轧TRIP钢中间缓冷时间及贝氏体等温时间对组织和力学性能的影响。结果表明,随着中间缓冷时间的延长,试验钢中的铁素体和残余奥氏体体积分数增加,贝氏体体积分数减少;抗拉强度基本不变,屈服强度逐渐降低,断后伸长率和强塑积变化不明显。中间缓冷时间为6 s时,可满足CSP产线的要求。对贝氏体相变时间的研究表明,当等温时间为15 min时,试验钢中的残余奥氏体主要分布于铁素体/铁素体界面、铁素体/贝氏体界面以及贝氏体中,体积分数约为7.1%,表现出良好的TRIP效应。其抗拉强度、屈服强度、断后伸长率和强塑积分别达到744.0 MPa、522.5 MPa、29.3%和21.8 GPa·%,力学性能最优。当等温时间延长至50 min时,试验钢中的贝氏体含量增加,残余奥氏体体积分数减少至2.7%,强塑积明显下降。 相似文献
16.
17.
18.
A hot-rolled and controlled rolled 16MnCr5 steel was analyzed after similar industrial cooling conditions. The hot rolled steel had a ferrite–bainite microstructure whereas the controlled rolled steel had a ferrite–pearlite microstructure. The prior austenite grain size was found to be the controlling factor based on a cooling analysis. The effect of prior austenite grain size on the bainite start temperature had to be considered in the transformation model. 相似文献
19.
The microstructure characteristics and mechanical properties of a low-silicon TRIP steel containing phosphorus and vanadium at different finish rolling temperatures were studied by laboratory hot rolling experiments. Different ratios of multiphase microstructure (ferrite, granular bainite and retained austenite) are obtained. With a decrease in finish rolling temperature, the volume fractions of ferrite and retained austenite increase. EBSD analysis reveals that most of the ferrite grains are fine, and decreasing of finish rolling temperature leads to an increase in low angle boundaries. Under the joint effects of fine grain strengthening, dislocation strengthening and precipitation strengthening, higher strength is obtained. When the finish rolling temperature is decreased to 800 ℃, the steel has excellent mechanical properties: Rp02=470 MPa; Rm=960 MPa; Rp02/Rm=049; A50=197%; n=025. 相似文献
20.
Textures and Properties of Hot Rolled High Strength Ti-IF Steels 总被引:1,自引:0,他引:1
The texture evolution in a high strength Ti-IF steel during the processing of hot rolling, cold rolling, and annealing is studied. For comparison, both ferrite rolling and austenite rolling are employed. It is found that the texture type is the. same after ferrite rolling and austenite rolling, but the texture intensity is much higher in the ferrite rolled sample. Furthermore, texture characteristics at the surface are absolutely different from those at the mid sec tion in both ferrite rolled and austenite rolled samples, as well as under the cold rolled and annealed conditions. The shear texture { 110 } 〈001 〉 disappears and orientation rotates along { 110 } 〈001 〉→ { 554 } 〈 225 〉→ { 111 } 〈 112 〉→{111}〈110〉→{223}〈110〉 during cold rolling. Compared to the austenite rolled sample, the properties of the cold rolled and annealed sheet which is subjected to ferrite rolling are higher. 相似文献