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根据钢管冷斜轧过程的变形特点,建立了辊型设计系统。把辊型设计的结果作为初始参数,由刚塑性有限元分析成型过程,将速度场、应变和应力反馈到辊型设计系统,调整辊型设计的初始参数,绘制出适应钢管冷斜轧工艺要求辊型图。 相似文献
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为研究不同轧辊转速、送进角、轧辊人口锥角等工艺参数对大VI径厚壁P92钢管二辊斜轧延伸过程分层缺陷形成倾向性的影响,借助于商用有限元软件MSC.SuperForm,对不同工艺条件下大口径厚壁P92钢管二辊斜轧延伸过程进行了三维热力耦合模拟;采用Oyane韧性断裂准则分析了轧件损伤场及钢管分层缺陷的倾向性。研究结果表明:钢管内表邻近顶头接触区存在破裂高危带,轧件最大损伤特征值随轧辊转速的降低、送进角和轧辊入口锥角的增大而减小,发生分层缺陷的倾向性降低。此研究为揭示钢管分层缺陷形成机制,确定缺陷发生的敏感工况,制定防止或减轻分层缺陷的有效措施提供科学依据。 相似文献
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斜轧穿孔是无缝管生产中穿孔工艺的主要生产方法。穿孔质量与效率的好坏直接影响着轧制钢管的产品质量。本文就三辊穿孔过程中顶头前伸量的变化,用刚塑性有限元方法对其进行分析。在理论上分析了前伸量对变形的变化关系。 相似文献
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摘要:针对60Si2CrVAT超高强度弹簧钢实际冷卷成形工况,采用准静态拉伸试验和不同微观表征手段研究了经Q&T (Quenching&Tempering)和Q-I-Q-T(Quenching-Isthothermal Quenching-Tempering)工艺热处理后试验钢的组织形貌及冷变形前后力学性能的差异,并利用Deform-3D有限元数值模拟软件分析了2种工艺参数下的弹簧钢在冷卷成形过程中的应力、应变等场量参数的变化特征,预测了其冷卷成形过程中的断裂损伤概率。结果表明,Q-I-Q-T工艺复相组织弹簧钢的塑性更好,冷变形后的断面收缩率和伸长率比Q&T工艺马氏体中温回火组织弹簧钢分别高出了65%和66%。模拟结果显示,不同组织状态下的超高强度弹簧钢在卷制过程中的等效应力和等效应变分布规律近似,但Q-I-Q-T工艺复相组织弹簧钢在卷制过程中产生的等效应力和等效应变值更小,产生断裂的概率更低。 相似文献
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采用斜轧穿孔工艺生产大口径P92铁素体耐热无缝钢管过程中,钢管内表面易产生细小裂纹。通过金相分析、高温相变计算和高温加热试验等研究表明,内表面裂纹产生的主要原因是:中心有通孔的P92管坯在坯料加热过程中,由于加热温度过高和在炉时间过长(即表面氧化脱碳加重),导致管坯通孔近内壁产生大量的高温δ-铁素体相,管坯在随后的斜轧穿孔中,裂纹在塑性较差的高温δ-铁素体处产生和扩展。根据内表面裂纹的产生机制,通过对P92钢管化学成分的铬当量、镍当量按Creq<13%、Nieq>4%进行控制,坯料保温温度由原工艺的1220~1250℃降为1190~1220℃,对穿孔机轧辊转速、辊距和顶伸量参数优化等工艺改进措施,有效地解决了大口径P92无缝钢管内表面易产生裂纹的问题,提高了P92无缝钢管的成材率和生产效率。 相似文献
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从滑动机理、应变状态、金属的流动特点等方面研究分析了采用斜轧工艺生产白口铸铁球状体的形成机理,指出了采用该工艺生产白口球状体容易出现分层和贴皮缺陷,为研究该领域的技术人员提供了理论依据. 相似文献
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从减少钢管在斜轧变形过程中的反向扭转次数出发,研究了辊型对扭转的影响以及斜轧穿孔机和斜轧延伸机轧辊旋转方向的合理配置。研究结果对轧机设计、车间平面布置和提高产品质量有重要意义 相似文献
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针对现有普通链式拉拔设备条件下生产冷拔精密无缝钢管的工艺流程,分析了在该流程条件下的生产控制工艺,包括模具设计、退火、酸洗、润滑条件等控制要求,同时分析了该流程存在的热轧毛管供给困难、退火设施落后、拔制质量不稳定、生产成本高、环保压力大等诸多问题,指出了冷拔精密无缝钢管工艺控制的局限性。 相似文献
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Ming-gui QU Shu-hua SUN Xing-hong BAI Zhong-ping SHI Yang GAO Wan-tang FU 《钢铁研究学报(英文版)》2014,21(1):60-68
The hot deformation behavior of as-cast AISI M2high-speed steel containing mischmetal(RE)has been investigated on a Gleeble-3500simulator in the temperature range of 1 000-1 150℃and strain rate range of 0.01-10 s-1 at true strain of 1.0.The mechanical behavior has been characterized using stress-strain curve analysis,kinetic analysis,processing maps,etc.Metallographic investigation was performed to evaluate the mechanism of flow instability.The results show that the deformation activation energy decreases with increasing deformation temperature; the efficiency of power dissipation increases with decreasing strain rate and increasing temperature;flow instability is observed at low-to-medium temperature and higher strain rate region when the strain is smaller,but extends to lower strain rate and high temperature regions with the increment of strain,in which it is manifested as flow localization near the grain boundary.Hot deformation equations and processing maps are obtained.The optimal processing window is suggested and the deformation mechanism is dynamic recrystallization(DRX). 相似文献
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M. Preethi B. S. Murty S. Ganesh Sundara Raman R. Natarajan 《Transactions of the Indian Institute of Metals》2014,67(5):681-690
The present study is made to develop ultra fine grained microstructure in welded steel tubes, through multiple cold drawing passes followed by an annealing treatment. The average ferrite grain size is reduced from 16 to 1.9 μm. SAE 1019M steel grade used for a typical automotive driveline component is studied. Strains between 0.3 and 1.4 followed by annealing at 400, 450 and 500 °C are considered to optimize the combination of cold drawing strain and temperature required to produce ultra fine grained microstructure in steel tubes. At a strain value of 1.4 and annealing temperature, 500 °C, polygonal ferrite grains and fine carbide particles are obtained. This microstructure is found to be suitable owing to its combination of high strength and good ductility in steel tubes. Tensile strength as high as 1,061 MPa and 9 % elongation is obtained due to microstructural refinement. The strength is increased by 350 MPa compared to the strength of conventional cold-drawn welded tubes. 相似文献
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Dipen Kumar Rajak Nikhil N. Mahajan Senthil Kumaran Selvaraj 《Transactions of the Indian Institute of Metals》2020,73(3):587-594
Aluminium (Al) alloy foam is an engineering material which has emerged in the automobile sector where crash energy absorption, vibration and sound damping and weight reduction are required. Al-alloy foam is a lightweight material providing high strength and stiffness at relatively low density. The paper aims to study the innovative approach of manufacturing AlSi10Mg foam. The low-density and high-strength Al-alloy foam (AlSi10Mg) is fabricated using the melt route process resulting in a density of 0.70–0.90 g/cm3. After that, square mild steel thin-walled empty tubes and Al-alloy foam-filled mild steel tubes are tested to study enhanced energy absorption characteristics. The tests are carried out on universal testing machine with strain rate 10/s. Al-alloy foam, AlSi10Mg, is assessed macroscopically and microscopically using field emission scanning electron microscope and energy-dispersive X-ray analysis. The experimental results indicate that foam-filled tubes feature more energy absorption than empty tubes at strain rate 10/s. 相似文献
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通过高温压缩试验研究齿轮钢SAE8620H在950~1100℃、应变速率0.01~10 s-1条件下的高温变形行为.该合金钢的流动应力符合稳态流变特征,流变应力随变形温度升高以及应变速率降低而减小,其本构方程可以采用双曲正弦方程来描述.基于峰值应力、应变速率和温度相关数据推导出SAE8620H高温变形激活能Q=280359.9 J·mol-1.根据变形量40%和60%下应力构建该齿轮钢的热加工图,通过热加工图中耗散值及流变失稳区确定其热变形工艺参数范围.SAE8620H钢在在变形程度较小时宜选取低的应变速率进行成形,而在变形程度大时则要选取低温低应变速率或者高温高应变速率. 相似文献
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摘要:采用ThermecmastorZ热模拟试验机研究了EH40船板钢在850~1050℃,0.005~10s-1条件下的热变形行为,通过动态材料模型得到该区域的热变形与变形抗力方程并建立了EH40船板钢热加工图。结果表明,EH40船板钢的变形抗力模型的预测值与试验值吻合良好,EH40船板钢的热变形激活能为324.479kJ/mol,由热加工图确立出EH40船板钢最优的热加工窗口是应变不高于0.4,温度在850~1050℃,应变速率为小于10s-1的加工区域,较易发生动态再结晶。 相似文献