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基于胀弯成形的高强度钢板回弹特性实验与分析 总被引:1,自引:0,他引:1
高强度钢板是汽车车身结构件广泛应用的材料之一,对比普通碳钢,高强度钢板具有较高的强度、较高的屈强比、较低的延伸率等,使用过程中容易产生开裂、起皱和回弹等缺陷,特别是回弹问题严重影响了零件的尺寸精度。文章以胀弯成形为基础,通过MTS试验机进行成形实验,研究了低合金高强钢B410LA、双相钢DP500在不同冲压参数、模具几何参数等条件下成形后的回弹影响规律,并通过显著性分析得出,胀弯角度对侧壁卷曲的影响不显著,拉延筋凸筋的位置对冲压回弹有较大的影响。 相似文献
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高强钢材料性能对汽车零件扭曲回弹的影响 总被引:2,自引:0,他引:2
高强度钢板材料冲压性能的波动对冲压成形后零件精度的影响较大,主要表现在成形性能不稳定和回弹波动较大。文章侧重材料性能波动对冲压件扭曲回弹的影响,结合某汽车车身高强钢零件的冲压结果,借助有限元仿真工具,比较实验与仿真结果,在结果基本一致的基础上,研究高强度钢板的屈服强度、应变硬化指数、摩擦系数及板料厚度波动对该零件扭曲回弹影响规律。应用科学实验设计方法,考察了主要因素的影响规律,得到高强钢材料性能参数影响板料扭曲回弹的相关结论,从降低回弹波动及扭曲对制造精度的影响出发,提出了材料性能参数优化选取原则。 相似文献
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高强度钢是汽车轻量化的主要材料,但钢板强度高到一定程度时传统的冷成形技术无法再满足生产需求。随着热成形技术的应用,汽车高强度钢得到了长足的发展。本文立足于汽车的轻量化理念,介绍了热成形技术的研究现状,以及热成形技术在先进高强度钢中的应用与发展。 相似文献
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高强度钢后保险杠成形工艺优化及回弹控制 总被引:2,自引:1,他引:1
采用高强度钢板制造的保险杠能大大提高乘员安全性,但高强度钢板成形困难。采用有限元分析软件Dynaform对某轿车高强度钢后保险杠成形过程进行模拟仿真,并使用结果优化成形工艺。主要研究了工艺补充面对零件冲压成形以及回弹的影响。通过模拟结果和实际样件对比,对工艺补充部分进行了调整,并设置凸顶得到了优化的工艺型面及坯料尺寸,为同类相关高强度钢零件的生产起到了指导作用。 相似文献
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《锻压技术》2019,(12)
基于自行设计制造的回弹实验模具,针对帽形件进行了大量的实验研究与分析,比较了HC420LA、HC420/780DP和QP980这3种不同性能的高强度钢板在不同U形弯曲成形的冲压工艺及不同成形状态下的回弹规律,为实际生产和设计提供理论指导。结果表明:任一冲压工艺下,HC420LA钢的回弹都远小于HC420/780DP钢与QP980钢;帽形件侧壁回弹在自由弯曲成形工艺下最小,法兰边回弹在中间预压料弯曲成形工艺下最小,而带压边力弯曲工艺下的回弹始终最大;随料厚的增加,3种高强度钢板的回弹不断减小,但料厚为1.4 mm的QP980钢进行中间预压料弯曲成形时,回弹呈反向增大的趋势;3种高强钢板的回弹随凸凹模间隙的增大而增大,180~280 kN压边力区间对HC420/780DP钢和QP980钢影响较小,而板料法兰边回弹随弯曲角度的增大而增大。 相似文献
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在高强度钢板冲压成形过程中,常常因为显著的回弹和面畸变导致形状和尺寸精度出现问题.利用数值模拟方法分析了超高强度钢门槛板的成形,根据模拟结果提出了利用设置拉延筋控制高强度板冲压回弹的方法,制定了合理的门槛板冲压模具的拉延筋设置方案.实际生产验证了该方法对回弹控制的有效性. 相似文献
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Robert B. Ruokolainen David R. Sigler 《Journal of Materials Engineering and Performance》2008,17(3):330-339
Laminated steel has been implemented in vehicle structures by several automotive manufacturers to reduce in-cabin noise.
This study provides an understanding of how the adhesion between the steel skin and the viscoelastic polymer core affects
laminate formability. Material properties, including peel strength, shear strength, and tensile strength were determined.
The presence of the viscoelastic core was found to slightly reduce tensile properties of the laminate compared to the skin
sheet. Forming limit diagrams were also determined. These indicated that the viscoelastic core properties can significantly
affect formability of laminated steel compared to that of solid steel sheet. In general, the formability of laminated steel
was found to be similar to or less than that of the much thinner skin sheet material, which indicates that its formability
should be less than that of solid steel of the same gauge.
This article was presented at Materials Science & Technology 2007, Automotive and Ground Vehicles symposium held September
16-20, 2007, in Detroit, MI. 相似文献
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The increasing use of high strength steels in a variety of mechanical engineering applications has illuminated problems associated with galling in sheet metal forming operations. Galling is a tribological phenomenon associated with transfer of material from the steel sheet to the tool surface during forming resulting in seizure of the tool/steel sheet contact and extensive scratching of the steel sheet surface. As a result, a number of concepts have been developed in order to reduce the tendency of galling in sheet metal forming, including the development of new dry lubricants, new forming tool steel grades and improved surface engineering treatments such as the deposition of low friction CVD- and PVD-coatings. In the present study the potential performance of three commercial PVD coatings, including CrN, (Ti,Al)N and a CrC/C DLC-based coating, in the forming of hot and cold rolled high strength steel as well as electro and hot-dip galvanized high strength steel has been evaluated using pin-on-disc testing under lubricated contact conditions. Post-test examination of the tribosurfaces using FEG-SEM and EDS analyses was performed in order to evaluate the mechanisms controlling the tendency to material transfer and wear. The results show that in contact with the hot and cold rolled steel the material pick-up tendency of the PVD coatings tend to increase in the order CrC/C-CrN-(Ti,Al)N while in contact with the two galvanized steel sheets, the CrC/C and the (Ti,Al)N coating show a significantly lower material pick-up tendency as compared with the CrN coating. Further, the substrate hardness has a strong influence on the wear of the PVD coatings and consequently on the friction characteristics and galling tendency of the coating/substrate composite. Low substrate hardness, resulting in a low load bearing capacity, increases the tendency to cracking and subsequently chipping of the brittle coating. 相似文献
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设计开发了Cr-Mo-Nb-Ti-B系1180 MPa级高强复相钢产品。从组织控制的角度引入了贝氏体,以弥补铁素体与马氏体之间的软硬相高强度差,采用Gleeble-3500热模拟试验机、拉伸试验机和光学显微镜研究连续退火工艺中均热温度和过时效温度对复相钢力学性能及组织的影响规律。结果表明,均热温度在720~840 ℃时,随着温度的升高,贝氏体和马氏体含量逐渐增加,抗拉强度和屈服强度整体上不断提升,但超过840 ℃后抗拉和屈服强度降低。而随过时效温度的升高,抗拉强度呈单调递减趋势,屈服强度先波动后逐渐降低。当均热温度为790 ℃、过时效温度为280 ℃时,连退板的组织为铁素体、贝氏体和马氏体的复相组织,复相钢具备良好的加工成形性,折弯性、扩孔性能也均较同级别双相钢产品有大幅提升。 相似文献
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Warm and Hot Stamping of Ultra High Tensile Strength Steel Sheets Using Resistance Heating 总被引:5,自引:0,他引:5
A warm and hot stamping process of ultra high tensile strength steel sheets using resistance heating was developed to improve springback and formability. In this process, the decrease in temperature of the sheet before the forming is prevented by directly heating the sheets set into the dies by means of the electrical resistance, the so-called Joule heat. Since the heating time up to 800°C is only 2 seconds, the resistance heating is rapid enough to synchronise with a press. The effects of the heating temperature on the springback and formability of ultra high tensile strength steel sheets were examined. The springback in hat-shaped bending of the high tensile strength steel sheets was eliminated by heating the sheet. In addition, the ultra sheet having a tensile strength of 980MPa was successfully drawn by the heating. The heating temperature is optimum around 600°C due to the small springback and oxidation and the increase in hardness. 相似文献
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采用C-Si-Mn-Nb-Ti-Cr-Mo合金成分体系,全流程控制关键生产工艺参数,研发出具有良好塑性和成形性的800 MPa级冷轧低合金高强钢。结果表明,试验钢的显微组织由铁素体、马氏体和少量贝氏体组成,铁素体基体中有弥散分布的第二相粒子和碳化物沉淀相。试验钢的屈服强度在800 MPa以上,断后伸长率大于10.5%,抗拉强度和屈服强度相差小于35 MPa,扩孔率在56.5%以上,180°冷弯角度下弯曲无可见裂纹,表现出良好的成形性能。 相似文献
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Pedram Samadian Mohammad Habibi Parsa Amid Shakeri 《Journal of Materials Engineering and Performance》2014,23(4):1138-1145
High strength steels are desirable materials for use in automobile bodies in order to reduce vehicle weight and increase the safety of car passengers, but steel grades with high strength commonly show poor formability. Recently, steels with controlled microstructures and compositions are used to gain adequate strength after hot stamping while maintaining good formability during processing. In this study, microstructure evolutions and changes in mechanical properties of AISI 4140 steel sheets resulting from the hot stamping process at different austenitization temperatures were investigated. To determine the proper austenitization temperatures, the results were compared with those of the cold-worked and cold-worked plus quench-tempered specimens. Comparisons showed that the austenitization temperatures of 1000 and 1100 °C are proper for hot stamping of 3-mm-thick AISI 4140 steel sheets due to the resultant martensitic microstructure which led to the yield and ultimate tensile strength of 1.3 and 2.1 GPa, respectively. Such conditions resulted in more favorable simultaneous strength and elongation than those of hot-stamped conventional boron steels. 相似文献
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Effect of normal anisotropy on springback 总被引:1,自引:0,他引:1
Share of high and advanced high strength steels in automobile is increasing, however, such steels generally have poor formability and high amount of springback. One of the focus areas of research in high strength automotive steel is to increase the normal anisotropy to get better formability. Effect of strength and process parameters on springback has been studied by many researchers but that of anisotropy has not been studied by many. In the present work the effect of anisotropy on springback is predicted using finite element analysis for the benchmark problem of Numisheet-2005 [2005 Numisheet Benchmark 2, Springback prediction of a cross member, Proceedings of the 6th International Conference and Workshop on Numerical Simulation of 3D Sheet Metal Forming Processes, Detroit, USA, August 15–19, 2005]. An analytical model is developed to cross check the trends predicted from the finite element analysis. The effective stress has not been treated as a constant and the radial stress is considered in the present model. Both the models (FE and analytical) predict that higher anisotropy, in general, gives higher springback. Finite element analysis of the problem shows that springback is minimum for an isotropic material. 相似文献
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《Science & Technology of Welding & Joining》2013,18(1):52-61
AbstractApplications of advanced high strength steels in tailor welded blanks are a major focus to reduce vehicle weight and manufacturing cost, and to improve part performance. In the present work, formability of two types of laser welded steels in biaxial stretch forming has been studied. Laser welded blanks of the dual phase steel showed larger reduction of formability than those of high strength low alloy steel. This was due to formation of soft zones in the outer heat affected zone of dual phase steel where strain localisation and fracture occurred. Finite element simulations of dome testing incorporating local weld zone properties were able to accurately predict experimentally observed behaviour including deformation patterns and failure locations. In particular, the simulations have shown that under matching of the softened heat affected zone leads to reduced formability by localisation of strain; and that the fracture location changes from radial to circumferential plane when the flow curve of soft zone is evenly matched with the base metal. It was also concluded that the width of the soft zone has minor influence on formability during biaxial stretch forming. 相似文献