共查询到19条相似文献,搜索用时 180 毫秒
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通过对热镀纯锌、电镀纯锌、预磷化电镀纯锌和热镀锌铁4种钢板去锌前后力学性能的对比研究,定量分析了锌层对镀锌钢板力学性能指标的影响规律。在此基础上探讨了镀锌钢板冲压成形的变形机理,结果显示:与电镀纯锌、预磷化电镀纯锌和热镀纯锌镀层相比,锌铁合金镀层的延展性较差,变形过程中镀层和基板之间的不协调显著降低了钢板的整体成形性能。 相似文献
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热镀锌铁合金钢板冲压成形过程表面特性研究 总被引:1,自引:0,他引:1
热镀锌铁合金钢板在冲压过程中经常出现锌层的粉化和剥落等质量缺陷,加大了质量控制的难度.本文分析了不同预变形条件下热镀锌铁合金镀层的表面形貌和断面金相的演化,同时研究了正压力对摩擦系数的影响.结果表明:锌铁合金层镀层裂纹的萌生和发展是导致锌层粉化的根本原因.随着正压力的增大,锌铁合金钢板的摩擦系数明显降低,但当压力较大时降幅明显放缓. 相似文献
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利用板材成形试验机和网格应变自动测量分析系统对热镀锌钢板进行了成形极限试验和性能分析。结果表明,锌层对热镀锌钢板胀形变形有恶化作用,应将溶去锌层后的热镀锌钢板成形曲线FLC降低至25%,来保证足够的安全域度。单向拉伸性能中应变硬化指数n值与成形性能具有较强的相关性。n值愈大,FLC越高,板料的冲压成形性能越好。结合成形极限图分析了热镀锌钢板在实际冲压成形过程中的应变区域、变形模式及安全域度。为热镀锌钢板成形性能研究提供参考。 相似文献
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通过宏观单向拉伸实验和断口微观组织观察,研究分析了镀锌层对G550高强度镀锌薄板力学性能的影响,实验中所使用的试样厚度t分别为0.28,0.39,0.45和0.58mm,镀层厚度均为50μm左右。结果表明:这种镀锌板在去除镀锌层前后力学性能变化较为明显,尤其是屈服极限、抗拉极限、塑性应变比r、硬化指数n和伸长率δ变化较为明显,而杨氏模量E和泊松比μ几乎无变化;这种镀锌板的屈服极限和抗拉极限均高于裸板,而塑性应变比r、硬化指数n和伸长率δ均小于裸板;相比较于裸板,这种镀锌板的成形性能有一定的下降,后续成形工艺的设计需要考虑镀锌层的存在。 相似文献
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J. L. Milián 《Journal of Materials Engineering and Performance》1992,1(2):275-283
Although sheet formability depends significantly on the properties of the base metal, surface coatings used for corrosion
protection can affect the friction at the tool/sheet interface and, therefore, influence the amount of deformation. In an
effort to better understand the effects of surface coatings on formability, limiting dome height testing was done on samples
of drawing- quality aluminum- killed sheet steel with laboratory- produced electrodeposited zinc coatings of different characteristics.
The results showed that the formability of zinc- coated products was reduced compared to the uncoated steel in all strain
states. It was also shown that zinc coating crystallographic texture strongly influences sheet forming behavior and may be
as important a parameter as surface roughness in friction characterization.
The material in this article is intended for general information only. Any use of this material in relation to any specific
application should be based on independent examination and verification of its unrestricted availability for such use and
a determination of suitability for the application by professionally qualified personnel. No license under any USX Corporation
patents or other proprietary interest is implied by the publication of this paper. Those making use of or relying upon the
material assume all risks and liability arising from such use or reliance. 相似文献
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Formability of an anti-fingerprint clear coating on satin stainless steel sheet metal 总被引:1,自引:1,他引:0
Since several years the application of stainless steel sheet metal with anti-fingerprint coating increases in the household appliance industry. These imperceptible clear coatings improve the cleaning characteristics. In essence, they reduce the adhesion and visibility of fingerprints on satin stainless steel surfaces. The thickness of these coatings amounts to a few micrometers. They are applied by the stainless steel manufacturer in a coil coating process. The curing procedure by ultraviolet radiation and the nanoparticle reinforced coating system cause a high hardness and a good scratch resistance. The final painted sheets are further processed e.g. to covering parts. The final processor does not spend any effort on varnishing or curing on-site. During forming operations a damage of the clear coating in the form of crack formation and delamination can be observed. This paper deals with experimental analyses for the identification and quantification of the deformation-induced damages to the coating considering different states of stress. On the basis of the results a coating-specific forming limit curve is defined, that can be used in forming simulations to forecast the occurrence of inacceptable coating damages. The validation of the forming limit curve of the coating is demonstrated in an exemplary comparison of a finite-element-method simulation and the coating damages of a real drawn part. 相似文献
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圆角半径的确定一直是冲压件工艺设计的关键技术,本文采用实验与理论模型相结合的手段,研究了凸模圆角半径对钢板冲压成形的影响。结果表明:冲压成形中的开裂位置和凸模圆角大小有关;圆角处的减薄率基本上与相对圆角半径R/t成反比;极限成形高度随凸模圆角半径的增大而增大。 相似文献
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Two simulative forming tests for assessing the adhesion of metallic coatings on sheet steel, the double reverse Olsen adhesion test and a new test, the stretch-draw adhesion test, are contrasted. The strain states, the nature of the test results, and the responses of various hot dip galvanized and electroplated zinc and zinc alloy coatings are compared. The quantitative mass loss measurements of both tests are shown to have greater relevance than the qualitative visual rating system most commonly used with the double reverse Olsen test. Both tests effectively differentiate good and poor adhesion of alloy coatings. Only small amounts of zinc coatings are lost in both tests. The double reverse Olsen test is easier to perform but represents a sequence of strain states seldom encountered in actual stamping operations. 相似文献
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目的分析连续电镀锌生产线进行纳米镍技术改造的效果,以期进一步提高锌层的表面质量。方法应用模拟重力法高速电镀锌设备在IF钢(无间隙原子钢)表面进行纳米镍试验,探讨纳米镍对钢基板擦划伤部位的修复效果及机理,分析纳米镍时间对电镀锌层形貌和取向的影响。结果纳米镍优先沉积在基板的缺陷位置,对基板擦伤位置具有良好的填充作用,且镍层与基板结合良好。随着纳米镍时间的延长,锌层的结晶尺寸减小,结晶状态趋于致密,(002)基面织构系数明显增加。结论纳米镍技术嵌入连续电镀锌生产线,对修复基板缺陷、优化锌层结晶起到了良好的作用。 相似文献
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Forming limits of nickel coating on right region 总被引:1,自引:0,他引:1
The forming limits of nickel coating on the right region were studied, so as to direct the preparation of the material and help the production of workpieces. The electrodeposited nickel coating was prepared on steel substrate to form advanced structures, and its plastic instability was investigated by the Swift Plastic Instability Theory. By using the compound law for laminated sheet metals, explicit equations for the calculation of the instable eigen values were deduced. The forming limit diagrams of the nickel coating on the right region were plotted. It is exhibited that the forming limit of the coating sheet is between the forming limits of the individual nickel coating and steel substrate. The forming limit of the nickel coating is not so good as that of the steel substrate, and the forming limit strain of the coating sheet tends to diminish with the increase of thickness of the coating. The greater the normal anisotropic coefficient of the materials is, the better the forming limit is. 相似文献
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R. Srinivasan D. Vasudevan Palani Padmanabhan 《Journal of Materials Engineering and Performance》2012,21(7):1188-1192
This article deals with bend force behavior of electro-galvanized (EG) steel sheets in air bending process. A detailed experimental study was carried out on EG steel sheets of various coating thicknesses to investigate the influence of parameters such as coating thickness, orientation of the sheet, punch radius, die opening, die radius, and punch velocity on bend force behavior. From the results, it is found that zinc coating reduces the bend force and the increase in coating thickness reduces the bend force significantly. It is observed that the bend force is larger for larger punch radius, smaller die opening, and smaller die radius. It is also observed that the bend force is larger for 0° orientation than for 90° orientation. The bend force decreases with increase in punch velocity, and this influence is more prevailing in EG sheets than in plain sheets. 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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The punch load and strain distribution of two deformed sheet steels, aluminum killed drawing quality steel (AKDQ Bare) and
electro-galvanized drawing quality steel (AKDQ E.G.), are examined under the various process conditions including, die materials,
punch speed, blank holding force, drawbead height and lubricant. The punch load and strain distribution ot Bare sheet steel
forming is higher than that of E.G.sheet steel on the Kirkesite die set and are reversed on the GM 241 die set. The punch
load and strain distribution on the Kirkesite die set is lower than those of the GM 241 die set. The changes of punch load
and strain distribution ot the deformed cup for two sheet steels are affected by the frictional behavior of each sheet steel.
It shows that the changes of frictional behavior having to be considered in the die design. 相似文献