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正压力和滑动速度对镀锌钢板摩擦系数的影响 总被引:1,自引:0,他引:1
本文采用平板摩擦试验研究了正压力和滑动速度对热镀纯锌、电镀纯锌、预磷化电镀纯锌和热镀锌铁合金摩擦系数的影响.结果表明当滑动速度为1000mm/rmin、正压力处于1000N~4000N范围内,随着压力的增加所有镀锌钢板的摩擦系数明显降低,但压力较大时降幅明显放缓.由于预磷化层具有良好的润滑作用,预磷化电镀锌钢板的摩擦系数与滑动速度基本无关,且始终保持在较低数值.随着滑动速度的增加热镀纯锌、电镀纯锌和热镀锌铁合金的摩擦系数降低. 相似文献
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《塑性工程学报》2016,(2)
利用平板滑动摩擦实验研究了模具粗糙度、正压力以及滑动速度对合金化热镀锌板表面摩擦系数的影响规律,结合摩擦学理论对摩擦系数变化的原因进行深入的分析,采用光镜观察钢板摩擦后的截面形貌,对比不同实验条件下的锌层截面失效情况,进而验证摩擦系数变化规律的正确性。结果表明,模具粗糙度在0.4μm~1.2μm范围时,摩擦系数随着模具粗糙度的增加先减小后增大,模具粗糙度约0.8μm时最佳,此时锌层发生少量粉化失效;摩擦系数随着正压力增加而减小,在较高压力范围内减小的趋势变缓,随着正压力增加,锌层粉化与剥落失效加重;摩擦系数随着滑动速度增加而减小,当滑动速度增加到一定值时,摩擦系数减小的趋势变慢并趋于稳定,随着滑动速度增加,锌层粉化与剥落失效情况转好。 相似文献
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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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热镀锌合金化工艺对镀层表面摩擦特性的影响 总被引:3,自引:0,他引:3
采用SEM和AFM对不同合金化工艺的热镀锌合金化镀层断面结构和表面形貌进行观察和表征,并用摩擦系数仪测定了压力对不同工艺的镀层表面摩擦系数的影响,分析了合金化工艺和载荷对热镀锌合金化钢板(简称GA钢板)镀层表面摩擦特性的影响。结果表明,合金化时间为50 s时镀层表面的摩擦系数最大,此后随着合金化时间的延长镀层表面的摩擦系数基本保持不变;不同工艺的合金化镀层表面的相结构不同,当镀层表面以ζ相为主并伴有少量η相或以块状ζ相及致密的栅柱状δ相晶体为主时,镀层表面较平滑,表面没有出现明显的火山口状形貌时镀层表面的摩擦系数最小;随压应力的增加,镀层表面摩擦系数逐步增大,但是在较大压应力作用下,镀层表面摩擦系数的增幅明显降低。 相似文献
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用SEM和XRD观察和分析了铝含量和合金化时间不同的热镀锌合金化(GA)镀层的表面形貌和组织,用双杯突测量了GA镀层的抗粉化量。结果表明,锌液中铝含量小于0.16 mass%的热镀锌镀层合金化时,镀层表面的Ra值小于1.0μm,且镀层的粉化量小于30 mg/m2,满足汽车板的表面质量要求;此后随着锌液中铝含量的增加,GA镀层的粉化量迅速增加,说明GA镀层的抗粉化性能除与镀层中的铁含量有关外,还与镀层表面的粗糙度有关。锌液中铝含量为0.22 mass%热镀锌镀层合金化时,由于Fe2Al5Znx抑制层的抑制作用,镀层中的δ1k-相出现局部增多的现象,从而恶化了GA镀层的抗粉化性能。 相似文献
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1 INTRODUCTIONThephenomenonthattheinterfaceoftwospeci menscontactundertheeffectofmechanicloadisseeneverywhere[1] ,whilewhatistheact 相似文献
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C. Bonnet F. Valiorgue J. Rech C. Claudin H. Hamdi J.M. Bergheau P. Gilles 《International Journal of Machine Tools and Manufacture》2008,48(11):1211-1223
The characterization of frictional phenomena at the tool–chip-workpiece interface remains an issue. This paper aims to identify a friction model able to describe the friction coefficient at this interface during the dry cutting of an AISI316L austenitic stainless steel with TiN coated carbide tools. A new tribometer has been designed in order to reach relevant values of pressures, temperatures and sliding velocities. This set-up is based on a modified pin-on-ring system. Additionally, a numerical model simulating the frictional test has been associated in order to identify local phenomena around the spherical pin, from the standard macroscopic data provided by the experimental system. A range of cutting speeds and pressures have been investigated. It has been shown that the friction coefficient is mainly dependant on the sliding velocity, whereas the pressure has a secondary importance. Moreover, a new key parameter has been revealed, i.e. the average local sliding velocity at the contact. Finally, a new friction model has been identified based on this local sliding velocity. 相似文献
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Frictional behaviour in dry metal forming is studied with a developed tribometer using aluminium specimens and a DLC coated tool. The ratio of flattened area by smooth tool surface starts to increase sharply after the occurrence of bulk plastic deformation. As deformation proceeds, the contact pressure and frictional stress on the flattened area decrease by following Coulomb's law, because once flattened surface leaves the tool surface. A friction law with a constant friction coefficient at low pressure and the associated frictional stress at high pressure is proposed and confirmed. 相似文献
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The frictional behavior of the tool–chip interface has a significant role in the cutting mechanics. The frictional and normal forces, the contact length between the cutting tool and chip, the coefficient of friction and the stress distribution are the influential parameters. The behavior of the tool–chip interface in ultrasonic-vibration assisted cutting is different from conventional cutting and needs to be investigated. The ultrasonic-vibration assisted cutting has several advantages compared with conventional process. In the present study a frictional model has been developed for studying the above mentioned parameters and predicting the tool–chip behavior in ultrasonic-vibration assisted turning at different cutting speeds and vibration amplitudes. The results have been verified by experiments. 相似文献
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This paper deals with possible modifications of the frictional behaviour exhibited during the cutting process resulting from the influence of the most-commonly used heat isolating coatings deposited on a WC-Co carbide substrate. For this study, three- and four-layered coatings with intermediate Al2O3 ceramic layer and a monolayer TiAlN coating, which offer superior thermal protection of the carbide substrate, were examined. Orthogonal cutting tests were carried out by end-turning medium carbon steel and austenitic stainless steel workpieces. The experimental study was aimed at determining the fundamental frictional characteristics: dimensions of the tool-chip contact area, the friction force, the mean friction coefficient, the specific frictional energy and the corresponding thermal effects: the contact temperature and the frictional heat flux. Subsequently, results obtained for the mechanical, energy-based and thermal approaches to the frictional behaviour occurring in the carbide/ceramic coating-steel tribo-pairs were verified experimentally and the results obtained are discussed in detail. 相似文献
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F. Zemzemi J. Rech W. Ben Salem A. Dogui P. Kapsa 《Journal of Materials Processing Technology》2009,209(8):3978-3990
The characterization of frictional phenomena at the tool–chip–workpiece interface remains an issue. This paper aims to identify a friction model able to describe the friction coefficient at this interface during the dry cutting of a AISI4142 treated steel with TiN coated carbide tools. A new tribometer has been designed in order to reach relevant values of pressures, temperatures and sliding velocities. This set-up is based on a modified pin-on-ring system. Additionally a numerical model simulating the frictional test has been associated in order to identify local phenomena around the spherical pin, from the standard macroscopic data provided by the experimental system. A range of cutting speeds and pressures has been investigated. It has been shown that the friction coefficient is mainly dependant on the sliding velocity, whereas the pressure has a secondary importance. Moreover a new key parameter has been revealed, i.e. the average local sliding velocity at the contact. Finally a new friction model has been identified based on this local sliding velocity. 相似文献
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铝合金表面多弧离子镀TiN涂层的耐磨性能 总被引:1,自引:0,他引:1
采用多弧离子镀在ZL109铝合金表面进行了TiN涂层处理,并对涂层的载荷耐磨性进行了分析和讨论.结果表明,ZL109铝合金表面多弧离子镀TiN涂层后,其耐磨性得到明显提高.在1 N的载荷下,连续磨损90 min时,未镀膜试样的磨痕宽度几乎是TiN试样的2倍,镀有TiN膜试样的平均摩擦因数几乎是未镀样的50%.在2 N的载荷下,由磨痕的形貌和宽度随时间的变化可见,镀有TiN涂层的试样在磨损前期,主要以粘着磨损为主,在磨损后期以磨粒磨损为主. 相似文献