An Effect of Nonferromagnetic Gaps on the Magnetic Properties of Stacks of Steel Plates with Different Values of Magnetic Hardness: I. A Closed Circuit

Stacks of steel plates having different values of magnetic hardness and separated with nonferromagnetic gaps are investigated. The coercive force and the residual magnetic induction of a stack measured in a closed magnetic circuit depend on the layout of the plates in the stack and on the thickness of nonmagnetic gaps between them.__________Translated from Defektoskopiya, Vol. 41, No. 3, 2005, pp. 55–62.Original Russian Text Copyright © 2005 by Gorkunov, Mitropol’skaya, Povolotskaya.Dedicated to the Anniversary of the 100th Birthday of Corresponding Member of the Russian Academy of Sciences M. N. Mikheev     

Coercive Force of a Package of Steel Sheets with Different Degrees of Magnetic Hardness

Samples in the form of packages of steel plates with different degrees of magnetic hardness have been studied. Coercive forces of the composite samples with different contributions of harder materials and different orientations of plates with respect to one another in open and closed magnetic circuits have been calculated.     

球头铣削多硬度拼接淬硬钢的振动研究

研究了Cr12MoV淬硬钢单一硬度和多硬度拼接状态下的球头铣削振动规律,采用LMS Test.Lab软件对不同主轴转速及进给速度下的铣削振动信号进行时频域分析,获得了信号的时域特征及能量分布规律。实验和分析结果表明：振动信号的频谱由基波（刀齿通过频率）及其谐波组成,具有周期特性,在基波上出现最大幅值。在多硬度的过渡区,加速度信号峰值呈现阶跃变化。对比分析了单一硬度和多硬度拼接条件下铣削参数对加速度响应的影响规律,为铣削参数的优化和改善加工稳定性提供了依据。     

不同类型的贝氏体组织对低碳钢力学性能的影响

低碳贝氏体钢是高强度、高韧性、多用途的新型钢种,它的出现是社会需求和现代冶金技术发展的必然结果.目前,低碳贝氏体钢已经在工程机械上得到广泛应用.然而,实际生产中得到的低碳贝氏体钢并不是由单一贝氏体组织组成,往往是多种显微组织并存,因此并不能直接体现钢的力学性能与贝氏体组织之间的对应关系.针对这一情况,以低碳Mn-B-Cr-Mo-Nb钢为研究对象,在国内某钢铁公司进行控轧控冷试验.通过对终冷温度的控制,分别得到由全部粒状贝氏体,全部板条贝氏体以及粒状贝氏体+板条贝氏体组成的3种不同类型的低碳贝氏体钢.经过对这3种不同类型的贝氏体钢进行拉伸和冲击试验后发现:在化学成分相同的条件下,粒状贝氏体钢的强度最低,韧塑性最好;板条贝氏体钢板的强度最高,韧塑性最差:由粒状贝氏体+板条贝氏体组成的钢,其强度、韧塑性居中.由此可知,终冷温度对热轧钢板的显微组织和力学性能影响很大,通过对中温转变组织的控制,就可以进一步提高低碳贝氏体钢的综合力学性能.     

爱泼斯坦方圈测电工钢片直法流偏磁性能方法研究

为了克服传统爱泼斯坦方圈法中因电流表、电压表尤其是瓦特表的低准确性和频率特性而造成的低频段测试结果精度不够、高频段无法进行测试的不足,提出了采用数字示波器替代传统的电流电压表和瓦特表进行方圈试样动态磁特性以及铁损的测试,以达到提高方圈测试法低频准确性和最高测试频率的目的.同时采用在传统爱泼斯坦方圈上加绕偏置线圈产生直流偏置磁场的方法,用方圈测试法成功进行了电工钢片的直流偏磁特性测试.     

磁场干涉对不同磁属性材料干摩擦学特性的影响

提出并比较系统地研究不同磁属性材料自、互配副在磁场干涉下的干摩擦学特性,定义磁场干涉因子的公式,分析材料磁性与磁场影响程度的关系。结果表明：总体上,磁场干涉下,材料的干摩擦学特性与其磁导率有一定的对应关系,受磁场的影响程度随磁导率的增大而增大;配副材料的磁导率相差太大时,不利于发挥磁场的耐磨减摩效果;由于受各材料化学性能(成分)、力学性能和导热性能不同以及选配的影响,具有明显的系统依赖性;随着磁场的增大,在磨损率方面,铁磁性材料的磨损率有减小的趋势,抗磁性材料的磨损率有增大的趋势;对于顺磁性材料,当与高磁导率的铁磁性材料配副时,磨损率有增大的趋势,而与抗磁性材料配副时,磨损率有略微减小的趋势;在摩擦因数方面,含铁磁性材料的摩擦副的摩擦因数有减小的趋势,含抗磁性材料又不含铁磁性材料的摩擦副的摩擦因数却有增大的趋势。通过对环试样磨损率的分析得出,试样装卡装置的磁性会对试验结果造成一定影响;通过作为环试样的抗磁性锌黄铜磨损率有降低的趋势得出,在抗磁性锌黄铜背面添置铁磁性材料,即可克服磁场对抗磁性材料耐磨性能有不利影响。     

The Effect of Steel Hardness on the Performance of ZDDP Antiwear Films: A Multi-Technique Approach

X-ray absorption near-edge structure (XANES) analysis has been used to characterize the chemistry of antiwear films formed in a mineral base oil containing a zinc dialkyl dithiophosphate (ZDDP) additive. These films were formed by rubbing the AISI 1095 steel samples under a reciprocating boundary contact. The steel samples were tempered to produce different Vickers hardness values. The phosphorus L-edge XANES spectra show that these films differ slightly in their chemical nature, with longer chain polyphosphates being formed on samples with higher hardness value. The surface morphology of the films was investigated using Atomic force microscopy (AFM) and the film thickness was probed by Focussed ion beam and Scanning electron microscopy (FIB/SEM) techniques. Furthermore, the nanomechanical properties of these antiwear films were investigated by nanoindentation methods. Tribological measurements of the coefficient of friction (μ) and wear scar width (WSW) indicate that the poorest antiwear film was formed on the softest substrate, which exhibited the largest WSW and the highest average μ. FIB/SEM images show that the thicknesses of the antiwear pads and the degree of damage on the substrates both change with the hardness value of the samples.     

Developing Techniques for Testing Magnetic Properties of Electric Steels. II. Variations in Magnetic Properties and Their Effect on Reliability of Testing Results (review article)

The paper presents experimental data concerning the magnitude and character of variations in magnetic properties of electric steels (among a number of sheets, within one sheet, over the length and width of a roll, etc.). The paper also considers effects of variations in magnetic parameters of steel on the quality of fabricated components and reliability of measurements of steel parameters conducted in accordance with the existing State Standards by testing one selected sample cut from single sheets of a batch, or from the beginning or end of a roll on an Epstein's apparatus. The inhomogeneity of magnetic parameters is a natural consequence of the instability of the technological process of the steel manufacture on all its stages and on the stages of its transformation (chemical composition, smelting conditions in which slabs for rolling are produced, regimes of rolling and annealing, etc.), therefore these parameters usually obey the law of normal distribution. Feasibility of more efficient methods of steel testing designed to optimize and improve the reliability of testing results is discussed.     

激光焊接对镀锌平板力学性能及拉伸断口影响研究

采用光纤激光对海工装备中的镀锌平板进行焊接,对镀锌平板焊接接头母材区、热影响区、焊缝区的微观硬度进行测量,研究了焊接试样的拉伸性能和断口形貌。结果表明,激光焊接接头的强度和硬度均高于母材。焊缝区接头组织获得了低碳马氏体,因而接头硬度不及热影响区高。     

激光焊接对镀锌平板力学性能及拉伸断口影响研究

采用光纤激光对海工装备中的镀锌平板进行焊接,对镀锌平板焊接接头母材区、热影响区、焊缝区的微观硬度进行测量,研究了焊接试样的拉伸性能和断口形貌。结果表明,激光焊接接头的强度和硬度均高于母材。焊缝区接头组织获得了低碳马氏体,因而接头硬度不及热影响区高。     

不同纳米添加剂下GCr15/45钢自修复性能研究

利用高精度液压式往复试验机研究了纳米羟基磷酸钙、纳米二氧化钛、纳米氮化钛3种纳米添加剂润滑条件下GCr15/45钢对摩时的摩擦磨损性能,通过扫描电子显微镜和EDX能谱对磨斑进行了微观分析。结果表明:纳米润滑添加剂可以降低摩擦副摩擦因数和材料磨损量,表现出优良的抗磨损性能;3种纳米添加剂具有不同的自修复机制,其中纳米羟基磷酸钙和纳米二氧化钛的修复机制主要为铺展成膜自修复,而纳米氮化钛为铺展成膜自修复和原位摩擦化学自修复并存;纳米氮化钛的自修复效果最佳,纳米二氧化钛的自修复性能最差。     

退火工艺参数对冷轧无取向电工钢薄板显微组织和磁性能的影响

采用光学显微镜、扫描电镜、透射电镜、爱泼斯坦方圈等仪器系统研究了退火温度、退火时间及升温速率对冷轧无取向电工钢薄板组织及性能的影响。结果表明:可通过控制退火工艺参数使薄板发生回复和再结晶,获得一定临界尺寸的均匀粗晶从而提高电工钢的磁性能;在相同的试验条件下,升高退火温度和延长退火时间可提高电工钢的磁性能;退火温度对磁性能的影响大于退火时间的影响,并且随着升温速率的提高,电工钢的磁性能更加优异。     

MoDTC增强型磁性液体减摩性能试验研究

为提高磁性液体的减摩性能,在现有Fe3O4磁性液体的基础上,通过微量添加二烷基二硫代氨基甲酸钼（MoDTC）,制备一种MoDTC增强型磁性液体。对MoDTC增强型磁性液体微观粒子的结构、组成成分、磁性能进行测试分析,在不同载荷、速度条件下进行摩擦磨损试验,探究MoDTC含量对磁性液体摩擦磨损性能的影响。实验结果表明：MoDTC增强型磁性液体比铁磁性液体饱和磁化强度小,且剩磁几乎为0,具有较好的磁性能;在试验研究范围内,Fe3O4磁性液体润滑下的摩擦因数比油润滑低,MoDTC增强型磁性液体的摩擦因数低于Fe3O4磁性液体的摩擦因数,且MoDTC质量分数为6%时减摩效果较佳;当载荷在25~45 N范围内,MoDTC增强型磁性液体的摩擦因数先随载荷增大而减小,超过临界值30 N后,摩擦因数随载荷增大而增大。研究结果表明,磁性液体中加入适量的MoDTC具有较好的减摩性能,能在一定程度上改善磁性液体的润滑性能。     

细观组织对不同冷速下的GDL-1钢的力学性能的影响

对一种新型高强韧微变形钢(GDL-1)空冷和油淬后的力学性能进行了研究,探索了细观组织对力学性能的影响规律。结果表明,由于GDL-1空冷的显微组织以窄束状贝氏体加粒状贝氏体为主加少量马氏体,贝氏体组织中存在的超细化亚片条和亚单元尺寸,与残留奥氏体膜组合,使临界裂纹张开位移显著增大,从而获得优异的力学性能。     

The Effect of Magnetic Past History of an Article on the Result of Magnetic Inspection of Its Physical and Mechanical Properties upon Magnetization with an Open Magnetic Circuit (Limitations of Method Capabilities). II. Analytical Modeling

Based on the known analytical expressions describing magnetization processes of ferromagnetic materials and experimental results about the effect of a ferromagnetic body's preliminary magnetization on its residual magnetization, a procedure for calculating the maximum possible measurement error of the relative magnetization of a ferromagnetic body, which has been magnetized in a magnetic field of a given strength in an open magnetic circuit, has been suggested. The error is due to the uncontrolled preliminary magnetization of the body. The effects of the hard magnetic properties of a material, dimensions of specimens, and the strength of the magnetizing field on error have been estimated quantitatively. The applicability limits of the magnetic testing of physical and mechanical properties of articles without preliminary demagnetization have been determined.     

Effects of Additives on the Friction of Steel on Steel. II. Additive-Base Oil Interactions

The steel-on-steel friction characteristics imparted by an oil-additive blend depend on the combination of friction-modifying additive, oxidation inhibitor, and base oil used in the blend. Increased refining of mineral oils generally enhanced the friction modifier effectiveness. The results with synthetic fluids generally fell within the mineral oil range. Free-radical inhibitor-type oxidation inhibitors enhanced or reduced the effect of friction-modifying additives whereas peroxide decomposer-type oxidation inhibitors did not. The magnitude and direction of the base oil-inhibitor interaction effect varied markedly depending on which friction-modifying additive was used. The results suggest that limited base oil oxidation may be essential for additive response.     

氮、铬对铸态锰钢性能的影响

针对氮、铬对铸态锰钢性能的影响作了系统试验。结果表明：加入氮和铬得到了细化的奥氏体基体和弥散分布的团球状碳化物，显著提高了铸态锰钢的加工硬化能力，并使其具有足够的冲击韧性和良好的抗磨性能。     

Effect of Magnetic Hysteresis on Outputs of Magnetic-Modulation Transducers with Transverse Excitation. II: Phenomenological Approach to Calculations and Experimental Data

A phenomenological method has been developed for taking account of magnetic hysteresis in calculating amplitudes and phases of even harmonics of the output emf of magnetic-modulation transducers with transverse excitation at small amplitudes of input signals. The method has been tested in experiments.     

高超载比超载对Q345钢的疲劳性能的影响

采用Q345钢制作成紧凑拉伸试样,并在裂纹萌生后进行超载.通过疲劳裂纹扩展试验,研究高超载比超载对疲劳裂纹扩展速率的影响,分析其延寿机理.研究发现:较高的超载比使试样引入了残余压应力,使得有效应力强度因子降低至应力强度因子门槛值附近.可以降低疲劳裂纹扩展速率,抑制裂纹扩展,延长试样的疲劳寿命,通过此方法提高了含裂纹结构的使用寿命.