Force Parameter Model of 3-Roll Mills for Continuous Cold Rolling Wires

Based on experimental data, the mathematical model of rolling force parameters of 3-roll mills was studied. The structure ofthe model was theoretically set up and the coefficients were determined by static analysis of the data. The torque in continuous rollingwas measured, and the characteristics and efficiency of 3-roll mills are investigated.

Fin formation model during pre-roll ploughing of copper 3D outside fin tube

The mechanism of pre roll ploughing for 3D fins on the outside surface of copper tube was studied systematically, and especially the process and conditions of 3D fin formation were analyzed. The right mathematical model was also established. Based on the volume of fin ploughed out is equal to the volume of the metal extruded up by the extruding face of the tool, the relations between fin height, pre roll ploughing feed and pre roll ploughing depth have been achieved. With the increase of pre roll ploughing depth which must be equal to groove depth, the fin height gradually becomes larger. There are different critical feeds with the various depths of pre roll ploughing. The pre roll ploughing feed is the critical one, the height of fin is largest. And when the feed is above the critical one, the fin height will reduce with the increase of feed. The theoretical analysis basically accords with experimental results.

Elastoplastic 3D Deformation and Stress Analysis of Strip Rolling

An elastoplastic method for analyzing the 3D deformation, stress and transverse distribution of tension stress during cold strip rolling is developed. The analysis is based on the elastoplastic variational principle in which a kinematically admissible velocity field is constructed with the lateral flow function as an unknown function. The stress distribution and volume strain distribution are obtained by solving the simultaneous equations formed by the longitudinal differential equation of equilibrium and constitutive equations. The lateral flow function is determined by minimizing the total energy dissipation rate. Experimental investigation was carried out on a reversible cold mill. The front tension stress distributions in cold rolled strips were measured by a multi roll segmented tension sensing shapemeter. The calculated results are in good agreement with the measured ones.

3D FE Analysis of Thermal Behavior of Billet in Rod and Wire Hot Continuous Rolling Process

An FE model was developed to study thermal behavior during the rod and wire hot continuous rolling process. The FE code MSC. Marc was used in the simulation using implicit static arithmetic. The whole rolling process of 30 passes was separated and simulated with several continuous 3D elastic-plastic FE models. A rigid pushing body and a data transfer technique were introduced into this model. The on-line experiments were conducted on 304 stainless steel and GCr15 steel hot continuous rolling process to prove the results of simulation by implicit static FEM. The results show that the temperature results of finite element simulations are in good agreement with experiments, which indicate that the FE model developed in this study is effective and efficient.

Simulation of Hot Strip-Rolling Process Based on Dislocation Density Variation

Flatness and profile are important quality indexes of strip. Combining the influence function method to solve the elastic deformation of roll system with the variational method to solve the lateral flow of metal, the flatness and profile of the strip during cold continuous rolling were simulated. The B 3 spline function was used to analogize the lateral distribution of strip thickness. The transverse distributions of the exit thickness and the front tension stress for each pass were obtained. Compared with the measured results, it is proved that using the spline function to analogize the lateral distribution of strip thickness can improve the calculation accuracy of flatness and profile largely.

Rolling Texture in Ti_3Al

The orientation changes and deformation behaviours of a Ti_3Al-based alloy was investigated by using micro-structure obervalion, pole figure and ODF analysis, as well as Chemical micro-analysis. A {0001} fibretexture an0d a weak {1210} <1010> texture were found after 35% cold rolling at room temlierature. The activation process of slip systems was discussed concerning formation of the rolling texture. Because of the low ductility of the material it is believed that the grains were deformed by simple glide suggested by Sachs.

Environmental Embrittlement and Preferred Orientation of Cold-Rolled and Annealed Fe_3 (Al,Cr,Zr) Alloy at Ambient Temperature

The room temperature tensile properties of cold rolled and annealed Fe 3(Al,Cr,Zr) alloy are similar to those of warm rolled Fe 3Al alloys. The cold rolled Fe 3(Al,Cr,Zr) alloy is also susceptible to test environments. It has been shown that the ductility in various environments decreases in sequence of oxygen—oil—air—distilled water. The results of X ray diffraction analysis show that (211) preferred orientation of B 2 phase appears in cold rolled Fe 3(Al,Cr,Zr) alloy after recrystallization annealing.

Robust adaptive polarization analysis method for eliminating ground roll in 3C land seismics

To improve the data quality of converted waves, and better identify and suppress the strong ground-roll interference in three-component （3C） seismic recordings on land, we present an adaptive polarization filtering method, which can effectively separate the ground- roll interference by combining complex polarization and instantaneous polarization analysis. The ground roll noise is characterized by elliptical plane polarization, strong energy, low apparent velocity, and low frequency. After low-pass filtering of the 3C data input within a given time-window of the ground roll, the complex covariance matrix is decomposed using the sliding time window with overlapping data and length that depends on the dominant ground-roll frequency. The ground-roll model is established using the main eigenvectors, and the ground roll is detected and identified using the instantaneous polarization area attributes and average energy constraints of the ground-roll zone. Finally, the ground roll is subtracted. The threshold of the method is stable and easy to select, and offers good ground- roll detection. The method is a robust polarization filtering method. Model calculations and actual data indicate that the method can effectively identify and attenuate ground roll while preserving the effective signals.

A fatigue life prediction method of rolling bearing under elliptical contact elastohydrodynamic lubrication

In order to more accurately predict the contact fatigue life of rolling bearing, a prediction method of fatigue life of rolling bearing is proposed based on elastohydrodynamic lubrication （EHL）, the 3-paameter Weibull distribution ad fatigue strength. First,the contact stress considering elliptical EHL is obtained by mapping film pressure onto the Hertz zone. Then,the basic strength model of rolling bearing based on the 3-parameter Weibull distribution is deduced by the series connection reliability theory. Considering the effect of the type of stress, variation of shape and fuctuation of load, the mathematical models of the 尸 -tS-TV curve of the minimum life and the characteristic life for rolling bearing are established, respectively, and thus the prediction model of fatigue life of rolling bearing based on the 3-paameter Weibull distribution and fatigue strength is further deduced. Finally, the contact fatigue life obtained by the proposed method ad the latest international standard （IS0281： 2007） about the fatigue life prediction of rolling bearing are compared with those obtained by the statistical method. Results show that the proposed prediction method is effective and its relative error is smaier than that of the latest international standard （IS0281： 2007） with reliability R 〉 0. 93.

SIMULATION OF 3-D DEFORMATION AND MATERIAL FLOW DURING ROLL FORGING PROCESS USING SYSTEM OF OVAL-ROUND GROOVE

Basing on the analysis of the traits of the roll forging process, a system-model of computer simulation has been established. Three-dimensional rigid-plastic FEM has been used for the simulation of the deformation process in the oval and round pass rolling, including the entering, rolling, and separating stages. The analysis was conducted using the Deform-3D ver.5.0 code. The important information concerned with the deformation area characteristic, material flow, and velocity field has been presented. Otherwise, the location of the neutral plane in the deformation area was shown clearly.

Numerical simulation of involutes spline shaft in cold rolling forming

Design of forming dies and whole process of simulation of cold rolling involutes spline can be realized by using of CAD software of PRO-E and CAE software of DEFORM-3D. Software DEFORM-3D provides an automatic and optimized remeshing function, especially for the large deformation. In order to use this function sufficiently, simulation of cold rolling involutes spline can be implemented indirectly. The relationship between die and workpiece, forming force and characteristic of deformation in the forming process of cold rolling involutes spline are analyzed and researched. Meanwhile, reliable proofs for the design of dies and deforming equipment are provided.

Influence of deformation path on the forming effect in a multistep flexible rolling process

The flexible rolling process(FRP) is a novel three-dimensional(3 D) forming process that combines the multipoint and traditional rolling forming. The principle of FRP is based on thickness thinning, so the deformation path significantly impacts the forming effect. In this study, the multistep forming process with different deformation paths was introduced to improve the forming effect of FRP. For instance, with the convex surface part, three finite element models of multistep FRP(MSFRP) were established. The corresponding numerical simulations and forming experiments performed among different deformation paths showed the surface part with a longer effective forming region was obtained and the forming regions with more steps in MSFRP were smoother. Thus, the sheet-metal utilization rate was greatly improved. Moreover, the MSFRP can improve the longitudinal bending effect dramatically and thereby endowing the forming part with a better forming effect. Therefore, MSFRP is a prospective method for broad applications.

TEXTURE AND MECHANICAL PROPERTIES OF WARM ROLLED Fe_3Al BASED ALLOY

The rolling and recrystallization texture of B2 type Fe3Al based alloys were systematially investigated by ODF. The results showed that the rolling texture consisted of a strong β-fibre close to {111} <uvw> and a {001} <110> texture. In annealing process the rolling texture was strengthened at recovery stage and gradually disappeared during primary recrystallization. A strong shear texture was produced by only 20% Pass reduction, indicating that the Fe3Al is sensitive to shear stress. The corresponding room temperature tensile properties were measured. A correlation between texture mode and room temperature mechanical properties was observed.

ROLLING CONTACT FATIGUE BEHAVIOR OF CERAMIC BALLS LUBRICATED BY LUBRICANTS WITH EXTREME PRESSURE ADDITIVES

An experiment is conducted to investigate the effects of lubricant10#, which contains extreme pressure additives T304 and T305, on the rolling contact fatigue （RCF） life of the contact pairs of a Si3N4 ceramic ball and a steel rod. The experimental investigation is carried out using a ball-rod RCF test rig. The results show that the extreme pressure additives increase the anti-contact-fatigue performance of ceramic balls; When the content of the additives varies from 1% to 5%, the increasing gradient of the RCF life curve decreases; And the oil sample with 1% T305 additive corresponds to the maximal gradient of the RCF life curve, with the RCF life being increased by about 10.77 times. The fatigue surface of the ceramic ball is analyzed with scanning electron microscope （SEM） and X-ray electron dispersion analysis（EDAX）, and the physical model of extreme pressure additives＇ increasing the RCF life of the ceramic ball is proposed. It is found that the extreme pressure additives form a corrosive film and a transfer film on the surface of the ceramic ball, which decrease the surface tangential stress, and to increase the surface energy is the most effective means for increasing the RCF life.

1,3-二甲基硫脲在甲基磺酸中对钢的缓蚀作用

采用失重法、电化学法、表面分析测试研究了1,3-二甲基硫脲(DMTU)在甲基磺酸(MSA)中对冷轧钢的缓蚀作用。通过实验研究表明,DMTU对钢在0.10 mol·L^(-1) MSA中有明显的抑制腐蚀的作用,在温度达到40℃、DMTU浓度为100 mg·L^(-1)时,其缓蚀率达88.0%。动电位极化曲线表明DMTU是以阳极抑制为主的混合抑制型缓蚀剂,Nyquist图谱的高频容抗弧随着DMTU的浓度增大而明显增大。扫描电子显微镜(SEM)、原子力显微镜(AFM)微观形貌以及表面张力和接触角测试证实了DMTU对钢在MSA中的腐蚀产生了明显的抑制作用,缓蚀后钢表面疏水性增强。

0.94(Bi_(0.5)Na_(0.5)TiO_(3))-0.06BaTiO_(3)掺杂铌酸钠基反铁电陶瓷的储能特性研究

利用Bi^(3+)、Ba^(2+)取代A位Na^(+),利用Ti^(4+)取代B位Nb^(5+),以增强NaNbO_(3)基陶瓷的弛豫特性,获得较低的剩余极化强度。同时,Bi^(3+)6s和O^(2-)2p之间的轨道杂化及高极化率的Ba^(2+)的引入有利于陶瓷获得高极化强度,提高其储能特性。在此基础上,设计了(1-x)NaNbO_(3)-x[0.94(Bi_(0.5)Na_(0.5)TiO_(3))-0.06BaTiO_(3)](NN-x(BNT-BT),x=0.20,0.25,0.30,0.35)陶瓷体系,结合轧膜成型工艺,在1140~1160℃保温2 h制备出致密性良好的厚膜陶瓷样品。结果表明,随着BNT-BT掺杂量的增加,陶瓷的击穿强度明显提高。在外加电场为550 kV·cm^(-1)时,NN-0.35(BNT-BT)陶瓷的储能性能达到最优,储能密度和效率分别为6.7 J·cm^(-3)和79.67%。在外加电场为300 kV·cm^(-1)下,25~120℃温度范围内,NN-0.35(BNT-BT)陶瓷的储能密度和效率变化率分别为9%和7%;在10~500 Hz频率范围内,储能密度和效率变化率分别为3%和5%,表现出优异的温度和频率稳定性。此外,NN-0.35(BNT-BT)陶瓷兼具较高的功率密度(261.014 MW·cm^(-3))和较快的放电时间(19 ns),在脉冲电容器领域存在巨大的应用前景。

轧制油泥资源化利用制备Fe_(2)O_(3)脱硝催化剂

通过焙烧从固体废钢轧制油泥中分离固相,制备Fe_(2)O_(3)脱硝催化剂,利用X射线衍射分析、NH_(3)程序升温脱附、H_(2)程序升温还原等一系列表征手段探究催化剂的物化性质并考察其对氮氧化物(NO_(x))的氨选择性催化还原性能。结果表明,在450℃空气焙烧条件下制备的催化剂(H-450)在300~400℃温度窗口下的脱硝活性最佳,NO_(x)转化率在85%以上。H-450主要表现为γ-Fe_(2)O_(3)活性晶型,同时具有较多的低温可还原铁物种和B酸,因此具有较高的活性。抗SO_(2)和H_(2)O中毒性能试验结果表明,体积分数10%H_(2)O和体积分数100μL LSO_(2)同时存在的气氛比分别单独通入体积分数10%H_(2)O或体积分数100μL LSO_(2)的气氛对催化剂的毒化作用更严重。

Fe-3%Si钢CSP工艺轧制的热模拟试验

针对Fe-3%Si钢,根据CSP生产线的工艺特点,模拟现场CSP工艺条件进行加热、轧制和卷取热模拟试验,采用Gleeble-1500D热模拟试验机研究Fe-3%Si钢在模拟CSP工艺热轧过程中的再结晶行为。结果表明,道次压下量为45%-40%-40%-20%-35%-35%的压下工艺条件下,获得的晶粒尺寸较为细小,动态再结晶完成较好;随着卷取温度的提高,晶粒平均尺寸减小,且卷取温度在650℃时,晶粒相对均匀。研究结果可为CSP工艺取向硅钢热变形行为的研究提供试验依据。

TSCR工艺参数对Fe-3%Si钢带显微组织的影响

在实验室模拟薄板坯连铸连轧(TSCR)生产Fe-3%Si钢带,研究薄板坯连铸连轧不同工艺参数对Fe-3%Si钢带热轧和常化显微组织的影响.结果表明,TSCR工艺生产的Fe-3%Si钢带热轧显微组织沿板厚方向呈现组织不均匀性,1 200℃保温20 min,前两道压下量较大、道次递减的显微组织过渡层再结晶晶粒数较多且相对均匀细小,没有中心层拉长的条带组织,有利于二次再结晶的完善.显微组织平均晶粒尺寸与传统流程热轧平均晶粒尺寸相差1.5μm,具有几乎相同的位错形貌,头部和中部显微组织差别都很小.热轧显微组织质量决定了常化后显微组织的质量.

PAC-3拦截弹建模与仿真研究

以PAC-3拦截弹为例,建立了该型低速旋转导弹的六自由度空间运动模型、复合制导模型,并对其气动力/直接力组合控制系统进行了反设计,运用MATLAB6.5&SIMULINK工具箱开发了PAC-3拦截弹的数字仿真系统,最后选取蛇形机动目标为拦截对象进行仿真,结果验证了PAC-3的飞行性能和拦截能力,也说明了反设计的组合控制系统是有效的。