Improvement of Temperature Drop Model Parameters for 4200mm/3500mm Rolling of Baosteel Medium and Thick Plate

Based on the temperature situation during the rolling process of 4200 mm/3500 mm medium and thick plates at Baosteel,this article analyzes the influencing factors of temperature changes during the rolling process from the perspective of heat transfer theory and the temperature change law during the rolling process.The temperature loss during the four rolling processes is tracked on site,and the temperature drop model parameters during the rolling process of 4200mm/3500mm medium and thick plates at Baosteel are quantitatively provided.It is applied to actual rolling production and has achieved good results.

Distribution of Inherent Strains and Residual Stressesin Medium Thickness Plate Weldment

A fundamental theory for the analysis of residual welding stresses and deformation based on the inherent strain distribution along the welded joint is introduced. Distribution of inherent strains and longitudinal residual stresses in medium thickness plate weldment is calculated and analyzed. A new method of calculating inherent strains and longitudinal residual stresses is proposed.

THE DYNAMIC PLASTIC BEHAVIOR OF A SIMPLY SUPPORTED CIRCULAR PLATE IN A DAMPING MEDIUM WITH FINITE-DEFLECTIONS

A theoretical analysis is presented for the dynamic plastic behavior of a simply supported rigid, perfectly plastic circular plate in damping medium with finite-deflections subjected to a rectangular pressure pulse. Analytical solutions of every moving stage under both medium and high loads are developed.

Dufour Effects on Unsteady Hydromagnetic Radiative Fluid Flow past a Vertical Plate through Porous Medium

The objective of the present study is to investigate diffusion-thermo (Dufour effect) and radiation effects on unsteady MHD free convection flow past an impulsively started infinite vertical plate with variable temperature and uniform mass diffusion in the presence of transverse applied magnetic field through porous medium. At time t > 0, the plate is given an impulsive motion with constant velocity in the vertical upward direction against to the gravitational field. At the same time the plate temperature is raised linearly with time t and the level of concentration near the plate is raised to . A magnetic field of uniform strength is applied normal to the direction to the flow. The dimen- sionless governing equations are solved in closed form by Laplace-transform technique. The effect of flow parameters on velocity, temperature, concentration, the rate of heat transfer and the rate of mass transfer are shown through graphs.

Nonlinear vibration analysis of laminated composite Mindlin micro/nano-plates resting on orthotropic Pasternak medium using DQM

The nonlocal nonlinear vibration analysis of embedded laminated micro- plates resting on an elastic matrix as an orthotropic Pasternak medium is investigated. The small size effects of micro/nano-plate are considered based on the Eringen nonlocal theory. Based on the orthotropic Mindlin plate theory along with the von Kármán geo- metric nonlinearity and Hamilton＇s principle, the governing equations are derived. The differential quadrature method （DQM） is applied for obtaining the nonlinear frequency of system. The effects of different parameters such as nonlocal parameters, elastic me- dia, aspect ratios, and boundary conditions are considered on the nonlinear vibration of the micro-plate. Results show that considering elastic medium increases the nonlinear frequency of system. F^lrthermore, the effect of boundary conditions becomes lower at higher nonlocal parameters.

Similarity Solutions of Unsteady Convective Boundary Layer Flow along Isothermal Vertical Plate with Porous Medium

Similarity solution of unsteady convective boundary layer flow along isothermal vertical plate with porous medium is analyzed. The plate surface is reactive with the fluid and generates inert specie which diffuses inside the boundary. The flux of the specie at the plate is proportional to specie concentration at the plate. The governing equations of continuity, momentum, energy and specie diffusion are transformed into ordinary differential equation by using the similarity transformation and solved numerically by using free parameter method along with shooting technique. The dimensionless velocity, temperature and concentration profiles are obtained and presented through figures for different parameters entering into the problem. The local Skin-friction co-efficient, Nusselt number and Sherwood number at the plate for physical interest are also discussed through tables.

中部槽中板与槽帮自动组装设备设计

基于伺服电机驱动滚珠定位、位置传感器以及专用机械工装设计了中部槽中板与槽帮自动组装设备和自动传输机构。通过激光测距传感器测量槽帮端面位置并通过PLC控制定位气缸的实时调整,进而实现中部槽中板和槽帮的自动组装。最后通过非接触间接测量方式确定组装精度,自动下发检测结果。结合中板与槽帮的自动组装、检测形成闭环控制,提高中部槽制造的智能化水平。

中厚板探伤缺陷分析及质量改进

针对鞍钢Q460E中厚板钢板存在的探伤缺陷问题,采取扫描电镜成分分析、夹渣物检验、酸蚀低倍检验等方法,分析了连铸和模铸钢板中夹渣和裂纹缺陷的产生原因,并制定了改进措施。通过对比、归类国内外中厚板产品主要探伤标准,将探伤缺陷分为八个质量等级。统计改进前后各质量等级钢板占比,得出最优质量等级钢板占比显著上升,钢板内部质量明显提高。

中厚板卷产生镰刀弯的原因分析和控制措施研究

在钢厂生产中,积极做好镰刀弯缺陷的控制,可以有效提高中厚板材的板型质量。为此,以某钢厂生产的3500 mm中厚板轧制为例,阐述镰刀弯的概念,对镰刀弯的产生原因进行分析,结果表明该缺陷的形成主要有粗轧机和精轧机原始辊缝楔形、精轧机两侧刚度差值较大、推床对中精度及平行度差、精轧机支承辊及工作辊辊型不良等原因。同时,结合生产经验针对产生原因采取相应控制措施,经改进后,有效减少镰刀弯的缺陷,进一步提高板材的综合成材率。

中厚板Q235B表面纵裂原因分析及控制

Q235B中厚板是敬业集团2022年的主流产品之一,但是自进入4月份以后,大批量Q235B板材表面出现纵裂缺陷,每月纵裂缺陷品占Q235B总产量的比例最高达到0.41%,造成了严重的经济损失。针对中厚板Q235B表面纵裂缺陷造成大量板材降级问题,通过跟踪Q235B板坯的炼钢连铸生产过程,对比纵裂缺陷品的工艺参数,研究了纵裂的原因并制定了相关控制措施。从钢水质量、浇注稳定性、铸坯凝固平衡性三方面入手,通过控制钢水冶炼成分碳含量0.15%~0.17%、硫含量小于0.012%,保证精炼软吹效果、减少钢中夹杂物,稳定铸坯拉速波动小于0.1 m/min,优化浇注工艺、水口插入深度115~125 mm,结晶器冷却制度、平衡铸坯宽窄面热流密度等措施,使Q235B板坯表面纵裂纹发生率得到明显控制,9月份纵裂缺陷品占比0.128%,较8月份减少0.283%。

15种医院口腔抑菌制剂微生物限度检查方法的建立

目的建立15种医院口腔抑菌制剂的微生物限度检查方法。方法以醋酸氯己定口崩片、醋酸氯己定洗剂、复方替硝唑溶液、碘甘油、甲醛甲酚涂剂、硼酸甘油涂剂、人工唾液、脱敏糊剂、干髓糊剂、锌麝酚醛糊剂、牙周塞糊剂、甲硝唑膜、复方克林霉素膜、多聚甲醛新失活剂、多聚甲醛牙髓失活剂为样品(制剂1-15),按2020年版《中国药典(四部)》通则1105,1106,1107项下方法,采用平皿法、薄膜过滤法和培养基稀释法,对5种常见菌(金黄色葡萄球菌、铜绿假单胞菌、枯草芽孢杆菌、白色念珠菌和黑曲霉)进行回收试验,并进行控制菌(金黄色葡萄球菌、铜绿假单胞菌和大肠埃希菌)检查方法适用性试验。结果制剂1-5、9-11、14-15需氧菌总数检查均采用薄膜过滤法,其余制剂均采用平皿法;制剂1-3、6-8、12-13霉菌和酵母菌检查均采用平皿法,其余制剂均采用薄膜过滤法,试验菌回收比均在0.5~2.0范围内;控制菌检查,制剂1-3、5、9-11、14-15均采用薄膜过滤法,其余制剂均采用培养基稀释法,试验组相应阳性菌均能正常检出。结论所建立的方法适用于此15种医院口腔抑菌制剂的微生物限度检查。

等离子-MAG复合焊Q960钢工艺应用研究

文中介绍了应用等离子-MAG复合焊接技术于中厚板焊接的一个工业化应用案例,研究结果表明等离子-MAG复合焊可工业化应用于批量中厚板高强钢焊接,等离子-MAG复合焊接8 mm以下低碳钢及低合金钢可以不用开坡口一道焊接至完全熔透。焊缝间隙保证在0~1.2 mm范围内可以确保等离子-MAG复合焊接12 m长直焊缝的完全熔透且正反面成形美观。在同样屈服强度960 MPa母材及焊丝匹配的情况下,焊接接头抗拉强度等离子-MAG复合焊略高于普通MAG焊,-40℃低温冲击韧性等离子-MAG复合焊稍低于普通MAG接头。

钢混组合梁结构比选及受力分析

对于50 m跨径的钢混组合桥梁,比较了不同结构形式的经济性指标,推荐采用装配式π形组合梁。同时,以工程为依托,介绍了50 m跨钢混组合梁桥的设计。

A THEORETICAL MODEL OF MAGNETOELASTIC BUCKLING FOR SOFT FERROMAGNETIC THIN PLATES

As an essential model of magnetoelastic interaction between magnetic field and mechanical deformation, the study on magnetoelastic buckling phenomenon of soft ferromagnetic plates in a magnetic environment has been conducted. One of the key steps for the theoretical prediction of the critical magnetic field is how to formulate magnetic force exerted on the magnetized medium. Till today, the theoretical predictions, from theoretical models in publications, of the magnetoelastic buckling of ferromagnetic cantilevered beam-plate in transverse magnetic field are all higher than their experimental data. Sometimes, the discrepancy between them is as high as 100%. In this paper, the macroscope formulation of the magnetic forces is strictly obtained from the microscope Amperion current model. After that, a new theoretical model is established to describe the magnetoelastic buckling phenomenon of ferromagnetic thin plates with geometrically nonlinear deformation in a nonuniform transverse magnetic field. The numerical method for quantitative analysis is employed by combining the finite elemental method for magnetic fields and the finite difference method for deformation of plates. The numerical results obtained from this new theoretical model show that the theoretical predictions of critical values of the buckling magnetic field for the ferromagnetic cantilevered beam-plate are in excellent agreement with their experimental data. By the way, the region of applicability to the Moon-Pao's model, or the couple model, is checked by quantitative results.

Experimental Study of the Diffusion of a Confined Wall Jet through a Perforated Plate: Influence of the Porosity and the Geometry

This paper investigated lateral diffusion of a confined two-dimensional wall jet (air inlet height: 5 cm) through a perforated plate. We considered two plates with porosities of and . The plates were positioned at distances of 10 cm and 20 cm below the jet inlet. The experiments were realized using 2D Laser Doppler Anemometer (LDA). Different profiles of mean and fluctuating velocities are presented. The presence of a perforated plate strongly modified the airflow pattern compared to an empty enclosure. The velocities above and below the plate depend on several parameters, including the porosity and the plate’s position relative to the inlet slot and the longitudinal position. The difference between the flow velocity above and below the plates could not be related using a universal formula that depends on these parameters. We also investigated the influence of a porous media of a height of 20 cm (a stack of spheres having a diameter of 3.75 cm) located below the perforated plate. The results highlight that the porous medium strengthens the effects of the perforated plate on the flow.

MULTI-MODE NETWORK ANALYSIS FOR DISCONTINUITIES IN PARALLEL-PLATE WAVEGUIDES PARTIALLY FILLED WITH MULTI CHIRAL RODS

The reflection and transmission characteristics of the guided modes in parallel-plate waveguides partially filled with one or multi chiral rods have been investigated by a method, which combines the multi- mode network theory with a rigorous mode matching procedure. The formulas of the reflection and transmis- sion coefficient matrix are derived. The numerical results for different cases are presented and have indicated that the chirality parameters and the geometrical dimensions of the chiral rods have significant influence on the reflection and transmission characteristics of the guided modes.

激光摆动焊接工艺参数对不锈钢焊缝成形与气孔率的影响

采用激光摆动焊接实现了5 mm厚1Cr18Ni9Ti不锈钢的焊接,获得成形良好、低气孔率的接头.分析了焊接速度、摆动幅值、摆动频率、摆动形式对焊缝成形和气孔率的影响,从匙孔、熔池流动、气泡逸出的角度揭示了工艺参数影响气孔率的主要机理.结果表明,对于5 mm厚不锈钢激光摆动焊接,适当提高焊接速度和摆动幅值,更利于减小气孔率;激光摆动频率在100~300 Hz可以兼顾较低气孔率和较好的焊缝成形;“8”形摆动激光可以获得相对较优的焊缝成形,焊缝气孔率最低,达到2.94%;而线性摆动激光获得焊缝成形最差,气孔率最高,达到19.13%.

Scale effects on nonlocal buckling analysis of bilayer composite plates under non-uniform uniaxial loads

Scale effects are studied on the buckling behavior of bilayer composite plates under non-uniform uniaxial compression via the nonlocal theory. Each isotropic plate is composed of a material that is different from others, and the adhesive between the plates is modeled as the Winkler elastic medium. According to the symmetry, effects of the Winkler non-dimensional parameter, the thickness ratio, the ratio of Young＇s moduli, and the aspect ratio are also considered on the buckling problem of bilayer plates, where only the top plate is under the uniaxial compression. Numerical examples show that the Winkler elastic coefficient, the thickness ratio, and the ratio of Young＇s moduli play decisive roles in the buckling behavior. Nonlocal effect is significant when the high-order buckling mode occurs or the aspect ratio is small.

厚板多层焊接的焊缝位置修正

针对中厚板多层多道焊接示教繁琐且焊缝坡口会随焊接层数和道数的增加而产生变形的问题,基于激光视觉的机器人中厚板焊接系统,提出一种多层多道和多层单道焊缝位置修正方法。通过在每层焊接之后重新扫描焊缝以获取当前焊缝的三维信息,提取焊缝信息特征并对焊道位置进行修正,以重新设定下一层焊道的起点与终点位置。通过V型厚板多层单道焊接实验与焊缝三维模型焊后分析表明,对焊缝位置进行修正可有效消除由于焊接过程中变形带来的影响,厚板焊接盖面层焊缝余高可平均控制在2 mm以内,提高工业机器人对多层焊接的适应性。