RESEARCH ON STRAIGHTENING TECHNOLOGY CAM SYSTEM

Automatic straightening process is a nonlinear process, and affected by manyfactors. The straightening technology CAM system has been designed and built up to straightenshafts, which mainly consists of the straightening technology's database and the model ofstroke-controlled precise straightening calculation model. The operational test of the CAM systemhas been passed.

Innovation in the Computing System of Straightening Force

Currently in China, the computing system of the straightening force of the six-rollers straightening machine generally follows the traditional computing system. The force status of the traditional computing system for the straightening force deviates far away from the actual force status of the roller system in the six-rollers straightening machine. In the traditional system, the computing model of the straightening force of the six-roller straightening machine was based on the roller shape of hyperbola, which led to the length of the contacting line between the tube and the straightening roller to be excessively short, i.e., only 0.1~）.2 of the length of the roller. Thus the constructed computing system has relatively large difference from the actual measured result. To solve the above problems, flattening straightening and bend straightening are analyzed on the basis of materials mechanics and bend beam theory, the roll er shape using the envelope method of A.I4.~e：mKoB is generated, and a new computing system for straightening force in six-rollers straightening machine is built. The roller shape of the straightening roller, on which the new computing system for the straightening force is based, is designed according to the envelope method under the condition of ideally full contacting between the tube and the roller body of the straightening roller, therefore the new computing model accords with the practical status of straightening force. According to the comparison of the new computing system with finite element method and the actual measured result of straightening force, it has been proved that the computation accuracy of the new computing system for straightening force satisfies the practical requirements of engineering. New six-rollers straightening machines are designed and manufactured according to the new calculation system, and the new machines not only have higher precision and quality, but also have adopted the force sensor and computer and combined with the new computing system for straightening force to realize the fully automatic adjustment of the straightening machine. The new six rollers straightening machine have obtained notable economical and social benefits.

The Role of Corrugation Die Parameters on the Mechanical Properties of Aluminum Alloy (AA 5083) Processed by Repetitive Corrugation and Straightening

The microstructure and mechanical properties of aluminium alloy (AA 5083) processed through Repetitive Corrugation and Straightening (RCS) was studied. The RCS process consists of corrugating a flat specimen with a pair of systematically grooved dies and straightening was done with two parallel flat dies. The aluminium samples were subjected to RCS process using two different die: Die I-semi grooved die with breath = height = 5 mm and θ = 30。 and Die II-semicircular profile with radius = 10 mm. The specimens were subjected to maximum 8 passes for die I but the other one went upto 14 pass. The grain refinement was studied from the microstructure examination using TEM. The mechanical properties such as tensile strength, hardness and the grain size were compared. The tensile strength and hardness were found increasing with respect to the number of passes. The tensile strength increased 25% in the sixth pass when compared to the parent material. But the strength and hardness values were reduced at 8th pass due to the surface cracks. The TEM studies showed that the Die-I is superior to Die-II in terms of grain refinement.

Longitudinal crack on slab surface at straightening stage during continuous casting using finite element method

Deformation behavior of slab at the straightening stage during continuous casting was simulated by the explicit dynamic finite element method,and the stress distribution along the width direction of the slab and its change regularity at slab center during continuous casting were obtained.The influence of distribution and change of stress on the propagation of longitudinal cracks on slab surface was discussed.The results show that the tensional stress appears on slab surface at the inner arc side and the compressive stress appears on slab surface at the outer arc side at stages 6-8 in straightening zone during continuous casting.Longitudinal cracks generally appear on slab top surface and do not appear on slab bottom surface,which are also observed in industry.

The mathematic model of tension straightening process of magnesium alloy and experimental validation

The stress-strain curve of bending bar and the stress relax curve of AZ31 was obtained by a tension test using Gleeble-1500.The tension straightening process mainly consisted of the elastic loading-I and unloading stage,the elastic loading-II and unloading stage,and the elastic-plastic loading stage,which were based on the stretch force change during straightening.The circular bar straightening under one-dimensional bending was investigated and assumed to be linear strain-hardening elastic-plastic material.According to the elastic-plastic mechanics theory,the mathematical displacement-force model of a tension straightening process established,on which was based,the predicted displacement of tension straightening for various original deflection was calculated.The tension straightening experiment for AZ31 magnesium was conducted under the guidance of the predicted displacement.The experiment results present good straightness when there is a stress relaxation phenomenon or the temperature of tension straightening is 25℃.

Evaluation of straightening capacity of plate roll straightener

Straightening machine is widely used for improving the quality of the defective mild steel plates.In general,the capacity of straightening machine is affected by material properties,the initial shape of the incoming plate and the plastic ratio.The mechanics model describing the capacity of the machine was developed.The deviation of the straightening capacity curves was studied.Then,the presented model was evaluated by comparative study to filed production data.Finally,the influences of overstretch,straightening speed,strengthening coefficient,elastic modulus,width of the plate on the straightening capacity were studied.It is convenient to determine whether the plate can be straightened or not by a series of straightening capacity curves.The straightening speed,width of the plate and elastic modulus of the material are more sensitive to the straightening capacity than the strengthening coefficient.

A Solution of Drawing Straightening Roller Curve by Conjugate Revolving Quadric Theory

Based on the theory of conjugate revolving quadric theory,the analytic method of calculating the straightening roller curve in the procedure of straightening the bar has been given. Meanwhile,the equations,which describe roller curve and the longitudinal section,are given and simulated in computer. A brief method of designing and drawing the straightening roller curve is introduced.

Microstructure and Mechanical Properties of Cross-rolled Ti_(50)Ni_(47)Fe_3 Shape Memory Alloy

The microstructures, the phase transformation characteristics, and the mechanical properties of the Ti50Ni47Fe3 alloy in as-forged and as-cross-rolled states were investigated. It is found that, after cross-rolling, the phase transformation temperature （Ms） of the alloy decreases drastically and the grains get refined. Moreover, its yield strength and fracture strength after cross-rolling hit 540 MPa and 687 MPa respectively, up by about 200 MPa over those in as-forged state.

Surface morphology and mechanical properties of the nanocrystalline tensile-straightening rollers treated by the ultrasonic particulate peening

Tensile-straightening rollers of a pickling line at Baosteel are surface nanocrystallined by the ultrasonic particulate peening(USPP)method.Surface morphology and mechanical properties of the rollers were characterized by scanning electronic microscope(SEM),a roughness meter and a microhardness tester.Results have indicated that there are a lot of randomly distributed impact pits on the surface after the USPP and that surface roughness can be adjusted within a range of Ra 1.5-2.5.The grain size in the surface layer is refined significantly.The microhardness of the surface layer can reach 920 HV after the nanocrystalline treatment.The dependency of the two main influencing factors,i.e.the working gas temperature and pressure,on the surface roughness and microhardness is presented.

Possibility of a Straightening Flow-Meter by Using Woven Screen

In this paper, the possibility of the flow rate measurement for a circular pipe flow by using a wo-ven screen with the property of straightening un-uniform flows is discussed. The resistance coefficient and the flow rate coefficient are estimated from the pressure difference caused by the woven screen under the experiment ranges of the wire Reynolds number, Red = 2.2 × 102-1.8 × 103, and of the open area ratio, β = 0.28-0.65. As a result, the resistance coefficient decreases and the flow rate coefficient increases as the wire Reynolds number Red or the open area ratio β increases. In addition, both coefficients are not affected by the difference between uniform and turbulent pipe flows approaching the woven screen. Therefore, the possibility of a flow-meter having the property to straighten the un-uniform flow is expected.

刮板输送机技术发展历程(四)——智能化成套装备

采煤工作面机器人群包括智能刮板输送机,它不仅要自适高效输送煤流而且要引导智能采煤机沿着工作面截割煤炭、牵引智能液压支架安全支护岩层顶板,因此刮板输送机智能性直接影响采煤机组智能性。认为,断链监测与保护技术、链张力实时感控技术、煤流量在线监测技术和机身自动调直技术是智能刮板输送机的关键感控要素,目前这些技术已达到成熟应用,为刮板输送机无人化运行提供了重要保障。自2010年起,我国刮板输送机智能化技术创新加速,研发成功超大功率、超长运距智能刮板输送机,以此构建了超级智采工作面。指出,未来刮板输送机永磁电机智能驱动、智能力感刮板链、全耐磨整体成型中部槽、数字孪生控制系统将成为新一代高级智能刮板输送机的发展方向,进而推进煤矿智采工作面进入高级智能化层次。

高精度铝板矫直机辊系拉力条件提升方案

结合高精度铝板矫直机的辊系参数特点,分析了辊系拉力条件对设备矫直能力的影响,介绍了采用夹送辊装置改善拉力条件、提升矫直能力的技术方案。

钢结构热矫正工艺评定试验方法研究

热矫正是一种调整钢结构尺寸的工艺,其中火焰矫正是最常用的方法,它通过局部加热和冷却来改变钢材的应力状态,实现矫正目的。欧洲钢结构规范EN1090-2要求进行火焰矫正工艺评定,但当前的国际和国内规范并未具体规定热矫正工艺评定的试验方法。热矫正工艺评定试验需要考虑母材性能、热源、加热控制和冷却控制等影响因素,并将这些因素分为重要因素和次要因素。提出了浅表热矫正和全厚度热矫正的试板形式和尺寸,以及热矫正过程中需要详细记录的各项变素。将拉伸、冲击、硬度试验和微观金相试验作为评定热矫正效果的检验内容。研究得出结论,建议根据钢结构的材质、厚度和工厂具体情况,拟定热矫正工艺评定方案,组织试板的热矫正工艺试验和理化试验,并编制热矫正工艺指导书。此外,培训具备相应技能水平的热矫正作业人员,以保证热矫正作业要求的有效执行。通过工艺评定和技能两方面的保证,确保热矫正后钢结构的产品质量。

基于弹塑性理论的复杂截面导轨校直模型研究

为解决具有复杂截面导轨的横向和纵向弯曲变形校直问题,建立校直挠度的理论模型,并给出明确的校直行程公式。首先,分析导轨基于线性强化弹塑性材料的弹塑性阶段应力与应变几何关系;其次,依据弯矩与应力的表达式,结合弯矩的轴向变化规律,确定塑性阶段校直压力的范围,得到校直压力与总校直挠度和初始挠度的关系;最后,建立校直的理论计算模型。为验证理论模型的正确性,在ABAQUS中建立导轨的线性强化弹塑性力学模型,采用一端固定一端滑动的约束,加载头加载的方式,仿真校直压力与挠度之间的关系。结果表明,理论模型与有限元仿真的挠度与校直压力曲线规律完全一致,验证了理论模型的可行性与正确性。

拉伸孪晶对AZ31镁合金薄板可轧性和组织性能的影响

通过弯曲限宽矫直工艺在AZ31镁合金薄板中预置了拉伸孪晶,随后对原始板材和预置孪晶板材进行轧制,对比分析了初始组织对板材在轧制过程中的塑性变形协调能力的影响,探索了不同轧制压下量对两种板材的组织和力学性能的影响。结果表明:弯曲限宽矫直后板材的强度和塑性都得到了提升,轧制后的原始板材剪切变形带较少。在后续的拉伸试验中,在相同压下量下塑性变形能力也明显提升。

基于改进堆叠降噪自编码器的连铸机扇形段故障特征提取

为了提取连铸机扇形段在正常浇铸状态下的故障特征,设计一种利用鲸鱼优化算法(WOA)改进的堆叠降噪自编码器(SDAE)网络模型,命名为WOA-SDAE,并应用于扇形段拉矫力信号特征学习和故障分类。首先,从完整的浇铸周期中获取正常浇铸状态下的数据,对低频的拉矫力信号进行时域特征提取,将一维拉矫力信号转换为多维时域特征信号,并建立评价体系以寻找最优时域参数;其次,运用堆叠降噪自编码器与softmax分类器组成网络模型对故障信号进行分类,采用鲸鱼优化算法确定SDAE模型中隐含层层数与节点数。通过实际生产过程中的连铸机扇形段拉矫力信号来验证所提方法的可行性。试验结果表明,WOA-SDAE可有效提取扇形段的故障特征,在测试集上的识别准确率达到92.23%。

玉米茎秆扶直包扎装置设计与试验

针对玉米植株在受到重大自然灾害时茎秆折断情况,从人因工程学角度设计了一套玉米茎秆扶直包扎装置。首先,以郑单958品种玉米植株为研究对象,建立扶直包扎物理对象模型,再基于此模型设计计算了便于用户操作的扶直包扎装置主要尺寸;最后,搭建了实物样机模型,并对玉米茎秆进行扶直包扎试验。结果表明:扶直包扎装置能够将折伤后玉米茎秆扶直且稳固,便于操作,促进玉米增产增质;传统组和装置组的扶直包扎效率分别为60.7株/min和16.7株/min,利用扶直包扎装置完成玉米茎秆扶直包扎效率高于传统包扎组,且扶直包扎效率稳定,具有很好的市场应用前景,对其他农林枝木的包扎具有一定的参考价值。

方坯连铸机安装技术实践与分析

对连铸机设备安装施工过程的要点进行分析,详细阐述了连铸机钢包回转台、结晶器及振动装置、拉矫机、液压系统和辊道的安装流程、安装技术要求。通过现场安装连铸机生产线设备,不仅充分了解了设备的结构和运行原理,而且积累了安装经验,为设备后续的正常运转、维修保养奠定了基础。

锅炉制造火焰矫正工艺探讨

介绍了锅炉集箱部件在制造过程中因不均匀焊接、热循环导致弯曲变形而进行火焰矫正的工艺方法和注意事项,比较了国内外锅炉行业标准和钢结构建造标准对热矫正的规定和指导性条款,考虑到热矫正对材料性能可能产生的不利影响,建议锅炉行业工艺规范标准化。