Development of Technology and Equipment for Non-destructive Testing of Defects in Sewing Mandrels of a Three-roll Screw Mill 30-80

The conditions of heating and cooling of piercing mandrels made of 4X5MFS steel of a three-roll screw mill 30-80 in the production of a closed cavity of steel vessels of small volume are determined.It is established that multiple cycles of heating up to 600℃ and cooling with water up to 80℃ for about 7 seconds/1 cycle lead to the formation of ridges,shells and cracks on the surface and in the volume of the tool.The loss of structural strength of the material leads to the breakdown of the mandrel during the stitching process.The technique and equipment of magnetic powder control have been developed to establish the dynamics of the growth of internal and external defects of mandrels.An equation is obtained that allows determining the increase in the number of defects in the sewing tool of a screw rolling mill.The technology of non-destructive testing made it possible to develop a rational plan for replacing the sewing mandrels,which allows for predicting the appearance of defects leading to a complex breakdown of the deforming tool at the NPO Pribor machine-building enterprise.

Strengthening pelletization of manganese ore fines containing high combined water by high pressure roll grinding and optimized temperature elevation system

Pelletization is one of useful processes for the agglomeration of iron ore or concentrates. However, manganese ore fines are mainly agglomerated by sintering due to its high combined water which adversely affects the roasting performance of pellets. In this work, high pressure roll grinding(HPRG) process and optimization of temperature elevation system were investigated to improve the strength of fired manganese ore pellets. It is shown that the manganese ore possesses good ballability after being pretreated by HPRG twice, and good green balls were produced under the conditions of blending 2.0% bentonite in the feed, balling for 7 min at 16.00% moisture. High quality roasted pellets with the compressive strength of 2711 N per pellet were manufactured through preheating at 1050 °C for 10 min and firing at 1335 °C for 15 min by controlling the cracks formation. The fired manganese pellets keep the strength by the solid interconnection of recrystallized pyrolusite grains and the binding of manganite liquid phase which filled the pores and clearance among minerals. The product pellets contain high Mn grade and low impurities, and can be used to smelt ferromanganese, which provides a possible way to use imported manganese ore fines containing high combined water to produce high value ferromanganese.

Manufacturing of aluminum alloy ultra-thick plates by multidirectional forging and subsequent rolling

A combinatory large deformation model of multidirectional forging and subsequent rolling was proposed for producing high performance aluminum alloy ultra thick plates. The results show that fine grain (2～ 3?μm ) structures were obtained when total deformation coefficient λ = 32 at 250 ～ 350?℃ under a strain rate of about 0.1?s -1 . The development of fine grained structure can be characterized by the formation of strain induced high energy dislocation and then transforms into new grain under large deformation at moderate temperature. The very fine secondary particles formed during large deformation play important role in retain the stability of the fine grained structures.

FE SIMULATION OF CENTER CRACK OCCURRENCE IN TUBE ROUNDS DURING TWO-ROLL ROTARY ROLLING PROCESS

With the aid of FE （finite element） code MSC.Superform 2005, 2-D coupled thermo-mechanical simulation of center-crack occurrence in round billet during 2-roll rotary rolling process was presented using Oyane ductile fracture criteria. A simple modeling is put forward based on the spiral motion of the workpiece as an essential characteristic in movement. The influence of the feed angle and the entry cone angle of the main roll on the process was taken into account in the modeling. The soundness for simplifying the 3-D rotary rolling into a 2-D problem was discussed. By adopting the parameters of Diescher piercer in 140mm mandrel mill of Bao Steel, the distribution and development of strain/stress were analyzed, and the eigen value of ductile fracture as well. The critical percentage of diameter reduction was obtained from the simulation. The result showed a good agreement with the experimental value, and therefore was of widely guiding significance to the practical process for rationally formulating the deformation parameters of steel tube piercing.

Hourglass Control in Dynamic Explicit Simulation of Cold Ring Rolling Process

Hourglass is remarkably aroused in ring rolling simulation with reduced integration element because of violent ring vibration and small contact area of ring with forming rollers. Hourglass energy can be reduced by improving mesh density. Combined approach of artificial damping and artificial stiffness can control the hourglass. A ring with rectangular section is simulated with the weight factor of artificial stiffness resistance set to 0.2. The artificial damping hourglass control coefficient is set to 0.1, and the artificial stiffness hourglass control coefficient is set to 0.001. The ratio of hourglass energy to internal energy is reduced to 2.5 percent. Compared with axial spread width test, the effectiveness of hourglass control in ring rolling simulation is verified.

联合收割机裂纹转子与滚动轴承故障诊断系统研究--基于卷积神经网络

首先,介绍了传统神经网络,在其基础上引出了改进的卷积神经网络;然后,搭建了转子和滚动轴承的动力学模型,对转子和轴承的裂纹模型进行分析研究;最后,实现了联合收割机裂纹转子与滚动轴承故障诊断系统。实验结果表明:基于卷积神经网络的诊断模型达到稳定识别精度的迭代次数更少,且识别精度更高,效果更好,证明了系统的可行性和可靠性。

联合收割机滚动轴承故障诊断系统研究--基于声场空间分布特征

首先,介绍了联合收割机滚动轴承振动机理和故障特征,并研究了基于声场空间分布特征的故障诊断流程;然后,对联合收割机滚动轴承的声音信号采集及特征提取进行了深入研究;最后,利用神经网络算法的模式识别对联合收割机滚动轴承的故障进行诊断。验证结果表明:系统对联合收割机滚动轴承故障的综合诊断率为91.67%,系统具有可行性。

大规格薄壁镁合金无缝管二辊斜轧穿孔的数值模拟

目前,采用三辊斜轧穿孔的大规格薄壁镁合金管容易出现尾三角。因此,本文提出采用二辊锥辊穿制坯料直径为110 mm的大规格AZ31镁合金薄壁无缝管的方法。分析了二辊和三辊斜轧穿孔的原理,根据镁合金材料的特点,制定了相应的变形工艺参数,并采用Deform-3D有限元软件对整个过程进行了数值模拟。分析了等效应变、轧制速度、等效应力等结果。模拟结果表明,管形均匀,尾部截面圆整。

不同初轧温度下钛合金三辊斜轧穿孔工艺研究

根据三辊斜轧穿孔工艺的技术特征与钛合金塑性变形特点,通过有限元软件对TC4钛合金进行不同初轧温度的穿孔轧制有限元模拟,分析轧制过程应力、应变、温度、材料流动情况。以初轧温度为变量进行穿孔实验,对比不同温度下轧制力及轧后毛管微观组织。结果表明:三辊斜轧穿孔工艺完全适合钛合金生产,并且不同初轧温度下均可获得变形魏氏组织的钛合金毛管,验证了三辊斜轧穿孔生产钛合金管的可行性与有效性,为工艺推广提供指导和依据。

含分层储能的冷热电联供系统运行优化

为提高冷热电联供型微电网对可再生能源的消纳能力,解决源-荷的不确定性使得系统运行稳定性降低的问题,提出含分层储能的三级混合时间尺度滚动优化方法。日前优化目标为日运行成本最低;日内上层以燃料成本和蓄热罐功率变化惩罚成本最低为目标对冷热能进行优化,下层以电网交互成本和蓄电池功率变化惩罚成本最低为优化目标对电能进行优化;实时电系统反馈以电系统削峰填谷作用量和功率波动量最低为优化目标;得出最优的系统中各设备的出力计划。结果表明:该优化方法和分层储能能够有效达到削峰填谷的作用,各设备功率波动率均处于较低水平;冬季典型日的日运行成本比日前成本有所降低。

基于动态订单合并的滚动配取路径多目标优化

外卖配取过程中实时订单的不断插入具有强烈的不确定性,需持续进行滚动优化以动态更新配取路径。动态条件下,有效地合并取餐与配送作业(dynamic order combination,DOC)可显著减少冗余路径。本文将动态配取路径规划问题转化为变长开放链滚动优化问题,并构建多目标滚动配取路径规划模型对DOC与节点排序进行集成决策。考虑滚动优化框架下紧前决策对紧后决策的调度影响,模型在兼顾配取效率和客户满意度的同时,考虑了基于look-forward的滚动调度后效性。针对该模型,本文基于NSGA-Ⅲ框架开发了多目标元启发式算法进行求解,并设计了基于插入限制规则的元胞数组解编码和混合PMX&SBX交叉方式以适应模型的复杂可行域结构。通过一系列的仿真实验,本文验证了所提出的模型和算法的有效性与优越性。

TZΦ219 mm三辊连轧管机组简介

太原重工股份有限公司采用多项先进技术和创新技术,制造出了国产首台套TZΦ219 mm三辊连轧管机组,主要对该机组的产品规格、技术指标、工艺流程、设备主要组成进行介绍,并分析其运行效果。

精轧螺纹吊底平台在大体积高桩墩台中的应用与创新

从工程实际出发,对墩台施工水上作业平台工艺进行对比分析,介绍精轧螺纹吊底平台的工艺特点、原理、流程及操作要点。结合全直桩基墩台结构特点,对桩基与上部结构连接方式的设计进行创新,在钢管桩外侧设置4块扇形钢板,并围焊成环形,与精轧螺纹吊底平台共同形成一种新型组合支承结构,提高吊底和底模的周转率,加快工程进度,确保大体积高桩墩台施工的安全和质量,经济和技术效益明显。可为类似墩台施工、钢管桩与上部结构连接方式设计提供参考。

Centrifugal Casting of High Speed Steel/Nodular Cast Iron Compound Roll Collar

The centrifugal casting of compound HSS/nodular cast iron roll collar was studied,and the factors affecting transition zone quality were analyzed.The pouring temperature and interval in pouring are the main factors affecting transition zone quality.By controlling process parameter and flux adding during casting,high quality roll collar was obtained.The cause,why in the casting of HSS part,segregation appears easily,was analyzed and the countermeasure eliminating segregation was put forward,the measure eliminating heat treatment crackling was also put forward.

基于临界空穴扩张比理论的不锈钢管高温韧性损伤研究

针对不锈钢管在高温塑性加工过程中出现的裂纹缺陷,在Gleeble-3800热模拟试验机上对TP321奥氏体不锈钢光滑棒材进行高温拉断试验,得到了TP321在温度850~1180℃、应变速率0.01~10 s^(-1)下的真应力-真应变曲线和试样拉伸断裂瞬间的等效塑性应变。结合有限元仿真,对试验结果进行了数值模拟,得到了应力三轴度的数值,从而计算出了临界空穴扩张比参数V GC。在此基础上,验证了临界空穴扩张比参数韧性断裂准则在高温下的适用性。发现在特定温度范围内TP321断裂瞬间的V GC与应变速率相关性较小,与温度呈线性关系,并建立了奥氏体不锈钢断裂瞬间的V GC与温度的数学表达式。将得到的V GC准则应用于TP321管坯的不同辊形斜轧穿孔过程中的韧性损伤,对比分析了不同辊形斜轧穿孔仿真结果,发现V GC准则可准确预测缺陷情况。

基于模态分解在联合收获机轴承故障诊断研究

联合收获机滚动轴承的状态监测和故障诊断是目前保证其稳定运行的重要手段,而敏感故障特征的提取是轴承故障诊断的关键问题。为此,针对REB振动信号的非平稳、非线性特点及现有轴承故障诊断方法过于依赖监督学习算法等问题,提出了基于经验模态分解(EMD)能量熵的特征提取方法进行模型特征选取,并用于训练人工神经网络(ANN)对轴承故障进行分类。研究结果表明:提出的基于模态分解在联合收获机轴承故障诊断及分类中具有较强的可靠性,提出的健康指数(HI)可以系统表示不同的故障类型和严重程度,并可以成功地检测出联合收获机在运行过程中的故障类型,可为开发轴承自动诊断和预测系统提供参考。

Accu—Roll轧管机组主减速机输出轴联轴器大过盈量装配

介绍了采用油温加热装配工艺,实现Accu-Roll轧管机组主减速机输出轴联轴器大过盈量装配。

含光伏与储能的冷热电联供系统混合时间尺度滚动优化运行研究

为解决冷热电联供系统源荷供需能量匹配性差异显著的问题,提出三阶段混合时间尺度滚动优化方法。日前阶段以日运行成本最低为优化目标,综合考虑CO_(2)、SO_(2)和NO_(x)的处理成本,制定逐时计划;日内阶段根据冷热电相关设备的响应差异,建立了冷热和电能分时间尺度的双层优化模型;实时电反馈优化以电设备功率调整量最小为目标;最终得到各设备的最佳出力计划。结果表明:三阶段混合时间尺度滚动优化方法能够有效平抑负荷和可再生能源出力波动,各设备功率波动率均处于较低水平;不同典型日下的日运行成本比日前成本均有所降低,冬季、过渡季和夏季典型日的成本节约率分别为0.99%、1.10%和2.01%。

基于PIO-RBF神经网络斜轧穿孔机调整参数预测

针对无缝钢管二辊斜轧穿孔生产工艺中轧机调整参数对钢管质量影响较大,但其设定值精度不高的问题,提出了基于鸽群算法改进RBF神经网络斜轧穿孔机调整参数预测模型。首先,综合分析了传统的二辊斜轧穿孔调整参数数学模型并确定了主要特征参数,其次,建立了两辊斜轧穿孔时轧机参数(轧辊间距、导板间距和顶头前伸量)的RBF神经网络预测模型,并提出鸽群算法优化RBF神经网络的中心、方差(宽度)和隐层与输出层之间的连接权值。针对某厂采集的304L管的生产数据,对提出的预测模型进行了训练和验证。通过与基于聚类分析的RBF神经网络模型对比,将经PIO-RBF神经网络模型预测得到的轧机调整参数(轧辊间距、导板间距和顶头前伸量)数据与实际数据比较,其相对误差均可控制在9%以内。结果表明,由PIO-RBF神经网络建立的预测模型对轧辊间距、导板间距及顶头前伸量具有较高的预测精度且适用性强。

基于机理与数据驱动的热连轧板凸度组合预测

针对传统热连轧出口板凸度预测方法存在的模型精度低、解释性差等缺陷,提出了一种将机理与数据驱动相结合的热连轧板凸度组合预测模型。通过热连轧板凸度机理预测模型得到热连轧板凸度基准值,将该基准值与实际值之间的偏差量作为机器学习模型的预测变量,再将偏差量预测值与基准值进行求和得出组合预测模型的板凸度预测值,并将该组合预测策略应用至多个神经网络进行方法验证。研究结果表明,提出的热连轧板凸度组合预测模型相较于传统预测模型具有更好的预测性能,其中有97%以上预测数据的绝对误差小于0.02 mm,82%以上预测数据的绝对误差小于0.01 mm,同时该组合预测方法具有较好的可行性与普适性,所提出的模型能够实现机理模型与数据驱动模型的优势互补,使得模型更加符合实际物理意义,该组合模型既缓解了神经网络预测结果由于过程黑箱导致解释性差、可信度低的问题,又弥补了机理模型预测结果偏离生产工况、无法实时修正的缺陷,对热连轧板带钢的板形控制以及热连轧产品质量的改善具有重要意义。