Solution for slab forging with bulge between two parallel platens by strain rate vector inner-product integration and series expansion

A new linear integration was developed. First, effective strain rate for slab forging with bulge was expressed in terms of two-dimensional strain rate vector, and its inner-product was integrated term by term. Second, a summation process of term by term integrated results and a formula of the bulging were introduced, and an analytical solution of stress effective factor was obtained. It is proved that the expression of power by the above linear integration is the same as that of traditional immediate integration. Also, the solution was simplified by series expansion and compared by slab forging test with the others. It turns out that the calculated result of total forging pressure is basically in agreement with measured value in the actual press test.

全钢子午线轮胎胎侧径向单条实鼓的原因分析及解决措施

分析全钢子午线轮胎胎侧径向单条实鼓的原因并提出相应的解决措施。径向单条实鼓分为强光下呈现胎侧部位凹陷和凸起两种形式,产生的原因主要有对应位置胎体帘线密、胎体帘线稀开、胎侧/内衬层复合件接头大或裂开等。通过采取调整缝合器压合轮间隙、碟簧片间距,规范压合底辊形式,打磨压合轮及规范胎侧/内衬层接头大小等措施,有效解决了全钢子午线轮胎胎侧径向单条实鼓的问题。

Inner-product of strain rate vector through direction cosine in coordinates for disk forging

A new linear integration for plastic power was proposed.The effective strain rate for disk forging with bulge was expressed in terms of two-dimensional strain rate vector,and then its direction cosines were determined by the ratio of coordinate increments.Furthermore,inner-product of the vector for plastic power was term integrated by term and summed.Thereafter,through a formula for determination of bulge an analytical solution of stress effective factor was obtained.Finally,through compression tests,the calculated results of above formula were compared with those of Avitzur’s approximate solution and total indicator readings of the testing machine.It is indicated that the calculated compression forces are basically in agreement with the measured ones if the pass reduction is less than 13.35%.However,when the reduction gets up to 25.34% and 33.12%,the corresponding errors between the calculated and measured results also get up to 6% and 13.5%,respectively.

Analytical Solution for Three-dimensional Forging Taking into Account Bulging of Sides by Mean Yield Criterion

Currently, for some complex plastic deformations, the analytical solution can not be obtained by using Mises yield criterion, because Mises yield criterion is nine dimensions, the velocity field is complex, and the solving methods are not innovative. Corresponding solutions of these problems are that yield criterion is linearized to reduce the variable numbers, and the velocity field and the solving methods are reasonably simplified, respectively. In this paper, a new linear yield criterion--mean yield（MY） criterion and inner-product of strain rate vector are used to analytically solve 3D forging taking into account bugling of sides. The velocity field is expressed as a vector in three dimensions, and rotation and divergence are applied to confirm that the velocity field is kinematically admissible. Then, the corresponding strain rate tensor of the velocity field is transformed into principal one by making the determinant of coefficients of the tensor cubic equation be zero. By using MY criterion, the plastic power is term by term integrated and summed according to inner-product of strain rate vector. An upper bound analytical solution is obtained for the forging, and verified by a pure lead press test. The test result turns out that the total pressure calculated by MY criterion is higher by 2.5%-15% than measuring value. In addition, a measuring formula of bulging parameter （a） is proposed, but the values of a measured by the formula are lower than those optimized by the golden section search. The total pressure calculated by MY criterion is compared with the ones by twin shear, Trasca yield, and Mises yield criterion. The comparing result shows that the total pressure calculated by MY criterion is slightly higher than the mean value of that by twin shear and Trasca yield criterion, and lower than that by Mises yield criterion, but more close to that by Mises yield criterion compared with that by other two. The proposed analytical solving methods can be effectively used to other complex plastic deformation, simplifying the solving process and obtaining the reasonable results.

有鼓形平板锻造的应变速率矢量分析解法

该文开发了一种应变速率矢量的线性化积分方法.首先将有鼓形平板锻造等效应变速率表示成二维应变速率矢量,化为矢量内积后进行逐项积分;其次将逐项积分结果求和并引进鼓形参数计算公式,进而得到应力影响因子的解析解.结果表明,上述线性积分方法所得到的功率表达式与传统直接积分法的表达式相同.按该公式计算的总锻造力与按Avitzur公式计算的结果基本一致,两者比压缩试验的测量值高4.2%.

有鼓形圆坯锻造应变速率矢量内积的积分

提出了一种新的线性化积分方法。首先将有鼓形圆盘锻造等效应变速率表示成二维应变速率矢量,对该矢量的内积进行了逐项积分;其次,将逐项积分结果求和并证明了求和结果与传统直接积分法的塑性功率表达式相同;最后由速度场推导出圆盘锻造应力影响因子的解析解与相应的鼓形参数b的计算公式。此外,进行了实际的压缩试验并按上述公式计算了应力状态系数;并将计算结果与Avitzur公式的计算结果及实验机的压力读数进行了比较,结果表明,计算的总压力与Avitzur公式的计算结果基本一致,但高于实测压力值,该解仍属于上界解。

车用CNG全复合材料气瓶内胆鼓包的成因与预防

根据近年来对车用压缩天然气(CNG)全复合材料气瓶定期检验的实际经验,对检验中发现的该类气瓶塑料内胆向内鼓包现象的原因进行了分析,且通过了一定的实验验证。根据鼓包成因分析,从气瓶设计、使用、检验等方面提出了相应的预防措施,对提高气瓶的安全性能有一定的参考价值和实际意义。

36Mn2V管材内表面鼓包缺陷成因分析

天津钢铁集团有限公司生产的36Mn2V圆坯用于轧制非调质处理N80级石油套管时,在钢管内壁发现鼓包缺陷。经过对缺陷样品进行扫描电镜和金相分析,发现圆坯中存在复合型非金属夹杂物是形成鼓包缺陷的原因。通过在炼钢过程中选择合适的脱氧剂、强化脱氧,在精炼过程中保证充足的吹氩时间和吹氩强度、保证足够的镇静时间,在连铸进程中控制好液面、拉速、水口插入深度、保护浇注等措施,有效减少了圆坯中的夹杂物含量,避免了内鼓包缺陷的再次发生。

应变矢量内积法求解带鼓形的矩形坯锻压(英文)

提出一种新的线性化积分方法用于求解平锤头压缩带外端的矩形件。在锻压过程中,锤头没有覆盖整个工件,并且工件的侧面通过变形产生鼓形。应用该方法得到了平均锻压力,同时在求解的过程中进行了下列假设:工件与工具间的摩擦力为常数,工件是刚-塑性材料,锻压是在低速度下进行的。然后,通过纯铅的锻压实验,将由黄金分割法得到的优化结果与试验机的实测值进行比较,结果表明优化值比实测值高2.60%-10.14%,这在工程上都是允许的。

螺旋风管在国防工程中的质量控制

本文主要介绍了螺旋风管的优点、施工工艺及质量控制标准。

渤海海域辽东凸起南段潜山构造演化及其对油气成藏的控制

受多期构造运动影响,渤海海域辽东湾坳陷辽东凸起潜山的构造演化过程相对复杂。根据新处理的三维地震资料和钻井资料,分析辽东凸起南段潜山的地层结构和构造特征,探讨构造演化及其对油气成藏的影响。研究结果表明:辽东凸起南段潜山发育中生界和太古宇双层结构,经历“潜山物质基础发育期(三叠纪中期之前)—潜山构造发育期(三叠纪中晚期—白垩纪末期)—潜山改造埋藏期(古新世—渐新世末期)—潜山稳定埋藏期(中新世—全新世)”4个阶段构造演化;基底和强走滑作用控制辽东凸起南段潜山于沙三段沉积末期开始隆升,止于东营组沉积末期。辽东凸起潜山发育走滑和伸展两类断裂,走滑断裂控制了辽东凸起的构造格架,对潜山的形成起到关键作用,伸展—走滑双重作用控制潜山内幕裂缝的发育,改善潜山内幕油气储集能力。

钢管超声波测厚示值减小的原因分析

在使用超声波测厚仪对钢管壁厚进行测量时,有时会出现示值小于钢管实际壁厚的情况,并且这些钢管内表面往往伴有许多鼓包和翘皮出现。对这种情况进行了分类统计,并取样进行分析。指出钢管超声波测厚示值减小是由分布在壁厚中间和靠近内表面区域的异常夹杂物引起的,内表面的鼓包和翘皮是由分布在壁厚靠近内表面边缘区域的异常夹杂物引起的;钢管内表面的翘皮与二辊斜轧穿孔变形产生的毛管内折有本质的区别。

燃气轮机排气温度监视和保护功能分析

介绍了燃气轮机排气温度分散度监控的基本功能。以某厂的DLN2.0+燃烧室为例,说明了燃气轮机排气温度分散监视和保护功能的重要性。分析了火焰筒鼓包和破裂的形成机制对燃气轮机排气温度分散度的影响,提出了相应措施,以防止因燃烧恶化对热通道部件的伤害。

聚氨酯弹性体引射筒注射模设计

分析了引射筒塑件的结构特点,结合聚氨酯弹性体塑料的高弹性特性,针对塑件外形及内部均存在环形倒扣结构的特点,经过对比分析确定了模具结构方案;该模具结构设计采用液压缸抽芯机构成型塑件外侧凹槽,采用强制脱模机构成型环形内凸起,并合理设置模具冷却系统,避免塑件变形;经实际生产验证,该模具结构合理,冷却系统可靠,成型的塑件质量高。

罩式炉产量的提升

针对罩式炉设备老化、加热程序固化给产量提升带来的严重影响,实施了一系列的改进。针对加热罩煤气管道腐蚀堵塞、内罩腐蚀鼓肚、炉台和加热罩间密封不严、冷却罩冷却效率低等问题,通过更换不锈钢波纹软管、内罩材质改为310S、炉台支撑腿精度找正、在焦炉煤气中添加天然气、加热罩通信升级、建立罩式炉退火模型、优化国产备件等措施,罩式炉产量由设计的84万t/a提升到最高94.2万t/a,成为国内的平均单炉产量高的产线之一,提升效果明显。

椭圆形拉深件的内涨式切边模

介绍了椭圆形拉深件由内向外进行切边的工艺过程和模具结构.并着重分析了模具工作过程以及在模具设计与制造过程中的特点.

基于ANSYS/Ls-dyna的螺旋曲面液压充模胀形研究

针对螺旋定子金属管内外高压胀形方法,采用ANSYS/Ls-dyna有限元软件进行胀形过程仿真,通过改变胀形参数,比较了内外高压胀形方法对胀形系统压力、螺旋曲面贴膜效果及胀形位移的影响规律,验证了内外高压胀形的工艺可行性。

螺旋定子内曲面高压胀形方法研究

等壁厚橡胶层定子的出现大幅提高了螺杆马达和螺杆泵的整体性能,其定子金属壳内螺旋曲面具有多头、大导程、连续光滑的几何特征,该类零件的高效低成本制造是目前急需解决的关键问题。本文提出采用内高压充模胀形工艺方法实现其加工制造。采用计算机仿真、优化设计与胀形实验相结合的方法,研究了成形压力、管件壁厚、工件螺距和界面摩擦系数对成形的影响规律。胀形分析结果和实验结果一致性好,均达到了螺旋定子内曲面的加工要求,获得了壁厚均匀的内螺旋曲面。

管坯结构对小半径薄壁弯头内胀冷推弯成形的影响

针对Ф40 mm×1 mm铝合金管材且弯曲半径为1倍管径的L形弯管成形,以数值模拟技术为平台,建立了内胀冷推弯有限元模型,研究了管坯端头不同补偿角度对弯管成形质量的影响。结果表明:补偿角度过大时,弯管内侧易产生压缩起皱,降低补偿角度则能有效防止弯管产生压缩起皱,且随着角度的降低,成形弯管减薄区域不断扩大,同时弯管弯曲内侧有效长度不断降低,易造成成形不足;补偿角度为45°时,起皱现象消失,外侧壁厚最大减薄率为7. 1%,整体成形质量较佳。以45°补偿角度进行内胀冷推弯试验,成形出符合要求的1倍弯曲半径弯管,且试验结果与模拟结果整体较吻合。

37Mn5管材内壁表面上鼓包缺陷形成原因分析

针对37Mn5合金管坯经穿管后在管材内壁表面上形成大量条状鼓包缺陷,利用金相显微镜、扫描电镜及能谱分析等检测手段,对鼓包进行分析。结果表明,在管坯基体中存在较大尺寸的复合型条状夹杂物。此类夹杂物分割了金属基体的连续性,在管壁上形成小夹层。在穿管过程中因受到轴向摩擦力和轴向碾制力挤压,小夹层皱起并与基体脱离形成鼓包。因此,提高钢水的纯净度是减少或消除鼓包缺陷的主要措施。