拉拔管材道次延伸系数的近似计算方法

拉拔管材时道次延伸系数的取值范围,在有关手册或专业教材中都能找到。可是在落实具体的拉管配模(含衬芯)工艺时,常常使人为难。因为延伸系数λ,是管子外径D和壁厚S的函数。缺少经验的工艺人员往往掌握不好减径量ΔD和减壁量ΔS的搭配关系。为此,作者设计了一种近似计算方法,可以迅速掌握设计拉拔管材的工艺流程。设外径减缩系数K_D和壁厚减缩系数K_S分别定义为:K_D=D_0/D_H和K_S=S_0/S_H,式中D_O、S_O和D_H、S_H分别为拉拔前和拉拔后的管子外径、壁厚。道次延伸系数λ与K_D和     

游动芯头圆盘拉伸紫铜圆管工艺规程计算方法

本文作者提出的“在大型卷筒拉伸机上采用游动芯头多道次连续拉伸中小规格紫铜圆管工艺规程计算方法”又称“ZBL法”。其计算程序分为3个步骤：拉伸次数n的计算；各拉伸道次管子壁厚的计算；各拉伸道次管子外径的计算。各道次管子的壁厚减缩系数呈等比数列；各道次管子的外径是通过呈等差数列的径差计算出来的。     

LF6铝合金厚壁筒体强力旋压工艺的研究

针对外径为Φ６５５ｍｍ，壁厚为８０ｍｍ的大直径厚壁铝合金管坯的变薄旋压，提出了合理的旋压加工工艺制度、并结合旋压加工成形的特点分析其组织及性能。     

喷灌用薄壁铝管的制造方法

1 前言随着农用喷灌技术的日益发展,纯铝管广泛地用于农用喷灌。而近几年来用户对农用喷灌用铝管的质量要求愈来愈高,尤其是要求其喷灌铝管的外径愈来愈大(最大外径为125毫米),壁厚愈来愈薄(最小壁厚为1.0～1.5毫米),这显然对喷灌用薄壁铝管的拉伸带来了一定的难度。我厂生产铝管已有十多年的历史,但以     

毛细铜/钛复合管材的游动芯头拉拔制备及组织性能

在热旋制备界面结合质量优异的铜/钛双金属复合管坯的基础上,对复合管进行了游动芯头拉拔加工,重点研究了复合管材游动芯头拉拔加工成形能力以及拉拔加工对复合管材组织性能的影响.研究结果表明,游动芯头拉拔方式,特别是减壁拉拔,对铜/钛复合管材结合界面有较大的破坏作用,且难以实现多道次连续拉拔加工,单道次拉拔加工量不宜超过30%;575℃保温70 min的道次间退火虽然对界面元素扩散情况影响不大,但能缓解加工硬化和残余应力,使得铜/钛复合管材的平均剥离强度由变形态的7.8 N·mm-1提高到退火态的17.1 N·mm-1,大幅度提高铜/钛复合管材的后续拉拔加工性能.通过严格控制拉拔减壁量,合理制定了铜/钛复合管材的拉拔加工工艺,成功制备了结合性能优异的毛细规格铜/钛复合管材.      

圆管拉拔工艺流程设计计算方法

本文推荐的设计计算圆管拉拔工艺流程的ＫＤ－ＫＳ方法，能方便地对道次减径量和减壁量进行搭配，以利控制成品管的性能。ＫＤ－ＫＳ方法适用性广，特别适用于由成品管尺寸选择中间管坯尺寸。     

豆形截面钢丝辊模拉拔工艺数值模拟研究

采用二辊五道次辊模拉拔方法成形豆形截面钢丝.依据豆形截面钢丝形状的特殊性及AISI70号钢材的特性,设计了各道次孔型形状.其中第一、二、四、五道次的道次压缩率相等,辊子采用横辊摆放;第三道次的道次压缩率为0,该道次的辊子采用与横辊呈90°的立辊摆放.计算并设计出各道次辊模组成的孔型型腔的截面尺寸和形状,再利用Deform-3D模拟软件对五道次辊拉拔过程进行仿真模拟,分析了工件辊模拉拔过程的变形机理,并对辊模拉拔过程中工件的等效应力、等效应变、模具的载荷等进行了分析,同时选取特殊点进行应力应变比较.研究结果表明,通过辊模拉拔方法生产的豆形截面钢丝,其成形效果良好.     

高速钢丝和弹簧钢丝的温拔

经过感应加热后，对高速钢丝和弹簧钢丝进行了温拔，为了分析钢丝的温拔工艺过程，测定了拉拔温度和拉拔力，拉拔速度恒定不张，研制了一种新型润滑剂，它允许有更大的减面率，得到较好的表面质量，测定了加热后拉拔钢丝的机械性能，应用了统计分析的方法估算拉丝模型角度，道次减面率和拉拔温度对钢丝机械性能以及整个拉拔工艺过程的影响。由于温拔增加了道次减面率和总减面率，使高速钢丝的拉拔工艺得到了很大改进，也减少了中间热     

热拉拔工艺对AZ61镁合金丝材组织与性能的影响

采用自制热拉拔装置将AZ61镁合金粗挤压棒材拉拔成丝,研究拉拔温度、道次变形量等热拉拔工艺对单道次拉拔后丝材组织、力学性能的影响规律,并对拉拔过程中断丝情况进行统计,确定能够实现稳定热拉拔的工艺参数范围.结果表明,当道次变形量为15%时,随着温度的升高,丝材中的孪晶组织逐渐减少,强度逐渐降低,延伸率逐渐升高,丝材在350℃时发生动态再结晶.当拉拔温度一定时,随着道次变形量的增加,丝材的加工硬化程度增加,强度、硬度升高,延伸率下降.但当拉拔温度为300℃,道次变形量增加到25%时,丝材发生动态再结晶,使强度硬度下降,延伸率升高.过高的拉拔温度和道次变形量会使丝材发生断裂,随着温度的提高,丝材所能承受的最大变形量逐渐减小.     

一种利用真伸长快速制定钢丝连接拉拔工艺的方法

指出了常规采用压缩比拟定钢丝连续拉拔工艺方法之不足，假定钢丝连续拉拔时道次变形程度之差恒定，给出了一种利用真伸长快速，合理制定钢丝连续拉拔工艺的方法。     

The effect of amount of possession of the trait of hostility on accuracy of perception of hostility in others.

Some theories of personality hold that an individual's perception of others is influenced by his own personality characteristics; more specifically, that a trait of low social value will be projected more into others, and that insight into the possession of these characteristics reduces this distortion. These 2 hypotheses were tested by having a group of college students rate each other (including themselves) on degree of friendliness or hostility. Agreement with group rating about self yielded the insight score. In general, the hypotheses were supported; the "friendly" Ss were most accurate in their perception of others, and insight was positively associated with accurate perception. From Psyc Abstracts 36:04:4HL16M. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Comparison of rates of infection of two methods of emergency ventricular drainage

The rates of infection of two methods of external ventricular drainage in use at Atkinson Morley's Hospital--namely, (a) percutaneous drainage with Rickham reservoirs and (b) tunnelled ventriculostomies--were compared in this retrospective review. Percutaneous drainage of CSF with Rickham reservoirs was associated with a 27% rate of infection as identified by positive microbiological cultures; tunnelled ventriculostomy catheters had a 10% infection rate. The difference in the infection rate between the two methods was statistically significant (P < 0.015). Other variables examined, including the age and sex of the patients and the reasons for ventricular drainage, were not associated with an increased rate of infection. Most infections from either method were caused by a coagulase negative staphylococcus. The average duration of ventricular drainage before identification of positive cultures was 5.7 days for Rickham reservoirs and 6.0 days for ventriculostomies.     

浅析《野草》的版画特征

鲁迅先生一生热爱美术作品,对版画中木刻兴趣尤甚.<野草>作为其"写心之作",亦呈现出一些与木刻版画一致的审美特征:一是具有木刻版画的色彩特征,多对比、多冷色,有阴郁的美感;二是具有木刻版画的力度特征,环境描写、人物刻画处处刀锋毕现,遒劲有力,有一种"力之美".     

四辊破碎机车刀架的改造

针对四辊破碎机车刀架车削中存在的几个问题,详细介绍了电动车刀架的结构和工作原理,建立主要设计参数的数学表达式,并进行适当的分析。改造后,这种电动车刀架运行平稳、可靠、方便、省力,取得了预期的效果。     

转炉炉壳热应力分析

根据实际转炉建立实体模型。以有限元为手段,考虑了炉衬和炉壳材料的物性参数随温度变化的特点和炉衬与炉壳之间膨胀间隙,计算了转炉炉壳在温度载荷和炉衬膨胀压力同时作用下的热应力。所得结果可为转炉炉壳设计提供依据。     

Comparison of the results of surgical and conservative treatment of fractures of the diaphysis of the tibia

In this paper is treated the fundamental problematic of the fracture of the diaphysis of the tibia and the therapeutic results after the conservative and operative treatment are confronted. Among 518 patients with 433 open fractures and 35 with closed fractures of the diaphysis of the tibia, successful treatment of more 2/3 was obtained in the period from 1968 to 1972. Following our casuistics and literature, whose results are similar, we find out that the average total treatment of the osteosynthesis of the fracture of the diaphysis was shortened for 2,5 months depending upon the type and the localisation of the fracture. Apolied methods of the operative and conservative and conservative treatment in relation to the velocity of the medical cure as well as to the extreme anatomical-functional results are analised. We noticed that osteosynthesis, made by the intermedullary nail and the extension of the canals or by a small AO table, by the achieved stability makes conditions of immediate motions and an early rehabilitation. Because of that it gives the best functional results.     

Results of treatment of cancer of the cardia

Cancer of the cardia is traditionally discussed with cardiac cancer of the lower portion of the esophagus and upper gastric cancer invading the esophagus, and the specific characteristics of cancer of the cardia have never been clearly defined. We reviewed the outcome of 172 patients with adenocarcinoma of the cardia who had undergone radical surgery between 1949 and 1994 in the Division of Gastrointestinal Surgery of the Cancer Institute Hospital. The centers of the tumors were located within 2 cm above and below the boundary between the esophagus and the stomach, and their longitudinal diameter was less than 8 cm. We divided the patients into an early period (1949-1979; n = 79) and a late period (1980-1994; n = 93), and focused on the historical transition. There were no differences in patient gender or histology between the two periods. However, the late period was associated with fewer cases of esophageal invasion and shorter longitudinal diameter, as the age of the population advanced. The number of advanced cancers such as the localized and infiltrative type had decreased, and early cancer and early clinical stage had become more common, but despite the fact that the number of early cancers had increased, extended dissection, such as thoracic and paraaortic lymph node dissection, was performed more frequently. By clinical stage, the long-term outcome markedly improved in Stage I patient in the late period, and tended to improve in Stage II and III patients. This appears to have been attributable to the prevention of micrometastasis by extended dissection, although the number of early cancers is another major potential cause. There were no differences in the outcome of Stage IV patients between the two periods, and further advances in multimodality therapy must be awaited. The range of resection is basically proximal gastrectomy, and if there are adequate indications, the prognosis is favorable. In view of the status of lymphatic flow and lymph node metastasis, and long-term results, lateroaortic lymph node dissection is important. Since the number of early cancer patients has been increasing, if intraabdominal recurrence is prevented, intrathoracic lymph node dissection will contribute greatly to the outcome of such patients.     

焦炭热性能指标意义浅析

通过对焦炭在高炉内的历程及其变化规律的剖析,阐述焦炭热性能指标的意义,形象地把焦炭在高炉内的损耗分为三部分(M1,M2,M3)。指出M2对焦比及焦炭价格有一定的指导作用。     

参与式农业基地建设行动方案设计

为了编制实用性强的基地建设行动方案,首先,确定参与式发展的主体,搭建一个"决策框架";其次,针对行动目标,提出不同参与主体,如管理者、农民、消费者等团队与个人的目标及行动内容;最后,工作应向重塑伙伴式合作关系,挖掘农民自我发展潜力,完成三大角色的转换,打造农业基地文化等方向推进.