7A04铝合金复杂零件的超塑性成形工艺研究

用超塑性成形工艺对外侧表面带凸耳的空心圆锥体铝合金(7A04)零件进行了成形试验,通过分析和试验确定了合理的超塑成形工艺和模具结构。该零件须分两步进行超塑成形:先成形空心圆锥体,再成形凸耳;超塑性成形工艺制造该零件比原机加工工艺简单,节省材料超过60%。     

石油开采防护H2S危害的研究

石油开采的众多硫化物中,H2S所占的比例较大,稠油油藏伴生出了H2S气体,热采工艺加速了H2S的生成和浓度上升;由于H2S使嗅神经麻痹,臭味反而不易嗅到,往往会出现＂闪电＂式中毒死亡,危害极大。在石油开采中应用好常规防护技术和开展新型高效脱硫剂与＂高效吸收固硫剂装置＂的研究具有重要的现实意义;学习借鉴加拿大油田H2S的防护经验,建立我国含H2S油气田井作业许可制度。我们要认真深刻的吸取＂12.23＂重庆开县罗家16H天然气井喷失控硫化氢中毒重大事故的教训,在含H2S油气田井的石油开采中,只有认真搞好H2S防护的安全教育和检测报警工作、落实H2S防护对策、制定详细的事故应急预案、定期组织应急演练,才能达到防患未然的目的。     

Numerical modelling of electrohydraulic free-forming and die-forming of DP590 steel

Electrohydraulic forming (EHF) is a high energy rate forming process in which the strain rate in the sheet metal can vary from 5 × 10² to 10⁵ s⁻¹ depending on various factors. Several mechanisms have been reported to cause an improvement in formability in EHF such as material deformation mechanisms, inertial effects and the dynamic impact of the sheet against the die. EHF is a complex high speed forming process and experimental work alone is not sufficient to properly understand this process. To understand the variation of some influential variables in EHF, electrohydraulic die-forming (EHDF) and free-forming (EHFF) of DP590 dual phase steel were simulated in ABAQUS/Explicit by considering the fluid/structure interactions. Three-dimensional finite element simulations were conducted by modelling the water with Eulerian elements with a view to investigating the effect of released energy on the sheet deformation profile history, strain distribution, loading path and damage accumulation type. The Johnson–Cook constitutive material model was used to predict the sheet behaviour and the parameters in this model were calibrated based on experimental test results available for DP590 at various strain rates. The Johnson–Cook phenomenological damage model was also used to predict the ductile failure (damage accumulation) in both EHDF and EHFF. Predicted final strain values and damage accumulation type showed good agreement with the experimental observations.     

Cobalt induced changes in immune response and adenosine triphosphatase activities in rats

Abstract

The immuno‐biochemical effects of cobaltous chloride in rats receiving iron‐sufficient and deficient diets were investigated. Rats receiving 100 ppm or more cobalt showed a significant reduction in thymus and body weights along with a marked decrease in hemoglobin, hematocrit, sheep agglutinins and plaque forming cells. These effects were more pronounced in rats receiving cobalt mixed with iron‐deficient diet than those fed on iron‐sufficient diet. The Na⁺‐K⁺ and mitochondrial (Oligomycin‐sensitive) Mg²+ATPase activities in brain and liver of rats fed with iron‐deficient diets were decreased significantly. However, the ATPase activities in these tissues from rats fed with cobalt mixed with iron‐sufficient diets were not altered.     

永善县地质灾害类型与成因研究

永善县是云南省地质灾害严重的县之一,本文分析了永善县的地质灾害类型(主要灾害为滑坡、崩塌、泥石流)及其特征;并详细研究了其形成因素,为灾害的治理和预防提供一定的依据.     

扭—压复合加载变形基础的研究

扭—压复合加载成形工艺是一种有效地利用工件与工具间摩擦的有害作用,达到减小变形力、改善工件组织性能的新方法。本文介绍了实现扭—压变形的实验装置,并对工艺因素对扭—压复合加载变形的影响作了阐述。     

冷弯成形过程的计算

通过将冷弯变形分离为两部分,一部分为约束变形,另一部分为待定的反弹变形,然后使用两个简单函数来分别模拟,再利用弹性理论中的能量原理获得了整个变形过程的计算公式.最后通过实例计算验证了公式的有效性.     

U型夹箍自动滚弯成形

介绍了洗衣机U型夹箍自动滚弯成形新工艺。采用钢带经校平、成U形截面、弯圆形、切断 ,压连接端自动连续成形。不但生产效率高 ,产品质量稳定 ,而且大大减轻了工人的劳动强度 ,节省了生产空间。     

汽车翼子板零件的成形与工艺分析

通过对汽车翼子板零件投料冲压试验,对零件进行了应变测试分析,评价试验钢板的成形效果,分析了冲压工艺、表面粗糙度和板厚等条件对零件冲压生产的影响,得到翼子板零件的最佳用材方案及冲压工艺条件。     

不锈钢棒材无模成形温度场有限元模拟

采用有限元法对不锈钢棒材无模成形温度场进行了研究 ,并利用有限元分析软件对其进行了模拟 ,该模拟结果很好地反映了拉伸件在整个变形过程中的温度分布规律 ,为无模成形的进一步研究提供了可靠的依据