火灾高温作用下波纹腹板钢梁剪切屈曲系数研究

波纹腹板钢梁具有优良的抗剪切性能,在常温条件下,它的剪切屈曲模式通常有3种:局部剪切屈曲、总体剪切屈曲和相关剪切屈曲.根据火灾燃烧不同时刻波纹腹板钢梁的温度变化,考虑火灾高温对结构钢材料性能的影响,研究了波纹腹板钢梁在火灾高温作用下的3种剪切屈服模式,给出了高温下波纹腹板钢梁临界剪切屈曲应力和剪切屈曲系数的计算表达式,...     

冷却速度对X70管线钢感应加热弯管组织性能的影响

弯管是油气输送管道的重要组成构件之一。冷却速度的快慢决定弯管材料的最终性能 ,是感应加热弯管的关键参数。为确定合适的冷却速度范围 ,研究了冷却速度大小对管线钢材料组织、性能的影响规律 ,确定了保证材料组织性能冷却速度的下限值。     

关于工厂企业绿地建设的探讨：以宝钢为例

生态园林是现代城市绿化发展的趋势和方向。对于污染较为集中的工厂企业来主，绿地建设是环境保护的重要方面。而发展生态园林，走绿地的生态建设道路已成为工厂企业发化的有效途径。本文从生态园林的指导思想出发，结合宝钢的绿化实例，探讨了工厂企业在绿地建设方面的若干问题。     

植筋锚固技术在ESP扩建改造工程中的应用

通过工程实例，介绍植筋锚固技术在建筑结构改造加固中的运用。     

大尺度薄板激光焊接前后的弹性实验

研究了激光焊接对大尺度薄板弹性的影响。实验测试了焊接前后的弹性ˉ位移曲线。通过显著性检验 ,判断弹性改变是否发生。实验结果对汽车行业采用激光加工技术具有一定的参考意义。     

商用车铝合金与钢制轮辋生命周期环境影响评价对比分析

基于生命周期评价(LCA)理论,运用Ga Bi软件建模,采用EDIP 2003评价体系,对某款商用车铝合金轮辋和钢制轮辋的生命周期环境影响进行了评价和对比分析.结果表明:在原材料获取阶段铝合金轮辋对环境的影响要远远大于钢制轮辋;制造阶段两种轮辋对环境的影响相差不大;使用阶段钢制轮辋对环境的影响大于铝合金轮辋;综合所有阶段来看,当车辆总行驶里程低于11.6万km时,铝合金轮辋对环境的影响更大,超过11.6万km后,钢制轮辋对环境的影响更大.     

Predictive control based double-electrode submerged arc welding for filet joints

Double-electrode submerged arc welding (DE-SAW) is an innovative process to achieve the same metal deposition rate at reduced heat input. To maximally take advantage of this new capability, the heat input needed to produce acceptable welds needs to be reduced. A joint gap is successfully introduced to reduce the required heat input but it introduces variations affecting currents/heat input. To minimize the resultant variations in currents and resultant welds, the process is modeled and a multivariable predictive control algorithm is developed to control the currents at desired levels. Experiments verified the effectiveness of the resultant feedback controlled DE-SAW process.     

Friction stir welding: Process,automation, and control

This article provides an introduction to the basic principles of friction stir welding (FSW) as well as a survey of the latest research and applications in the field. The basic principles covered include terminology, material flow, joint configurations, tool design, materials, and defects. Material flow is discussed from both an experimental and a modeling perspective. Process variants are discussed as well, which include self-reacting (SR-FSW), stationary shoulder, friction stir processing (FSP), friction stir spot welding (FSSW), assisted FSW, and pulsed FSW. Multiple aspects of robotic friction stir welding are covered, including sensing, control, and joint tracking. Methods of evaluating weld quality are surveyed as well. The latest applications are discussed, with an emphasis on recent advances in aerospace, automotive, and ship building. Finally, the direction of future research and potential applications are examined.     

A comparative study on the effect of GTAW processes on the microstructure and mechanical properties of P91 steel weld joints

Modified 9Cr-1Mo (P91) steel is widely used in the construction of power plant components. In the present study, a comparative study on influence of activated flux tungsten inert gas (A-TIG), and gas tungsten arc (GTA) welding processes on the microstructure and the impact toughness of P91 steel welds was carried out. P91 steel welds require a minimum of 47 J during the hydrotesting of vessels as per the EN1557: 1997 specification. Toughness of P91 steel welds was found to be low in the as-weld condition. Hence post-weld heat treatment (PWHT) was carried out on weld with the objective of improving the toughness of weldments. Initially as per industrial practice, PWHT at 760 °C – 2 h was carried out in order to improve the toughness of welds. It has been found that after PWHT at 760 °C – 2 h, GTA weld (132 J) has higher toughness than the required toughness (47 J) as compared with A-TIG weld (20 J). The GTA weld has higher toughness due to enhanced tempering effects due to multipass welding, few microinclusion content and absence of δ-ferrite. The A-TIG weld requires prolonged PWHT (i.e. more than 2 h at 760 °C) than GTA weld to meet the required toughness of 47 J. This is due to harder martensite, few welding passes that introduces less tempering effects, presence of δ-ferrite (0.5%), and more alloy content. After PWHT at 760 °C – 3 h, the toughness of A-TIG weld was improved and higher than the required toughness of 47 J.     

Research evolution on intelligentized technologies for arc welding process

This paper presents some new evolutions of research works in the IRWTL at SJTU on intelligentized technologies for arc welding dynamic process and robot systems, including multi-information sensing of arc welding process, such as characteristic extraction of weld pool image, voltage, current, and sound, arc-spectral features; multi-information fusion algorithms for prediction of weld penetration; intelligentized modeling of welding dynamic process; intelligent control methodology for welding dynamic process; intelligentized technologies for robotic welding, such as guiding and tracking seam technology and intelligent control of weld pool and penetration in robotic welding process; and development of autonomous welding robot system for the special environment. The ideas of intelligentized welding manufacturing technology (IWMT) and intelligentized welding manufacturing engineering (IWME) are presented in this paper for systematization of intending researches and applications on intelligentized technologies for modern welding manufacturing. The studies of intelligentized welding presented in this paper establish the foundation work of intending researches and applications on intelligentized technologies for modern welding manufacturing.